| crystalhelix | 06-08-2004 03:22 PM |
Alignment for A Stock auto cross- Shine on me, gods of the suspension forum!
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I plan on getting a more aggressive alignment on my STi.
If I am also installing a 22mm FSB, will I experience more neutral steering, oversteer, or will I still understeer (I will be playing with pressures if you have any reccomendations)?
I will be keeping the stock top hats so my camber won't be that extreme but it will be more aggressive.
Thanks,
Justin
:banana: :huh:
If I am also installing a 22mm FSB, will I experience more neutral steering, oversteer, or will I still understeer (I will be playing with pressures if you have any reccomendations)?
I will be keeping the stock top hats so my camber won't be that extreme but it will be more aggressive.
Thanks,
Justin
:banana: :huh:
| TyrannoSullyRex | 06-08-2004 03:30 PM |
[QUOTE][i]Originally posted by crystalhelix[/i]
[B] I will be keeping the stock top hats so my camber won't be that extreme but it will be more aggressive.
[/B][/QUOTE]
you would have to if you are running A-Stock.
max camber front, start with zero toe all around.
[B] I will be keeping the stock top hats so my camber won't be that extreme but it will be more aggressive.
[/B][/QUOTE]
you would have to if you are running A-Stock.
max camber front, start with zero toe all around.
| crystalhelix | 06-08-2004 03:36 PM |
^That was acually the plan. What about a little toe up front? I do use it as my daily driver. Someone told me 1/8" is good.
Thanks,
Justin
Thanks,
Justin
| DonA | 06-08-2004 03:36 PM |
I would hold off the front bar till after the alignment... If you feel you want to try it after then go for it.
I feel the STi is a slow in -- fast / early out car and do better with that approach
I feel the STi is a slow in -- fast / early out car and do better with that approach
| TyrannoSullyRex | 06-08-2004 03:40 PM |
[QUOTE][i]Originally posted by crystalhelix[/i]
[B] ^That was acually the plan. What about a little toe up front? I do use it as my daily driver. Someone told me 1/8" is good.
Thanks,
Justin [/B][/QUOTE]
just be aware, toe out shreds tires for daily driving, don't come back complaining.
[B] ^That was acually the plan. What about a little toe up front? I do use it as my daily driver. Someone told me 1/8" is good.
Thanks,
Justin [/B][/QUOTE]
just be aware, toe out shreds tires for daily driving, don't come back complaining.
| trhoppe | 06-08-2004 03:57 PM |
[QUOTE][i]Originally posted by DonA[/i]
[B] I would hold off the front bar till after the alignment... If you feel you want to try it after then go for it.
[/B][/QUOTE]
Disagreed. Front bar is the first mod you should do for AS and quickly. Its the cheapest thing that will make a huge difference. You want to keep the negative camber that you get.
Now for the aligment. You want max negative front camber and the least amount of rear negative camber. 1/8" (for trailered AS car) or 0 (for daily driven) toe out front and 0 rear toe to start off with. That is something you can play with later.
1) Loosen every bolt in the front suspension. All 3 top mount bolts, two lower strut bolts, all lower control arm bolts, everything. Take 1 ratcheting tie down and use it to pull the bottom of the hub forward. Take a second one and pull the bottom of the hub out to the side. Now, with all the pulling and pressure on everything adjust the camber bolt for max negative camber, then tighten down the ratchets some more to make sure all the slack is taken out, and then tighten all the bolts. You should be able to get -1.5 front camber, and -5.0 or more front caster.
2) Loosen every bolt in the rear suspension. Take a ratcheting tie down and pull the bottom of the rear wheels closer together. Then tighten down all the bolts. There are no camber bolts in the rear, but you can take the slack out of everything.
3) A little front toe out (1/8" total) will give you a tiny bit more turn in (while wearing out the tires a bit more), while you should not need any rear toe out at all with the STi. On a trailered AS car, I would definetly toe the front out a bit. On a daily driven one, you might want to keep it at 0 to save on tires.
If you feel like the car is pushing and you want a little more rotation, you can adjust the rear toe at the track. Mark where the eccentric bolt is, and adjust a few ticks per wheel. Then you can adjust back to 0 after the event.
-Tom
[B] I would hold off the front bar till after the alignment... If you feel you want to try it after then go for it.
[/B][/QUOTE]
Disagreed. Front bar is the first mod you should do for AS and quickly. Its the cheapest thing that will make a huge difference. You want to keep the negative camber that you get.
Now for the aligment. You want max negative front camber and the least amount of rear negative camber. 1/8" (for trailered AS car) or 0 (for daily driven) toe out front and 0 rear toe to start off with. That is something you can play with later.
1) Loosen every bolt in the front suspension. All 3 top mount bolts, two lower strut bolts, all lower control arm bolts, everything. Take 1 ratcheting tie down and use it to pull the bottom of the hub forward. Take a second one and pull the bottom of the hub out to the side. Now, with all the pulling and pressure on everything adjust the camber bolt for max negative camber, then tighten down the ratchets some more to make sure all the slack is taken out, and then tighten all the bolts. You should be able to get -1.5 front camber, and -5.0 or more front caster.
2) Loosen every bolt in the rear suspension. Take a ratcheting tie down and pull the bottom of the rear wheels closer together. Then tighten down all the bolts. There are no camber bolts in the rear, but you can take the slack out of everything.
3) A little front toe out (1/8" total) will give you a tiny bit more turn in (while wearing out the tires a bit more), while you should not need any rear toe out at all with the STi. On a trailered AS car, I would definetly toe the front out a bit. On a daily driven one, you might want to keep it at 0 to save on tires.
If you feel like the car is pushing and you want a little more rotation, you can adjust the rear toe at the track. Mark where the eccentric bolt is, and adjust a few ticks per wheel. Then you can adjust back to 0 after the event.
-Tom
| Watkinsm3 | 06-08-2004 04:05 PM |
Hey now!
I'll just throw out my info the hell of it...
Max up front like someone else said. I've only got -1.1 right now but I gonna fiddle with it some more to see if I can squeeze some more out of it. I zeroed out the rear toe and threw about an 1/8 of total toe out in the front. Tire wear doesn't seem to horribly affected at this point
I might experiment with a hair more toe in the front but if the car is daily driven it might be a little too darty with a 1/4.
Mind what DonA said though... watch yer turn-in as its REALLY easy to overdrive the car at this point.
-Matt
I'll just throw out my info the hell of it...
Max up front like someone else said. I've only got -1.1 right now but I gonna fiddle with it some more to see if I can squeeze some more out of it. I zeroed out the rear toe and threw about an 1/8 of total toe out in the front. Tire wear doesn't seem to horribly affected at this point
I might experiment with a hair more toe in the front but if the car is daily driven it might be a little too darty with a 1/4.
Mind what DonA said though... watch yer turn-in as its REALLY easy to overdrive the car at this point.
-Matt
| solo-x | 06-08-2004 04:57 PM |
i'll put another vote in for the info that tom and matt have offered, with additional emphasis on _big_ front swaybar. 22mm ain't gonna cut it. 26mm is getting closer, 28-30mm is probably as much as you can go before running into other problems.
matt, is the subaru more darty then a honda/acura? i'm just wondering because i don't think 1/8" or even 1/4" total toe out up front should be too bad on the street. my car uses 1/8" total toe out on both ends and i don't think it's that darty at all. tire wear on the other hand is a little on the excessive side. my "street" azenis have about 15k on them and you can tell they aren't happy with the alignment, but they are holding up. inner shoulder is down to about 3/32 while the rest of the tread face is at about 5/32.
tom, how do you tighten everything down when the car is strung up with the ratcheting tie-downs and i assume the wheels on? is this done on a trailer? also, any concern with bending wheels and whatnot? double wishbone suspension should have a lot of slop i can take up. :D
nate
matt, is the subaru more darty then a honda/acura? i'm just wondering because i don't think 1/8" or even 1/4" total toe out up front should be too bad on the street. my car uses 1/8" total toe out on both ends and i don't think it's that darty at all. tire wear on the other hand is a little on the excessive side. my "street" azenis have about 15k on them and you can tell they aren't happy with the alignment, but they are holding up. inner shoulder is down to about 3/32 while the rest of the tread face is at about 5/32.
tom, how do you tighten everything down when the car is strung up with the ratcheting tie-downs and i assume the wheels on? is this done on a trailer? also, any concern with bending wheels and whatnot? double wishbone suspension should have a lot of slop i can take up. :D
nate
| jmott | 06-08-2004 05:16 PM |
[QUOTE]tom, how do you tighten everything down when the car is strung up with the ratcheting tie-downs and i assume the wheels on? is this done on a trailer? also, any concern with bending wheels and whatnot? double wishbone suspension should have a lot of slop i can take up. :D
nate [/B][/QUOTE]
which cars double wishbone suspension?
I can't picture how you could add much camber with this method on a doulbe wishbonje suspension.
if its a c5 vette you can get enough camber with the stock adjustment methods anyway.
nate [/B][/QUOTE]
which cars double wishbone suspension?
I can't picture how you could add much camber with this method on a doulbe wishbonje suspension.
if its a c5 vette you can get enough camber with the stock adjustment methods anyway.
| trhoppe | 06-08-2004 05:34 PM |
[QUOTE][i]Originally posted by solo-x[/i]
[B] i'll put another vote in for the info that tom and matt have offered, with additional emphasis on _big_ front swaybar. 22mm ain't gonna cut it. 26mm is getting closer, 28-30mm is probably as much as you can go before running into other problems.[/quote]
Like nate said, 26mm is a good start...
[quote]tom, how do you tighten everything down when the car is strung up with the ratcheting tie-downs and i assume the wheels on? is this done on a trailer? also, any concern with bending wheels and whatnot? double wishbone suspension should have a lot of slop i can take up. :D
nate [/B][/QUOTE]
We actually did that on the alignment rack with the wheels off. The car is on that jack that the alignent machine has. There is plenty of room to get in there and tighten the bolts once you have the ratcheting straps tight. The straps were tightened to the walls of the shop ;)
-Tom
[B] i'll put another vote in for the info that tom and matt have offered, with additional emphasis on _big_ front swaybar. 22mm ain't gonna cut it. 26mm is getting closer, 28-30mm is probably as much as you can go before running into other problems.[/quote]
Like nate said, 26mm is a good start...
[quote]tom, how do you tighten everything down when the car is strung up with the ratcheting tie-downs and i assume the wheels on? is this done on a trailer? also, any concern with bending wheels and whatnot? double wishbone suspension should have a lot of slop i can take up. :D
nate [/B][/QUOTE]
We actually did that on the alignment rack with the wheels off. The car is on that jack that the alignent machine has. There is plenty of room to get in there and tighten the bolts once you have the ratcheting straps tight. The straps were tightened to the walls of the shop ;)
-Tom
| Watkinsm3 | 06-08-2004 05:35 PM |
[QUOTE][i]Originally posted by solo-x[/i]
[B]
matt, is the subaru more darty then a honda/acura? i'm just wondering because i don't think 1/8" or even 1/4" total toe out up front should be too bad on the street. my car uses 1/8" total toe out on both ends and i don't think it's that darty at all. tire wear on the other hand is a little on the excessive side. my "street" azenis have about 15k on them and you can tell they aren't happy with the alignment, but they are holding up. inner shoulder is down to about 3/32 while the rest of the tread face is at about 5/32.
[/B][/QUOTE]
Nothing close to the what the integra was like... I was just thought I should throw that in since he mentioned "daily driven" and some just aren't ready to make that sacrifice... of course this is the motorsports forum so... maybe I should have left that part out. :D
Before you commit to the statement about it not being darty... just remember how long you've been driving a car like that on the streets... I'd imagine your perspective might be a hair skewed at this point.
On the OTHER hand ... Nate, you and Tom are right on about the front bar... bigger is better! No substitute for size! Do it... don't look back. This will help out incredibly to keep what little camber you can dial into the car.
-Matt
[B]
matt, is the subaru more darty then a honda/acura? i'm just wondering because i don't think 1/8" or even 1/4" total toe out up front should be too bad on the street. my car uses 1/8" total toe out on both ends and i don't think it's that darty at all. tire wear on the other hand is a little on the excessive side. my "street" azenis have about 15k on them and you can tell they aren't happy with the alignment, but they are holding up. inner shoulder is down to about 3/32 while the rest of the tread face is at about 5/32.
[/B][/QUOTE]
Nothing close to the what the integra was like... I was just thought I should throw that in since he mentioned "daily driven" and some just aren't ready to make that sacrifice... of course this is the motorsports forum so... maybe I should have left that part out. :D
Before you commit to the statement about it not being darty... just remember how long you've been driving a car like that on the streets... I'd imagine your perspective might be a hair skewed at this point.
On the OTHER hand ... Nate, you and Tom are right on about the front bar... bigger is better! No substitute for size! Do it... don't look back. This will help out incredibly to keep what little camber you can dial into the car.
-Matt
| Watkinsm3 | 06-08-2004 05:39 PM |
Thanks for the "stretching" technique Tom... I wasn't 100% sure if the vision in my head was correct so I held off on doing it. Gonna go string the car up in the next week or so looking for that last half a degree of camber!!!.
-Matt
BTW - Larry confirmed no 275s Victoracers on the back of the STi when I saw him in DC :p :p :p :lol:
-Matt
BTW - Larry confirmed no 275s Victoracers on the back of the STi when I saw him in DC :p :p :p :lol:
| trhoppe | 06-08-2004 05:54 PM |
[quote]BTW - Larry confirmed no 275s Victoracers on the back of the STi when I saw him in DC [/quote]
LALALALALALALALA I CAN'T HEAR YOU LALALALALALALALA
-Tom
LALALALALALALALA I CAN'T HEAR YOU LALALALALALALALA
-Tom
| NegativeC | 06-08-2004 06:47 PM |
[QUOTE][i]Originally posted by trhoppe [/i]
[B]Take a second one and pull the bottom of the hub out to the side.
-Tom [/B][/QUOTE]
What side might you be talking about? Towards the front or back of the car? I have just about the make method as you except for this one bit.
[B]Take a second one and pull the bottom of the hub out to the side.
-Tom [/B][/QUOTE]
What side might you be talking about? Towards the front or back of the car? I have just about the make method as you except for this one bit.
| crystalhelix | 06-08-2004 07:48 PM |
OK -
I got an alignment tonight. I already have the 22mm bar ordered so it will have to do for now and in the future I will upgrade it as I learn to be a better driver. I have to change my oil and go out for a ride. I will post later on the settings I used and what I think.
Larry is running 255's in the front and 245's in the back. He was switching over to MX's, did he do that yet? He had victoracers last I talked with him.
Until LAter,
Justin
PS - thanks for all the great info! The suspension gods have smiled on me:D
Peace
I got an alignment tonight. I already have the 22mm bar ordered so it will have to do for now and in the future I will upgrade it as I learn to be a better driver. I have to change my oil and go out for a ride. I will post later on the settings I used and what I think.
Larry is running 255's in the front and 245's in the back. He was switching over to MX's, did he do that yet? He had victoracers last I talked with him.
Until LAter,
Justin
PS - thanks for all the great info! The suspension gods have smiled on me:D
Peace
| solo-x | 06-08-2004 10:00 PM |
[QUOTE][i]Originally posted by jmott[/i]
[B] which cars double wishbone suspension?
I can't picture how you could add much camber with this method on a doulbe wishbonje suspension.
if its a c5 vette you can get enough camber with the stock adjustment methods anyway. [/B][/QUOTE]
j00 don't n0s? i drive a honduh, y0! :eek:
nate - hunting for some place to "stretch" his car...
[B] which cars double wishbone suspension?
I can't picture how you could add much camber with this method on a doulbe wishbonje suspension.
if its a c5 vette you can get enough camber with the stock adjustment methods anyway. [/B][/QUOTE]
j00 don't n0s? i drive a honduh, y0! :eek:
nate - hunting for some place to "stretch" his car...
| Watkinsm3 | 06-08-2004 10:15 PM |
[QUOTE][i]Originally posted by crystalhelix[/i]
[B]
Larry is running 255's in the front and 245's in the back. He was switching over to MX's, did he do that yet? He had victoracers last I talked with him.
[/B][/QUOTE]
Last I talked to him... 275s in the front and 255s in the rear and no intention of changing but I could be wrong about his intentions.
-Matt
[B]
Larry is running 255's in the front and 245's in the back. He was switching over to MX's, did he do that yet? He had victoracers last I talked with him.
[/B][/QUOTE]
Last I talked to him... 275s in the front and 255s in the rear and no intention of changing but I could be wrong about his intentions.
-Matt
| AUTOwrXER | 06-08-2004 10:58 PM |
[QUOTE][i]Originally posted by Watkinsm3[/i]
[B] On the OTHER hand ... Nate, you and Tom are right on about the front bar... bigger is better! No substitute for size! Do it... don't look back. This will help out incredibly to keep what little camber you can dial into the car.
-Matt [/B][/QUOTE]
Has anyone measured the camber curve on these cars to see what you really are losing with roll/compression? I know the huge front bar is the popular choice, but without knowing the camber curve I'm reluctant to jump on board. If camber loss isn't huge, you are shifting the weight transfer percentage further forward (from a bad starting point) and creating more of a solid axle effect (not to mention the extra weight).
Anyone tried the opposite approach and removed/disconnected the front bar?
Joel
[B] On the OTHER hand ... Nate, you and Tom are right on about the front bar... bigger is better! No substitute for size! Do it... don't look back. This will help out incredibly to keep what little camber you can dial into the car.
-Matt [/B][/QUOTE]
Has anyone measured the camber curve on these cars to see what you really are losing with roll/compression? I know the huge front bar is the popular choice, but without knowing the camber curve I'm reluctant to jump on board. If camber loss isn't huge, you are shifting the weight transfer percentage further forward (from a bad starting point) and creating more of a solid axle effect (not to mention the extra weight).
Anyone tried the opposite approach and removed/disconnected the front bar?
Joel
| MNbiker | 06-08-2004 11:40 PM |
[QUOTE][i]Originally posted by AUTOwrXER [/i]
[B]Anyone tried the opposite approach and removed/disconnected the front bar?[/B][/QUOTE]
I did.......it's REAL ugly (can you say POSITIVE camber?:eek: )
-Steve
p.s. I still believe a better ultimate solution would be sky-high spring rates and little/no bars, but that doesn't help much with a stock car....
[B]Anyone tried the opposite approach and removed/disconnected the front bar?[/B][/QUOTE]
I did.......it's REAL ugly (can you say POSITIVE camber?:eek: )
-Steve
p.s. I still believe a better ultimate solution would be sky-high spring rates and little/no bars, but that doesn't help much with a stock car....
| crystalhelix | 06-09-2004 12:05 AM |
[QUOTE][i]Originally posted by Watkinsm3 [/i]
[B]Last I talked to him... 275s in the front and 255s in the rear and no intention of changing but I could be wrong about his intentions.
-Matt [/B][/QUOTE]
I know he had some new tires from Kuhmo on the way. 275's are teh huge!!:eek:
Thanks everyone,
I took your advice and went out to my alignment shop tonight and got hooked up.
I already had neg. camber and near zero toe in the rear so I had them adjust the fronts.
Stock 2004 STi w/6500miles
Starting values
LF
Toe 0.13"
Camber +0.2
RF
Toe -0.08"
Camber -0.2
End values
LF
Toe +.01"
Camber -1.0
RF
Toe 0.0"
Camber -1.1
Rears FYI (did not adjust)
LR
Camber -1.3
Toe +0.04
RR
Camber -1.4
Toe +0.03
This was the best the tech could do on my stock camber bolts. The car feels awesome. I had to take some crap out and go hit some twisties right after I changed the oil. I was throwing stuff all over the inside of the car from work
EDIT: I went out for a ride tonight. The car feels like a different car. I pushed it in a sweeper and it felt fantastic. I could not induce much understeer but I was already pushing it pretty fast through the turn. Let me know what you think.
Please look over my numbers and make any suggestions. I will update after I get the car through a test n tune at the end of the month.
Justin
THANKS EVERYONE FOR THE GREAT INFO!!!!!
[B]Last I talked to him... 275s in the front and 255s in the rear and no intention of changing but I could be wrong about his intentions.
-Matt [/B][/QUOTE]
I know he had some new tires from Kuhmo on the way. 275's are teh huge!!:eek:
Thanks everyone,
I took your advice and went out to my alignment shop tonight and got hooked up.
I already had neg. camber and near zero toe in the rear so I had them adjust the fronts.
Stock 2004 STi w/6500miles
Starting values
LF
Toe 0.13"
Camber +0.2
RF
Toe -0.08"
Camber -0.2
End values
LF
Toe +.01"
Camber -1.0
RF
Toe 0.0"
Camber -1.1
Rears FYI (did not adjust)
LR
Camber -1.3
Toe +0.04
RR
Camber -1.4
Toe +0.03
This was the best the tech could do on my stock camber bolts. The car feels awesome. I had to take some crap out and go hit some twisties right after I changed the oil. I was throwing stuff all over the inside of the car from work
EDIT: I went out for a ride tonight. The car feels like a different car. I pushed it in a sweeper and it felt fantastic. I could not induce much understeer but I was already pushing it pretty fast through the turn. Let me know what you think.
Please look over my numbers and make any suggestions. I will update after I get the car through a test n tune at the end of the month.
Justin
THANKS EVERYONE FOR THE GREAT INFO!!!!!
| Watkinsm3 | 06-09-2004 11:24 AM |
[QUOTE][i]Originally posted by AUTOwrXER[/i]
[B] Has anyone measured the camber curve on these cars to see what you really are losing with roll/compression? I know the huge front bar is the popular choice, but without knowing the camber curve I'm reluctant to jump on board. If camber loss isn't huge, you are shifting the weight transfer percentage further forward (from a bad starting point) and creating more of a solid axle effect (not to mention the extra weight).
Anyone tried the opposite approach and removed/disconnected the front bar?
Joel [/B][/QUOTE]
I think that tire wear alone speaks for the positive camber gain due to body roll. This ain't no double wishbone like Nates Honda so there is minimal dynamic camber change. As for for shifting the weight percentage further forward? nah, I don't buy it. With the stiffer roll rate you'll get a faster weight transfer up front, same total amount of weight transfer left to right but a higher percentage of the weight will be shifted to the outside rear. Its the rear percentage shift that generates the understeer but giving more grip to the rear.
-Matt
EDIT : I'll make the measurements this weekend draw a model for you, regarding camber curves, if that' what it takes. Plus I should have done it already
[B] Has anyone measured the camber curve on these cars to see what you really are losing with roll/compression? I know the huge front bar is the popular choice, but without knowing the camber curve I'm reluctant to jump on board. If camber loss isn't huge, you are shifting the weight transfer percentage further forward (from a bad starting point) and creating more of a solid axle effect (not to mention the extra weight).
Anyone tried the opposite approach and removed/disconnected the front bar?
Joel [/B][/QUOTE]
I think that tire wear alone speaks for the positive camber gain due to body roll. This ain't no double wishbone like Nates Honda so there is minimal dynamic camber change. As for for shifting the weight percentage further forward? nah, I don't buy it. With the stiffer roll rate you'll get a faster weight transfer up front, same total amount of weight transfer left to right but a higher percentage of the weight will be shifted to the outside rear. Its the rear percentage shift that generates the understeer but giving more grip to the rear.
-Matt
EDIT : I'll make the measurements this weekend draw a model for you, regarding camber curves, if that' what it takes. Plus I should have done it already
| solo-x | 06-09-2004 12:40 PM |
[QUOTE][i]Originally posted by Watkinsm3[/i]
[B] Before you commit to the statement about it not being darty... just remember how long you've been driving a car like that on the streets... I'd imagine your perspective might be a hair skewed at this point.[/B][/QUOTE]
:D
i thought all my posts came with an inferred disclaimer?
nate
[B] Before you commit to the statement about it not being darty... just remember how long you've been driving a car like that on the streets... I'd imagine your perspective might be a hair skewed at this point.[/B][/QUOTE]
:D
i thought all my posts came with an inferred disclaimer?
nate
| Watkinsm3 | 06-09-2004 12:51 PM |
If I spent all the time necessary to get through the disclaimer that comes along with each of your posts I'd still be struggling to get through your first post. :eek: ;)
-Matt
-Matt
| DrBiggly | 06-09-2004 05:07 PM |
26mm bar? Weak! When I autox'd my S10 I had ~ a 36mm bar on it. It's still on there and feels better than my H-stock Jetta on a lot of things...that's on 450 treadwear all seasons. :D
Cliff notes: Big front bar is good on a stock car. :)
Cliff notes: Big front bar is good on a stock car. :)
| Watkinsm3 | 06-09-2004 05:19 PM |
[QUOTE][i]Originally posted by DrBiggly[/i]
[B]
Cliff notes: Big front bar is good on a stock car. :) [/B][/QUOTE]
Especially when you got the juice in the rear to rotate the car under throttle.
[B]
Cliff notes: Big front bar is good on a stock car. :) [/B][/QUOTE]
Especially when you got the juice in the rear to rotate the car under throttle.
| AUTOwrXER | 06-11-2004 12:29 PM |
[QUOTE][i]Originally posted by Watkinsm3[/i]
[B]With the stiffer roll rate you'll get a faster weight transfer up front, same total amount of weight transfer left to right but a higher percentage of the weight will be shifted to the outside rear. Its the rear percentage shift that generates the understeer but giving more grip to the rear. [/B][/QUOTE]
I'd love to see the camber curves when you get them. I have to disagree with you on the statement above, however. A bigger bar will help turn in as it loads the outside tire more quickly. This can also be accomplished through stiffer springs (not legal in stock) or more compression damping (which becomes important when tuning setup for transitions compared to sweepers). That part of your statement I agree with.
I have to disagree with the statement that the total amount of weight transfer left to right does not change. This is true for the whole car, but not for each end of the car. The total weight of the front of the car (or the rear of the car, for that matter) cannot change without acceleration or decceleration. The role of the sway bar is to increase roll resistance, which is done by relocating weight from the inside tire to the outside tire (left to right or vice-versa) on the end of the car with the sway bar addition. In the case of adding a front sway bar, you will relocate weight from the inside front wheel to the inside rear wheel. To compensate, the same amount of weight shifts from the outside rear wheel to the outside front wheel. In the end, the weight front to rear and side to side is the same, but the cross weights have changed significantly. The front has more weight on the outside tire and the rear is more balanced than before the sway bar addition.
[B]With the stiffer roll rate you'll get a faster weight transfer up front, same total amount of weight transfer left to right but a higher percentage of the weight will be shifted to the outside rear. Its the rear percentage shift that generates the understeer but giving more grip to the rear. [/B][/QUOTE]
I'd love to see the camber curves when you get them. I have to disagree with you on the statement above, however. A bigger bar will help turn in as it loads the outside tire more quickly. This can also be accomplished through stiffer springs (not legal in stock) or more compression damping (which becomes important when tuning setup for transitions compared to sweepers). That part of your statement I agree with.
I have to disagree with the statement that the total amount of weight transfer left to right does not change. This is true for the whole car, but not for each end of the car. The total weight of the front of the car (or the rear of the car, for that matter) cannot change without acceleration or decceleration. The role of the sway bar is to increase roll resistance, which is done by relocating weight from the inside tire to the outside tire (left to right or vice-versa) on the end of the car with the sway bar addition. In the case of adding a front sway bar, you will relocate weight from the inside front wheel to the inside rear wheel. To compensate, the same amount of weight shifts from the outside rear wheel to the outside front wheel. In the end, the weight front to rear and side to side is the same, but the cross weights have changed significantly. The front has more weight on the outside tire and the rear is more balanced than before the sway bar addition.
| AUTOwrXER | 06-12-2004 12:45 AM |
I just caught a mistake in the above and edited it so that it makes sense. I always have to think the roll bar thing through twice before I get it right...
I just remembered that I forgot to finish my point about increasing weight transfer at the front end. The additional downward force on the outside front tire allows that tire to generate more grip (from Ff=Cf x Fv), but with increasing increments of vertical force (Fv) a tire generates a lower coefficient of friction (Cf). Effectively you have put more force on the outside tire and thereby lowered the overall Cf of the front end of the car. At the same time, you have done the opposite to the rear, making the Cf increase. Result = understeer. Weight transfer percentage is the amount of weight transfered across the front end of the car divided by the weight transferred across the rear end of the car (x 100). Our cars already have too high a front weight transfer percentage. Ideal is 50% (if you like your car balanced) to 55% front (if you like a little predictable understeer).
Without having tried different bars on this car in stock form, I would venture a guess that the reason the car feels better with the front bar is that it is undersprung in stock form, and the increased rate of weight transfer helps the car turn in (meaning it will also be much better in slaloms). I bet that the car suffers worse in sweepers because of the weight transfer I described above. Of course, I will be wrong if the camber curve goes to hell and there is not enough caster to save the day. That's why I want those camber curves ;)
One important thing about the front roll bar is that it increases wedge when in use, allowing powerful rear-wheel drive cars to get on the gas earlier. This is a huge benefit to a Camaro, but not so much to us.
The other downside that I haven't mentioned (beyond the weight transfer issue) is that a big sway bar limits independent motion of the suspension. Again, not a big deal with a solid-axle Camaro, but this one affects those of us with fully independent suspensions. The bigger the bar, the more our suspension acts like a solid axle (as movement at one wheel affects the other wheel).
Joel - whose brain is about to take a big dump and demand Guinness
I just remembered that I forgot to finish my point about increasing weight transfer at the front end. The additional downward force on the outside front tire allows that tire to generate more grip (from Ff=Cf x Fv), but with increasing increments of vertical force (Fv) a tire generates a lower coefficient of friction (Cf). Effectively you have put more force on the outside tire and thereby lowered the overall Cf of the front end of the car. At the same time, you have done the opposite to the rear, making the Cf increase. Result = understeer. Weight transfer percentage is the amount of weight transfered across the front end of the car divided by the weight transferred across the rear end of the car (x 100). Our cars already have too high a front weight transfer percentage. Ideal is 50% (if you like your car balanced) to 55% front (if you like a little predictable understeer).
Without having tried different bars on this car in stock form, I would venture a guess that the reason the car feels better with the front bar is that it is undersprung in stock form, and the increased rate of weight transfer helps the car turn in (meaning it will also be much better in slaloms). I bet that the car suffers worse in sweepers because of the weight transfer I described above. Of course, I will be wrong if the camber curve goes to hell and there is not enough caster to save the day. That's why I want those camber curves ;)
One important thing about the front roll bar is that it increases wedge when in use, allowing powerful rear-wheel drive cars to get on the gas earlier. This is a huge benefit to a Camaro, but not so much to us.
The other downside that I haven't mentioned (beyond the weight transfer issue) is that a big sway bar limits independent motion of the suspension. Again, not a big deal with a solid-axle Camaro, but this one affects those of us with fully independent suspensions. The bigger the bar, the more our suspension acts like a solid axle (as movement at one wheel affects the other wheel).
Joel - whose brain is about to take a big dump and demand Guinness
| AUTOwrXER | 06-14-2004 11:44 PM |
Matt - Any word on the camber curves?
Also, how much spacer did you say you were running to clear the 245 Hoosiers?
Also, how much spacer did you say you were running to clear the 245 Hoosiers?
| Watkinsm3 | 06-15-2004 11:33 AM |
Woah... I didn't even see all the posts here! Didn't get to look at the curves (the camber ones at least) this weekend as I was in AC for my friend's bachelor party :devil: . His wedding is this weekend so hopefully I'll get to the measuring next week. Sorry about that thought I'd have a little more free time than I did/do.
Actually I don't think our arguments are that different here.... the two major points of contention are...
1. I believe camber maintained by the big front bar will more than offset the lose of grip due to wedge and increased front biased roll resistance.
2. You also make this statement...
[QUOTE][i]Originally posted by AUTOwrXER[/i]
[B] One important thing about the front roll bar is that it increases wedge when in use, allowing powerful rear-wheel drive cars to get on the gas earlier. This is a huge benefit to a Camaro, but not so much to us.
[/B][/QUOTE]
Which I don't agree with as well... Maybe for a regular WRX but an STi? I don't think so at all. I believe the STi (due to its different drive line and differential than a WRX) should stay away from an overly rear stiff (FWD like, except Nate's) setup as much as possible.
There are some other things you mentioned I'd like to comment on... but stupid meetings here at work call me away...
-Matt
EDIT : Havn't test fitted hoosiers yet.
Actually I don't think our arguments are that different here.... the two major points of contention are...
1. I believe camber maintained by the big front bar will more than offset the lose of grip due to wedge and increased front biased roll resistance.
2. You also make this statement...
[QUOTE][i]Originally posted by AUTOwrXER[/i]
[B] One important thing about the front roll bar is that it increases wedge when in use, allowing powerful rear-wheel drive cars to get on the gas earlier. This is a huge benefit to a Camaro, but not so much to us.
[/B][/QUOTE]
Which I don't agree with as well... Maybe for a regular WRX but an STi? I don't think so at all. I believe the STi (due to its different drive line and differential than a WRX) should stay away from an overly rear stiff (FWD like, except Nate's) setup as much as possible.
There are some other things you mentioned I'd like to comment on... but stupid meetings here at work call me away...
-Matt
EDIT : Havn't test fitted hoosiers yet.
| subrew2 | 06-15-2004 01:00 PM |
I'm tending to agree with Matt on this. I came from low-powered front drive stuff, before my 2.5RS. I treated my 2.5 like I did my Yugo and CRX. Set it up like a front driver, drove it like a front driver. When I ran g-stock, the biggest improvements to the car included a big front bar to reduce body roll, lots of rear compression (which helped to reduce squat coming off corners) lots of rear toe out to help it rotate on throttle, and lots of front rebound to help keep it sucked down
With the STi, it has the beans to actually rotate coming off corners, so for A-stock, I would run the big front bar, some good rebound up front to help keep it sucked down during transitions. I would be way more cautious on the rear compression and toe, because from my experience driving it, I wouldn't want it any looser on throttle. I would focus on getting it to turn in better.
For my STU/ESP setup, I am going to set up the car to be less dancy on corner entry than I usualy do. I don't have to get so much rotation done on corner entry, casue It will rotate with the throttle. I'm probably going to run spring rates opposite of the STX WRX guys. Stiffer fronts than rears. We'll see, once I get the parts in.
Chris H.
[url]www.subrew.com[/url]
ESP STi
With the STi, it has the beans to actually rotate coming off corners, so for A-stock, I would run the big front bar, some good rebound up front to help keep it sucked down during transitions. I would be way more cautious on the rear compression and toe, because from my experience driving it, I wouldn't want it any looser on throttle. I would focus on getting it to turn in better.
For my STU/ESP setup, I am going to set up the car to be less dancy on corner entry than I usualy do. I don't have to get so much rotation done on corner entry, casue It will rotate with the throttle. I'm probably going to run spring rates opposite of the STX WRX guys. Stiffer fronts than rears. We'll see, once I get the parts in.
Chris H.
[url]www.subrew.com[/url]
ESP STi
| subrew2 | 06-15-2004 01:02 PM |
Oh yeah, Matt: If you have any used 255 Victos you want to sell, let me know. I want to get something to run on this summer. Practice tires basically.
Chris H.
Chris H.
| AUTOwrXER | 06-15-2004 10:05 PM |
FWIW, I'm not disagreeing with any of the opinions here. I'm speaking from a theoretical perspective to people who have had a chance to try different setups. I raced the car for the first time 2 days ago. As in all things with motorsports, theory is usually just a starting point.
Matt - as far as "over-stiffening" the rear is concerned, can you explain why you think this would be detrimental when we have another 2 driven wheels to accelerate the car? I talked to a multi-time SP national champ about this, and he recommended I go with the rear spring bias (aka FWD setup).
Joel
Matt - as far as "over-stiffening" the rear is concerned, can you explain why you think this would be detrimental when we have another 2 driven wheels to accelerate the car? I talked to a multi-time SP national champ about this, and he recommended I go with the rear spring bias (aka FWD setup).
Joel
| Watkinsm3 | 06-16-2004 10:36 AM |
[QUOTE][i]Originally posted by AUTOwrXER[/i]
[B] FWIW, I'm not disagreeing with any of the opinions here. I'm speaking from a theoretical perspective to people who have had a chance to try different setups. I raced the car for the first time 2 days ago. As in all things with motorsports, theory is usually just a starting point.
[/B][/QUOTE]
That's fine... and personally I don't mind being asked "why". If I can't answer that question then I should probably look at the solution I'm using again.
[QUOTE][i]Originally posted by AUTOwrXER[/i]
[B] Matt - as far as "over-stiffening" the rear is concerned, can you explain why you think this would be detrimental when we have another 2 driven wheels to accelerate the car? I talked to a multi-time SP national champ about this, and he recommended I go with the rear spring bias (aka FWD setup).
Joel [/B][/QUOTE]
I guess you could run a rear stiff setup but I'd imagine you would have to run the diff fully locked to keep too much power from going to the rear wheels. With a stiffer rear bias and the diff in auto/open the car will have trouble putting the power down (for the same reasons most RWD cars would have the same problem). In a straightline this wouldn't be too big of a problem with awd as the fronts willl help you out. The down side is that when you are exiting corner and trying to put power down the car is going to be REALLY loose. I'm pretty sure you'll have to give up on throttle to keep the back in line.
As for your National Champ statement? oh well... he is and I'm not... Has he driven the car? a WRX? Maybe he suggested that because that is a good setup for a regular WRX (and most AWD cars for that matter) as most AWD cars pick up alot of their traits from FWD cars. Especially using the rear stiff setup for rotation as they don't rotate under throttle like a RWD car does... With the potential rear power bias in the STi? it definitely behaves more like a rear drive car than a front.
-Matt
[B] FWIW, I'm not disagreeing with any of the opinions here. I'm speaking from a theoretical perspective to people who have had a chance to try different setups. I raced the car for the first time 2 days ago. As in all things with motorsports, theory is usually just a starting point.
[/B][/QUOTE]
That's fine... and personally I don't mind being asked "why". If I can't answer that question then I should probably look at the solution I'm using again.
[QUOTE][i]Originally posted by AUTOwrXER[/i]
[B] Matt - as far as "over-stiffening" the rear is concerned, can you explain why you think this would be detrimental when we have another 2 driven wheels to accelerate the car? I talked to a multi-time SP national champ about this, and he recommended I go with the rear spring bias (aka FWD setup).
Joel [/B][/QUOTE]
I guess you could run a rear stiff setup but I'd imagine you would have to run the diff fully locked to keep too much power from going to the rear wheels. With a stiffer rear bias and the diff in auto/open the car will have trouble putting the power down (for the same reasons most RWD cars would have the same problem). In a straightline this wouldn't be too big of a problem with awd as the fronts willl help you out. The down side is that when you are exiting corner and trying to put power down the car is going to be REALLY loose. I'm pretty sure you'll have to give up on throttle to keep the back in line.
As for your National Champ statement? oh well... he is and I'm not... Has he driven the car? a WRX? Maybe he suggested that because that is a good setup for a regular WRX (and most AWD cars for that matter) as most AWD cars pick up alot of their traits from FWD cars. Especially using the rear stiff setup for rotation as they don't rotate under throttle like a RWD car does... With the potential rear power bias in the STi? it definitely behaves more like a rear drive car than a front.
-Matt
| AUTOwrXER | 06-16-2004 12:30 PM |
I've been talking to Steve Holscher, who is IMO one of the best setup guys in SP. He's driven a number of WRXs and the STi, and is familiar with the power-on oversteer available. My take on the Auto mode DCCD setting is that it lets you rotate the car under power and then shifts the distribution up front. If that is the way it is adjusting power, then going stiffer in the rear would cause that power shift sooner, which is not necessarily a bad thing. Just a guess, but I do hold Steve's opinion in high regard.
| Smittys_STi | 06-23-2004 03:23 PM |
any word on those camber curves? ;)
| trhoppe | 06-23-2004 03:27 PM |
They suck? The more the car leans over the more camber it loses. The "exact" numbers can't be found unless someone has a copy of "Roll Center" or does some SERIOUS math.
-Tom
-Tom
| AUTOwrXER | 06-23-2004 04:12 PM |
Shouldn't you be able to get a good idea by using tow straps and pulling the car down while on the suspension rack? You can pull it down .5" at a time and take measurements at each interval...right?
| Watkinsm3 | 06-23-2004 05:29 PM |
[QUOTE][i]Originally posted by Smittys_STi[/i]
[B] any word on those camber curves? ;) [/B][/QUOTE]
Yeah... they're coming. I'm still detoxing from the wedding this past weekend! Like Tom said... there's a BUNCH of work involved and given the choice I'll do pretty much anything instead of work!
I'm going to use two methods so I could compare the results. I'll post these up in case I'm off track (very rare but has happend before... once... long ago :D ).
Both of these methods ignore any bushing flex (for obvious reasons).
Method 1 :
A. Measure all arm lengths, joint positions and pivot points (as precisely as possible.
B. Enter these numbers into a modeling program (I have a couple) or write my own program to do the analysis (it's nice to be computer geek sometimes)
C. Record camber change through compression and extension
D. Repeat data gathering for a couple different steering positions
Method 2 :
A. Remove the spring and replace struts and wheel.
B. Manually move wheel through compression/extension and take manual measurements to record change in camber.
C. maybe do one other steering input since I'm lazy and we're only looking to confirm that the computer related results are accurate.
Numbers can (and probably will) vary between the computer and actual testing... but the actual change should match up and that's what we're really interested in here.
The tough part here is to measure that actual amount of roll experienced in cornering and I'm assuming the program "Roll Center" that tom mentioned probably could help there. I'll see how ambitious I get once I get the first set of data.
Needless to say, its a ton of work... especially when I'm not getting paid for it!!! :) I have a double header event this weekend and I think I'm going up to Devons the weekend after for another double header for the 3rd/4th... It'll be tough to find the time mid-week to do it. Patience is in order
-Matt
PS... I'm very inclined to just agree with Tom's statement...
[quote]They suck[/quote]
[B] any word on those camber curves? ;) [/B][/QUOTE]
Yeah... they're coming. I'm still detoxing from the wedding this past weekend! Like Tom said... there's a BUNCH of work involved and given the choice I'll do pretty much anything instead of work!
I'm going to use two methods so I could compare the results. I'll post these up in case I'm off track (very rare but has happend before... once... long ago :D ).
Both of these methods ignore any bushing flex (for obvious reasons).
Method 1 :
A. Measure all arm lengths, joint positions and pivot points (as precisely as possible.
B. Enter these numbers into a modeling program (I have a couple) or write my own program to do the analysis (it's nice to be computer geek sometimes)
C. Record camber change through compression and extension
D. Repeat data gathering for a couple different steering positions
Method 2 :
A. Remove the spring and replace struts and wheel.
B. Manually move wheel through compression/extension and take manual measurements to record change in camber.
C. maybe do one other steering input since I'm lazy and we're only looking to confirm that the computer related results are accurate.
Numbers can (and probably will) vary between the computer and actual testing... but the actual change should match up and that's what we're really interested in here.
The tough part here is to measure that actual amount of roll experienced in cornering and I'm assuming the program "Roll Center" that tom mentioned probably could help there. I'll see how ambitious I get once I get the first set of data.
Needless to say, its a ton of work... especially when I'm not getting paid for it!!! :) I have a double header event this weekend and I think I'm going up to Devons the weekend after for another double header for the 3rd/4th... It'll be tough to find the time mid-week to do it. Patience is in order
-Matt
PS... I'm very inclined to just agree with Tom's statement...
[quote]They suck[/quote]
| Smittys_STi | 06-24-2004 09:39 AM |
Well be sure to post once ya do get them ... I'm defintely interested (as well as many others I'm sure) ...
Thanks!
-Smitty
Thanks!
-Smitty
| AUTOwrXER | 06-24-2004 11:24 AM |
Damn. That's more involved than I thought. Good information to have, but I'm too lazy to get it...
| trhoppe | 06-24-2004 11:28 AM |
Therefore my conclusion makes it easy "they suck"
I GUARANTEE you that after you would do the numbers you would come to the conclusion that "they suck"
-Tom
I GUARANTEE you that after you would do the numbers you would come to the conclusion that "they suck"
-Tom
| DrBiggly | 06-24-2004 11:46 AM |
[QUOTE][i]Originally posted by trhoppe[/i]
[B] Therefore my conclusion makes it easy "they suck"
I GUARANTEE you that after you would do the numbers you would come to the conclusion that "they suck"
-Tom [/B][/QUOTE]
:lol: :lol: Tom, don't sugar coat it..tell us how you really feel! :)
[B] Therefore my conclusion makes it easy "they suck"
I GUARANTEE you that after you would do the numbers you would come to the conclusion that "they suck"
-Tom [/B][/QUOTE]
:lol: :lol: Tom, don't sugar coat it..tell us how you really feel! :)
| Watkinsm3 | 06-24-2004 12:42 PM |
[QUOTE][i]Originally posted by trhoppe[/i]
[B] Therefore my conclusion makes it easy "they suck"
I GUARANTEE you that after you would do the numbers you would come to the conclusion that "they suck"
-Tom [/B][/QUOTE]
I agree 100% with you Tom... but its not the conclusion I really want here. I'd really like to see what the suspension/wheels/chassis is doing out there. I found the program (susprog3d) and looked at it briefly as I never really did too much with it. once the data is entered and the calcs are done you can move the suspension through variious levels of travel and simulate roll as well. That combined with the ability to change the front bar in the program might show some useful results as well.
Obviously the more data inputed the better the results will be... I guess I just have to buckle down and get to it.
-Matt
[B] Therefore my conclusion makes it easy "they suck"
I GUARANTEE you that after you would do the numbers you would come to the conclusion that "they suck"
-Tom [/B][/QUOTE]
I agree 100% with you Tom... but its not the conclusion I really want here. I'd really like to see what the suspension/wheels/chassis is doing out there. I found the program (susprog3d) and looked at it briefly as I never really did too much with it. once the data is entered and the calcs are done you can move the suspension through variious levels of travel and simulate roll as well. That combined with the ability to change the front bar in the program might show some useful results as well.
Obviously the more data inputed the better the results will be... I guess I just have to buckle down and get to it.
-Matt
| Watkinsm3 | 06-24-2004 12:54 PM |
Here are some quick shots I took...
They had a subaru template in the program already (no idea what model!!!!!)
-1 degree camber static and 5 degrees castor
Static :
[img]http://www.sendusbeer.com/watkins/img/design/sus_subaru_1.jpg[/img]
3 Degrees of roll (i think its measured in degrees!) :
[img]http://www.sendusbeer.com/watkins/img/design/sus_subaru_2.jpg[/img]
Just thought someone might care. I wanna take the measurements before I start getting REAL crazy with this.
-Matt
They had a subaru template in the program already (no idea what model!!!!!)
-1 degree camber static and 5 degrees castor
Static :
[img]http://www.sendusbeer.com/watkins/img/design/sus_subaru_1.jpg[/img]
3 Degrees of roll (i think its measured in degrees!) :
[img]http://www.sendusbeer.com/watkins/img/design/sus_subaru_2.jpg[/img]
Just thought someone might care. I wanna take the measurements before I start getting REAL crazy with this.
-Matt
| trhoppe | 06-24-2004 01:09 PM |
Sweet. I just got the software myself.
I'll take some measurements tonight :banana:
-Tom
I'll take some measurements tonight :banana:
-Tom
| trhoppe | 06-24-2004 01:28 PM |
Roll Center also calculates roll in degrees.
Unfortunately this software only allows you up to 4 degrees of roll. We have WAY more body roll then that in a stock car.
-Tom
Unfortunately this software only allows you up to 4 degrees of roll. We have WAY more body roll then that in a stock car.
-Tom
| DrBiggly | 06-24-2004 02:06 PM |
So you're saying this software won't work for what we're looking for?
| Watkinsm3 | 06-24-2004 03:55 PM |
[QUOTE][i]Originally posted by trhoppe[/i]
[B] Roll Center also calculates roll in degrees.
Unfortunately this software only allows you up to 4 degrees of roll. We have WAY more body roll then that in a stock car.
-Tom [/B][/QUOTE]
Not true! you can only have 4 active at once but you can change the scaling!!!!
Load a model...
Choose Roll Bump tab
Click Increments
[img]http://www.sendusbeer.com/watkins/img/design/designer.jpg[/img]
-Matt
EDIT : You'll also notice there are calc buttons and results buttons on that same tab... You can get some sweet tabular results as well but running those!!! nice stuff!
EDIT 2 : quick test... start with -1 camber 20mm bump and 4deg of roll... showed 0.99 degree of camber on the outside front!
EDIT 3 : I do agree that there should be a larger range (more than 3 data points!)
[B] Roll Center also calculates roll in degrees.
Unfortunately this software only allows you up to 4 degrees of roll. We have WAY more body roll then that in a stock car.
-Tom [/B][/QUOTE]
Not true! you can only have 4 active at once but you can change the scaling!!!!
Load a model...
Choose Roll Bump tab
Click Increments
[img]http://www.sendusbeer.com/watkins/img/design/designer.jpg[/img]
-Matt
EDIT : You'll also notice there are calc buttons and results buttons on that same tab... You can get some sweet tabular results as well but running those!!! nice stuff!
EDIT 2 : quick test... start with -1 camber 20mm bump and 4deg of roll... showed 0.99 degree of camber on the outside front!
EDIT 3 : I do agree that there should be a larger range (more than 3 data points!)
| trhoppe | 06-24-2004 08:10 PM |
Matt - Youve got to get the version I have 4.51, it roxors. Email me [email][email�protected][/email]
[img]http://www.tomhoppe.com/misc%20pics/increments.jpg[/img]
-Tom
[img]http://www.tomhoppe.com/misc%20pics/increments.jpg[/img]
-Tom
| trhoppe | 06-24-2004 09:22 PM |
-1.0 static camber at 0 bump (stock) :eek:
SusProg3D Subaru.s3d Front Roll and bump
Chassis roll values calculated every 1.00 degrees. Right hand turn.
Semi dynamic roll centre. Roll starts at 0.787 bump.
Outer wheel (LH) roll centre
camber caster kpi scrub tramp toein offset height fvsax
0.00 roll [b]-1.68[/b] 5.18 15.000 0.129 0.011 0.000 0.000 3.586 70.413
1.00 roll [b]-1.06[/b] 5.28 14.358 0.123 0.018 0.000 -5.203 3.447 75.677
2.00 roll [b]-0.41[/b] 5.37 13.686 0.108 0.025 0.001 -10.530 3.022 82.382
3.00 roll [b]0.27[/b] 5.48 12.981 0.087 0.033 0.003 -16.115 2.287 91.219
4.00 roll [b]0.98[/b] 5.59 12.240 0.065 0.040 0.007 -22.126 1.199 103.397
5.00 roll [b]1.74[/b] 5.70 11.461 0.049 0.047 0.012 -28.782 -0.316 121.248
6.00 roll [b]2.53[/b] 5.83 10.639 0.045 0.054 0.020 -36.402 -2.376 149.933
7.00 roll [b]3.36[/b] 5.96 9.771 0.061 0.061 0.031 -45.479 -5.172 203.574
8.00 roll [b]4.25[/b] 6.10 8.850 0.109 0.068 0.046 -56.835 -9.033 339.694
-Tom
SusProg3D Subaru.s3d Front Roll and bump
Chassis roll values calculated every 1.00 degrees. Right hand turn.
Semi dynamic roll centre. Roll starts at 0.787 bump.
Outer wheel (LH) roll centre
camber caster kpi scrub tramp toein offset height fvsax
0.00 roll [b]-1.68[/b] 5.18 15.000 0.129 0.011 0.000 0.000 3.586 70.413
1.00 roll [b]-1.06[/b] 5.28 14.358 0.123 0.018 0.000 -5.203 3.447 75.677
2.00 roll [b]-0.41[/b] 5.37 13.686 0.108 0.025 0.001 -10.530 3.022 82.382
3.00 roll [b]0.27[/b] 5.48 12.981 0.087 0.033 0.003 -16.115 2.287 91.219
4.00 roll [b]0.98[/b] 5.59 12.240 0.065 0.040 0.007 -22.126 1.199 103.397
5.00 roll [b]1.74[/b] 5.70 11.461 0.049 0.047 0.012 -28.782 -0.316 121.248
6.00 roll [b]2.53[/b] 5.83 10.639 0.045 0.054 0.020 -36.402 -2.376 149.933
7.00 roll [b]3.36[/b] 5.96 9.771 0.061 0.061 0.031 -45.479 -5.172 203.574
8.00 roll [b]4.25[/b] 6.10 8.850 0.109 0.068 0.046 -56.835 -9.033 339.694
-Tom
| trhoppe | 06-24-2004 09:29 PM |
-2.5 static camber at 0 bump (mine) ;)
SusProg3D Subaru.s3d Front Roll and bump
Chassis roll values calculated every 1.00 degrees. Right hand turn.
Semi dynamic roll centre. Roll starts at 0.787 bump.
Toe variation has NOT been calculated.
Outer wheel (LH) roll centre
camber caster kpi scrub tramp toein offset height fvsax
0.00 roll [b]-3.23[/b] 5.18 16.569 0.141 0.010 0.000 0.000 4.013 64.762
1.00 roll [b]-2.65[/b] 5.27 15.964 0.135 0.017 0.000 -4.529 3.895 68.804
2.00 roll [b]-2.04[/b] 5.36 15.330 0.120 0.025 0.000 -9.144 3.534 73.804
3.00 roll [b]-1.40[/b] 5.46 14.667 0.098 0.032 0.000 -13.940 2.914 80.152
4.00 roll [b]-0.73[/b] 5.57 13.970 0.075 0.041 0.000 -19.025 2.003 88.484
5.00 roll [b]-0.02[/b] 5.69 13.237 0.054 0.049 0.000 -24.544 0.754 99.907
6.00 roll [b]0.72[/b] 5.81 12.465 0.040 0.058 0.000 -30.693 -0.912 116.534
7.00 roll [b]1.51[/b] 5.94 11.648 0.040 0.068 0.000 -37.760 -3.113 142.968
8.00 roll [b]2.34[/b] 6.08 10.783 0.063 0.079 0.000 -46.191 -6.043 191.494
My conclusion from 2 minutes of number crunching??
My car runs a static -2.5 camber. With that and a bigass front bar and a lot of front spring, the wheel is perfectly damn level at the middle of the turn with full load. The tire temps as well as many pictures prove that. I assume then, that you I'm encountering maybe 5 degrees of roll.
A stock car would probably get closer to 8 ;) :eek:
-Tom
SusProg3D Subaru.s3d Front Roll and bump
Chassis roll values calculated every 1.00 degrees. Right hand turn.
Semi dynamic roll centre. Roll starts at 0.787 bump.
Toe variation has NOT been calculated.
Outer wheel (LH) roll centre
camber caster kpi scrub tramp toein offset height fvsax
0.00 roll [b]-3.23[/b] 5.18 16.569 0.141 0.010 0.000 0.000 4.013 64.762
1.00 roll [b]-2.65[/b] 5.27 15.964 0.135 0.017 0.000 -4.529 3.895 68.804
2.00 roll [b]-2.04[/b] 5.36 15.330 0.120 0.025 0.000 -9.144 3.534 73.804
3.00 roll [b]-1.40[/b] 5.46 14.667 0.098 0.032 0.000 -13.940 2.914 80.152
4.00 roll [b]-0.73[/b] 5.57 13.970 0.075 0.041 0.000 -19.025 2.003 88.484
5.00 roll [b]-0.02[/b] 5.69 13.237 0.054 0.049 0.000 -24.544 0.754 99.907
6.00 roll [b]0.72[/b] 5.81 12.465 0.040 0.058 0.000 -30.693 -0.912 116.534
7.00 roll [b]1.51[/b] 5.94 11.648 0.040 0.068 0.000 -37.760 -3.113 142.968
8.00 roll [b]2.34[/b] 6.08 10.783 0.063 0.079 0.000 -46.191 -6.043 191.494
My conclusion from 2 minutes of number crunching??
My car runs a static -2.5 camber. With that and a bigass front bar and a lot of front spring, the wheel is perfectly damn level at the middle of the turn with full load. The tire temps as well as many pictures prove that. I assume then, that you I'm encountering maybe 5 degrees of roll.
A stock car would probably get closer to 8 ;) :eek:
-Tom
| trhoppe | 06-24-2004 09:46 PM |
See what happens when you lower the car too much?? -2 inch "drop dawg" same -1.0 static camber at 0 bump :eek:
usProg3D Subaru.s3d Front Roll and bump
Chassis roll values calculated every 1.00 degrees. Right hand turn.
Semi dynamic roll centre. Roll starts at 0.787 bump.
Toe variation has NOT been calculated.
Outer wheel (LH) roll centre
camber caster kpi scrub tramp toein offset height fvsax
0.00 roll [b] -1.40 [/b] 5.21 14.593 -0.027 0.013 0.000 0.000 -2.021 128.968
1.00 roll [b] -0.59 [/b] 5.32 13.753 -0.035 0.022 0.000 11.605 -1.685 162.833
2.00 roll [b] 0.27 [/b] 5.44 12.863 -0.065 0.031 0.000 22.339 -0.725 230.710
3.00 roll [b] 1.18 [/b] 5.57 11.918 -0.129 0.041 0.000 31.526 0.730 434.440
4.00 roll [b] 2.15 [/b] 5.71 10.910 -0.238 0.051 0.000 38.804 2.516140786.480
5.00 roll [b] 3.19 [/b] 5.86 9.831 -0.397 0.063 0.000 44.120 4.467 -385.916
6.00 roll [b] 4.30 [/b] 6.02 8.674 -0.612 0.075 0.000 47.643 6.453 -180.496
7.00 roll [b] 5.50 [/b] 6.19 7.430 -0.884 0.087 0.000 49.655 8.381 -112.453
8.00 roll [b] 6.80 [/b] 6.38 6.088 -1.214 0.101 0.000 50.472 10.199 -78.707
-Tom
usProg3D Subaru.s3d Front Roll and bump
Chassis roll values calculated every 1.00 degrees. Right hand turn.
Semi dynamic roll centre. Roll starts at 0.787 bump.
Toe variation has NOT been calculated.
Outer wheel (LH) roll centre
camber caster kpi scrub tramp toein offset height fvsax
0.00 roll [b] -1.40 [/b] 5.21 14.593 -0.027 0.013 0.000 0.000 -2.021 128.968
1.00 roll [b] -0.59 [/b] 5.32 13.753 -0.035 0.022 0.000 11.605 -1.685 162.833
2.00 roll [b] 0.27 [/b] 5.44 12.863 -0.065 0.031 0.000 22.339 -0.725 230.710
3.00 roll [b] 1.18 [/b] 5.57 11.918 -0.129 0.041 0.000 31.526 0.730 434.440
4.00 roll [b] 2.15 [/b] 5.71 10.910 -0.238 0.051 0.000 38.804 2.516140786.480
5.00 roll [b] 3.19 [/b] 5.86 9.831 -0.397 0.063 0.000 44.120 4.467 -385.916
6.00 roll [b] 4.30 [/b] 6.02 8.674 -0.612 0.075 0.000 47.643 6.453 -180.496
7.00 roll [b] 5.50 [/b] 6.19 7.430 -0.884 0.087 0.000 49.655 8.381 -112.453
8.00 roll [b] 6.80 [/b] 6.38 6.088 -1.214 0.101 0.000 50.472 10.199 -78.707
-Tom
| trhoppe | 06-24-2004 09:53 PM |
Please take all these numbers with a BIGASS grain of salt ;)
They are not from exact measured numbers. They are from an ESTIMATION of a front suspension which *looks* right.
Static, 0 pitch,yaw,roll
[img]http://www.tomhoppe.com/misc%20pics/3d.jpg[/img]
Static, 45 pitch, 0 yaw,roll
[img]http://www.tomhoppe.com/misc%20pics/3d_45.jpg[/img]
-Tom
They are not from exact measured numbers. They are from an ESTIMATION of a front suspension which *looks* right.
Static, 0 pitch,yaw,roll
[img]http://www.tomhoppe.com/misc%20pics/3d.jpg[/img]
Static, 45 pitch, 0 yaw,roll
[img]http://www.tomhoppe.com/misc%20pics/3d_45.jpg[/img]
-Tom
| DrBiggly | 06-24-2004 11:33 PM |
Tom,
So the important number to watch in those calculations is what you have in bold there?
So the important number to watch in those calculations is what you have in bold there?
| trhoppe | 06-24-2004 11:40 PM |
Thats teh camber
-Tom
-Tom
| Watkinsm3 | 06-25-2004 11:40 AM |
[QUOTE][i]Originally posted by trhoppe[/i]
[B] Thats teh camber
-Tom [/B][/QUOTE]
Castor changes are also interesting as well.
For those of you that LOVE graphic views I put this together from Tom's STOCK data. Remember these are based off a subaru template, niether of us have measured and entered data yet. Anyway, on to the bling!
[img]http://www.sendusbeer.com/watkins/img/design/sus_subaru_stock_Graph.jpg[/img]
Specs for this graph...
[quote][i]Originally posted by trhoppe[/i]
[B] -1.0 static camber at 0 bump (stock)
SusProg3D Subaru.s3d Front Roll and bump
Chassis roll values calculated every 1.00 degrees. Right hand turn.
Semi dynamic roll centre. Roll starts at 0.787 bump.[/b][/quote]
-Matt
[B] Thats teh camber
-Tom [/B][/QUOTE]
Castor changes are also interesting as well.
For those of you that LOVE graphic views I put this together from Tom's STOCK data. Remember these are based off a subaru template, niether of us have measured and entered data yet. Anyway, on to the bling!
[img]http://www.sendusbeer.com/watkins/img/design/sus_subaru_stock_Graph.jpg[/img]
Specs for this graph...
[quote][i]Originally posted by trhoppe[/i]
[B] -1.0 static camber at 0 bump (stock)
SusProg3D Subaru.s3d Front Roll and bump
Chassis roll values calculated every 1.00 degrees. Right hand turn.
Semi dynamic roll centre. Roll starts at 0.787 bump.[/b][/quote]
-Matt
| crystalhelix | 06-25-2004 11:50 AM |
Well, this thread has officially become technologically advanced. It makes an engineer proud. I can't wait to see where this goes.:lol:
| MNbiker | 06-25-2004 01:12 PM |
Hey Tom,
For comparison sake, it would be mighty interesting to see a similar camber curve for a Civic Si, Miata, or similar double wishbone suspension. Come on, you KNOW you want to goof off playing with car stuff at work this afternoon! ;)
-Steve
For comparison sake, it would be mighty interesting to see a similar camber curve for a Civic Si, Miata, or similar double wishbone suspension. Come on, you KNOW you want to goof off playing with car stuff at work this afternoon! ;)
-Steve
| subrew2 | 06-25-2004 02:11 PM |
I won't have access to a full-on laser style alignment machine, but I will be stringing my car up tomorrow. I'm installing my new Tein Flex setup on the '04 STi, and wanted to measure the camber change throughout the range of suspension travel. I've done this before on my Yugo (no jokes please) and more recently on my CSP Fiat 124 Spider.
I'll try to get it all collected and posted by Monday.
Chris H.
[url]www.subrew.com[/url]
I'll try to get it all collected and posted by Monday.
Chris H.
[url]www.subrew.com[/url]
| Watkinsm3 | 06-25-2004 02:14 PM |
[QUOTE][i]Originally posted by trhoppe[/i]
[B] -2.5 static camber at 0 bump (mine) ;)
[/B][/QUOTE]
Hey Tom... did you change the ride height data to match your car for this data output? Obviously this would have some change on the output data... mostly just curious if you did or not.
Another thing I noticed about the graph i posted... while castor appears to linear camber appears to not be. Meaning the line "visually" has a curve to. To me it looks like its gains positive camber faster the more roll that is applied... This could just be an illusion. I might have to extrapolate that data further out so there are enough data points for excel to build a decent best fit curve and find the equation for the line. I assumed positive camber gain would be linear... hmmm...
Oh wait... I just made the graph...
The dark lines are linear best-fits... the others represent the datapoints. Basicly the same setup as Tom used
20mm bump ( same as tom )
-1 deg camber
1 deg of roll up to 10 deg (to get a better curve example)
[img]http://www.sendusbeer.com/watkins/img/design/sus_subaru_stock_Graph2.jpg[/img]
As for the bump during roll? probably not gonna happen unless you are experiencing some jacking effects due to shocks and what not. I think this is a fairly safe assumption to make... That being the case... these numbers are actually being generous as to the amount of negative camber you can retain. I gotta think about what I just said some more but I believe its accurate.
-Matt
[B] -2.5 static camber at 0 bump (mine) ;)
[/B][/QUOTE]
Hey Tom... did you change the ride height data to match your car for this data output? Obviously this would have some change on the output data... mostly just curious if you did or not.
Another thing I noticed about the graph i posted... while castor appears to linear camber appears to not be. Meaning the line "visually" has a curve to. To me it looks like its gains positive camber faster the more roll that is applied... This could just be an illusion. I might have to extrapolate that data further out so there are enough data points for excel to build a decent best fit curve and find the equation for the line. I assumed positive camber gain would be linear... hmmm...
Oh wait... I just made the graph...
The dark lines are linear best-fits... the others represent the datapoints. Basicly the same setup as Tom used
20mm bump ( same as tom )
-1 deg camber
1 deg of roll up to 10 deg (to get a better curve example)
[img]http://www.sendusbeer.com/watkins/img/design/sus_subaru_stock_Graph2.jpg[/img]
As for the bump during roll? probably not gonna happen unless you are experiencing some jacking effects due to shocks and what not. I think this is a fairly safe assumption to make... That being the case... these numbers are actually being generous as to the amount of negative camber you can retain. I gotta think about what I just said some more but I believe its accurate.
-Matt
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