| RACER1269 | 02-06-2006 03:41 PM |
Street Mod spring rates
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i was wondering what kind of spring rates some of you SCCA Street Mod guys were using on your coilovers and do you like what you have? thanks :D
| Scoobyslack1 | 02-06-2006 05:19 PM |
This won't help you much.
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I have DMS 40s with soft springs -180 all the way around. It has a smooth ride, but not too soft. I do have big sway bars on and the car is less than 2700lbs.
| subbyspeed | 02-06-2006 07:26 PM |
I'll be 250 in the front and 375 in the rear. With kyb's set full stiff in the rear and almost full on the front. :)
But i'm in the GC chassis. Don't know how different it'll act in your car.
But i'm in the GC chassis. Don't know how different it'll act in your car.
| flyboymike | 02-06-2006 07:26 PM |
Well, I'm an STX guy, but suspension-wise we're allowed nearly the same stuff. I've got Crucial Racing springs with Koni insert dampers, 257 lb/in front and 217 lb/in rear. Very streetable, but pretty good for the cones.
| BIGSKYWRX | 02-06-2006 09:01 PM |
You might not want to know :) There are some guys running 10/12kg springs! I'd guess these might be a tad stiff on the street :D
| thrdeye | 02-06-2006 09:06 PM |
9k/10k here - in STX.
| DrBiggly | 02-06-2006 11:05 PM |
This thread should be moved into the Motorsports forum.
That being said, it will be dependent upon your chassis (GC in this case) for starters. Also the tires being used; race tires require a bit of a different setup than say some sticky street tires (a la STX.)
Also, it depends on how dedicated one is to ultimate performance for the class and autox in general vs. dealing with it on a day-to-day basis. :)
-Biggly
That being said, it will be dependent upon your chassis (GC in this case) for starters. Also the tires being used; race tires require a bit of a different setup than say some sticky street tires (a la STX.)
Also, it depends on how dedicated one is to ultimate performance for the class and autox in general vs. dealing with it on a day-to-day basis. :)
-Biggly
| thrdeye | 02-06-2006 11:26 PM |
Everytime I get frustrated at the stiff springs, I just put the GF in the car for some boob-jigglin action!
| flyboymike | 02-07-2006 12:42 AM |
[QUOTE=thrdeye]Everytime I get frustrated at the stiff springs, I just put the GF in the car for some boob-jigglin action![/QUOTE]
XD
Best reason for stiff springs ever!
XD
Best reason for stiff springs ever!
| Clreic | 02-07-2006 12:51 AM |
been thinking of 13k/11k, but maybe thats to stiff? then again this is not for my daily driver :)
| RACER1269 | 02-07-2006 05:34 AM |
well i was asking because i just got a set of JIC coilovers with 7Kf/5Kr springs. and i didnt think that was a bad place to start but alot of the locals did. i have whiteline bars 24f/26r, GC caster/camber plates, and some Goodyear GC-SC dot slicks (like the Kumo V710s)
it feels good to me other than the bouncing around. the car drive on my re92s like it did with my kumo mx now, well maybe not taht good but i definilty feel the difference. anyway i was just wanting to make sure i havnt over done it. i tend to do that alot. im more for function than form most the time too. so a harsh ride isnt that big of a deal to me.
i cant wait till this weekend i might try this stuff out. if not we have a divisonal race end of this month i will be doing. :banana:
thanks
it feels good to me other than the bouncing around. the car drive on my re92s like it did with my kumo mx now, well maybe not taht good but i definilty feel the difference. anyway i was just wanting to make sure i havnt over done it. i tend to do that alot. im more for function than form most the time too. so a harsh ride isnt that big of a deal to me.
i cant wait till this weekend i might try this stuff out. if not we have a divisonal race end of this month i will be doing. :banana:
thanks
| Car vs. Driver | 02-07-2006 09:16 AM |
I'm running 10k/8k ... daily driver :) I'l lprobably bump the rear up to 10K as well when I get my big front bar.
| RACER1269 | 02-07-2006 11:32 AM |
so my buddy has a ss camaro he just got a few parts from Strano. he got bars, springs, and koni shocks. he was telling me that his rear springs are like 180 lbs. i always heard the rule was go soft as you can get away with. the subarus dont seem to go by that rule? also when i added my front whiteline 24mm bar that was the biggest difference yet, but everyone is screaming back bar this and that.
thanks for the input guys.
thanks for the input guys.
| Prestige Motorsports | 02-07-2006 11:42 AM |
9k front, Whiteline 25-28 front sway bar
12.5 k rear, no sway bar
12.5 k rear, no sway bar
| Car vs. Driver | 02-07-2006 11:47 AM |
Ok .. so what advantage does no rear bar and a higher rear rate give you? Do you have to go faster or slower into a turn to get better response and rotation?
| SloRice | 02-07-2006 12:00 PM |
The reason people put big bars on the rear is because it raises the effective spring rate of the rear end, which helps get rid of the understeer. So by running no rear bar and higher spring rates in the rear, you are doing the same thing, but allowing the independent rear suspension to move independently and giving that inside tire the ability to stay on the ground instead of 3-wheel motioning like the suby's do.
[disclaimer]That's how I understand it....but may not be correct[/disclaimer]
I will be running a 10k front / 12k rear setup with the Strano FSB and no RSB this season.
[disclaimer]That's how I understand it....but may not be correct[/disclaimer]
I will be running a 10k front / 12k rear setup with the Strano FSB and no RSB this season.
| Car vs. Driver | 02-07-2006 12:02 PM |
Interesting ... I may have to play around with this a bit.
| mccanixx | 02-07-2006 12:03 PM |
Currently ~750lbs 650lbs 20mm rear sway, and I don't dog leg. It's still streetable, marginally.
| thrdeye | 02-07-2006 12:05 PM |
I ran no rear bar for a while. What your are trying to prevent as much as possible, is dog-legging around tight turns. If you dog leg, the rear LSD no worky and you don't go very fast out of the corner. Once the car flattens out and all four are on teh ground it "hooks up" and you take off. If you use a higher spring rate, you make the suspension more independent, just like slorice said. This gets all four wheels on the ground. I currently run a stock rear sway with 10 k springs (550 lb). The rear springs, IMHO, could stand to be just a little stiffer, but I don't dog leg out of turns.
| jcroy66 | 02-07-2006 01:15 PM |
When we experimented with no rear bar, the car turned in RIGHT NOW. And then it proceeded to push badly the whole rest of the way through the corner. At first I thought it was just me, that I was just overdriving the corner. But upon discussion with others, it seemed to be fairly universal.
| Car vs. Driver | 02-07-2006 01:16 PM |
What was the setup you ran other than not having a rear bar?
| jcroy66 | 02-07-2006 01:38 PM |
At the time, our suspension setup included JIC FLT A2-RSs with 8K/10K spring rates, Hotchkis FSB, Noltec front sway bar endlinks, 245/40-17 Kumho MXs. I think alignment was front camber -3.5, rear camber -0.6, total front toe 1/8", total rear toe 1/8".
I think it's possible that someone could make a no-RSB setup work for a WRX, but I'm not convinced it would be the best use of one's time/money/effort. Since Tom just edumacated me about the mechanical LSD that an STi has, maybe it would be worth it for an STU STi. I hadn't realized that an STi's rear diff sent no power to the wheel with traction if the other wheel had 0.000000 traction (it seems like a silly idea to me personally). So for a BSP or SM STi, I'd look to replace the diff instead.
I think it's possible that someone could make a no-RSB setup work for a WRX, but I'm not convinced it would be the best use of one's time/money/effort. Since Tom just edumacated me about the mechanical LSD that an STi has, maybe it would be worth it for an STU STi. I hadn't realized that an STi's rear diff sent no power to the wheel with traction if the other wheel had 0.000000 traction (it seems like a silly idea to me personally). So for a BSP or SM STi, I'd look to replace the diff instead.
| omahasubaru | 02-07-2006 02:03 PM |
[QUOTE=SloRice]The reason people put big bars on the rear is because it raises the effective spring rate of the rear end, which helps get rid of the understeer. So by running no rear bar and higher spring rates in the rear, you are doing the same thing, but allowing the independent rear suspension to move independently and giving that inside tire the ability to stay on the ground instead of 3-wheel motioning like the suby's do.
[disclaimer]That's how I understand it....but may not be correct[/disclaimer][/QUOTE]
Correct except I want to clarify one point.
Should read:
[i]...people put big bars on the rear is because it raises the effective spring rate on the loaded rear tire...[/i]
It isn't an equal increase except in a straight line, once you corner it transfers the stiffness increase to the loaded tire, which is why IMHO bigger rear bar is a bad choice if you're willing to increase spring rates as you can over load that loaded tire with big bars. Lifting the rear inside tire as mentioned is also a bad side effect.
[disclaimer]That's how I understand it....but may not be correct[/disclaimer][/QUOTE]
Correct except I want to clarify one point.
Should read:
[i]...people put big bars on the rear is because it raises the effective spring rate on the loaded rear tire...[/i]
It isn't an equal increase except in a straight line, once you corner it transfers the stiffness increase to the loaded tire, which is why IMHO bigger rear bar is a bad choice if you're willing to increase spring rates as you can over load that loaded tire with big bars. Lifting the rear inside tire as mentioned is also a bad side effect.
| AUTOwrXER | 02-07-2006 02:32 PM |
[QUOTE=RACER1269]so my buddy has a ss camaro he just got a few parts from Strano. he got bars, springs, and koni shocks. he was telling me that his rear springs are like 180 lbs. i always heard the rule was go soft as you can get away with. the subarus dont seem to go by that rule? also when i added my front whiteline 24mm bar that was the biggest difference yet, but everyone is screaming back bar this and that.
thanks for the input guys.[/QUOTE]
The setup for a Camaro is so different it's really not worth trying to compare the two. The soft rear springs on the Camaro (some ESP cars run as low as 125#) is to put power down exiting corners. This is also why you see solid 35mm sway bars up front on Camaros. They have a solid rear axle, which means that they don't gain or loose any camber on that end (very much unlike a McStrut Subaru). Furthermore, most of the Camaro drivers are copying what the successful drivers in their class have done, which is a soft setup. We copy here too, only the top cars are generally setup much stiffer.
thanks for the input guys.[/QUOTE]
The setup for a Camaro is so different it's really not worth trying to compare the two. The soft rear springs on the Camaro (some ESP cars run as low as 125#) is to put power down exiting corners. This is also why you see solid 35mm sway bars up front on Camaros. They have a solid rear axle, which means that they don't gain or loose any camber on that end (very much unlike a McStrut Subaru). Furthermore, most of the Camaro drivers are copying what the successful drivers in their class have done, which is a soft setup. We copy here too, only the top cars are generally setup much stiffer.
| KevinHeist | 02-07-2006 02:38 PM |
im running close to 400ft-lbs in the front, buot 380 or so in the rear.
| Warp3 | 02-07-2006 03:41 PM |
On my 99RS, I'm currently running 350 lb spring rates on both front and rear (Ground Controls over off-the-shelf Koni yellows) and have a Whiteline 22mm bar in the front and a Whiteline 18-22mm adjustable (set on 22mm) in the rear. I do get a bit of three-wheeling action on occasion, which kinda sucks since I still have the factory open rear diff.
In the future I will likely up the spring rates a bit and get the Konis revalved to match, though (along with a rear LSD, of course...hehe).
Shane -- SM 729 (CCar Region)
In the future I will likely up the spring rates a bit and get the Konis revalved to match, though (along with a rear LSD, of course...hehe).
Shane -- SM 729 (CCar Region)
| Impala SS AutoXer | 02-07-2006 06:18 PM |
[quote]The setup for a Camaro is so different it's really not worth trying to compare the two.[/quote]
Very true. My Impala SS (96) is pretty similar to a Camaro (just, umm, bigger :D ) in regards to rear suspension. I've modified about everything....except the rear springs! Found that every time I tried anything stiffer back there, it simply spun the rear tires if I tried to lay down any power on corner exit. So the stock springs are still in place in back.
On the original topic, I'll mention that some of the local BMWs in SM (see my location to figure out who that would be ;) ) are running in the ballpark of 1000 lb springs :eek: .
Very true. My Impala SS (96) is pretty similar to a Camaro (just, umm, bigger :D ) in regards to rear suspension. I've modified about everything....except the rear springs! Found that every time I tried anything stiffer back there, it simply spun the rear tires if I tried to lay down any power on corner exit. So the stock springs are still in place in back.
On the original topic, I'll mention that some of the local BMWs in SM (see my location to figure out who that would be ;) ) are running in the ballpark of 1000 lb springs :eek: .
| crystalhelix | 02-07-2006 09:40 PM |
600/500, no rear bar last season, pretty sure I had too much camber in the back last year :(
trying the bar out again next year but switching coil-overs (had JIC FLT-A2)
trying the bar out again next year but switching coil-overs (had JIC FLT-A2)
| makofoto | 02-07-2006 10:48 PM |
650/550 with custom valved Tein Flex's, relatively soft Hotchkis bars all around ... but rears set to full stiff. Front Spec C helical Torsen2 LSD.
With 245/40 and 45 S-05's and 710's I ended up two wheeling sometimes.
[IMG]http://images12.fotki.com/v239/photos/4/43793/2687469/MakobyAlbert39_95-vi.jpg[/IMG]
With 245/40 and 45 S-05's and 710's I ended up two wheeling sometimes.
[IMG]http://images12.fotki.com/v239/photos/4/43793/2687469/MakobyAlbert39_95-vi.jpg[/IMG]
| nate49509 | 02-07-2006 10:58 PM |
[QUOTE=thrdeye]Everytime I get frustrated at the stiff springs, I just put the GF in the car for some boob-jigglin action![/QUOTE]
TTIWWOP :lol:
TTIWWOP :lol:
| ChrisW | 02-07-2006 10:59 PM |
[QUOTE=Impala SS AutoXer]Very true. My Impala SS (96) is pretty similar to a Camaro (just, umm, bigger :D ) in regards to rear suspension. I've modified about everything....except the rear springs! Found that every time I tried anything stiffer back there, it simply spun the rear tires if I tried to lay down any power on corner exit. So the stock springs are still in place in back.
On the original topic, I'll mention that some of the local BMWs in SM (see my location to figure out who that would be ;) ) are running in the ballpark of 1000 lb springs :eek: .[/QUOTE]
Ed, a certain EVO is also running 1000+ spring rates as well. I currently run a 500F 600R, but that will change when the ohins get revalved.
On the original topic, I'll mention that some of the local BMWs in SM (see my location to figure out who that would be ;) ) are running in the ballpark of 1000 lb springs :eek: .[/QUOTE]
Ed, a certain EVO is also running 1000+ spring rates as well. I currently run a 500F 600R, but that will change when the ohins get revalved.
| Patrick Olsen | 02-07-2006 11:25 PM |
[QUOTE=RACER1269]well i was asking because i just got a set of JIC coilovers with 7Kf/5Kr springs. and i didnt think that was a bad place to start but alot of the locals did. i have whiteline bars 24f/26r, GC caster/camber plates, and some Goodyear GC-SC dot slicks (like the Kumo V710s)[/QUOTE]
I think you might want less stagger between the front and rear spring rates to help the car rotate, but that's a driver feel kind of thing.
And, somewhat off the subject, but related to what you posted... the GSCS is not at all like the V710. It's a DOT "slick", yes, but it's a road race tire, not an auto-x tire. I've never run them personally, but a friend of mine ran them on his SCCA ITE Mustang for road racing - when he auto-x'd it, he put Victoracers on it. You'll never get enough heat in the GSCS's at an auto-x to make them grip.
As for spring rates, I'm on the pretty soft side at 315#f/280#r with off-the-shelf Koni inserts. For my daily driver I can't see going much firmer than these on some of the crappy roads I have to drive every day.
Pat Olsen
'97 Legacy 2.5GT sedan
I think you might want less stagger between the front and rear spring rates to help the car rotate, but that's a driver feel kind of thing.
And, somewhat off the subject, but related to what you posted... the GSCS is not at all like the V710. It's a DOT "slick", yes, but it's a road race tire, not an auto-x tire. I've never run them personally, but a friend of mine ran them on his SCCA ITE Mustang for road racing - when he auto-x'd it, he put Victoracers on it. You'll never get enough heat in the GSCS's at an auto-x to make them grip.
As for spring rates, I'm on the pretty soft side at 315#f/280#r with off-the-shelf Koni inserts. For my daily driver I can't see going much firmer than these on some of the crappy roads I have to drive every day.
Pat Olsen
'97 Legacy 2.5GT sedan
| PhilC | 02-08-2006 08:55 AM |
[QUOTE=Impala SS AutoXer]On the original topic, I'll mention that some of the local BMWs in SM (see my location to figure out who that would be ;) ) are running in the ballpark of 1000 lb springs :eek: .[/QUOTE]
But with the E36 suspension the rear would have a wheel rate of about half that because of the motion ratio you get when the rear springs are that far inboard. 1000 lb springs on the rear of a BMW not== the same thing as 1000 lb springs on a strut suspension.
But with the E36 suspension the rear would have a wheel rate of about half that because of the motion ratio you get when the rear springs are that far inboard. 1000 lb springs on the rear of a BMW not== the same thing as 1000 lb springs on a strut suspension.
| omahasubaru | 02-08-2006 09:53 AM |
Have run:
500f/600r no bars (STS 2.5 RS)
Will be trying 400f/500r stock front bar only (STS 2.5 RS)
Planning to run 350f/300r stock front bar only on my own car (SM) for decent handling and some comfort. That's only because it's the rates I have to work with and my car will only see a few events this year.
In my opinion I have found that a 20% stiffer than front rear rate works best. I'm no longer sold on no swaybars like I was in 2005, I think some (but not a lot) of a front bar is needed, assuming you have decent spring rates and can get lots of camber/caster.
Just tossing my $0.02 into the mix.
500f/600r no bars (STS 2.5 RS)
Will be trying 400f/500r stock front bar only (STS 2.5 RS)
Planning to run 350f/300r stock front bar only on my own car (SM) for decent handling and some comfort. That's only because it's the rates I have to work with and my car will only see a few events this year.
In my opinion I have found that a 20% stiffer than front rear rate works best. I'm no longer sold on no swaybars like I was in 2005, I think some (but not a lot) of a front bar is needed, assuming you have decent spring rates and can get lots of camber/caster.
Just tossing my $0.02 into the mix.
| DMS North America | 02-09-2006 10:23 AM |
Just a note, you can not compare a DMS progressive 180lb spring to an ERS type spring (linear) not the same rating system :)
Progressive numbers from DMS are lower than what a linear would be.
-mark
Progressive numbers from DMS are lower than what a linear would be.
-mark
| Jaxx | 02-09-2006 11:58 AM |
7k/8k tien HA 8 front 8-10 rear depending on grip/track temp
22 front -20-22-24 rear set to 20 as at 22 it was lifting the inside wheel (lame w/o a lsd)
22 front -20-22-24 rear set to 20 as at 22 it was lifting the inside wheel (lame w/o a lsd)
| sstrano | 02-09-2006 07:20 PM |
Someday I'm going to just tattoo a conversion factor for metric springs in my hand. Much as I hate to say it, I wish you all would just speak english, literally when it comes to rates. :)
First, lets recognize there is going to be a huge difference between an SP or SM car vs. a STS, STX, STU car. Has to be. The tires are completely different. And it kills me when the distinction is ignored.
And for the record, I run 600/150 on my Camaro (was 500/150 when I won ESP in 2004). There are 4th gen Camaro's with 1200+./300+ springs in them too (and more than one, so it's not like everyone just copies. But many do, and my "soft" setups seem to work pretty well. But as Joel mentioned it's not quite the same car!
I think many ST cars are too stiff. I think some SP cars are too soft, and there are a few that are WAY too stiff IMHO. You aren't going to generate the roll in an ST car because you don't have R-tire grip. Right away you should know you don't need to be as stiff. On the other hand, I find that folks tend to run very stiff setups to cover for poor shock damping, or a general lack of being on the ball. Stiffer cars change direction faster, a help when you go "oops, I need to be there!!!".
I like the 500-600 area for cars on R-comps with a lot of front roll stiffness. And in the rear, similar spring rates and I'll run no bar to a 25mm bar. That depends on if you have crappy rear shocks that have no droop travel. :)
Jen: your car doesn't make a tremendous amount of front grip. Where a car on R tires will yank a rear tire up with those shocks and no bar, yours won't. So you need a bar. I'd have told you that would not have worked well on your car, especially with the alignment that way.
First, lets recognize there is going to be a huge difference between an SP or SM car vs. a STS, STX, STU car. Has to be. The tires are completely different. And it kills me when the distinction is ignored.
And for the record, I run 600/150 on my Camaro (was 500/150 when I won ESP in 2004). There are 4th gen Camaro's with 1200+./300+ springs in them too (and more than one, so it's not like everyone just copies. But many do, and my "soft" setups seem to work pretty well. But as Joel mentioned it's not quite the same car!
I think many ST cars are too stiff. I think some SP cars are too soft, and there are a few that are WAY too stiff IMHO. You aren't going to generate the roll in an ST car because you don't have R-tire grip. Right away you should know you don't need to be as stiff. On the other hand, I find that folks tend to run very stiff setups to cover for poor shock damping, or a general lack of being on the ball. Stiffer cars change direction faster, a help when you go "oops, I need to be there!!!".
I like the 500-600 area for cars on R-comps with a lot of front roll stiffness. And in the rear, similar spring rates and I'll run no bar to a 25mm bar. That depends on if you have crappy rear shocks that have no droop travel. :)
Jen: your car doesn't make a tremendous amount of front grip. Where a car on R tires will yank a rear tire up with those shocks and no bar, yours won't. So you need a bar. I'd have told you that would not have worked well on your car, especially with the alignment that way.
| sstrano | 02-09-2006 07:21 PM |
[QUOTE=Jaxx]7k/8k tien HA 8 front 8-10 rear depending on grip/track temp
22 front -20-22-24 rear set to 20 as at 22 it was lifting the inside wheel (lame w/o a lsd)[/QUOTE]
And one of the 2 prime reasons for the mongo front bars!!!!
22 front -20-22-24 rear set to 20 as at 22 it was lifting the inside wheel (lame w/o a lsd)[/QUOTE]
And one of the 2 prime reasons for the mongo front bars!!!!
| DrBiggly | 02-09-2006 07:46 PM |
Sam,
Conversion factor is about 56#s per 1k. Or if you generalize it like I do, it's about 50#s per 1k to make round numbers. Only after 8-10k to I add another 50#s to my conversion factor to keep it closer.
8k == about 450#s and just round up/down from there. Since most folks go in 2k increments, just add/subtract 100#s accordingly. :)
-Biggly
Conversion factor is about 56#s per 1k. Or if you generalize it like I do, it's about 50#s per 1k to make round numbers. Only after 8-10k to I add another 50#s to my conversion factor to keep it closer.
8k == about 450#s and just round up/down from there. Since most folks go in 2k increments, just add/subtract 100#s accordingly. :)
-Biggly
| omahasubaru | 02-10-2006 08:57 AM |
kg/mm conversion table
[img]http://www.nebraska-subaru.com/interactive/albums/albun70/kgmm_lbin_conversion.png[/img]
I don't have a nice table like this for converting nm/mm to lb/in though. :( May put one together eventually.
I'm with you on speaking english for rates Sam. Of course I now stear away from any of the Japanese coilovers as having run a nicely built setup with Koni's 8611's (zzyzx motorsports) I can't even think about going to back to that other stuff. It's just 'wrong'. :p
[img]http://www.nebraska-subaru.com/interactive/albums/albun70/kgmm_lbin_conversion.png[/img]
I don't have a nice table like this for converting nm/mm to lb/in though. :( May put one together eventually.
I'm with you on speaking english for rates Sam. Of course I now stear away from any of the Japanese coilovers as having run a nicely built setup with Koni's 8611's (zzyzx motorsports) I can't even think about going to back to that other stuff. It's just 'wrong'. :p
| skuttledude | 02-10-2006 10:37 AM |
omahasubaru...you are my new friend..I've been looking everywhere for a proper conversion chart. Many Thanks!
| solo-x | 02-10-2006 11:44 AM |
sam, what many of us are finding on the ST cars is that while the tires don't generate as much grip as the r-comps, we ARE getting more roll from the tire sidewall being so soft and deflecting. chassis roll relative to suspension position is lower on an ST car, but chassis roll relative to ground plain is the same or higher as an SP/SM car. also, the tire spring rate and damping rate is lower on the ST tires, effectively reducing the overall spring rate of the car. (springs in series) ultimately, imo the spring rate and overall roll stiffness for an ST car should be pretty close to that of an SP/SM car. even on the bumpy old topeka surface. the one area that MUST be softer though is bump damping on the shock. the ST tires aren't as forgiving of load spikes as r-comps are.
nate
nate
| ratt_finkel | 02-10-2006 12:04 PM |
[QUOTE=solo-x]sam, what many of us are finding on the ST cars is that while the tires don't generate as much grip as the r-comps, we ARE getting more roll from the tire sidewall being so soft and deflecting. chassis roll relative to suspension position is lower on an ST car, but chassis roll relative to ground plain is the same or higher as an SP/SM car. also, the tire spring rate and damping rate is lower on the ST tires, effectively reducing the overall spring rate of the car. (springs in series) ultimately, imo the spring rate and overall roll stiffness for an ST car should be pretty close to that of an SP/SM car. even on the bumpy old topeka surface. the one area that MUST be softer though is bump damping on the shock. the ST tires aren't as forgiving of load spikes as r-comps are.
nate[/QUOTE]
Nate,
So you think the majority of ST cars will benefit from decreased compression relative to rebound dampening? What about on the new smooth surface at HRP? Wouldn't additional spring rate be beneficial to additional grip? Obviously, you don't wan't to just slap on 1000lb springs on every car. But the new surface should allow for higher spring rates no?
nate[/QUOTE]
Nate,
So you think the majority of ST cars will benefit from decreased compression relative to rebound dampening? What about on the new smooth surface at HRP? Wouldn't additional spring rate be beneficial to additional grip? Obviously, you don't wan't to just slap on 1000lb springs on every car. But the new surface should allow for higher spring rates no?
| solo-x | 02-10-2006 03:44 PM |
[QUOTE=ratt_finkel]Nate,
So you think the majority of ST cars will benefit from decreased compression relative to rebound dampening? What about on the new smooth surface at HRP? Wouldn't additional spring rate be beneficial to additional grip? Obviously, you don't wan't to just slap on 1000lb springs on every car. But the new surface should allow for higher spring rates no?[/QUOTE]
only compared to their SP/SM counterparts. ie, an STU STi would run roughly the same bar and spring rates as a BSP STi would except the bump damping on the STU car would be less aggressive.
the new surface at HPT will likely allow a touch more spring and bump damping for everyone. i'd expect the difference between SP/SM cars and ST cars to be the same though.
additional spring rate is only beneficial to grip if the added spring lets you run a lower ride height or if the car was too soft to begin with. otherwise it could hurt things just as much as it can help. one thing to keep in mind about increasing springs rates and overall roll stiffness is that as suspension stiffness increases the tires tend to heat up quicker. that might be another factor with nationals moving later in the year with possibly cooler air temps. of course, the chance of rain increases a little as well, so it all might just be a wash, no pun intended.
nate
So you think the majority of ST cars will benefit from decreased compression relative to rebound dampening? What about on the new smooth surface at HRP? Wouldn't additional spring rate be beneficial to additional grip? Obviously, you don't wan't to just slap on 1000lb springs on every car. But the new surface should allow for higher spring rates no?[/QUOTE]
only compared to their SP/SM counterparts. ie, an STU STi would run roughly the same bar and spring rates as a BSP STi would except the bump damping on the STU car would be less aggressive.
the new surface at HPT will likely allow a touch more spring and bump damping for everyone. i'd expect the difference between SP/SM cars and ST cars to be the same though.
additional spring rate is only beneficial to grip if the added spring lets you run a lower ride height or if the car was too soft to begin with. otherwise it could hurt things just as much as it can help. one thing to keep in mind about increasing springs rates and overall roll stiffness is that as suspension stiffness increases the tires tend to heat up quicker. that might be another factor with nationals moving later in the year with possibly cooler air temps. of course, the chance of rain increases a little as well, so it all might just be a wash, no pun intended.
nate
| ratt_finkel | 02-10-2006 04:06 PM |
[QUOTE=solo-x]only compared to their SP/SM counterparts. ie, an STU STi would run roughly the same bar and spring rates as a BSP STi would except the bump damping on the STU car would be less aggressive.
the new surface at HPT will likely allow a touch more spring and bump damping for everyone. i'd expect the difference between SP/SM cars and ST cars to be the same though.
additional spring rate is only beneficial to grip if the added spring lets you run a lower ride height or if the car was too soft to begin with. otherwise it could hurt things just as much as it can help. one thing to keep in mind about increasing springs rates and overall roll stiffness is that as suspension stiffness increases the tires tend to heat up quicker. that might be another factor with nationals moving later in the year with possibly cooler air temps. of course, the chance of rain increases a little as well, so it all might just be a wash, no pun intended.
nate[/QUOTE]
In addition to the new surface being smooter. We all know it's also going to be significantly slicker as well.
So with that in mind, and with your theory. Won't softer suspended cars have a better advantage? I know at our local sealed asphault lot I can run lower pressures and shock settings.
the new surface at HPT will likely allow a touch more spring and bump damping for everyone. i'd expect the difference between SP/SM cars and ST cars to be the same though.
additional spring rate is only beneficial to grip if the added spring lets you run a lower ride height or if the car was too soft to begin with. otherwise it could hurt things just as much as it can help. one thing to keep in mind about increasing springs rates and overall roll stiffness is that as suspension stiffness increases the tires tend to heat up quicker. that might be another factor with nationals moving later in the year with possibly cooler air temps. of course, the chance of rain increases a little as well, so it all might just be a wash, no pun intended.
nate[/QUOTE]
In addition to the new surface being smooter. We all know it's also going to be significantly slicker as well.
So with that in mind, and with your theory. Won't softer suspended cars have a better advantage? I know at our local sealed asphault lot I can run lower pressures and shock settings.
| solo-x | 02-10-2006 04:19 PM |
depends on if you think a car has more mechanical grip with softer springs or not. i don't. of course, this is a seperate issue from tire pressure and shock settings.
tire pressure changes don't just change the spring rate of the tire but also the slip angle it likes to operate at and how tolerant of sidewall roll over the tire is. it's also dependant on tire construction. hoosier says to increase tire pressure to increase grip, the v710's work the other way.
shocks are more complicated. they are driven by driver preference as much as any other concern. your stock class car is a bit of a different animal too.
nate - doesn't think the new surface will be all that slick....
tire pressure changes don't just change the spring rate of the tire but also the slip angle it likes to operate at and how tolerant of sidewall roll over the tire is. it's also dependant on tire construction. hoosier says to increase tire pressure to increase grip, the v710's work the other way.
shocks are more complicated. they are driven by driver preference as much as any other concern. your stock class car is a bit of a different animal too.
nate - doesn't think the new surface will be all that slick....
| ratt_finkel | 02-10-2006 04:37 PM |
[QUOTE=solo-x]depends on if you think a car has more mechanical grip with softer springs or not. i don't. of course, this is a seperate issue from tire pressure and shock settings.
[/quote]
Assuming roll is in control and everything is else up to par, why do you think so?
[QUOTE=solo-x]
tire pressure changes don't just change the spring rate of the tire but also the slip angle it likes to operate at and how tolerant of sidewall roll over the tire is. it's also dependant on tire construction. hoosier says to increase tire pressure to increase grip, the v710's work the other way. [/quote] Right, I'm aware of that.
[QUOTE=solo-x]
shocks are more complicated. they are driven by driver preference as much as any other concern. your stock class car is a bit of a different animal too.
nate - doesn't think the new surface will be all that slick....[/QUOTE]
Not talking about my car, moreso the Evo since that's what I'll be campaigning this season.
More expierenced folk tell me not to expect much from the new site in terms of grip.
[/quote]
Assuming roll is in control and everything is else up to par, why do you think so?
[QUOTE=solo-x]
tire pressure changes don't just change the spring rate of the tire but also the slip angle it likes to operate at and how tolerant of sidewall roll over the tire is. it's also dependant on tire construction. hoosier says to increase tire pressure to increase grip, the v710's work the other way. [/quote] Right, I'm aware of that.
[QUOTE=solo-x]
shocks are more complicated. they are driven by driver preference as much as any other concern. your stock class car is a bit of a different animal too.
nate - doesn't think the new surface will be all that slick....[/QUOTE]
Not talking about my car, moreso the Evo since that's what I'll be campaigning this season.
More expierenced folk tell me not to expect much from the new site in terms of grip.
| DrBiggly | 02-10-2006 07:35 PM |
Nate,
Nationals has been a "wash" for quite a while hasn't it? It hasn't failed to rain and screw things up for at least a class or two for the past few years to my knowledge. 2004 was dry for both days of STX I know; not sure if it was dry for all of the days or not.
I say make it a wet event for all of the days; the rain won't matter then. :)
-Biggly
Nationals has been a "wash" for quite a while hasn't it? It hasn't failed to rain and screw things up for at least a class or two for the past few years to my knowledge. 2004 was dry for both days of STX I know; not sure if it was dry for all of the days or not.
I say make it a wet event for all of the days; the rain won't matter then. :)
-Biggly
| AUTOwrXER | 02-10-2006 11:00 PM |
STX had wet conditions in 2004. Cormier made up a little time on Tom in the wet, but not enough ;)
| DrBiggly | 02-11-2006 12:16 AM |
I know STX was wet in 2003, and in 2005. Basically it's wet every year. Why don't they just go ahead and wet down things all of the time? Saves folks from worrying about tires; drive in the wet and you know what you need to bring.
Not to mention it isn't the SCCA TireRack "Who-Got-The-Driest-Run" Championships at that point. :)
-Biggly says bring on the rain
Not to mention it isn't the SCCA TireRack "Who-Got-The-Driest-Run" Championships at that point. :)
-Biggly says bring on the rain
| flyboymike | 02-11-2006 12:25 AM |
[QUOTE=DrBiggly]I know STX was wet in 2003, and in 2005. Basically it's wet every year. Why don't they just go ahead and wet down things all of the time? Saves folks from worrying about tires; drive in the wet and you know what you need to bring.
Not to mention it isn't the SCCA TireRack "Who-Got-The-Driest-Run" Championships at that point. :)
-Biggly says bring on the rain[/QUOTE]
I want to know
Have you ever seen the rain
Coming down on an autocross?
</CCR>
Not to mention it isn't the SCCA TireRack "Who-Got-The-Driest-Run" Championships at that point. :)
-Biggly says bring on the rain[/QUOTE]
I want to know
Have you ever seen the rain
Coming down on an autocross?
</CCR>
| sstrano | 02-13-2006 06:28 PM |
[QUOTE=solo-x]sam, what many of us are finding on the ST cars is that while the tires don't generate as much grip as the r-comps, we ARE getting more roll from the tire sidewall being so soft and deflecting. chassis roll relative to suspension position is lower on an ST car, but chassis roll relative to ground plain is the same or higher as an SP/SM car.
[/QUOTE]
All true. However a spring and/or bar change does not change the amount of deflection in the tire, and that has nothing to do with the camber curve of the suspension.
And I'm not buying the chassis roll relative to the ground is higher. A look at pics of R-comp tires shows the huge amount of deflection we get, which is as much if not more than street tires.
[/QUOTE]
All true. However a spring and/or bar change does not change the amount of deflection in the tire, and that has nothing to do with the camber curve of the suspension.
And I'm not buying the chassis roll relative to the ground is higher. A look at pics of R-comp tires shows the huge amount of deflection we get, which is as much if not more than street tires.
| RACER1269 | 02-14-2006 08:57 AM |
well im atleast heading in the right direction it seems. went out sunday and had a few runs. my mods as of now are (new parts JIC FLT A2 coilovers, GC caster camber plates, slighty used set of goodyear dot slicks. and some brake pads, and a alignment) along with already having Whiteline front 26mm and rear 24mm? bars. i have utec, catless and few other engine mods.
we had a helicopter on the training pad so that caused for quiet mess sunday so i only got one timed run, and one with a stop watch ( something about a timing wire broke). my first and only timed run was a 59.853 there was a AS STI that used to be faster than me and he only ran a 62.975 and a friend in my class that i used to be 2 seconds ahead, im now 5-6 seconds ahead. i really didnt get into it that first run either since everyone was spinning out like crazy, it was a cautious run. and the tire temps were 74*outside 85*middle and 91* inside. i put some +camber back in and adjusted the tire psi ran that second time and things got more even. it was like 50* sunday too so yeah it seems its going to be hard to get enough heat in these tires.
car felt awesome though. feels like it should have came from the factory like this, it actually turns now. wooot :banana:
we had a helicopter on the training pad so that caused for quiet mess sunday so i only got one timed run, and one with a stop watch ( something about a timing wire broke). my first and only timed run was a 59.853 there was a AS STI that used to be faster than me and he only ran a 62.975 and a friend in my class that i used to be 2 seconds ahead, im now 5-6 seconds ahead. i really didnt get into it that first run either since everyone was spinning out like crazy, it was a cautious run. and the tire temps were 74*outside 85*middle and 91* inside. i put some +camber back in and adjusted the tire psi ran that second time and things got more even. it was like 50* sunday too so yeah it seems its going to be hard to get enough heat in these tires.
car felt awesome though. feels like it should have came from the factory like this, it actually turns now. wooot :banana:
| DrBiggly | 02-14-2006 10:19 AM |
Question: When you added camber, how did the car feel after that? I actually think that your first tire temps were correct given what I've learned recently. :)
-Biggly
-Biggly
| RACER1269 | 02-14-2006 10:30 AM |
well i admit i hit it a bit harder the second lap, but it did slide around alot more. i liked the way it felt the first lap, i just didnt want to heat up the inside like that. but if that is normal then i can put it back. i dont have a camber gauge so i just kinda eyeballed it. i did mark it so when my guy finishes up the alignment this week i will see what the - camber was at.
so its normal to have the heat higher on the inside with the proper set up?
so its normal to have the heat higher on the inside with the proper set up?
| DrBiggly | 02-14-2006 11:15 AM |
Yes. The reason that the inside is hotter is that when the tire is unloaded in a corner, it's going to basically be dragging along only on that inside edge and that is when it gets hotter. Go with what gets you more grip; perfect tire temps across the board are not the indicator of maximized grip; just maximized wear. If you wanted good wear for autox, you'd do it on 500 treadwear all-seasons. :)
-Biggly
-Biggly
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