| ChaosThom | 08-14-2001 03:13 PM |
Help: tire lift in Autocross!
My rear inside tire is lifting off the ground in hard turns just like a front wheel drive car (e.g., Jetta). I haven't seen this happening to any other RSs. My setup is simple: front strut tower brace, Whiteline end links front and rear, Whiteline 20-22-24mm rear bar set at 20mm, Yokohama A520 225/45 16, stock springs and struts.
I'm thinking that the front rebound is too soft assuming that most of the power is being transferred to the rear of the car so it's acting like a rear wheel drive car.
Any ideas on what the cause is and how to fix it?
:confused:
I'm thinking that the front rebound is too soft assuming that most of the power is being transferred to the rear of the car so it's acting like a rear wheel drive car.
Any ideas on what the cause is and how to fix it?
:confused:
| -=DriftxKing=- | 08-14-2001 03:37 PM |
Get a KAAZ rear diff and set it to full locking. Then you wont have to worry about wheelspin :D
| Travis R | 08-14-2001 03:45 PM |
If your inside rear tire is lifting in a corner then you either need to decrease the rear roll stiffness (smaller sway bar) or increase the front roll stiffness (stiffer springs or sway bar). This has nothing to do with shock settings. The reason you haven't seen it happen to other RS's is because they are probably running the stock rear sway bar.
| Streetman | 08-14-2001 04:01 PM |
I'm fairly certain you need to upgrade your springs/struts. The 20mm swaybar wasn't made for the stock suspension. You've got a good start on your setup. You just need to finish it.
| AWMIII | 08-14-2001 05:07 PM |
My wrx lifted wheels on its stock suspension autoxing several times. I had that problem fixed.
| Tony | 08-14-2001 05:20 PM |
It's not a problem. My car does it too and it's got a very stiff setup. Lifting the inside rear means you get more grip on the outside front, which is a goog thing. Same reason Porsches lift their inside front, traction in a turn where you need it.
Tony
Tony
| ColinL | 08-14-2001 05:29 PM |
911s lift their inside front because the engine is hanging over the rear axle, AND they have a front bar too hard or rear bar too soft.
In How To Make Your Car Handle, Fred Puhn actually uses a 911 lifting a front inside tire as an example of a car that *doesn't* have the front / rear roll stiffness sorted properly.
In How To Make Your Car Handle, Fred Puhn actually uses a 911 lifting a front inside tire as an example of a car that *doesn't* have the front / rear roll stiffness sorted properly.
| Tony | 08-14-2001 06:11 PM |
I agree the engine over the rear axle is contributing with the 911 but a FWD car has some of the same issues with the engine so close to the front axle.
My point was that if the FWD car wasn't lifting it's inside rear it'd probably be in chronic understeer (well, more chronic understeer than usual) and if the 911 wasn't lifting it's inside front it'd lose traction in the rear while trying to accelerate. And since our cars are more like FWD than RWD the I don't see it as a problem that needs fixing unless it's like VW kind of lifting (1+ ft) then there's a problem.
Tony
My point was that if the FWD car wasn't lifting it's inside rear it'd probably be in chronic understeer (well, more chronic understeer than usual) and if the 911 wasn't lifting it's inside front it'd lose traction in the rear while trying to accelerate. And since our cars are more like FWD than RWD the I don't see it as a problem that needs fixing unless it's like VW kind of lifting (1+ ft) then there's a problem.
Tony
| Templar | 08-14-2001 07:48 PM |
Hey Thom,
It was said earlier, but there are two frames of thought on this. When you lift the inside wheel on either end of the car you need to either increase stiffness on the other end, or decrease that stiffness. However, it is an interesting problem seeing as how I have watched several RSs autocross with your same settup and never seen a wheel lift. I ran like that for some time and never lifted.
It is feasable that your adjustable rear bar is a little bit off in its manufacture and is actually giving you a bit stiffer setting than it indicates, but they would have had to drill the holes in the wrong locations for that to happen.
My suggestion is to tighten the front up, but you would be better off by doing it with struts than with an anti roll bar. You are always better off by controlling body roll with your suspension than with roll bars. Most true race cars either don't have anti roll bars, or have very small ones. I have been talking with some of the local "super autocrossers" who have been racing for twenty or more years. These are guys who race in SOLO 1 along as doing some professional road racing. They actually think that with the right suspension and correct settings, I should be able to ditch my front sway bar entirely. But that is another long and boring story.
Kent
It was said earlier, but there are two frames of thought on this. When you lift the inside wheel on either end of the car you need to either increase stiffness on the other end, or decrease that stiffness. However, it is an interesting problem seeing as how I have watched several RSs autocross with your same settup and never seen a wheel lift. I ran like that for some time and never lifted.
It is feasable that your adjustable rear bar is a little bit off in its manufacture and is actually giving you a bit stiffer setting than it indicates, but they would have had to drill the holes in the wrong locations for that to happen.
My suggestion is to tighten the front up, but you would be better off by doing it with struts than with an anti roll bar. You are always better off by controlling body roll with your suspension than with roll bars. Most true race cars either don't have anti roll bars, or have very small ones. I have been talking with some of the local "super autocrossers" who have been racing for twenty or more years. These are guys who race in SOLO 1 along as doing some professional road racing. They actually think that with the right suspension and correct settings, I should be able to ditch my front sway bar entirely. But that is another long and boring story.
Kent
| Lurker | 08-14-2001 08:01 PM |
Did [B]I[/B] do that?
[IMG]http://www.photoreflect.com/scripts/prpv.dll?Photo?s=0&i=00H20073000055&p=[/IMG]
I hope that shows up...
[IMG]http://www.photoreflect.com/scripts/prpv.dll?Photo?s=0&i=00H20073000055&p=[/IMG]
I hope that shows up...
| ChaosThom | 08-15-2001 08:14 AM |
Thanks for the help. Looks like I'm going to need to get a spring and strut combination that works with my driving style. I'm thinking Whiteline low (20mm drop) with KYB AGX. That will let me adjust the ends enough to get good balance. Struts with rebound and compression adjustments would be better. Know of any at a not too expensive price?
In the short term (budget restraints), I could take Whiteline's recommendation and get a 22mm adjustable front bar. At the speeds we autocross, the loss to the independent suspension characteristics may be minimal.
Meanwhile, I discovered that my 2 front transmission mount bolts are stripped. Hunter Subaru probably did it when they had my transmission out twice. I'm going to try to get it fixed Friday so I can make the CCR event at CMP this weekend.
In the short term (budget restraints), I could take Whiteline's recommendation and get a 22mm adjustable front bar. At the speeds we autocross, the loss to the independent suspension characteristics may be minimal.
Meanwhile, I discovered that my 2 front transmission mount bolts are stripped. Hunter Subaru probably did it when they had my transmission out twice. I'm going to try to get it fixed Friday so I can make the CCR event at CMP this weekend.
| Travis R | 08-15-2001 09:55 AM |
A car cornering on three wheels does not have the same cornering force as a car cornering on four wheels. Unfortunately I think the RS is going to need pretty stiff springs to over come this (assuming race tire grip), and that makes for a pretty uncomfortable street car (IMO).
As far as adjustable shocks, KYB are the cheapest. Compression and rebound are adjustable, but not separately, one knob changes both. I think DMS makes a set of coil overs that are true double adjustable, but they aren't cheap. If you were really serious, you could send Koni a stock strut (as a template) and have them make you a set of quad adjustable shocks ($$$$). They have independant adjustments for high and low speed compression and rebound. But like I said before the shocks won't really change the tire lifting situation. You have to do that with springs.
Good luck
As far as adjustable shocks, KYB are the cheapest. Compression and rebound are adjustable, but not separately, one knob changes both. I think DMS makes a set of coil overs that are true double adjustable, but they aren't cheap. If you were really serious, you could send Koni a stock strut (as a template) and have them make you a set of quad adjustable shocks ($$$$). They have independant adjustments for high and low speed compression and rebound. But like I said before the shocks won't really change the tire lifting situation. You have to do that with springs.
Good luck
| ColinL | 08-15-2001 10:46 AM |
I have 7kg/mm springs up front (~392lb/in) and 6kg in the rear (~335lb/in) and you're right Travis, it is not very comfortable.
The folks exasperated with DMS Gold bouncing in the Suspension forum wouldn't be able to tolerate my setup, that's for sure. Bouncing on the highway? Oh heck yeah. Jarring on a bumpy road? You bet. Awesome at speed? Uh huh. Eliminated body roll? Nope, sorry.
Have a look: (all images NOT owned by me, source page is [url=http://www.midivsolo.org/EventPictures/event-3-2001-pictureindex.htm]here[/url], and WARNING they are all 2048x1500 and 500-650kb)
Gary(gg)-- 98RS, stock springs, KYB AGX struts, stock rear bar, Michelin Pilot SX MXX3 tires. (lightly prepped for STS)
[url=http://www.midivsolo.org/EventPictures/event_3_2001_images/P1010757.JPG]click me[/url]
ColinL-- 99RS, Tein HAs with aforementioned springs, whiteline 20mm adj rear bar, camberplates, Kumho victoracer V700s. (honestly, lightly prepped for SM)
[url=http://www.midivsolo.org/EventPictures/event_3_2001_images/P1010758.JPG]click me[/url]
Remember that I have stickier tires, and Gary's a better driver. :D
Oh, and it's not the same corner but here's a WRX sedan that was running in GS:
[url=http://www.midivsolo.org/EventPictures/event_3_2001_images/P1010732.JPG]click me[/url]
Body roll is evil, mmmmkkay? ;)
The folks exasperated with DMS Gold bouncing in the Suspension forum wouldn't be able to tolerate my setup, that's for sure. Bouncing on the highway? Oh heck yeah. Jarring on a bumpy road? You bet. Awesome at speed? Uh huh. Eliminated body roll? Nope, sorry.
Have a look: (all images NOT owned by me, source page is [url=http://www.midivsolo.org/EventPictures/event-3-2001-pictureindex.htm]here[/url], and WARNING they are all 2048x1500 and 500-650kb)
Gary(gg)-- 98RS, stock springs, KYB AGX struts, stock rear bar, Michelin Pilot SX MXX3 tires. (lightly prepped for STS)
[url=http://www.midivsolo.org/EventPictures/event_3_2001_images/P1010757.JPG]click me[/url]
ColinL-- 99RS, Tein HAs with aforementioned springs, whiteline 20mm adj rear bar, camberplates, Kumho victoracer V700s. (honestly, lightly prepped for SM)
[url=http://www.midivsolo.org/EventPictures/event_3_2001_images/P1010758.JPG]click me[/url]
Remember that I have stickier tires, and Gary's a better driver. :D
Oh, and it's not the same corner but here's a WRX sedan that was running in GS:
[url=http://www.midivsolo.org/EventPictures/event_3_2001_images/P1010732.JPG]click me[/url]
Body roll is evil, mmmmkkay? ;)
| skidplatez | 08-16-2001 11:38 AM |
In a 2000 I don't think it's that big a problem I lift my inside rear a lot on the course and I usually can't even tell I'm doing it. We have the limited slip rear so It's not like your losing a lot of power, and if the rearend is staying put(not oversteering) you don't need anymore traction back there.
my $0.19999999999
I should point out that I haven't had anyone tell me I am lifting my tire since I installed my DMS so maybe I'm not doing it anymore.
my $0.19999999999
I should point out that I haven't had anyone tell me I am lifting my tire since I installed my DMS so maybe I'm not doing it anymore.
| AWMIII | 08-17-2001 09:15 AM |
I used to lift my inside fronts in my old 95 M3 on race rubber. It has the engine in the front.
| pmanliu | 04-04-2016 03:15 PM |
Bringing this back from the dead...
Car is a '15 WRX with RCE (Yellow) lowering springs, and rear 22mm White RSB/Kartboy Endlinks (set to medium stiff).
I was told that my inner rear tire was lifting this past weekend on hard turns and had a couple questions:
1) Is this actually detrimental to the diff? I also tripod entering my parent's driveway (maybe once a week or so). Car is autocrossed maybe 5-6x a year.
2) What can i do to minimize lift? I'm planning on setting the RSB to the softest setting, or ditching it altogether and going back to stock sway + RCE springs only. The car did feel great with the aftermarket springs/RSB as the last time i auto-x'd it was on completely stock suspension.
3) Traction on 3 or 4 wheels - Can't seem to find a consistent answer, but is traction noticeably reduced when cornering hard on 3 wheels? I'm not a professional auto-x'er by any means, but want to continuously improve my driving technique.
Car is a '15 WRX with RCE (Yellow) lowering springs, and rear 22mm White RSB/Kartboy Endlinks (set to medium stiff).
I was told that my inner rear tire was lifting this past weekend on hard turns and had a couple questions:
1) Is this actually detrimental to the diff? I also tripod entering my parent's driveway (maybe once a week or so). Car is autocrossed maybe 5-6x a year.
2) What can i do to minimize lift? I'm planning on setting the RSB to the softest setting, or ditching it altogether and going back to stock sway + RCE springs only. The car did feel great with the aftermarket springs/RSB as the last time i auto-x'd it was on completely stock suspension.
3) Traction on 3 or 4 wheels - Can't seem to find a consistent answer, but is traction noticeably reduced when cornering hard on 3 wheels? I'm not a professional auto-x'er by any means, but want to continuously improve my driving technique.
| subydude | 04-04-2016 03:45 PM |
Until you start getting some hopping coming out of corners it's not slowing you down. That tire has maybe 5% of the total car's grip when you're loaded up so 3 wheels on the ground vs 4 at that point is a non issue.
When you get to the hopping, read the STU thread in the autox section and try to follow the setup there.
When you get to the hopping, read the STU thread in the autox section and try to follow the setup there.
| pmanliu | 04-04-2016 05:16 PM |
[quote=subydude;44305943]Until you start getting some hopping coming out of corners it's not slowing you down. That tire has maybe 5% of the total car's grip when you're loaded up so 3 wheels on the ground vs 4 at that point is a non issue.
When you get to the hopping, read the STU thread in the autox section and try to follow the setup there.[/quote]
Thanks subydude! Don't think the car is hopping yet - i wasn't aware that my tire was off the ground till i saw the picture.
Do you know there is any major concern on damaging the differential? I'm really enjoying the setup as is, but willing to go to a softer setting if needed.
When you get to the hopping, read the STU thread in the autox section and try to follow the setup there.[/quote]
Thanks subydude! Don't think the car is hopping yet - i wasn't aware that my tire was off the ground till i saw the picture.
Do you know there is any major concern on damaging the differential? I'm really enjoying the setup as is, but willing to go to a softer setting if needed.
| subydude | 04-04-2016 05:26 PM |
You're not damaging the diff.
| Esquire | 04-05-2016 10:19 AM |
Getting some lift on the inside wheel is normal. I wouldn't worry about it. I get lift on the inside front wheel in my E92 M3 on the track. During hard cornering your loading up the outside suspension which result in lift on the inside. Happens with racecars all the time.
| 181stLeader | 04-05-2016 10:41 AM |
I was getting this problem as well with my set up, 27mm adj front bar set at 29mm, 24mm rear bar set at anything above 22mm, whiteline group 4 coilovers with 5k front 4k rear springs.
It was bad enough that when I would get on throttle to power out of the corners I would not be able to put the power down until the wheel came back down. My rear bar was over powering the rear spring and allowing the wheel to lift. I dialed the rear bar down to the smallest setting and it helped quite a bit(I still feel the wheel lift ever so slightly on tighter corners but its not bad), I did swap it for an STi rear bar for a while and that eliminated the inner rear wheel lift. It really comes down to me getting stiffer springs.
It was bad enough that when I would get on throttle to power out of the corners I would not be able to put the power down until the wheel came back down. My rear bar was over powering the rear spring and allowing the wheel to lift. I dialed the rear bar down to the smallest setting and it helped quite a bit(I still feel the wheel lift ever so slightly on tighter corners but its not bad), I did swap it for an STi rear bar for a while and that eliminated the inner rear wheel lift. It really comes down to me getting stiffer springs.
| DrFraserCrane | 04-05-2016 11:05 AM |
[quote=pmanliu;44305863]
I was told that my inner rear tire was lifting this past weekend on hard turns and had a couple questions:
1) Is this actually detrimental to the diff? I also tripod entering my parent's driveway (maybe once a week or so). Car is autocrossed maybe 5-6x a year.[/quote]
anecdotal data point would be Danny Kao who had some diff issues last year when running his '15 wrx in DS with a rear bar and getting lots of inside rear tire lift.
my take: given the open diffs on this car, free spinning a rear wheel and having it touchdown seems like a recipe for disaster with continued application.
I was told that my inner rear tire was lifting this past weekend on hard turns and had a couple questions:
1) Is this actually detrimental to the diff? I also tripod entering my parent's driveway (maybe once a week or so). Car is autocrossed maybe 5-6x a year.[/quote]
anecdotal data point would be Danny Kao who had some diff issues last year when running his '15 wrx in DS with a rear bar and getting lots of inside rear tire lift.
my take: given the open diffs on this car, free spinning a rear wheel and having it touchdown seems like a recipe for disaster with continued application.
| pmanliu | 04-05-2016 02:36 PM |
[quote=DrFraserCrane;44307908]anecdotal data point would be Danny Kao who had some diff issues last year when running his '15 wrx in DS with a rear bar and getting lots of inside rear tire lift.
my take: given the open diffs on this car, free spinning a rear wheel and having it touchdown seems like a recipe for disaster with continued application.[/quote]
Interesting - is Danny on these forums? would be interested in reading more about his situation.
my take: given the open diffs on this car, free spinning a rear wheel and having it touchdown seems like a recipe for disaster with continued application.[/quote]
Interesting - is Danny on these forums? would be interested in reading more about his situation.
| Annihilator817 | 04-05-2016 02:40 PM |
[quote=AWMIII;773469]My wrx lifted wheels on its stock suspension autoxing several times. I had that problem fixed.[/quote]
[URL=http://s1125.photobucket.com/user/Annihilator817/media/Devens%204%207%2012/7085927111_3528854554_o.jpg.html][IMG]http://i1125.photobucket.com/albums/l581/Annihilator817/Devens%204%207%2012/7085927111_3528854554_o.jpg[/IMG][/URL]
[URL=http://s1125.photobucket.com/user/Annihilator817/media/Devens%204%207%2012/7085927111_3528854554_o.jpg.html][IMG]http://i1125.photobucket.com/albums/l581/Annihilator817/Devens%204%207%2012/7085927111_3528854554_o.jpg[/IMG][/URL]
| KC | 04-05-2016 02:57 PM |
[quote=pmanliu;44308563]Interesting - is Danny on these forums? would be interested in reading more about his situation.[/quote]
Yes. Check the autox forum. (This thread existed before the autox forum did - going to ask to have it moved)
--kC
Yes. Check the autox forum. (This thread existed before the autox forum did - going to ask to have it moved)
--kC
| Annihilator817 | 04-05-2016 03:28 PM |
A rear tire in the air causes the front tire to spin, which means you can't use WOT without losing traction and accelerating slower on corner exit.
IMO, these cars rotate fine with the stock bars. No need to go bigger unless you're attending a drift event.
IMO, these cars rotate fine with the stock bars. No need to go bigger unless you're attending a drift event.
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