Okay so I've been having a hell of a problem with oversteer in my car this season. Brief rundown of the car is it's an STS Integra (1991), 8K front/ 10K rear springs, Koni yellows, 22mm rear sway bar, -3 deg camber front, -1.5 degrees rear, 0 toe. 33PSI front, 32psi rear on 215/45/16 Hankook RS2's.

I notice the oversteer mostly on corner entry, mid corner the rear end comes back in very nicely and the car feels excellent in sweepers. It's just entry and slaloms that are killing me. The car oversteers with any shock settings. I've tried full stiff front, soft rear. full soft front, full stiff rear. half stiff all around.

The next thing I'm going to try is Polyurethane bushings except the rear trailing arms, which have the stiff rubber OEM bushings. After I get all those in, I'll get it corner weighted and aligned.

Somebody please point me in the right direction.

 

maybe its you and somthing your doing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DA9 Integra &raquo;</TD></TR><TR><TD CLASS="quote">Okay so I've been having a hell of a problem with oversteer in my car this season. Brief rundown of the car is it's an STS Integra (1991), 8K front/ 10K rear springs, Koni yellows, 22mm rear sway bar, -3 deg camber front, -1.5 degrees rear, 0 toe. 33PSI front, 32psi rear on 215/45/16 Hankook RS2's.

I notice the oversteer mostly on corner entry, mid corner the rear end comes back in very nicely and the car feels excellent in sweepers. It's just entry and slaloms that are killing me. The car oversteers with any shock settings. I've tried full stiff front, soft rear. full soft front, full stiff rear. half stiff all around.

The next thing I'm going to try is Polyurethane bushings except the rear trailing arms, which have the stiff rubber OEM bushings. After I get all those in, I'll get it corner weighted and aligned.

Somebody please point me in the right direction. </TD></TR></TABLE>

Less traibraking? More rear pressre? More rear camber?

&lt;-- crappy autocrosser, and a stock one at that..

 

coner entry only? mid corner & exit is ok? try less rebound on the rear

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DA9 Integra &raquo;</TD></TR><TR><TD CLASS="quote">Okay so I've been having a hell of a problem with oversteer in my car this season. Brief rundown of the car is it's an STS Integra (1991), 8K front/ 10K rear springs, Koni yellows, 22mm rear sway bar, -3 deg camber front, -1.5 degrees rear, 0 toe. 33PSI front, 32psi rear on 215/45/16 Hankook RS2's.
</TD></TR></TABLE>

try stiffer springs up front-or softer springs in the rear
either way when, the weight transfers under braking, it won't be as drastic.

Also, check your front and rear toe settings. Too much toe will definately give you that responsive, intial turn in. Anything more than 1/16" of neg. toe is a lot.
good luck


Modified by vtecjj at 5:10 AM 6/20/2006

 

Sorry, but the spring rate has little to do with how much weight gets transfered under braking. That is only a function of center of gravity, wheel-base and how much friction the tires can provide.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">Sorry, but the spring rate has little to do with how much weight gets transfered under braking. </TD></TR></TABLE>
It doesn't <u>change</u> the weight transfer, but it helps you handle the weight transfer better because the heavier springs up front keep the nose up under extreme braking, and that in turn lessens the scary dynamic suspension changes at the rear of the car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">Sorry, but the spring rate has little to do with how much weight gets transfered under braking. That is only a function of center of gravity, wheel-base and how much friction the tires can provide.</TD></TR></TABLE>

Lemme change the punctuation of the post you replied to.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecjj &raquo;</TD></TR><TR><TD CLASS="quote">Try stiffer springs up front, or softer springs in the rear. Either way, when the weight transfers under braking, it won't be as drastic.</TD></TR></TABLE>

I read it wrong the first time. Maybe that helps.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">Sorry, but the spring rate has little to do with how much weight gets transfered under braking. That is only a function of center of gravity, wheel-base and how much friction the tires can provide.</TD></TR></TABLE>

This is true in a straight line, right up to the point where you turn in. As soon as you introduce lateral loading, spring rates begin to have an effect on weight transfer.

I think the culprit is the 22mm rear bar. Working in conjuction with your 10K springs and presumably stock front bar, I think it is doing exactly what you would expect .

 

I don't want to take away grip at the front, I'll lose all the speed in sweepers.

Shock rebound in the rear isn't the problem, because I've run full soft and it still oversteers.

I don't think it's the 22mm rear bar and springs, because my whole setup is almost a direct copy of an STS Civic Si.

I'm hoping it's alignment issues.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DA9 Integra &raquo;</TD></TR><TR><TD CLASS="quote">I'm hoping it's alignment issues.</TD></TR></TABLE>

Have you tried more rear tire pressure? I would have started them both higher, but I think more rear pressure would get you more adhesion, or at least smaller slip angles until you hit the limit.

 

Had the same problem in my 93 GSR and Chris Lock has it correct, 22mm is fine for RR with steady state cornering but a bit too much bar for tossing the car in Solo II. During Solo II you just don't have the time to gradually apply steering input as in RR. Think about the number of turns on the average Solo II run in less than a sixty second time frame compared to the number of turns on a road course in a single laps time frame. I have been on the Progress bar with 850lbs springs in the rear of a lightened DA and went back to the 19mm ST bar for Solo II. You can't always apply RR suspension setups to Solo II and just like a Civic is not an Integra. And yes I will be at Packwood running EP in my Integra, see you there.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DA9 Integra &raquo;</TD></TR><TR><TD CLASS="quote">I don't want to take away grip at the front, I'll lose all the speed in sweepers.
</TD></TR></TABLE>
...so are the days of our lives. Choose and perish! I have done little autoX, but optimizing for low speed sections goes against my philosophy. If your car is good in sweepers, then that's great for FWD! Don't do anything that will hurt that.

 

Its always hard to judge what someone considders oversteer over the internet. Looking at your setup it doesn't look like the car would be much trouble. Aside from the pressures looking a little on the low side most cars I have driven with simmilar setups have been fairly neutral.

My first guess would be driving habits. Do you have sharp quick steering inputs or do you move slower and smoother? Have you tried getting a second opinion by having a local FWD hot shoe drive your car?

 

I'll have some Honda FWD guy drive it this weekend hopefully.

Those tire pressures give me even heat across the tire, the Hankooks like really low pressures for some reason. I'm not the only one to find that out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RineRacing &raquo;</TD></TR><TR><TD CLASS="quote">Its always hard to judge what someone considders oversteer over the internet. </TD></TR></TABLE>

Indeed. I rode with a guy a few weekends ago, and he commented about this very same thing at turn in... I wouldn't even consider what he felt as oversteer as much as just feeling the rear-end become un-weighted. The tires never broke loose.

However if there is something a-miss with your car, this could also be causing some bad characteristics.

Since we can not tell exactly what you mean by "oversteer", then I would say if you're not spinning, ie, able to continue on with the course, and catchable, then your oversteer on turn in is a good thing, and you should merely tighten the nut behind the wheel. Get used to it, drive it, apply throttle, and be smooth.

-dave
8)


Modified by emwavey at 11:47 AM 6/21/2006

 

too bad you don't want the tire temps to be even across the tread face. 10 degrees hotter on the inside edge is about right. however, you first need to get the car on a skidpad to find out if your suspension is even in the right neighborhood before a pyrometer will tell you any useful information.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by emwavey &raquo;</TD></TR><TR><TD CLASS="quote">if you're not spinning, ie, able to continue on with the course, and catchable, then your oversteer on turn in is a good thing, and you should merely tighten the nut behind the wheel. </TD></TR></TABLE>

I can catch it in sweepers, but it's really hard to catch in fast transitions and sweepers. Most of the time, it likes to let go completely in the rear, and I have to drive right up to that point and drive on the limit. A few local Honda guys said that it sounds like the toe in the back is becoming dynamic. They said to get rid of the snap oversteer on entry, replace the suspension bushings because the rear toes out on entry and toes in mid corner. Which would explain it being easy to catch it in sweepers, but not slaloms.

 

what about a bit more tire stagger F/R?

 

How would that help? Assuming it's an alignment problem, running a narrower tire in the rear would only compound the problem.

 

I would say more rear negative camber or less rear stiffness.. That (camber) seems low and the break away would be instant as you enter a slalom or corner. The rear tires would go to no grip with -1.5 camber. I would go with -2.0

 

It is possible you need more low speed bump force from your front dampers or less rear low speed rebound. On corner entry, the front outside corner is compressing while rear inside is extending. If you have corner entry oversteer, you are getting too much weight transfer at the rear and not enough at the front, proportionately. So to reduce oversteer, you need to reduce stiffness at the rear or stiffen the front, or both. Depending on the characteristics of your current dampers (Koni yellows), it is possible that the rear low speed rebound is not changing enough to have an effect on handling at corner entry when you change the settings. If you can stiffen front low speed bump or decrease rear low speed rebound, you will get more weight transfer at the front and less grip there, so more towards understeer and thus less oversteer. Rule is always soften the end where you want more grip (rear), or stiffen the end where you want less grip (front). Whatever stiffens the end such as springs, bars, dampers or tires, you get the required effect. It is just that dampers have a more pronounced effect at corner entry and exit. Camber will affect the car in all corners, and toe will have a marked effect on corner entry. If you have tried all the damper effects you can make, then alignment is about all you have to play with, that and tire pressures. It could just be that your rear suspension is too stiff compared to your front suspension for your driving style. Easy and very cheap fix is to disconnect rear sway bar and try the car. If you still have entry oversteer, then it is not likely a suspension stiffness issue.

 

Try adding more rear camber...I had the same problem as you but changed the camber to - 2.7 and now the rear is totally planted on turn in and in transitions! It may push some in sweepers so if it does play with the amount a little to get it to your liking.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DA9 Integra &raquo;</TD></TR><TR><TD CLASS="quote">How would that help? Assuming it's an alignment problem, running a narrower tire in the rear would only compound the problem.</TD></TR></TABLE>


I guess you have no idea what tire stagger is... tire stagger is alternating the tire circumference by augmenting the air pressure. eg: less pressure in the rear in relation to the front. Stagger is NOT a difference in width, although I can see how you would be confused.

Try a little less pressure in rear in comparrison the your front's

 

I really don't see how you come to the conclusion that "tire stagger" only relates to the tire pressure. I presumed, as did DA9 Integra, that you were talking about staggering the tire sizes, hence staggered tires. Your actual intention of suggesting staggered tire pressures would have been more clear had you mentioned pressures.