I have hotchkis sway bars (front set to soft and rear set to stiffest) and falken rt615's properly inflated in the front and very slightly over inflated in the rear...

i've found that this setup has given me perfect handling, but whenever I am doing some spirited canyon runs (or sharp turns on the streets) my outside tire will always squeal...

so in a right turn, the left tire squeals, and in a left turn the right tire squeals...

should i put the front sway bar to stiff??? (the rear is on stiff and it never squeals)

maybe a camber adjustment???

thanks!

 

if your front outside tire is squealing, it's because it's losing traction (obviously)

by "properly inflated" what do you mean exactly? stock pressures? RT-615's like higher pressures, if I was in your shoes I would go buy a contact tire pyrometer or an infared temperature gauge and check what temperatures your tires are running at on the inside, outside, and center. That tells you a HUGE amount about what is going on with the tires.

Google "reading tire temperatures" - the temperatures will tell you everything about what is the proper tire pressure to run, how your car is handling at the limit, and what your alignment is doing for your tires and your traction. Knowing your tire temperatures across the tread is critical.

Truthfully I would put the rear on medium and leave the front on soft, there's really no reason to bump the rear all the way up. After you get a way to check the temps, I would correct the pressures, they are too low if you're running stock numbers.

 

also one thing that would help with that is lowering your car. It will give your car a lower center of gravity and less wheel hop on those tight turns

 

umm... really now? I've never noticed that on a racetrack. You'd see an improvement from higher spring rates and stiffer valving, but "lowering the center of gravity" is just marketing jargon.

One thing I forgot to mention, stay off the gas in a corner, if your car is pushing through a corner using up a huge amount of your traction, you have little-to-no traction to spare for acceleration, you should be accelerating OUT of a corner and barely keeping the gas pressed while cornering - it should look like this:

full throttle>full brake for corner>get off brake>slight gas>start cornering>as you're straightening the wheel, apply more gas gradually and evenly with unwinding the wheel

Needless to say, you should go to an autocross course in your area, it'll teach you more about the handling of your car than any spirited driving on any public road can do, and did I mention it's safe? and cheap? www.myautoevents.com - just do a search for your area, a full set of laps costs about $25-$40.

 

well i used the shoe polish method to get the right tire pressures

i always brake before the turn, then slowly accelerate into it and then fly out of it

i dont think i want to put the rear on medium because ive been driving with it on stiff for so long that i am used to having almost no body roll... medium introduces too much roll for me

 

I agree with your teaching of techniques but it does lower the center of gravity when lowered to a certain height. It's not marketing jargon as you say...anybody who has tried the differences will tell you the same. I've done the exact same corners/turns when my car was at stock height and when it was lowered...same wheels/tires/pressure...and there was a huge difference. If you don't believe it, that's fine because i don't really care...i'm just trying to help someone out with what i know...
also, i'm not trying to argue or anything and definitely don't want to turn this thread into an argument because that will definitely not help this guy.

 

thanks buddah

 

sure thing mike

 

just wanted to pop in again and shake hands. I wasn't calling you out, I'm just tired and it might've seemed that way, I'm just here to help as well. My side of thinking is coming from years of suspension geometry measurement and testing on full-bodied race tracks and on the streets, and I can say that lowering the car does not lower the center of gravity, the center of gravity is constant unless acted upon, and changing the suspension geometry does get the car closer to the ground, but the actual center of gravity within the suspension travel does not change. The differences in cornering and handling are due to increased spring rates and tighter piston valving in the shock.

Also, you said using the shoe polish method, that is actually a very inaccurate way to measure your tires, but the benefit is that it can be done for next to no money at all. Knowing the actual percentage range of temperatures across the tread will allow you to make changes within the suspension to get maximum traction out of your tires. As an example, I can guarantee if I put my pyrometer on your tires, the outsides of the tire that is losing traction around the corner will be a good deal 15% hotter than the rest of the tire. If you bumped the pressures up to 39F/35R HOT those tires would be much happier.

I measure my own alignments, and if you're wondering what would be some decent specs for your setup, I would go with something like:

Front Camber Left -1 1/2 degrees
Front Camber Right -1 17/32 degrees

Rear Camber Left -1 25/32 degrees
Rear Camber Right -1 5/8 degrees

Front Total Toe 1/16"
Rear Total Toe 1/16"

 

Why should the right camber be different than the left?

Also, im going to try 39/35, right now i'm at 31/32.... isnt it generally true that higher pressure will provide less traction though?? I remember when I had my rears set at 35 it was bulging and the contact patch was pretty small...

I guess i'll need to get my hands on a pyrometer... but in the mean time i'm going to give your tire pressures a try, thanks

 

Ive had the RT615s on my tC and on my current car (STi) and its in the nature of those tires to squeal when at or near thier traction limit. I recently installed camber plates on the STi allowing me to run -2.5 degrees of front negative camber (maximum avaialble from the stcok camber bolts is about -1) and there is still noticeable squeal on track. It sounds like increasing tire pressures will help a lot on the handling of your car. Ive founce that anywhere from 38-40 PSI when hot offers the best overall performance and feedback. Ive run both 225-45/17 and 245-45/17 and have had similar results with both sizes with regards to PSI and performance. If you want tires that dont squael when puched, get off of street tires and get some R-comps.

I have a video of the STi at Horse Thief Mile (where American Touge is run) on 245-45/17 RT615 at -2.5 front camber, -1.7 rear at 38 PSI hot:

RIGHT CLICK AND SAVE AS 30MB

 

Good to see you again, Instigator! I have the same wheel/tire setup you had on your tC, what PSI were you runnning front and rear? Thanks.

 

I run cold PSI of about 35 PSI. After my first session on track I get the HOT PSI to 40 PSI ( Ill start around 32PSI at the track) and then adjust based on what the car is doing throughout the day. On the STi, Ive been doing more like 39 front, 37 rear which helps the car to rotate a little better.

 

Thanks!

 

weight naturally shifts to the outside wheels when cornering. An LSD can help put traction to the ground.

I think otocan has different left and right alignment settings because there is more weight on one side vs the other.

naturally, dialing some more camber will help keep the outside tires flat in a turn.

 

which is what i dont get... if there is more weight on the outside, shouldnt it hold better in the turn??? shouldnt the inside tire loose traction first?

 

k im getting my alignment done tomorrow... should it be toe in or toe out on the front / rear?

 

You should have zero toe ( or as close to it as possible) front and rear or you will have tire wear issues. The only time you should be playing with toe values is if you are tuning a track car for more or less oversteer.

 

well i dont drive too much (ive had the car for 7 months and i havent even broken 5k miles yet) so tire wear isnt a problem for me...

im going to do a 1/8" total toe out in the front and zero the back toe, -1.5 degree front camber and -1.25 degree rear camber and see how that works out

 

also, will i need any alignment kits for those values??

should i buy http://www.dezod.com/pd_progress_alignment_kittc.cfm

or two of http://www.dezod.com/pd_ingalls_engi...r_kittc_05.cfm

and how much negative camber will the stock rear setup allow me?