Going 4yrs strong.

 

Sorry for the bump.

How much camber are you track guys running?

Edit: sleepy grammar correction

 

street car with a few track days per year. -3 in front; -2.5 in back; 265/30/19

 

My car has TruHart front camber arms and SPC rear camber arms.

Alignment specs are -1.5 front, -2.5 rear.

 

Im on the Figs track spec front uppers, which are fantastic. I run the fronts on most tracks maxed out- which is around -3.7 deg. There are two problems that you'll run into; first problem you will start to run into is the suspension upright will start to contact the coilover spring on droop. I am on Penskes so your mileage may vary based on the spring size your coilover has. Penskes have a 65 or 68mm front spring diameter iirc, other brands can have a larger 70-80mm springs which will cause this interference sooner- like maybe around -2,8 to -3 depending. Second is the castle nut up front will start to get pretty close to the tire. I run a Advan A052 in 295/30 front on a 18x10 +28 and its about as close as i want it to be atm. For the rear I have all the Figs links. Set up after changing all the links and arms is a process but once dialed in you really don't have to mess with it much. For the rear i run -2 to -2.8 depending on track, weather and aero set up for the event.

 

Let's also be fair here. Not every street tire is going to tolerate running that much camber, and many will shred if you push them hard at those numbers. Love the setup, just need to be aware you've put a lot of time and effort into optimizing your setup to work well with your driving and your tire selection. I'm doubtful a set of PS4S would survive even a 20 minute session at a fast track set up that way without cording.

 

I agree. Unless you're running a full slick, -3.7 degrees isn't of much use. Besides, wouldn't that much in the front affect braking performance? Wouldn't -2.5-3 be the optimum range for even a 200 treadwear tire (A052, RE71R, RS4)? Not making fun of your setup, just gotta kinda agree with Lobux on this.

 

I had yoko AD08R on the camber and size listed above, and admittedly it was not bad but not nearly as great as r888s. R-comp + stiff sidewall with increased camber is much fun. Haven't noticed any weird wear either when i had r888s (granted they're like 100tw or so). I have michelin cup 2 240s (240 tw), but I haven't tracked them yet on my camber settings.

 

Yes for sure this set up is not for everyone. This is what works on MY car in the events I run. There is no one size fits all solution in car set up, and different tire compounds (even all 200tw) will react massively different on the same chassis and shock set up. I have been doing this long enough and collected the independent data to know this to be true.
Lobux, yes, you are mostly right. This works for me because I don't run a full 20 min session. Since I do TT and Time Attack and in these events I need the tire to get up to max grip quickly and then I use it extremely hard for 2 MAYBE 3 laps max.


The new technology inside the super 200's TW category mind blowing (excluding the rs4 you mentioned). What all the cheater tires are doing now blows the prosumer R-compounds of 5 years ago out of the water. Construction and chemistry have jumped 20 years in the last 3. FWIW Every new performance street tire can tolerate -3/-4 deg of camber no problem. -6/+ is where you are pushing it. You have to remember tires are designed to drive on a variety of surfaces like the highly cambered road surfaces here in the US. It will obviously wear the patch touching the road quicker but not typically by some insane amount. Scrubbing to the direction of travel is what kills tires. This is caused by one or both of two things. 1. Toe 2. Car set up or driving that scrubs the front (i.e understeer). High camber and scrub is what will kill tires quickly, especially on track. In my scenario I have a substantial amount of front aero which helps to control the tire killing scrub. My camber numbers were arrived at though a LOT of testing with a tire temperature probes and shock potientiometer data captured by a full logging suite. I've also discussed set up directly with Yokohama engineers trackside since the tire I run (A052) is spec to the series and they have a few races a year they do track side support.

As far as Braking performance the surface level answer feels intuitive, but again depends on many things. For ME I approach all of this with performance (track) driving as my use case, and have built my car to be adjustable for such things. So the short answer is No. For me, it does not reduce braking performance since I can adjust the brake balance as needed by running staggered pad compounds as well as constantly monitoring and adjusting shock characteristics in dive and roll to maintain platform stability. Thats for me though. For everyone else that may not be as serious about set-up or want to get into the weeds, think of it this way- during a 2:00 min lap, a car setup with emphasis on cornering will see substantially more gains on the 45 seconds too 1 minute of hard cornering per lap vs the 8-12 seconds of threshold braking. The answer MAY be yes, but again whats the goal?

This is the same reason Ferrari brings 3 different cars to Road and Track tests. One for 0-60, one for figure 8, one for 60-0... all set up just so

 

Will - so you only run 3 hard laps in time attack and then cool off? How many chances to do this do you get in a day? I figured you ran 20-30 min sessions like they do at HPDE.

 

Yeah its typically standard 20-30 min session format and I CAN run as much as id like in that time, however when a car is set up to use it tires at their maximum (Even a super a 200TW) you really only have a lap or two at peak performance. Yes they can physically go longer but you aren't doing anything but torturing the tire and driving down on power.

I built a scatter plot using inertial data form the accelerometer, drag coefficent and raceweight- its not 100% accurate as far as power figures, but i'm more interested in the delta spread of the values. You can pretty clearly see from lap 1 to lap 4 on any day over 75deg the car loses about 20hp once it heat soaks. After speaking with a few tuners i trust they say that Lexus/Toyota are notorious for running conservative timing under certian conditions. Here's an idea of what that plot looks like broken down by best laps on two different days about 15* air temp apart.



I do drive longer on some days- like if its cool or I am testing something, learning a track or am just burning tires off, but typically at my home tracks in a car that hasn't changed much I do 2-3 and come in to preserve components.

 

Thanks for the replies.

I track/autocross and weekend drive my car on Bilstein B6 and oem 2011 springs. I have superpro offset front upper control arm bushings which put me at -1.4 front camber on both sides. In the rear I'm at -2.1 left and -2.0 right. 0 front toe. 0.24 rear toe in total.

I'm trying to achieve better tire wear and more equal temperatures across the front tires while on track. I'm just using an IR gun for temps though and chalk to check how much it's rolling over.

With Hankook RS4 275/35R18 on 18x9.5 rear tire wear and temps are pretty good with 36psi hot. Front outer shoulder is still hotter than the rest of the tire and rolls about 0.5mm past the end of the thread with 38psi hot so I want to improve this.

What would be the better option? Get coilovers (not penske or ohlins too expensive) to lower it and gain some natural camber or an adjustable upper control arm/ball joint?

 

-1.4 in the front is probably a bit too low. For average street driving that is more than enough, but on track you will experience more outside wear. -2 in the rear isn't a bad value, but it would certainly handle better if you changed the camber up front to between -2.5 or -3.0 and left the rear to -2.0. -2.8 front seems to be the optimal amount for grip and tire wear (could be wrong however).

Adjustable control arms would be the way to go here, so that way you can test multiple values to find what you believe suits it best. Coilovers generally don't offer too much in the camber adjustability department, but combining both a coilover with an adjustable upper control arm would provide best results. If working with a fairly limited budget, I'd say go with the adjustable upper control arms.

 

What are you allowed to run in your class? You'd be way ahead to run a better rear LCA bushing in the front if you can, and toe out 3mm total. Might fix the hot outside issue too without adding camber.

 

@Yri What I meant by coilovers for camber gain is if I lowered the front lets say 1inch it might gain me another -0.5-1 degree due to double wishbone geometry. (I don't know the exact numbers I just searched alignments for guys lowered about that much) After corner balance I'm not sure where it would end up though.

@Lobuxracer we run the same rules as SCCA solo. So I run in STU which allows 1 control arm to be changed or modified . I have the RR USRS rear LCA bushing (bearings not allowed in STU) and super pro bushings everywhere else on the car except for the 2 bushings on the rear knuckle. I also just started running time attack but classing for that is based off of modification points. I think I'll give the front toe out a try but toe out in 0.5mm increments. 3mm front toe out might kill tires on the street because I do still drive the car on weekends and to motorsport events.

As much as I'd like to get the figs UCA I don't think the open rod end will have a long service life if being driven on the street as well.

When the SPC adjustable ball joint slips what does it do go max negative? If max negative adds -1.5 that would theoretically put me at -2.9 or do you not want to run that ball joint on max negative?