Track musings - camber, temperature and wear

[Super Roo]

Those camber plates have been around for a while. Please note you will have to have someone cut into your frame to install these.

Oh, well that’s not going to happen! I’m clearly not familiar with how that whole cam bolt assembly hangs together and interacts with the chassis, which is why I asked. Sounds a bit brutal. Thanks for the info.

 

[BruceN]

Your pressures were a little too high. You want the temperature gradient to be linear.

That being said, I intentionally over-inflate my tires at the track to get a little more life out of them. At the correct pressure, per pyrometer, the outer edges get destroyed with hardly any wear on the middle or inside. When slightly over-inflated, I get a little more use of the middle of the tire. The inside looks new when the outside is corded.

Camber is maxxed out at -1.5F and -2.0R for me. The only real solution is more camber, but the downsides to more camber are a car that doesn't drive as nicely on the street; it will tramline more, and if you don't track it much, the insides of the tires will wear more quickly. I'm going to get the new A-arms and see how -2.0F and -2.8R works for me.

Tires matter too. The worst I used were Dunlop Sport Maxx Race 2, and the best are the current ones I have, Nankang CR-S. Cup 2's, Cup 2 LTS, and Cup 2R's were in between. Grippiest were the Cup 2RS, but I corded them in a single track day. The CR-S look like they have 2 track days in them. This car wrecks tires when driven hard at its stock suspension camber limits.

I tracked an Elise for many years. Given its narrower tires, and lower weight, it needed a lot less camber, and I got great tire life at the track. It wasn't ideal, since I didn't want to make it a track-only car, but given the blend of street/track miles, I got a good balance of tire wear. I think I was around -2.5 camber front and rear.

Did you get the UCAs to increase camber, and if so, what did you find?

 

[BruceN]

I’ve got upper control arms in my I4 Emira. I believe we’re running about -3.5F and -3R. I’ve honestly not driven the car that much since the change (various niggles, plus additional mods underway). I’ve done various other suspension mods, sway bars, solid bushes on lower arms and various links. Still with stock (Sport I4) springs/dampers, but lowered about 10mm by moving shock circlips. Car is more darty, corners much flatter, but does feel harsher (I suspect the sway bars are the main contributor to making the car feel much firmer on the road).

Outside edge of tyres no longer get chewed up on track, wear is pretty even across the entire width. Tyre pressures don’t seem to increase as much as they did on track, with factory camber, it just seems like the tyres are not working as hard on track, with that additional camber.

I’m sure you could do upper arms and just dial in a bit more negative camber (but not as much as I’m running). I’m sure you could get it to where you’re not wrecking tyres on track whilst also not wrecking the inside of the tyres on road. I don’t see why upper control arms would sacrifice comfort, but you will probably get more tramlining.

I'm thinking more about UCAs for next season - did you have before and after track time comparisons for your camber? My tire wear is ok, but I have to believe that moving from my current -1.3 FL and -1.6 FR to somewhere around -2.5 wouldn't result in significantly improved cornering....

 

[BruceN]

GRP sells A-arms that are easy to install and super easy to change the camber on. The only draw back is camber changes the TOW and you have to adjust that when changing camber. we setup a string measurement to check the toe out F/toe in R and i will post the number next time we put everything back together.
What I do know is I am at 3.5 Front and 3.4 rear degrees and the tires are wearing evenly at 34 Psi

how was your before/after track experience with this change? That's quite a dramatic change from stock

 

[BruceN]

I am on Nitron ClubSports, which are borderline adequate, stiffness could be harder for the track, but I'm also street driving it, so I don't want to ruin streetability. I did not update the anti-roll bars, so the relationship changed. Relative to my spring rate my anti-roll bars are now softer, but on the flip side, the car doesn't lean as much.

I'm still figuring it out. All I know is that, for now, i need more negative camber. I'm going to try about -2.5f -2.3r and see how that does. It'll make the car much more likely to follow road imperfections on the street, but I can't be wasting one set of tires per track day.

Did you go ahead with increasing camber and what did you find out?

 

[OppositeLock]

I ordered them a few weeks ago, still waiting on them. My plan is around -2.5F maybe -2.3R and 0 toe in rear.

 

[mr.suntorytime]

I ordered them a few weeks ago, still waiting on them. My plan is around -2.5F maybe -2.3R and 0 toe in rear.

should be good to go in a week or two.

 

[Honcho]

I ordered them a few weeks ago, still waiting on them. My plan is around -2.5F maybe -2.3R and 0 toe in rear.

Don't forget caster can add more dynamic camber so you can still have a lower static camber number for braking.

 

[OppositeLock]

@Honcho , how do you add dynamic camber? That comes from the lengths of the a-arms, no? If they're set up for the correct static camber, how can I influence dynamic?

 

[Honcho]

@Honcho , how do you add dynamic camber? That comes from the lengths of the a-arms, no? If they're set up for the correct static camber, how can I influence dynamic?

As far as I understand you’d need to increase castor. This is where chassis dynamics start to become a rabbit hole and probably beyond the setup capabilities of most not on factory support. I’ve found on previous cars there is a limit to how much static camber you can add before you start to impact braking performance. This video explains it quite well

 

[Honcho]

…at the moment I am looking to increase front camber too. It seems like there are some quality options out there but most seem to be beyond what I’m willing to spend. My main issue I have with the dynamics right now is steering responses mid corner. I’ve got a set of R1’s on right now which have helped things a bit but hopefully can figure out a more budget friendly front camber adjustment setup. For those that have updated rollbars, have you noticed much improve meant in mid corner steering?

 

[mr.suntorytime]

…at the moment I am looking to increase front camber too. It seems like there are some quality options out there but most seem to be beyond what I’m willing to spend. My main issue I have with the dynamics right now is steering responses mid corner. I’ve got a set of R1’s on right now which have helped things a bit but hopefully can figure out a more budget friendly front camber adjustment setup. For those that have updated rollbars, have you noticed much improve meant in mid corner steering?

you can install some unibals.
These press in to your control arms (chassis side) and will sharpen your steering significantly. stops the arms from deflecting under load.
they run $575 a set for top/bottom or $1150 for the full set.

Unibal suspension bushing set for Emira & Evora

8x Unibal bushing to replace the OE rubber bushings in either the UCA, LCA or both. Spherical bearing contrusction:PTFE lined steel outer race and stainless steel spherical inner bearing.Made in Germany ASSEMBLED IN THE USA Order 2x for full set of upper and lower control arm bushings. Vehicle...

www.darkworks-design.com