JM51526

You can get -1.1 front and -1.75 rear by loosening everything and pulling out on the bottom of the wheels as you tighten everything. I had 3R racing (they run the McLarens in Pirelli World Challenge series) in Denver do mine.

Piciu

Thx!
-1,1 does not seem like enough though.
M3 guys have -1,2 OEM and most of them go for -2,3 front camber.

I'm so surprised everybody here says that OEM camber is ok for tracking with stock height.

lobuxracer

iTrader: (2)

They are on McPherson struts, not a double wishbone suspension. Totally different animal.

Piciu

I can't judge it, not enough knowledge . You're saying that double wishbone would translate into better tire contact in the corner with the same camber angle compared to McPherson?

Anyway, next week I'm doing alignment - I'm really curious what values are there now and if they would explain a bit tire damage (apart from your argument about pushing too much

lobuxracer

iTrader: (2)

Yes, that is what I am saying. McStruts describe an arc and their camber curve is pretty simple. Double wishbones can do all kinds of things with camber gain depending on all the factors involved in designing the suspension.

Piston1047

Lobux is right, the movement of your roll center and instant center during cornering with double wishbone vs. mcstrut is completely different.

I looked at your track video and I see many areas where your high speed late appexing is probably contributing to most of the "tire damage" you mention. Work on your lines a little more and I guarantee you wear will go down. After that go to a wider tire upfront, square setup is ideal for track but is not always feasible given cost or other factors. As you get better you can move up to stickier tires and race pads. This, and maybe the addition of a stiffer suspension is the only time that addition camber might be necessary if the correct analysis is done regarding tire temp across the contact patch. In you vehicles current configuration and since your still learning your limits on track , the only thing additional neg camber over oem is going to do, is increase braking distance and induce snap overseer during those late apex's. The last thing you want to do is spin out or possibly stuff you F into a wall.

Piciu

Gentlemen, for sure there is work to be done to become more fluent and have better line etc
BUT, I was driving IS-F NOT harder than my previous BMW e90 and with OEM setup, handling was just disappointing. Cornering speeds were not higher in IS-f for sure (maybe even lower in some slow corners).
I understand higher mass (+200kg vs 330i e90) etc, but still, this is competitor to M3, it should be good in the corners 'out of the box', shouldn't it???
At least brakes are amazing

The plan is:
- I have alignment scheduled for Monday morning, I will also put new PSS in front (OEM size). I will report back current alignment - really can't wait to see it
- if all is good I will go to the same track on Tuesday afternoon - I will go with lower pressure than recently (36psi cold) and test it - if needed, I will increase it slightly when hot depending on feeling/tire usage

Piciu

I did alignment and afterwards car behaved a bit better. I also lowered tire pressure. Anyway, as I managed to sell some old parts from BMW times, I've bought Enkei PF01s and when spring comes I will put Cup2 on them.

Quick question:
- how lowering the car on coilovers would affect camber?

mikersoft

iTrader: (1)

In most cases, lowering will increase negative camber. Depending on the set-up (shocks, spring rates, ride height & tires), you may end up with perfect camber for your needs & not need any further adjustments.. However, as you get faster at the track and/or begin using stickier tires, you may find out it's still not enough.. I know some lowered on Penske coilovers have done mods to further increase camber at the track (RR Racing, bbong). I may go that route too one day.

-Mike

Piston1047

Yes, as mike said you will get increased static negative camber. The key is you need to understand at what camber you tires are at their performance peak. Since you are interested in running R compound tires this is even more important. R-compound tires of different brands or compund makup require different camber or pressures to behave at their peak. For example a camber/pressure setup on a toyo RA1 is completely different than a Toyo R888 for max performance.

Where exactly did you lower pressure (all around, just front ,just rear)? what where you before and after values? Do you have a tire pyrometer? You really can't fine tune pressure and camber unless you understand the tire temp distribution along the tire patch, so I'm assuming you have this data and I'm interested to know your numbers.

Piciu

Thanks for info guys.
Last time on track it was still with PSS, OEM size. My initial pressure was 2,3 bar on all 4 tires, which raised quickly to 2,8 bar after 20min session.
Unfortunately I don't have pyrometer, but my 'handometer' was 'showing' that outside part was much warmer than inside of the tire. It would be great to have full data, but for these couple of trackdays a year I will not invest in new 'gadget'. But maybe I will be able to rent it or I will give the idea to my M3 friend of mind

When I switch to CUP2, I will run even lower pressure on them. My colleague with e90 M3 was using 2,0 bar cold if I'm not mistaken, but I will experiment on my own. For the moment staying with OEM suspension and let's see how it will behave on CUP2s.