just another sunroof-less ZHP autocross STX build and events chronicle

[bcleaver]

Play around with pressures, but I found running the Rivals a bit lower (34-35 range) was faster for me. Curious what you find

[M0nk3y]

I have no clue on Rival pressures. Never ran them.

You should be getting more camber out front though I would think, I'm around -3.6* with my plates maxed....and BMW needs as much camber up front as possible.

Be careful with too much toe out, especially with caster you'll gain dynamic camber with toe...too much toe will end up causing understeer.

[GoGators]

Well, the 3.0 measurement is mechanical, so no good way to discern how much error is in that measurement. I need to set the car up and take it get a laser alignment check done at some point.

so, I ran a variety of pressures on sunday. I did find substantially better traction at 36psi, but I was eating the entire 'nub' on the side of the rivals, front and rear. running at 38-39psi, there was noticeably less grip front and rear, but didn't eat up the nub/sidewall. going to run 35-36 at national tour in a couple weeks bc I figure I wont get the tires up to temperature anyway...

sunday the car felt great. and I was much more comfortable with the left foot braking. I ended up winning STX, 8th in PAX, 10th in raw time of 75 entrants. pretty happy with that result. you will see in the video, I think I could have eaked out bit more speed at the end slalom....

[M0nk3y]

If you don't mind comments.

It seems like you get really late on your slaloms. It looks like you're driving cone to cone, not 2-3 cones ahead. You'll notice on the first video (and second one) by the end of that first opening slalom your frantically going back and forth by the last cone and killing your momentum.


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[M0nk3y]

I'll try to find a better video, but look at my steering inputs versus yours.

Starting at 0:46 seconds, look at the back slalom and how my steering inputs are much more minimal compared to yours...with maintaining and even increasing some speed through the section.




It's something I'm still not perfect at, but that just sticks out

[GoGators]

Yea, agree Kyle. thanks for the observation! it seems like I start the slalom pretty well, but then get behind in my turning and do scrub speed by about the 3 cone...

[M0nk3y]

How'd Dixie go?

[GoGators]

it went "okay".... I will put a video together today or tomorrow...

Saturday, was extremely wet in the AM, I was in heat 2, so it was a mix of wet spots to completely dry through our heat. the car pushed in the corners with the tires at 35psi front&rear. my times dropped each run and I hit no cones, ran in 16th of 20. BRZs/FRs filled 11 of the top 14 positions.

SUnday was all dry. I upped my rear tire pressure and lowered the front. Car rotated better, still not great. my first two runs I was very happy with, other than I glancingly tipped over cones. so, my third and final run I ran conservatively, too conservatively and only barely improved my time over the coned runs.

overall I finished in 18 of 20. I think I should have done as well as 15th...

I don't ever see me really competing with a well prepped BRZ/FRs...

it was certainly an learning experience.
results:

http://scca.cdn.racersites.com/prod/...%20Results.pdf

[GoGators]

Video of my best driven laps from Dixie Solo National Tour.

You will see that I have not solved the pushing condition encountered anytime I am not stomping on the brake to turn. Car just pushes coming out of every turn. any tire screech you hear in the video is front tire... (mic is under the hood)

Currently I am running the struts/shocks at 'fairly loose' . the frnt sway bar is set to middle section and the rear bar to less stiff.

the car felt pretty well balanced before I added the rear camber bars and LSD... so.. I want to keep the rear camber I am currently running (~3.2 deg) bc I am killing the outer part of the tire tread less than I was at stock rear camber. so, I reckon, I am going to try and loosen the rear (since I cant think of a way to get more grip up front) by stiffening the sway bar and more tightening up the rear shocks.

open to suggestions....

[GoGators]

overall... there were 52 cars at the event. only 4 posted faster passes than my quickest.

video of two runs from our local event this past weekend. still trying to resolve the lack of front grip / understeer so I put the camera on the front wheel. changes for this week, from last week, are full stiff on rear bar and ~3 deg neg camber in rear and more stiff on the rear shocks. ran 35psi up front and 40psi out back.

the view of the front wheels showed a couple things, one I think I am too low on front tire pressure.... and that I am def putting the outer tire at zero camber when fully loaded. so, even though it is against conventional wisdom, I reckon I will go stiffer on the front bar to try and get more front grip.