A couple of pics from the weekend...
05-09-2007, 12:44 PM
#1
Melting Slicks
Thread Starter
A couple of pics from the weekend...
A little too tight on my line here:
This was a long, decreasing radius sweeper. It was key to stay very tight on the exit since the next gate forced you left. I probably should have been out about half a car-width and made more of a late-apex out of it (I did in other laps).
Ready to rock:
Gettin' mah lean on even w/ the 38mm T1 front bar:
I'd actually like thoughts on this pic (and the 1st), you can compare to static ride-height in the 2nd pic. FWIW this pic follows the 1st pic, just after apexing the car and as I'm getting back into the throttle heavy. It really doesn't look like I get too much compresion on the outside. Looking at the static pic wheel-gaps seem about the same, but I wonder if I'm bottoming out the stock length shocks on the outside corner? I am un-weighting the inside front a good bit: too much bar front bar/not enough spring?
-TJ
This was a long, decreasing radius sweeper. It was key to stay very tight on the exit since the next gate forced you left. I probably should have been out about half a car-width and made more of a late-apex out of it (I did in other laps).
Ready to rock:
Gettin' mah lean on even w/ the 38mm T1 front bar:
I'd actually like thoughts on this pic (and the 1st), you can compare to static ride-height in the 2nd pic. FWIW this pic follows the 1st pic, just after apexing the car and as I'm getting back into the throttle heavy. It really doesn't look like I get too much compresion on the outside. Looking at the static pic wheel-gaps seem about the same, but I wonder if I'm bottoming out the stock length shocks on the outside corner? I am un-weighting the inside front a good bit: too much bar front bar/not enough spring?
-TJ
05-09-2007, 07:14 PM
#2
Team Owner
bars only can do so much. First and last time I went auto-x I got lost so many cones and plenty were down when I started. I felt like a idiot lost. May be if they number them for me
05-11-2007, 06:04 PM
#4
Melting Slicks
Thread Starter
No thoughts on the suspension setup? I think running no back sway is letting the back outside corner drop enough that the front inside starts to lift (with the giant T1 front bar adding to the cross-lift). But the Catch 22 is that any back bar makes the car very twitch in transition (and everything is a transition in AX) and a hair loose mid-turn to exit (a LOT loose if I put the T1 back bar on. So I think maybe the answer is a bit more rear toe-in to allow for at least some back bar, stiffer springs to reduce roll in general, and shocks matched to the springs. But that's a lot to change at once... I could end up going the wrong way on the whole setup. That's why I lean towards coil-overs though so they're adjustable and easy to change spring rate.
-TJ
-TJ
05-11-2007, 06:38 PM
#6
You probably are getting into the bumpstops on the outside rear shock, probably causing some of that oversteer. The bumpstops are progressive, but do start kicking in early on stock length shocks.
In my experience, T1 bars front and rear on stock Z06 springs give the car a moderate push at autocross speeds. This was even with equal sized tires front and rear (315/17)
Try for around 1/4" toe in in the rear to help reduce power oversteer, and maybe raise the car 1/2". Also, rear pressures should be in the mid 20lb range with your wheel setup (hoosier or kumho) to get some bite back there.
In my experience, T1 bars front and rear on stock Z06 springs give the car a moderate push at autocross speeds. This was even with equal sized tires front and rear (315/17)
Try for around 1/4" toe in in the rear to help reduce power oversteer, and maybe raise the car 1/2". Also, rear pressures should be in the mid 20lb range with your wheel setup (hoosier or kumho) to get some bite back there.
05-12-2007, 12:11 AM
#9
Melting Slicks
Thread Starter
You probably are getting into the bumpstops on the outside rear shock, probably causing some of that oversteer. The bumpstops are progressive, but do start kicking in early on stock length shocks.
In my experience, T1 bars front and rear on stock Z06 springs give the car a moderate push at autocross speeds. This was even with equal sized tires front and rear (315/17)
Try for around 1/4" toe in in the rear to help reduce power oversteer, and maybe raise the car 1/2". Also, rear pressures should be in the mid 20lb range with your wheel setup (hoosier or kumho) to get some bite back there.
In my experience, T1 bars front and rear on stock Z06 springs give the car a moderate push at autocross speeds. This was even with equal sized tires front and rear (315/17)
Try for around 1/4" toe in in the rear to help reduce power oversteer, and maybe raise the car 1/2". Also, rear pressures should be in the mid 20lb range with your wheel setup (hoosier or kumho) to get some bite back there.
Correct. Believe it or not it's a common setup. The SS class guys that like to skirt the rules a bit run no back bar since the rules are writen you can't take it off... but if it breaks you don't have to replace it (or so I'm told) and run larger front bars (since they're open).
On the road course it's very unbalanced. Both T1s on work great for road course (go figure, that's what they were developed for). AutoX it just makes the back of the car go everywhere.
Nah, they're just rattle-canned outters. I'm tempted to have the outters annodized though.
-TJ
05-21-2007, 03:40 PM
#14
Melting Slicks
Thread Starter
Some shots from yesterday. This was a slower speed AutoX than I usually attend, on some pretty slick asphalt. Even still you can see the body movement.
-TJ
05-21-2007, 05:53 PM
#15
Safety Car
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My experience was just the opposite. When I went square 315's and T1 bars Front and Rear (albiet on T1 springs not Z springs and Bilstien sports) the butt was nearly uncontrolable. No actually was was completely uncontrolable. I unhooked the rear bar and it was better but still not neutral. It's perfect with a nice stagger and both bars on. and as you narrow the fronts it induces understeer more with each tire size drop.
05-21-2007, 09:28 PM
#17
Melting Slicks
Thread Starter
Haha. The event is a once a year event (the Duel at DeAnza) to benefit the Auto Tech program at a local community college. The lot leaves a lot to be desired, but you work with what you have. They put the tires around the light-poles, curbs/berms at the ends of the lot, and other obstructions.
-TJ
-TJ
05-22-2007, 02:30 AM
#19
Melting Slicks
Thread Starter