More negative camber = faster spin at Thunderhill :)
#1
More negative camber = faster spin at Thunderhill :)
To achieve more negative camber on GT3/RS OEM front suspension means either adding shims on lower control arm or rotating front strut tower or both. After tasting the fruits of more negative camber and proper alignment and corner balance - I want MORE negative camber. I was only able to get -1.8 front camber with 7 mm of shims added to the factory 8 mm shim so I have to rotate the front strut tower. I did notice one thing with the shim. It makes my front wheel rub against the wheel well near full lock on turns - this will be ameliorated once the front strut tower is rotated with more negative camber
The front strut tower is off set in such a way that by rotating it 180 degrees you will be able to get more negative camber ... but the studs on the strut tower are pressed in.
To get the pesky stud off, you need to press it out with a hydraulic press. I elicited help from Shad at Driving Ambition. The process is pretty simple as follow:
Loosen the 22 mm washer at the center of the strut tower then remove the nuts that secure the strut tower studs
Disconnect the control arm then lower the suspension assembly enough to remove the strut tower
Carefully press out the studs and re-install them in the corresponding position to facilitate 180 degree rotation
Once the front strut tower is rotated 180 degrees you can easily see the front ambers are a-lot more negative. Secure the front strut at it's minimum camber by pulling it toward you then have it aligned ASAP
The front strut now point a-lot more inward (more negative camber) compare with OEM set up
Off to alignment ... one thing I did before Alignment was that I removed 2 mm of shim on each lower control arm to make sure I don't have too much negative camber and also that the front tires do not rub against the wheel well
Shims completely removed ....
Here is what I put back - factory 8 mm and the additional 3 and 2 mm shims to a total of 13 mm
G-12 Alignment to the rescue as usual
This is what I ended up with. -2.6 camber front and -2.3 camber rear with 0.2 mm toe in front and 2 mm toe in rear. The front Caster has slightly increased to 9.0 which is not far off from OEM max spec of 8.5. The car is totally drivable on the street and not nervous at all
Now off to the track! I had a blast at Thunderhill this weekend. My RS definitely drive a-lot better. I can take turns at much faster speed and I went too hot on the first cold morning session and spun out on turn 4 as shown at the end of the video below. I got kind of spooked after the spin and sort of tip toe through the rest of the day lol. Great fun regardless.
Thunderhill
Here are some pictures from the track ... can't wait to get back soon to work on the drive some more
The front strut tower is off set in such a way that by rotating it 180 degrees you will be able to get more negative camber ... but the studs on the strut tower are pressed in.
To get the pesky stud off, you need to press it out with a hydraulic press. I elicited help from Shad at Driving Ambition. The process is pretty simple as follow:
Loosen the 22 mm washer at the center of the strut tower then remove the nuts that secure the strut tower studs
Disconnect the control arm then lower the suspension assembly enough to remove the strut tower
Carefully press out the studs and re-install them in the corresponding position to facilitate 180 degree rotation
Once the front strut tower is rotated 180 degrees you can easily see the front ambers are a-lot more negative. Secure the front strut at it's minimum camber by pulling it toward you then have it aligned ASAP
The front strut now point a-lot more inward (more negative camber) compare with OEM set up
Off to alignment ... one thing I did before Alignment was that I removed 2 mm of shim on each lower control arm to make sure I don't have too much negative camber and also that the front tires do not rub against the wheel well
Shims completely removed ....
Here is what I put back - factory 8 mm and the additional 3 and 2 mm shims to a total of 13 mm
G-12 Alignment to the rescue as usual
This is what I ended up with. -2.6 camber front and -2.3 camber rear with 0.2 mm toe in front and 2 mm toe in rear. The front Caster has slightly increased to 9.0 which is not far off from OEM max spec of 8.5. The car is totally drivable on the street and not nervous at all
Now off to the track! I had a blast at Thunderhill this weekend. My RS definitely drive a-lot better. I can take turns at much faster speed and I went too hot on the first cold morning session and spun out on turn 4 as shown at the end of the video below. I got kind of spooked after the spin and sort of tip toe through the rest of the day lol. Great fun regardless.
Thunderhill
Here are some pictures from the track ... can't wait to get back soon to work on the drive some more
Last edited by GT3 Chuck; 09-28-2009 at 12:24 PM. Reason: embedded links to commercial non sponsors
#3
lol
I am so tired after the event and I can just imagine how you felt after driving all the way back to the Bay. Great driving Joe - I will have to work harder to match your 2:06 time .... I need to find myself a passenger too
I am so tired after the event and I can just imagine how you felt after driving all the way back to the Bay. Great driving Joe - I will have to work harder to match your 2:06 time .... I need to find myself a passenger too
#6
Mikymu, granted my car weighs 500 lbs. more than yours, 996TT, but I recently destroyed a set of rear tires with my rear toe set at 0.10. My tire guy told me to reduce it to 0.03. I see yours are set at 2.1. Can't understand how you are not completely wasting your rear tires.
#7
Mikymu- Thanks for posting! Awesome! Why the spin out? Slick spot on track? It looked like no warning, just washed out.
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#8
Mikymu, granted my car weighs 500 lbs. more than yours, 996TT, but I recently destroyed a set of rear tires with my rear toe set at 0.10. My tire guy told me to reduce it to 0.03. I see yours are set at 2.1. Can't understand how you are not completely wasting your rear tires.
Yeah, first session of the day at 8 AM. The track was cold and slippery and I went too "happy" too fast. Not much I can do when the rear step out so fast - no amount of counter steer can save it. The track surface was much better after the sun bake it for an hour or so
#10
These CCW 18" are great and Nitto NT01 tires are super sticky. Lesson learned - don't go too fast in the first run of the morning
#11
Better check your lsd because if 90% track your lsd is gone by now : (. Never heard of toe going outwards due to braking and if your best laptime is > 2:06 u not braking that hard to cause ne toe to go outwards if at all it happens. Rear tail wag under braking on a straightline is mainly from a worn down lsd. I'm not challenging your remarks just offer another side of other variables that maybe the cause. Regards. Mike
#14
^^^
Hey Mike
Thanks for the advice on LSD. I am sure it's pretty much gone on my RS. The tail wag was noticeable on my first track event under hard braking - 130 mph down the straights at TH before turn 1. I tilt the rear wing pretty much all the way up which eliminated the rear sway. My description of the rear toe just to emphasize the need of toe in for better stability. I am still learning how to drive on the track and I am sure I don't brake hard enough for my rear toe to step out into the positive lol
Hey Mike
Thanks for the advice on LSD. I am sure it's pretty much gone on my RS. The tail wag was noticeable on my first track event under hard braking - 130 mph down the straights at TH before turn 1. I tilt the rear wing pretty much all the way up which eliminated the rear sway. My description of the rear toe just to emphasize the need of toe in for better stability. I am still learning how to drive on the track and I am sure I don't brake hard enough for my rear toe to step out into the positive lol
#15
In your RS- u can hit 143-144 mph just before t1 at thill provided u throttled early before t15 and brake late on t1 provided your lsd is functional. If your lsd is kaput invest in a Guard LSD- u wont go back. Your car has more mechanical grip then the 6gt3 so a 40/60 is all u need. If u go more aggressive have fun driving that thing in the rain. I have a 80/80 Guards unit- couldn't drive more then 55 mph in lite standing water. Mike