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Camber adjustments at top-mount wildly different left to right
I recently had a set of Tractive DDA coilovers installed on my 991.2 GTS (they're amazing! probably better to post about them in a separate thread). We're able to get -2º of camber all around but the positions at the top mounts are close to maxed-out in the negative direction on the driver side and close to maxed-out in the positive direction on the passenger's side. The coilover itself is properly assembled so it doesn't seem like it's a wrong camber plate or anything used on one of the shocks. Could this be an issue with the subframe being misaligned? Or something else? The shop tells me that they've seen GT4s with a similar issue.
Further down the line, I'd love to explore widening the front track with adjustable control arms and need the adjustment in the positive direction to balance out with negative camber from the control arm extending out. As you can see, it's possible currently on the passenger side but not the driver's side.
Thanks!
Last edited by francisluu; 11-19-2017 at 11:46 PM.
Something it’s assembled correctly. It is normal for one side to get max neg camber more than other side but not in the direction you are seeing. Are the struts possibilities rotated?
Is corner weight/ride height also equal left to right?
Good call. I just went outside and checked. Driver's side is 68.8cm ground to fender lip. Passenger side is 69.2cm.
These numbers being equal is obviously ideal, but what are the tolerances for ride height side to side? is 4mm going to contribute to one side being maxed on the negative and the other on the positive?
4mm delta ride height is not significant. Did you ever look at the original camber adjustments before changing the components? There is normal variability between chassis, for which the stock adjustment range allows compensation. Hard to say at this point whether the peculiar adjustment setup reflects something inherent in the chassis or some issue with the new components.
Don't measure ride height from fenders....you have to measure ride height underneath on the frame. I don't know the spots on a 991 but I know the spots on 997...but thats how you measure. I still think the the passenger side strut is probably rotated causing the neg camber at what looks like positive camber on the strut tops. Sub frame I believe is not adjustable on these cars...that wouldn't affect the camber per say.
those can help with a little more neg camber if you look at the photos he is on one photo with what looks like max neg camber and other side of car...other photo he looks like mx positive camber...however he is at around the same neg camber on the alignment machine on both sides. This is why I am thinking something like with strut is turned. 996/7 GT3 guys do this to get more neg camber.
the tops of the photos would look similar. Personally I prefer adjustable lower control arms for more neg camber as this also gives you the benefit on a wide front track.
on my 2017 GTS max neg camber in front I could get is at -1.6 degrees. However for these 991 cars with rear steer and running Michelin Pilot Sport Cup 2 tires this seems to be enough after looking at tire wear after 1 track event. Also 991 GT3 is finding that as recommended by Porsche that -1.5 degree works and anything over -2'ish the car goes slower in the corners. So interesting stuff.
The car's going back next week to the shop for a different issue (shorter spring to fit in a helper spring, a story for another time) and I'll have the alignment double-checked. To add more fuel to the mystery fire, the wheels seem to be sitting inboard from the fenders at different amounts:
The front passenger side wheel being so much more outboard than the driver's side seems to coincide with how much more on the positive side the camber is adjusted on the passenger side at the top mount.
Camber adjustments on the standard Carreras are only done at the top mount, correct? Adjustable control arms are only on the GT3s yeah?
can you put up the print out of the alignment with the current settings - note the position of the bolts, both sets are adjusted hard over to one side.
Also do a string check both sides and spirit level check both sides. Porsche have a tolerance of 10mm fender lip to center hub.
11-19-2017, 10:42 PM
Camber adjustments at top-mount wildly different left to right
and spirit level check both sides. Porsche have a tolerance of 10mm fender lip to center hub.
