Hi all,


Can someone tell me with any amount of certainty if the stock CS suspension is at all adjustable in terms of more negative camber? Can I get even an extra degree out of it? I have read that the strut bearings might be slotted and therefore able to be adjusted for a touch more. That true? And the rear as well?


Any info would be helpfull.


Thanks

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'06 Cayman S -JIC Cross, Quaife, CCW C14 wheels,MPSC's, Milltek cat back, GT3 seats Schroth harnesses, TC design bar, Pagid yellows, GT3 cup brake ducts,de-snorked, vanilla air freshener

Chis - I autocross a lot, and plan on some track time this fall, and this is what I've found. You can get up to -1.0 degree negative camber from the stock suspension, but that's about it. I worked with a very good facotry trained alignment guy, and my aim was to put more negative camber into the front, but I wanted to leave the rest of the settings as close to stock as possible because I drive about 500 miles each way to the AX events I run. So, I wanted to keep the other settings from wearing the tires in regular driving. It took him 6 full sweeps to get it right, but he was able to get the -1.0 in the front which has made a huge difference in dialing-out the understeer that's set in the car from the factory. We found that any more than -1.0 and it began to drastically effect the other settings. I also left the rear settings as they came from the factory, which already had a -.45 negative camber setting.



Any more than that, you'll have to go aftermarket for lowering springs (when you lower the car, the camber will automatically get more negative), coilovers, or adjustable camber plates.



I hope that helps you,



brad

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21-year PCA Member
PCA DE Instructor

I agree with Brad on the front camber. If you remove one of the three skirted bolts at the top of one of the struts (have to remove the plastic covers to see the bolts), you'll see that the hole is slotted (they all are), allowing about -1 degree (plus or minus .2) negative camber when the top bolts are pushed as far toward the center of the chassis as they will go. That's certainly better that the -.5 degree that came on the car, but less than half what I'd like for track and autocross. One could further lengthen the slots toward the center of the chassis for more negative camber, but I'm not sure what else may come into play if you grind away on the slots. Aftermarket camber plates are available from Mantis Sport (one of the cc sponsors). Either of those mods will remove the car from SCCA stock class.



Brad's -.45 degree of rear camber puzzles me, however, as my CS came with about -1.6, and is now -1.8. The camber spec range is -.7 to +.3 degree in front, and -1.8 to -.8 degrees rear, so -.45 would be out of the spec range, and to the undesirable side at that. Anything more than -.7 in front will also be out of the spec range, but to the desirable side.

Are you sure that standard rear camber spec is so negative? I recall seeing something around -0.5 degrees.



Currently I've got -1 on the front and -1.5 on rear.

Actually, the specs I reported above are from the dealer's Hunter alignment machine for the '05 987 (Boxster and Boxster S). There was no separate alignment program for the Cayman. I also noticed that the rear camber spec range for the 987 is the same as for the 986, but that the 986 front camber range was given as -.4 to +.6 (rather than -.7 to +.3).

Jim - so much for my memory, I dug out the alignment sheet, and the rear camber was -1.4, not .4.. sorry about that... Here's the full breakdown.



Specs as delivered on the car when we started:



Left Front : - 0.3 camber, 7.4 caster, .08 toe

Right Front: -0.4 camber, 7.6 caster, .04 toe

0.11 total toe, 0.02 steer ahead



Left Rear: -1.4 camber, 0.33 toe

Right Rear: -1.6 camber, .12 toe

0.45 total toe

0.10 thrust angle

--------------------------------------

What we changed it to:



Left Front : - 1.0 camber, 7.4 caster, .04 toe

Right Front: -1.0 camber, 7.6 caster, .04 toe

0.08 total toe, 0.00 steer ahead



Left Rear: -1.4 camber, 0.09 toe

Right Rear: -1.4 camber, 0.09 toe

0.18 total toe

0.00 thrust angle



I really like the way the car handles now - much, much less understeer, the front really bites on turn-in. I just put a little more than 3k miles on the car going to the Portland Parade and back and wear on the tires is very even. For AX, I have been putting 40 lbs in the fronts, and 38 on the rears, stone cold. When hot they both go up 5 lbs from there, and I get very good grip frm the PS2s, and I'm getting no rollover or shoulder wear on the fronts.



brad

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21-year PCA Member
PCA DE Instructor

Brad: Thanks, I feel better already. Your alignment looks good for a road and track compromise, and your alignment as delivered was better than mine; at least the front and rear toe parts, which were out of spec on mine.



I've become an alignment junkie, although I still have a lot to learn. I've learned that the 'as delivered' alignment may not be within specs, and that Hunter alignment machines may be out of calibration, thus giving inaccurate numbers. I discovered the latter when my eyeball (and later a Smart Camber Gauge) measures of front camber were more accurate than the Hunter measures. I was also puzzled by the claim that caster range is 7.5 to 8.5 degrees. More caster would be good, but the most we could get without a special adaptation was 7.8. Caster just does not seem to be easily adjustable on this car, so the 8.5 figure might be a tease.

Thanks for the responses guys, well done! I am plannig to get a suspension for next season but want to finish off this track season with a bit less tire wear on the outsides. I'm calling my alignment guy to book an appointment.

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'06 Cayman S -JIC Cross, Quaife, CCW C14 wheels,MPSC's, Milltek cat back, GT3 seats Schroth harnesses, TC design bar, Pagid yellows, GT3 cup brake ducts,de-snorked, vanilla air freshener

I got my car aliged yesterday and was a bit dissapointed with the results. I could only get -0.4 degrees negative in the front left. I could get a bit more on the right side but then what's the point? The rear I set to -1.4 both sides and adjusted the front with a bit more toe out for sharper turn in. I guess it's better then nothing but I was hoping for a bit more!


Have you guys thought of slotting the holes more? How much more before the inside of the top plate hits the tower?

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'06 Cayman S -JIC Cross, Quaife, CCW C14 wheels,MPSC's, Milltek cat back, GT3 seats Schroth harnesses, TC design bar, Pagid yellows, GT3 cup brake ducts,de-snorked, vanilla air freshener

Chris: Did you check to make sure that the strut top bolts are moved inward as far as they will go? My CS had .4 negative camber as delivered, with the strut bolts in the centers of the slots. Most can get around -1.0; some a little more (-1.2), and some a little less (-.8), but -.4 is coming up short of what you should be able to get. Another thing; the driver (or something of similar weight) should be in the driver's seat while the car is being aligned. My weight added .1 degree negative on the left and .2 negative on the right.



Yes, I thought about grinding the slots more toward the inside for more negative camber (see my first post in this thread), but I don't know what else that may do. I wouldn't grind away much; maybe 1/8-inch, which might give another .2 degrees negative. The more you grind away, the weaker that area may become. I haven't looked closely, but you can probably judge about how much more inward the strut top can move before it contacts metal by measuring how far the top plate comes out from the bolt. You'll probably have to remove the wheel/tire and go underneath to check that. Once you grind away on the slots, however, the car is no longer SCCA stock (maybe PCA as well), and the lost metal can't be replaced. In contrast, using camber plates to get more negative camber is reversible, though more expensive.

Chris and Jim, Mantissport has modifed stock upper strut bearing plates. with lowering springs HR, you can start off at a 1.6 degrees and go up.with stock springs 1 degrees to 2 max. Ernie

Anybody knows the torque specs for the strut top bolts. If I were to touch them I sure would like to know to what torque to tighten them back to.

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