FeralComprehension

More on this...

I've messed with the setting further and in an attempt to achieve the factory rake I would up with the front as high as the KW instructions will allow (actual ride height about 107mm, or RS - 18) and the rear as low as they'll go (actual ride height about 225 (=RS-10) as measured to the flat boss on the rear control arm).

How important is the rake setting? Factory is about 100mm across all 964 variants; I'm closer to 120mm higher in the rear.

Shamus964

So you have the KW's max UP in the front and max DOWN in the back, and you still have a rake of 120mm with the rear being higher? Something is wrong methinks.

Have you ever heard back from KW? I have dealt w/them (Adam) and they were pretty helpful. Have you double-checked the spring-lengths (both helper and main) in the front and rear vs. the specs given for the kit? Do you have the right kit for a pre-91 car with the different rear perch location? Also, could you please measure from the center of the wheel to the wheelarch just for a frame of reference.

PChar

Ferral, are you still running OEM size (16s) wheels?

I am running 18 " wheels on mine with KW V3 set at 58 mm above perch adjustment ring and I believe I am slightly below RS height. No problem with bad roads issues. I have set my rebound and compression a little more agressive in the front since the spring tend to run a little soft.

FeralComprehension

Correct.

I spoke to Brent (?) yesterday and while he was helpful he wasn't very informative. I got some stock answers about out of range adjustments potentially causing damage that wouldn't be covered under warranty and that KW doesn't necessarily try to replicate factory settings. I called KW Germany this morning and then sent a followup email at their request.

I haven't verified the springs; that's a good idea and I'll do it next time the wheels are off the car. According to the packaging my setup is for an early car, and the perches did bolt right in (the later cars have a different bolt pattern) so there shouldn't be any issue there, but good thoughts, thanks!

Front: 340mm, Rear: 315mm, so within the ranges specified by KW.

FeralComprehension

Yes, I have a set of C2 5-spokes and the original D90s.

ras62

Page 8 of the instructions shows about the same amount I have, this equates to RS +5mm. It sounds like you have the wrong shock or something drastic to be so far out on measurements.

Shamus964

Just for reference then you may have met your goal in the front, using the hub to wheel-arch lip as a measuring point which removed the tire from the measuring equation. I've got my levels and also some measurements of RS +5 from this thread: https://rennlist.com/forums/9033870-post18.html so I've done the math and it looks like you're right on in the front and 32mm too low in the rear...

340mm front / 315mm rear (FeralComp)
320mm front / 327mm rear (RS) - extrapolated from Boxsey's post in the thread I referenced above
325mm front / 332mm rear RS height +5 Boxsey911
320mm front / 312mm rear (Shamus964) - (I KNOW I'm too low in the back, basically 15mm too low)

ras62

340mm is roughly RS +20 yet FeralC stated he was RS -18? Confusing, one of those figures is wrong, I suspect the -18.

FeralComprehension

Well, the hub-to-fender measurement isn't factory proper- the factory measurements are "From road surface contact area of wheel to outer mouting hex bolt- "Crossmember to body."" I'll try and put up a photo later, but I'm no stranger to measurement tools and doubt that I've cocked this one up by 20% (though I've done dumber stuff!)

I just went and rechecked the easier measurements (Factory method front, hub to fender front/rear) and the figures I quoted are pretty close...

Shamus964

Some of it could be a tire construction difference - tire sidewalls aren't consistent by a long shot. The hub/wheelarch removes that variance, although it introduces some variance in that the front wings aren't always consistent either! Hand built car and all.

Close is all you'll be able to achieve at any rate, but I wanted to see where you were at w/the other measurement for an additional data point.

FeralComprehension

KW Germany sent my question to someone higher up at KW USA. I ended up speaking to Tom after a couple emails exchanged. He allowed that I could probably go 10mm higher in the front and that the potential issue is topping out the damper; there's no real bumpstop in that direction. At the rear, he thought that I could go quite a bit lower if needed- the only danger there is bottoming which is readily apparent and not terribly likely.

We had some additional conversation about KW's philosophy; he said they didn't really take the factory recommended geometry into consideration but rather worked for a drivable package. He also felt that while I should try and respect the factory's rake recommendation some divergence from that rec probably wouldn't make much difference.

So, I'll go a little higher in the front and drop the rear to get the rake right then see how it goes. Be a week or so before I can make these adjustments, but really, the car feels good even as it is with just a rough garage alignment.

Shamus964

Any pics of your car? Again - why you want to go lower in the rear escapes me since you're already lower than RS by a long way. Looking at the numbers you've given, something doesn't jive... I'm afraid either your under car measurements are off or the hub/wheel arch ones are.