Alignment question
 

Shortly I'll be taking my 87 in for a wheel alignment, the ride height has been lowered to Euro spec or slightly lower.
My question is; do the alignment specifications change for a lowered car or should the shop target the stock NA values?

Thanks
Blair

Blair,

When you lower the ride height of your car it will change the camber and toe settings,best thing is to have it corner balanced and realigned after you set the final ride height ...

Cheers !
Phil

I think what Blair's asking is when the car is lowered, if you should still adjust the alignment to the same specs or requirements as not lowered.

I can't answer this question with certainty, but I suspect that the alignment numbers should fall into the same ranges (roughly) whether lowered or not. Certain things may be forced upon you, such as front camber limitations (can't get more/enough neg. camber) or requirements (need more due to clearance issues).

All alignment specs are based on factory height. Once lowered, alignment specs are not longer possible, which is why all alignments always begin with ride height measurements.

????? The alignment specs are no longer possible? What does that mean? They should be possible unless his car was lowered a whole hell of lot.

I'm not going to stick my nose any further into something I don't completely understand, but will make a couple suggestions. Do a search and read. Start with this: http://forums.pelicanparts.com/porsche-911-technical-forum/614969-chime-my-alignment-specs.html.

You're right in that your settings will have changed due to the lowering and that getting them set correctly now is important. Your requirements will vary depending on what kind of driving you do. Cruising, puttering around town, spirited drives in the country or general stuff most people do, and the factory specs should be fine. Autocross or DEs will impose different requirements.

If you want the factory alignment specs, I see no reason you can't do it. My car is significantly lowered, and my alignment isn't that much off factory. It's a bit more aggressive, but I don't do a lot of track driving with it, either.

If the chassis is straight, lowering below euro may lose the positive camber adjustment range.

I lowered mine a bit lower than euro and it was quite difficult to get less than .5 negative camber. I ended up having to cut the fender to push the strut outward. My final reading was 0.75 negative camber front and 1.5 negative camber in rears.

At Euro height you will not have issues in obtaining Factory settings.

Also, if you go significantly lower you will most likely need a bump steer kit.

+1 set desired ride height, corner balance then align.

Jim, when you said you had difficulty going less than .5 negative, did you mean to a smaller number like .4 neg or .6 or .75 negative (what I suspect)? If the latter, that makes sense as many have expressed difficulty getting lots of negative camber up front. My camber is pretty close to yours, or perhaps the tiniest bit less. I think that was my limit for easy alignment. I would have preferred - .75, but I'm close so didn't muck about with it more.

Blair says he's at Euro height, so shouldn't have difficulty going with stock camber up front, as the factory specs indicate 0 degrees plus or minus 10'.

And a big plus 1 on the bump steer kit. It makes a HUGE difference, mind you I have raised spindles which might help a bit as well...

Just looking for to meet the "stock" settings, looks like I'll be OK.
Plan to corner balance prior to alignment.
Thanks for the feedback.

Blair

I could not get any less than .5 negative camber due to how low I went. It just would not go any further out.

My buddy with his 86, totally dumped it can't even get his arm under the car, the most he could get was 1.2 negative camber, we were trying to obtain 1.0 or less but he was maxed out. The only other option was to re-position the spindles.

first, to make sure we are all clear on this. if the top of the wheel angles in towards the center of the car from perpendicular, that is negative camber. if you move the top of the strut in towards the center of the car, that is in a negative camber direction and if you move it out, that is in a positive direction.

lets go over how the suspension is suppose to work.
lets start with zero camber and stock ride height, going straight and just the wheel moving up and down.
as the wheel moves up, due to the angle of the lower control arm, negative camber is created by "pushing" the bottom of the wheel out. as the wheel moves down, the bottom of the wheel moves in creating positive camber.
draw a circle and then draw a line from the center to the outside at about a 7 oclock position. as that radius (lower control arm) moves up, the point at the end of the radius gets further away from a perpendicular line drawn down the center of the cricle, until a max distance is reached at the 9 oclock position. just for numbers sake, lets say we have 2 degrees negative camber at the 9 oclock position. anything past the 9 ocloack position starts to add positive camber, which is bad.
so as you lower the car, the lower control arm changes its angle. we started at the 7 oclock position and zero degrees and now we have lowered it to the 8 oclock position. if nothing is changed, now we are sitting at 1 degree negative camber.
this is where you are at and things get tricky.
if you reset the camber back to zero, you can only gain 1 degree of camber from 8 oclock to 9 oclock, but....now you have to start limiting the travel of the suspension because you dont want to go past the 9 oclock possition because you start to lose that negative camber. so now comes the Tbars and sway bars. if you leave it at 1 degree, you get the added 1 degree as was intended originally, but now you have to think about tire wear and perhaps a little loss is braking since the wheels are no longer flat on the ground. where oh where to compomise.

back to reality. as the guy above was trying to say, i think, is that as you lower the car, you reach a point where the top of the strut can no longer be moved out to obtain the stock settings for the original ride height, which you may not want to do anyway.

another thing that comes into play when lowering is the change in roll center. im not going into that because i cant explain it well enough here and there are a lot of good books that can.

i know i did not give a real answer, but hopefully you can now make one on your own, or at least under stand what is going on, unless you already did.

if there is a spec for euro height, i would use that, or, i would go with something between the stock camber setting and the camber at the new height,