rockhouse66

I do not understand how the positioning of the struts (front and rear) in the slotted holes affects the alignment. Can someone explain? Is relocation of the strut mounts in the slots considered part of the alignment process? For what purpose?

I ask because I had my car aligned today at a tire store that seemed proficient. There were lots of small adjustments needed - no surprise, I bought the car a year ago and have no real service history on it - but in the end they were unable to achieve the correct camber on the right side of the car.

My car is lowered on Techart springs and I expected it to have a lot of negative camber but the left side is in spec and the right side has more camber. The technician made a large adjustment in the position of the RF strut at the upper mount. He made NO adjustments to either side on the rear upper mounts.

Wouldn't some movement of the rear upper mounts result in a change in the camber? All of the DIY spring replacement write-ups suggest you mark the location of the upper mounts so that you can put them back where they were when you reinstall. Why? Just to keep the original alignment in the ballpark or ?

I am not unhappy with the alignment (yet) but trying to understand which adjustment affects which measurement.

Slakker

Just had my alignment done by a Porsche race shop after lowering and they did not mess with the upper rear mounts, only the front. They were able to get -1.8 camber on each side just by adjusting the tops all the way.

They wanted -3.5 so I've purchased adjustable camber mounts for the front which add 1.5 degrees more available camber which is close enough. Your other option is GT3 control arms which will allow you to get as much camber as you want and fix any caster issues while you are at it.

FYI, I had a coupon for a local alignment place that discount tire gave me for $75. Instead, I used the race guy for $250. But they also got the preload off my drop links and checked for any other issues. At least for this initial setup, getting it done right was worth the extra. Plus, I picked his brain the entire time while his help did the alignment. That alone was probably worth it.

rockhouse66

Here is the alignment sheet and I wonder why they couldn't get the right side camber to equal the left side - especially when no changes were made to the rear strut mounting....??? Perhaps the way the rear strut mounts to the suspension, it doesn't really have any effect at the rear?? (if so, wondering why we mark the original location when doing work on the struts)

Slakker

That doesn't look right at all. How far did you lower it? Did you add anything else besides the springs?

rockhouse66

It is just lowered on Techarts and Koni Sports. I don't want to start a critique of the results as much as I want to understand how adjustment/movement of the strut tops plays into the alignment results.

Other than the right side camber, this all looks OK to me and is surely better than it was. The purpose in getting the alignment (other than having had all 4 struts out of the car) was to try to reduce what seemed to be extreme inside rear tire wear. Seems to me I am still going to have an issue with the RR in this regard.

rockhouse66

OK, I found some info on line that says the front camber adjusts with the upper strut mount and I see that it was moved quite a bit on the PS so I think they made a best effort to reduce the RF camber though I don't understand why it could not be reduced to match the LF.

I still haven't found anything on the rear struts but I am guessing that the camber is not adjusted by the top strut mount, though I still don't know what effect moving the rear upper strut mounts in their slots may have on the rear alignment.

Slakker

So if you assume that the alignment shop is competent, front adjustable camber plates and rear adjustable upper control arms (dogbones, set of 4) will solve your problems.

If you are interested, I have a set of used adjustable camber plates that I picked up on RL Classifieds but don't need now (just bought a used set of GT3 lower control arms which do the same thing). $300 shipped.

http://www.rennline.com/Sealed-Front...oductinfo/S20/

DBJoe996

Adjustment/movement of the strut top obviously changes the camber of the wheel. You have a before and after alignment diagram but that is just relative. The real question is - what are the correct specs for your lowered car w/Techarts and Koni Sports and how close are you to those specs? Of that I have no idea. Maybe someone knows.

jj1

How old are your springs? I'd figure out WHY the alignment is uneven. 1deg isn't a crazy amount, might just be too low that you can't compensate.

Front suspension is McPherson strut. The hub is mounted to the lower control and toe arm below and to the shock up top. So the shock mount is part of the alignment geometry. In the rear it's a multi-link system. The hub is mounted to a similar control arm/ toe arm below and two "dog bones" up top. They control the geometry in this set up. Changing the angle of the rear shock will not affect alignment.

Slakker

Sorry, I just reread the thread and I don't think I answered any of your questions in my previous posts. Yes, the front camber is adjusted using the upper strut mount. The rear camber is adjusted using the eccentric camber adjustment on the control arm. It is the funny looking bolt that looks like it has a sundial on it. The rear upper strut mount is not used for alignment (as jj1 stated).


Also, here is a good article that talks about the different things that can cause alignment challenges:

http://www.pelicanparts.com/techarti...ur_Carrera.htm

rockhouse66

Thanks all. I'm up to speed now I think. I compared the alignment specs between factory lowered setup (X74) and all the other configurations and the only difference is the camber which is a little more negative front and rear. The rear spec is 1 deg 40 min so I am close to that on the LR but not the RR. Slakker - thanks for the offer but I am going to dig deeper to learn why the camber is in range on one side and not the other before I start adding aftermarket parts.

alpine003

Has this car ever been in an accident before? That could be one explanation why they can't get the right adjusted correctly.

rockhouse66

Well, I don't think so and Carfax doesn't think so but that doesn't mean it hasn't. Would have to be a peculiar accident to affect camber alignment both front and rear on the right side of the car unless someone just slid full sideways into a curb.

Slakker

Could also be worn out bushings.

alpine003

Not really rare as you might think. I've seen it a few times. More recently, one of the guys I know drove though a big pot hole on passenger side. Just bent both front and rear control arms enough to not be able to get alignment in spec. Otherwise visually it didn't look noticeably bent in anyway. This particular scenario is probably not likely though in your case since our control arms are cast and would most likely crack or break.

Who installed the suspension? Did they line up everything correctly? (spring to the strut to the strut mounts)