Wheel alignment issues

[Damon88]

I just had a wheel alignment done from my local P dealership. Things didn't go as planned and was a little frustrated.

I booked my car in 3 weeks prior, to have the suspension adjusted Euro ride height, Corner balanced and wheel alignment done. My car gets dropped off, only to get a call later that day explaining that this is a major job that could potentially get expensive and takes days to get done. Explaining to me that setting the car to euro ride height and corner balancing is a tough job. I explained, I knew the process of doing this and kind of job, but got the hint that there was no time for this now. So to move ahead with wheel alignment and see how things go..At this point I agreed, so I could get my car back by the next day,

Backstory..

I just finished rebuilding everything on suspension and installing turbo tie rods. The only thing I didn't replace was the Spring plate bushings as they were done by the PO couple years back. The car was at, or very close to euro ride height before I removed the old parts.

So the wheel alignment is completed and I pick up my car. Was told they did the best to get it within OEM spec. Was then told that if I wanted it set up for more back and twisty roads, they would have set it up a differently and to come back another time. In all fairness, I never gave them any information on how I wanted the alignment set up.. I just wanted it to be a great daily driver and many spirited drives.. I was also told if I want it to be set up to Euro ride height I should remove the spring plates myself and get is close, then they will do the minor adjustments with another wheel alignment. If not then I could potentially be looking at a very expensive bill..

Measuring on a flat garage floor to top of wheel well, these are the measurements.

FL 25"
FR 25" 3/8
LR 25" 3/8
RR 26"

Side note: My car drives and brakes straight, so that's a positive ... haha

Not sure where to go from here... I'm not trying to bash the dealership..just explaining what I went through. Next I will try and find another shop that's willing to just make a little effort to get the car set up properly. Sorry for the long post. Would love some thoughts on this. Also thoughts on my wheel alignment.

Cheers to all.

[AndrewCologne]

If you want to drop an US spec SC to Euro height, then you have to dismount the front shocks at their top to take out the spacers before you can adjust the Euro height at the front.
After that the rear axle plates have to be pulled and re mounted with a specific angle to match the Euro height finally. Finally the needed fine adjustments at front and rear will give you the final wanted exact height.
BUT! It's not only about the visual height itself you measure – to result in an optimal adjusted suspension you finally should do a proper measure of the weights at all wheels. In German it's called "radlasten".

[blur911]

I wonder how many US cars have already had the spacers removed years ago by previous owners?


Don't go by fender heights, it varies with tires and wheels.
In front you want to end up with the control arms at least level, but preferably slightly inclined up towards the center of the car as a starting point for corner balancing.

Somewhere I have a diagram of the optimal angles of the front control arms and rear trailing arms for "Euro height". I'll look.
Edit: Euro ride height

Too bad they took out so much rear camber, a bit more would be nice IMO.

[Nditiz1]

I just went through a similar exercise to get a previously wrecked car to go straight. The car was previously a race car so it was low to begin with. I will say that there are some stock adjusters on SC spring plates that allow the rear to move slightly. Luckily in my case I had the upgraded adjusters on my plates. What blur911 said is key, you can't go by fender heights and various tires. Hell, if your car has ever been wrecked you might not even be able to go by actual ride height.

I did not realize how important corner balance was until I saw how far out of whack my car was with the ride height I wanted. My car sits lower than euro ride height and rides pretty good now. While my corner balance is almost perfect I have had to sacrifice ride height being even across the car. It is only a looks thing and I'd rather have a car go straight than look perfect in the wheel arches. My situation is very different from yours, but the point I'm trying to make is how does the car feel?

Something else that is a little bothersome is the aggressive rake. Your numbers show the front to be lower than the rear, but I think even stock ride height has the rear lower than the front from the fenders. Again ride height should be measured from torsion bars and not fenders.

[Damon88]

Andrew, thank you for responding. I installed new struts and rear shocks. I removed the front spacers.

Blur911, thank you also for responding. Good to know and this makes sense. I will re measure based on what the Bently manual says. I know nothing about good alignment set up for these cars. Interesting to hear about your rear camber comment. I will do some more searching and see if I can find some other people's set up and compare. cheers and thank you for the link.

[Damon88]

Originally Posted by Nditiz1

I just went through a similar exercise to get a previously wrecked car to go straight. The car was previously a race car so it was low to begin with. I will say that there are some stock adjusters on SC spring plates that allow the rear to move slightly. Luckily in my case I had the upgraded adjusters on my plates. What blur911 said is key, you can't go by fender heights and various tires. Hell, if your car has ever been wrecked you might not even be able to go by actual ride height.

I did not realize how important corner balance was until I saw how far out of whack my car was with the ride height I wanted. My car sits lower than euro ride height and rides pretty good now. While my corner balance is almost perfect I have had to sacrifice ride height being even across the car. It is only a looks thing and I'd rather have a car go straight than look perfect in the wheel arches. My situation is very different from yours, but the point I'm trying to make is how does the car feel?

Something else that is a little bothersome is the aggressive rake. Your numbers show the front to be lower than the rear, but I think even stock ride height has the rear lower than the front from the fenders. Again ride height should be measured from torsion bars and not fenders.

Thanks Nditiz1, I agree on the corner balancing. I wanted to have this done.. But clearly they didn't seem to want to do it. If they actually did the work that the car was booked in for, I'm sure these issues would have been dealt with. I don't know anything when is comes to alignment numbers. So I'm not sure about the aggressive rake.. I'm going to reach out to some other shops next week and see if I can get everything done. Unfortunately I will be paying for another alignment after lowering and corner balancing .

[Nditiz1]

Your alignment numbers don't look all that bad. This is going off memory and talks with icarp. Should have written this down LOL

Fender ride height
~25" up front
~24.5" in the rear

Should be 1/2 difference front to rear

Toe should be 0 front and rear
Caster looks good ( probably the max and both sides are close to each other)
I think camber should be 0 as well

Combination of icarp and Ray Scruggs and my forgetful memory.

[PeteKz]

Damon, you didn't say what your objective was for changing the ride height and alignment. Appearance? Street driving pleasure? Autocross? hard track use? Correct odd handling or tire wear? Those require different alignments. Since you took it to a Porsche dealer, I don't think you are setting it up for the track or autocross. The people who are serious about those sports do their own alignments and keep detailed notes of what they changed and how that affected track times.

That puts you back to appearance or street driving pleasure. Unfortunately, those also conflict. If you want the low rider "tuner" look, the suspension will suck. Truth. If you want a car that's great to drive on the street, then stick pretty close to Porsche's Euro recommendations (after removing the spacer). At least start there. If you still want a lower look, then think about installing raised front strut spindles and/or shorter diameter, lower profile tires. I agree with Nditiz1 comment: your current rear ride height is too high, and probably makes it look like a stink bug! Another problem with lowering below stock Euro ride height is that you start hitting the rubber bump stops in the shocks and struts during street driving. Then you need to install stiffer torsion bars, and then that creeps into replacing more stuff than you planned.

Next, who should do your alignment? Obvious answer, YOU. The hardest part is getting a flat floor on which to do your measurements. After that, strings, straight 2x4 boards, a carpenters square, your eyeballs, and patience are at least as good as the fancy alignment racks the dealer has. The reason they use those racks is not for precision, but because they can do it fast. I do not think they are all that accurate either, as I have seen numbers off by a degree on the same car when checked on different racks.

Even more importantly, you should change your alignment based on your tire wear and handling. If one or more tires are wearing on the inner edge more, then take out some camber on those wheels, and vice versa if they are wearing on the outside edges more. If the tires are feathering towards the inner edges of the tread blocks, take out some toe. If the car tends to dart to one side or the other, put back in some toe at the end that seems to be moving (rear end toe out makes the car feel like it's riding in and out of ruts in the road). Caster should be set about the same on both sides and to Porsche's recommendations. I experimented with the max and min caster, and the max on one side the the min on the other, and it didn't make much difference in handling, so your current numbers are probably good enough.

Ride height: Yes blur911 referred to a procedure that Porsche specifies for setting the suspension height based on the differences in height of suspension parts, but's it a PITA, and I don't think it makes a functional difference compared to the fender height method. If you have tires about the same diameter as the original tires, then your ride height numbers should be close to 25.5" at front fenders, and 25" at the rear fenders. If your tires are taller or shorter than the OE tires, add or subtract the difference in radius of your tires. It's much more important that you measure on a FLAT floor. Your garage floor probably is not as flat as it looks.

Do NOT go lower than these fender heights, because the changes in your roll center height will adversely affect your handling (it will actually make your car want to roll more in front), and you'll start compressing into the bump stops. Exception: If you install struts with raised spindles on them, then you can go lower on the front ride height by the amount of that spindle change. You can search for posts from Bill Verberg here if you want to see the graphics of roll center geometry. You can also look them up in Fred Puhn's excellent book, "How to Make Your Car Handle."

Corner balancing: I found out how significant this is in 911's after I installed RSR front bushings in my car over the winter. If your car drives straight under acceleration, braking, and cruising, it's probably close enough. You should get it done eventually, but because most of the other changes to the suspension will change the corner balance, you should do that AFTER you get everything else dialed in.

Adjustable rear spring plates: Nditiz1 referenced these on his car. I have them and like them. If you think you will be playing with the rear height adjustment and corner balancing more often than "set it and forget it," these are nice to have. And if you want the low look for the times you drive it to cars-n-coffee, you can lower them quickly before you go, then crank them back up to normal height for street driving.

And a question: What new struts and rear shocks did you install?

[blur911]

Like Pete says, a lot of us end up doing alignments at home with string and rulers. I've had better luck with that than with most alignment shops. Several times I've seen them not tighten the rear bolts enough and things move at the track.
Also as Pete mentioned, don't go too low or the roll center height gets wonky. Why I mentioned not letting the control arms get lower towards the middle of the car.
The front is simple to adjust, an 11mm wrench will do, I'd recommend lifting with a jack if you are trying to raise it using the adjusting screw though, makes it easier to turn. Also, figure out how much fuel you want in it first, I try to do it with at least half a tank, it does affect height.
As for camber, I'm running -2 degrees in back and -1.5 in front, it's set up for track and autocross, I believe stock Euro camber is zero front and -1 rear. I also raised the spindles on mine 19mm, so it sits that much lower while keeping proper front geometry. (stiffer springs too all around)

I also rolled the fenders on mine, so the combo of all the above makes fender measurements mostly irrelevant to compare to other cars, but a good reference point to have when adjusting things.

[Damon88]

Peter, Nditiz1 and Blur911, I appreciate all the help with this and you input. I have completely rebuilt the car with all stock suspension parts. I installed Bilstein B6 struts and shocks. I just want the car to be set at Euro ride height and no lower. My car will be a daily driver with lots of redline back road drives. I read through the Bentley and 101 projects books last night to understand how to measure the ride height and adjust. Before I replaced all these suspension parts, the car was set at Euro height. I rebuilt the car myself and have a good idea on setting this up. But after a long year of working on my car, I figured, taking it to the dealership to have the ride height/corner balanced and alignment would just be easier and done correct...nope. So I will go back to the drawing board and do it myself as both of you mentioned.

blur thank you for giving me your alignment numbers and link. This helps me a ton. I searched the forum to see if I could find others numbers with not much luck. Just do I could compare to what I have.

The positive of this ... more garage time !! haha

[phelix]

Is it just me or are the recommended values on the alignment sheet bizarre?

Front camber between 0.3 and 0.7 degrees
Rear camber between -0.2 and 0.2 degrees?

It’s like they’re meant for bias/cross plys?

[blur911]

Originally Posted by Damon88

Peter, Nditiz1 and Blur911, I appreciate all the help with this and you input. I have completely rebuilt the car with all stock suspension parts. I installed Bilstein B6 struts and shocks. I just want the car to be set at Euro ride height and no lower.

If you didn't re-index the torsion bars it shouldn't be too far off, just adjustments. Did you have the torsion bars out?
Are there any Road-racing type shops around you, they're probably the only ones with scales to corner balance?