Hi folks,

I recently had my C5 coupe lowered about 3/4" (not too much) and had an alignment done today at a place recommended by a friend. I was a bit dubious of the shop, but they had a new Hunter machine, and based on the recommendation, I went for it.

I've got two questions...
a) prior to the alignment, the inside of the two front tires was significantly more worn that the outsides. Based on looking at the alignment figures below, I'm suspecting this issue will repeat (is it the fact that the camber is at -0.5 rather than closer to -0.2, the preferred?)
b) The Corvette shop manual shows specified range for front caster at 6.4 - 7.4 (6.9 is recommended). The guy didn't follow my (provided) alignment specs from the manual and instead used what the Hunter machine said was spec (which was 6.9 to 7.9), and the actual reading was 7.7. So this suggests that the front caster is now out of spec per the GM guide. After asking him later, he said it wasn't a big deal, this figure just adjusts how the steering reacts, and that it was fine.

I'm wondering if I should go to another shop and get this redone, or (tell me honestly), am I just being overly **** here?

Here's the data...

Setting Range (per GM manual) Actual (left) Actual (right)
Front indiv. camber +0.3 to -0.7 -0.5 -0.5
Front indiv. caster 7.4 to 6.4 7.7 7.7
Front indiv. toe +0.14 to -0.06 0.03 0.04
Rear indiv. camber +0.32 to -0.68 -0.5 -0.2
Rear indiv. toe +0.09 to -0.11 -0.01 -0.02

Cheers
Jason

 

Do you have the before on the toe? I find toe eats tires more than camber..

---
Tom
99FRC

 

The before toe probably will not help since he had just lowered the car and that reading wouldn't show what it was before the car was lowered. I would go for more toe in at the front. I found that I got better street driving if I slight toe in especially with Run Flats. The car was less darty on irregular road surfaces with just a scosch of front toe in. It is interesting the rear camber setting is so far off from side to side. Although it is within spec (factory settings are wide) the guy should have been able to make it close to equal easily.

Personally, I would have been upset with the guy if he didn't set it where I said I wanted it. My local GY store just did one for me and the manager let me stand by the machine while he made the adjustments and explained each step he was performing. When he couldn't get a certain setting he recommended what he thought should be done and I had him try a couple of things to make sure the setting couldn't be reached in another way before we proceeded. It was a mutual effort and I quickly came to trust his ability to do the job.

Bill

 

When my cars get aligned, I usually get a sheet showing the specifications before and after.

depending on how much toe, tires can go quickly (experience on the daughters car. took 1 week to trash both fronts tires). Jason indicated he didn't do an alignment right after, but some time did pass, as indicated by his verbage.

I like a bit of toe out on the track. Helps in the corners. But too much can really make it change lanes whenever it wants. That's darty.

I too will not let anyone do alignments if they can't do it to my settings. I still have not taken my race car to a shop, but have been thinking about purchasing the tools to do it myself. Just can't find someone to trust.

 

Tom,
I just happened to think of something that I saw happen to a 5 Liter like yours last year. I was at a BMW club school at the Glen when one of the instructors put his 5 Liter (about the same year as yours) into the Carousel guard rails at speed. The corner worker that came over afterward to look at the car said it just shot off to the left all of a sudden. After some inspection the owner discovered the lower left ball joint was broken. It had what appeared to be an old crack and then freshly broken metal. This was in an area where the he could not see it when inspecting the car. Although, this could happen to any car I thought I would mention it since your car may have seen as much track time as his did. They do seem to make great track cars.

Bill

 

I would run less caster in the front (about 6.5) but that does not bother me as much as the toe out in the rear. With stock bushings on that car that will be a ton of toe out with the car under drivetrain load going down the road. I would set the car with about 1/8 inch of total toe IN in the rear for a street alignment. The front toe looks Ok and the camber is Ok the cross camber in the rear is a little slopy.

 

Yep. can happen to anyone/anycar if not maintained. Thanks for worrying, but my lower control arms are pretty fresh. about 2 years old now. With new Steeda X2 ball joints.

My last event went flawless. I think the 86 Mustang was scared because it saw me sell the 93 Mustang and buy the 99 FRC, and it was worrying about it being replaced..

Half the fun is in the making of a track car. Mine is an 86, and is part t-bird, part late-model-stock-car, part vendor, and even some 94 Mustang tossed in for good measure. Stripped and gutted to about 2900 pounds, with a mild engine (320 hp) for durability. Very tossable in the corners.

 

Hi folks,

Wow, thanks so much for your feedback. Let me try to address the comments/questions:

a) 5.0 Racer, the 'before' specs for me were (sorry about the formatting, I can't get these to seem to line up right):

Setting Before (left) Before (right)

Front indiv. camber -0.6 -0.4
Front indiv. caster 7.7 7.7
Front indiv. toe 0.01 -0.07
Rear indiv. camber -0.5 0.1
Rear indiv. toe 0.22 -0.17

So, the settings that were out were front right toe and rear left/right toe.

b) The old tires that were worn were all Goodyear stock runflats. The new tires that I have on the car are non-run-flat Michelin Pilot Sport PS2's (same as stock sizes)

c) The car is entirely for street driving (somewhat aggressively at times around the corners, but nothing like that needed for a track situation).

d) I didn't cut the bushings - just lowered 3/4".

You'll have to forgive me folks, as I'm not a tech master (you'll have to dumb down the comments for me a bit ). I guess the question I have is,
1) Do I need to get the front caster redone (Dale C, you are suggesting 6.5 instead of the 7.7 I have now) - what does that actually translate into (i.e. how will this impact how it drives/wears?)
2) Should I also get the front camber closer to the factory suggested -0.2 to prevent inside wear to the new tires?)
3) Dale C, when you say 1/8" toe in, can you clarify? (the data I'm reading I believe is in degrees)...again, forgive me, I'm a bit of a newbie.

 

Hi folks,

Sorry, just one more question - how accurate SHOULD they be able to get on these settings. The shop fellow said that adjusting one setting will change all the others, so I don't want to be overly silly when I provide the specs. (i.e. are they usually able to get within +/- 0.1 degree of all settings, or is that too tough?)