Corvette Z06 Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
52 Posts
Discussion Starter #1
I got my car cornerbalanced and aligned today. Here are the results:

Total weight: 3,209 pounds with driver

Left front weight: 875 pounds
Right front weight: 845 pounds
Left rear weight: 759 pounds
Right rear weight: 730 pounds

Front weight bias: 53.6%
Rear weight bias: 46.4%
Left weight bias: 50.9%
Right weight bias: 49.1%

Rake: 3/8 inch
Front camber: -2.3 degrees
Caster: +6.5 degrees
Front toe: 0
Rear camber: -1.4 degrees
Rear toe: 3/16" in total

The car turns in really quickly, which I wanted, but when looking at the car from the outside, it looks like it has too much rake. The rake was adjusted enough that I could feel the change from the driver's seat. I'll take some photos of the car this weekend with my girlfriend's digital camera.

What do you guys think?
 

·
Registered
Joined
·
602 Posts
How much fuel did you have in the car and how much do you weigh?

3209 lbs seems on the light side. My 2004 LeMans weighed in at 3300 Lbs even with me (200 Lbs) and about 6/10 tank of fuel.
 

·
Registered
Joined
·
5,491 Posts
Alignment looks good for AutoX but may need a touch of Front Toe OUT, like 1/16" or 1/8" each side, depending.

For high speed DE you will pprobably need to back off the front negative camber to around -1.8 to -2.0, otherwise the car will be too "twitchy" at high speed.

For both AutoX & High Speed you can adjust & tailor the Rear Toe IN for each course.

For the street it is a Very Agressive Alignment (possibly too agressive)and will wear the inside of street tires.

The true test of whether an alignment set up is correct (for the driving use intended) albeit street, high speed track or AutoX is actual tire temps across the face of the tire.

You've left out the most important suspension Spec:
Cross Corner Weight % Differential. What is it??
It should be as close to 50/50 as possible.
LF + RR = 1605# or 50.02%
RF + LR = 1604# or 49.98%
Yours is near perfect !!
I would try the car as it is and only make changes to improve the handling.

The only thing(s) I would consider changing are:

The optimum rake is 1/2". Yours is close but I would increase it to 1/2".

I DO NOT like your front to rear weight bias. It's too heavy in the front.
I would prefer something like 51/49 rather than the 53.6/46.4.

Note that increasing the rake will only make this spec worse.

You can effect the front/ rear weight bias a number of ways.
1. Changing the fuel load.
2. Physically moving things around in the car; such as relocating the battery to the back.
3. Dieting or Bulking up (F1 drivers do it all the time).
4. On a stock suspension the only adjustment is ride height at the spring perch bolts...but this will throw off the Rake, Corner Weights, Cross Corner %. It's a compromise on a stock suspension.
5. If your willing to change componants you can adjust Corner Weight seperate from Ride Height a number of ways
- Add ajustable sway bar links (preload can effect corner weight & ride height differently)
- Add Adjustable shocks (Bump settings will effect corner weight)
- Change leaf spring rates ( will change 2 corner weights simultaneously)
- Install coil overs (each corner spring can be individually tailored to spring rate, spring length, installed height, installed position and thus ride height and corner weight)
6. Physically remove things from the car such as A/C delete, Radio delete, Speaker Delete.
7. Use lighter materials & Hardware such as Titanium, Aluminum, Carbon Fiber
8. tire stagger
9. Add weight/balast (usually a bad thing and last resort)

Only make one change at a time.
Always check Cross Corner %.
 

·
Registered
Joined
·
52 Posts
Discussion Starter #4
The car weighs 3209 lbs. with me in it. I'm 135 lbs. The car has a lightweight ATI battery setup in it which probably got rid of 25 - 30 pounds, but it also has an LAPD tunnel plate in it, so it probably gained a couple of pounds there. In addition, the car has adjustable front endlinks, which is how the cornerweights got where they needed to be.

DJWorm,

Where do you take the rake measurements from? I told the person who did my alignment to use the suspension pickup points, but he said they were bolted onto the frame, and that he would rather use a point on the frame. I told him to use points that were as close to the tires as possible. My car looks like it has been lowered only in the front, but I don't really care how the car looks if the numbers and handling are right.

Oh well, at $225 for cornerbalancing and ride height, I'm thinking of getting my own equipment, especially if I'm going to be doing this a lot. Thanks guys!
 

·
Registered
Joined
·
602 Posts
What shop did your corner balance work?

I used West End Alignment in Gardena. Darren over there charges $110.
 

·
Registered
Joined
·
5,563 Posts
crznZ06 said:
Hmmm . . . Darin charged me $225.
For a good corner weight (and yours is perfect) and alignment, this isn't unreasonable and I wouldn't go to bed thinking you got taken.

My thoughts are exactly in line with DJ's. This is a very aggressive alignment for the street and you will eat through tires. If it is set up for a road course, you have a nice setup. I run a little bit of toe out in front as DJ mentioned. I'd run yours and see how you like it before making any changes though.

I sent you a PM about the rake with a little more info. :cheers:
 

·
Registered
Joined
·
602 Posts
That is what Darin charges for both alignment and corner balance. So that is consistent with his rates. I thought he did just the corner balance work.

My car was set-up somewhat more aggressively than yours. I have:
up front
-2.75
1/8 toe out

Back
-1.5
1/8 toe in

Rake I need to measure as I don't recall off-hand.
 

·
Registered
Joined
·
52 Posts
Discussion Starter #10
I might go to the California Speedway tomorrow to see if anyone drops out of the autocross so I can run. I might also go to the Streets of Willow if I can swing the money issue. Kinda tough though because I'm going to Spring Mountain next week.
 

·
Registered
Joined
·
5,491 Posts
You got your money's worth and a nice alignment.

The Rake measurments are taken on the frame rail just aft and before the front and rear wheels as outlined in the Service Manual.

You can however use a point on the frame rails at the axle center lines (traditional method).
These will be close but not exact and as long as you correlate with the Service Manual points and use the same method.

In a pinch (as at the track) you can use a thin sheetmetal plate on the ground underneath the tire and measure with a straight edge to the fender lip. Once correlated with the Service Manual points this methos is fairly accurate if the fender has not been pranged.
 
1 - 12 of 12 Posts
Top