MIKER

Has anyone performed this modification?
Was there a noticeable difference?
Why didn't GM set it up this way to begin with?

I was just reading through the Vette Improvement Program and I am considering performing this modification to my strut rod bracket. It says for '80-'82 Vettes, to simply modify the existing bracket and lower the holes down 1/2". ('63-'79 Vettes need only install a 1/2" drilled spacer between the strut rod mount and the bottom of the differential. (using 1/2" longer bolts!)
It says that this modification will lower the roll center of the rear and make the car hold the road better in constant turns. It cuts down the amount of camber change which results in better rear tire wear.

I can see how this would indeed help reduce camber change throughout the suspension travel but what puzzles me is why wouldn't GM have incorporated this simple, inexpensive, all gain, no loss modification into production???

I am seriously considering this modification. I would really appreciate any comments.

I think that this is a link to the .pdf download for the VIP article. (Pg 46-47 discusses the Strut Rod Bracket mod)
http://www.l81vetteregistry.com/vip.pdf

trw

From what I have read, you have to lower the exhaust also. Most have used 1" spacers.

Terry

Chris O'

Yes
No
??

:)

flynhi

I used the alum spacer on my 71 SB Conv before installing the Smart Strut. I was a novice at the time so it was hard for me to evaluate to effectiveness. But if Greenwood says it works, it works.
I have the spacer for sale. If interested:
will _shepherd@hotmail.com

Rowdy Rat

Actually, GM DID do this. In 1968, the strut rod bracket was modified from the 1963-67 configuration to lower the inboard pivot points in an effort to decrease camber change during suspension travel.

Considering that GM engineers are pretty smart characters, I would ask myself why they didn't lower the pivot points further than they did (they were obviously aware of the benefit of doing this). Was it simply an issue of clearance or was it reliability related? Personally, I doubt that ½" lower will have any ill effects on rear suspension parts, but then again, I'm not an engineer either.

I agree with the article that lowering the pivot points will reduce camber change. It SHOULD make the car feel more stable during turns, but to what degree this will improve handling I'm not sure.

Just something to think about...

Regards,


[Modified by Rowdy Rat, 1:11 AM 11/22/2001]

MARKUS_P

OK, first of all I´ve to say that zero degree camber changeis a good thing to have.
And it won´t hurt any suspension parts at all.
So why didn´t GM do this right from the biginning?
We all know that our vettes are fast cars with good torque and this means that if you´re not a well practiced driver you can create wonderfull unintentional 180 spins.
The only reason I can see why they GM decided to go this way is that they were probably thinking that the car gets more "fault forgiving".
I don´t know the amount of camber change, but as far as I know the tires wear down at the inside of the profile.
If you go into a turn, the vehicle weight forces the tire in and a camber setting as described before will help to keep the whole tire surface parallel to the pavement.
Nevertheless I´d go with smart struts or even this spacer to minimize camer change.
I´ll build my own 6 link susp. in appr. one month just the way Stingy has it.




[Modified by MARKUS_P, 6:09 AM 11/22/2001]

redvetracr

If and when (Because you ALL should) read the book "Chevrolet -Racing ? 14 years of raucious silence". You will get an idea who actually "builds cars" unfortunatly NOT engineers, BUT bean counters and lawyers. The "Corvette" was built for the masses, the average joe and NOT for the "few" (of us) who want to do more than "just drive it". There also was an statement "somewhere" where Dick Guldstrand said (among other things) basically, that the Corvette was built for (as he puts it) "joe average" the typical car buyer and the key to profits at GM. They want to sell a large volume of cars all based on the same design. To do this they MUST appeal to the large group of buyers in the middle of the market. If GM can`t sell hundreds of thousands of a particular part over the "life" of a model run, they are simply NOT interested. read the book and you will have a whole new understanding how GM operates (or at least how they did when our cars were designed and built) ...redvetracr

Lohkay

MIKER, whats this vette improvement program? A book? I'm very interested in it.

Pedro'74

Lohkay,

It's a series of articles written by Greenwood, published in the Corvette Fever magazine a long time ago (mid-80's?). You can download a copy from http://www.corvettefaq.com or use the link above.

-Pedro

427V8

GM cars ( and others too ) are made to be above all as safe as possible. This means the want the car to understeer since understeer is easier for a novice to drive and not kill themselves. That is why you see large camber changes front and rear on production cars.

People that like to dive fast want a more neutral handleing car so we have to undo a lot of things that are there for a reason, albet a bad reason :D:D

Hib Halverson

Lowering the inner pickup points for the rear lower arms on a C2/3 will improve limit-handling for all the reasons listed elsewhere in this thread.

The 68-82 pick-up points were slightly lower than those of 63-67, so a mid-year car can see a small gain in rear camber curve if the 68-79 bracket is installed.

Even better, because it lowers the pick-up points even more, is Vette Brakes and Products' "Smart Strut" kit that combines a new strut-rod mounting bracket with a set of high-performance strut rods. When we went to the 315/35ZR17 tires on the back of the Big-Block from Hell, VB's Smart Strut kit is what we used to optimize the rear camber curve for better handling and use with wide tires.

Anyone building a C2/3 and intending to drive the car hard in a sporting manner needs to consider this modification.




[Modified by Hib Halverson, 1:14 PM 11/22/2001]

Jason Staley

I have installed vette brake's "smart struts" bracket, which does the same thing as the spacer & factory bracket, and I also moved the rear end up in the car as mentioned in the Vette Improvement Program. With these two modifications, I very little toeout of the rear wheels and very little camber change. I haven't had my to a track yet to see just how good it is, but it is more predictable and sure footed than it use to be. In addition to these two changes I've also replaced the factory rubber x-member bushings with polyurathane bushings that I made. I wanted to raise the rearend - expecially since my car is lowered, but I didn't want all the rear end noise that would come from hard mounting the rear end x-member like the VIP program talks about. Anyway, I would definitely recommend using the spacer. It will make your car more predictable if nothing else. :flag