Lowering the suspension

Stallion · 06-18-05, 06:19 PM

I stepped back from my '78 the other day and noticed that I have quite a bit of space from the top of the wheel well to the tire. Somewhat of a high ride, I guess you could say.

I have two things that are going through my mind. I could lower the suspension, or I could put new wheels and tires on her and lower the suspension.

Question is, how would I go about lowering the suspension on my '78? How is that done?

Thanks!

WARVET · 06-18-05, 06:48 PM

If your talking about your rear suspension you can purchase longer spring bolts very inexpensively. This will allow you to lower the rear without any trouble. The front suspension is more difficult. Basically there are 3 options. 1. You can cut the springs down. (this is not easy and can cause issues if you don't do it right). 2. Put in coil over springs. 3. Put in a C4 type mono spring. (both 2 and 3 cost cash). Hope this helps.

akfox1 · 06-19-05, 01:32 AM

I just did it on my 69 a month ago. I cut the front springs and got the longer rear bolts. New wheels and tires too. Here is the link. Hope this helps.

http://corvetteactioncenter.com/foru...ad.php?t=67690

Stallion · 06-19-05, 02:29 AM

First off, what are coil over springs? I thought we just had the basic coil spring for the front suspension. No? How are these coil over springs be different then our front suspension now?

akfox1, I love what you did with your '69. So it's no big deal taking one coil out of the front springs? 1) how did you cut the actual springs? With what? 2) how did you know you did it "right"? It seems like one of those things that if done wrong and inaccurately, it could be terrible in the end.

I also like your wheel/tire combination. Those Torque Thrust IIs look real good. I was thinking the same thing (it was between that and the Cragar S/S). Did you have to modify anything else or would TTIIs bolt directly on my stock '78 drivetrain with no modifications or problems?

Thanks!

fine69 · 06-19-05, 08:48 AM

Hi Stallion,

To replace my stock coil springs, I purchased a pair of "Gymkhana" style front coil springs from Vette Brakes and Parts. The sales rep informed me that these springs have a 550 lb/in rating which supposedly helps handling and would be perfect for a big block.

He also said these springs inherently make the car sit lower.

I hope helpful.

-R

80convertible · 06-19-05, 11:33 AM

If I remember correctly, cutting a coil spring makes it stiffer so your 550lbs springs are actually stiffer than that. If I were to purchase new springs to cut, I'd consider VB&P 460lbs grand touring springs.

Stallion · 06-19-05, 03:11 PM

Why not just cut the stock springs that I already have on her?

JohnZ · 06-19-05, 03:23 PM

Cutting coil springs to "make the car look better" is NOT a good idea; opens up a whole new can of worms relative to spring rate, geometry, bump steer, limited jounce travel, bottoming-out on the jounce bumpers, loss of adequate adjustment capability for caster and camber, etc.

Stallion · 06-19-05, 04:12 PM

Then what do you think I should do, John?

80convertible · 06-19-05, 07:25 PM

Quote:

Originally Posted by Stallion

Then what do you think I should do, John?

I'd give the folks at Vette Brakes & Products a call and ask them a few questions. They are very friendly and will always answer tech questions.

JohnZ · 06-20-05, 01:01 PM

Quote:

Originally Posted by Stallion

Then what do you think I should do, John?

Unless there's some obvious functional problem, I'd leave it alone.

akfox1 · 06-20-05, 01:06 PM

Quote:

Originally Posted by Stallion

akfox1, I love what you did with your '69. So it's no big deal taking one coil out of the front springs? 1) how did you cut the actual springs? With what? 2) how did you know you did it "right"? It seems like one of those things that if done wrong and inaccurately, it could be terrible in the end.

I also like your wheel/tire combination. Those Torque Thrust IIs look real good. I was thinking the same thing (it was between that and the Cragar S/S). Did you have to modify anything else or would TTIIs bolt directly on my stock '78 drivetrain with no modifications or problems?

Thanks!

I cut the springs with a portable band saw. I cut off one full coil, but if I were doing it over, I would only cut about 3/4 coil. The only thing to watch is getting the coil seated again in the upper pocket, otherwise it is very straightforward.
The wheels are 17", part #5057861 from American Racing. They bolted right up with no mods.
I have no problems with geometry, handling, etc with the cut off springs. You do have to do another front end alignment when you get it all back together.

VBP · 06-22-05, 02:23 PM

Because of the age and probable mileage on a '78, the stock springs are probably fatigued and the ride height and quality are not anywhere near to what they should be.

While we don't recommend cutting your coil springs (FYI: 1 turn would be way too much), you can do it with a circular friction saw, cutoff wheel, etc. Just don't use a torch or any kind of heat.

The best thing would be to buy some coils that will drop the car since you have to pull out the stock ones anyways to cut them. Here is a link to the 550 coils referred to earlier in this thread: http://www.vbandp.com/detail.aspx?ID=357 . With the Corvette Forum discount code, you are only talking about $71.95 for the pair.

As far as coil overs, we have had much better test results with transverse composite spring systems - but that debate has been going on for years.

Here is a link to the coil overs sold by Mid America: http://www.madvet.com/shop?frame=1.6994 ... I (personally) have always had good sales / service with parts from Mid America...

Hope this helps.

Alan G.
Vette Brakes & Products, Inc.
http://www.VBandP.com
800-237-9991