I have a '94 coupe (daily driver only) with the stock front 73.2 and rear 39.3 (N/mm) leaf springs. I want better control over bumpy roads so I ordered a set of Koni yellow adjustables and need to use a softer set of leaf springs. Can someome recommend what spring rate would work well for this application? VBP said they can make any rate I want.

I also will install VBPs 32 and 26 mm sway bar to comensate for the softer springs.

 

Has no one ordered a custom tension leaf spring from VBP?

 

I don't believe mine was made to order but I have a VB&P spring that
they selected to meet a target I was seeking. In my case I was looking
for a higher rate.

I believe your 73.2/39.3 N/mm springs are the second softest rate used
for 88-96 C4's (the softest being the 60/26 N/mm.) Rear springs are
fairly easy to change but front springs require more disassembly of
the suspension.

My vote is that sway bars are devices for fine-tuning after adequate
springs have been chosen. Stepping down in spring rate and then
using the largest bars available may not be the most desirable approach.

The Koni Sport shock (Yellow Adjustable) at about $600 per set
is a LOT of technology for a 'daily driver only' vehicle. While they are
(single) adjustable shocks and thus able to be manually configured
for different conditions, this configuration requires effort and some
skill to accomplish well.

Before committing to changing your springs, can you provide some
more information about your usage, the car and the control issues on
bumpy roads? How/where do you drive? How much mileage, what
kind of wheels/tires and what maintenance on the vehicle? Describe
the circumstances and behavior you aim to improve.

Perhaps control on bumpy roads can be better achieved in another way.

.

 

The control issue over bumpy roads is mostly when taking a turn, the car will skip over the road if that makes sense. Also when driving in a straight path the rear end sometimes looses contact with the ground and shifts to the right or left if going over a bumpy road. I have Goodyear F1 tires about a year old (17X9.5 front and 17X11 rear) filled to 32 psi. The car has all new poly bushings, HD Bilsteins with about 50k miles on them, and all other suspension parts seem to be in good shape. From what I have read this is caused by a suspension that is too stiff without enough dampening. I would still like good control with a more pleasant ride. I am trying to accomplish the feel and control of some of the european cars that use soft springs, stiff shocks and fairly large sway bars (30mm would probably be a better choice than 32mm ). I was wondering if 60 N/mm front and 20 N/mm rear is adequate or if I should go for an even softer spring, and if this will acheive what I'm looking for. I drive this car everwhere so even a modest improvement will be worth it for me.

 

You may want to post this in the autox/roadracing forum; lots of experience in there with spring rates, shocks, sway bars, etc.

 

We can manufacture any spring rate or target range you want, that is true. However, Slalom4me is right that more information is needed and it may not be the springs.

It sounds to me like you may just want to change the shocks first. If you have Heavy Duty Bilstein Shocks, that may be the reason for the bounce. We offer Bilstein Sport Shocks which have been designed with more dampening to work best with composite springs and help to eliminate the bouncy feel when using a stiffer spring or one of our adjustable springs.

If you still feel like you need more control after you change the shocks, then perhaps you do need to try some springs, sway bars or making some adjustments to your rear rods. Also, a point to note, is that our components are also packaged in systems where we have determined which components work best with each other for whatever driving style you desire. We also discount our components when we package them in systems, making it more affordable then doing it one piece at a time. Not to mention time and labor of taking it apart several times.

If your Corvette is just a daily driver, the adjustables may be too much. If you plan on taking her out on the track some day, then adjustables are the way to go. You then have the ability to set her up for street driving, then on a track day make your adjustments and have at it. I always first recommend to my customers to decide a plan so you don't have to buy and then re-buy or take apart and then take apart again etc. What are your plans for driving your Corvette?

We would love to discuss your project further. Please feel free to call us toll free at 1-800-237-9991.

Best Regards,
Pattie Cooke, Sales Mgr.
VBP (Vette Brakes and Products)

 

I have a good condition front FX3 spring from my 95 if you are interested. It is the softest spring, I believe the 60nM. It could be an inexpensive fix, if it didn't work you wouldn't be out much compared to the alternatives.(it does have cut middle bushings, so it would lower your front)