steve40th

Just curious what path to go here in Hawaii. I am stick in this class, and everything in my class is WELL prepped.
Besides tires, which are obvious. WHat leaf spring, sway bar, shock, end links etc etc would you get. VB&P?
No coil overs here, rather stay with leaf spring.
I see some very stiff suspensions in BSP, so lay it on me!
Current set up.
93 Auto, ZO7 1991 sway bars, QA1 shocks, Soft 1993 springs, Urethane bushings in rear compnents from Bat wing, to camber bars. Still have original ball joints and bushings up front, 140k miles, and use 275/40KDs up front 315 KD's in rear.

ltborg

well its good you dont want to go to coils because im pretty sure you cant in sp since it changed the type of spring being used. i know a bunch of people who just change sway bars to stiffer ones and leave the stock springs. vb and p has a popular set. id get at least z51 springs if not something like the 1984 z51 springs but i dont know what the national guys are running in terms of that.

i do know the nationals cars run 315/315s or 315/335s so if you would be willing to go up in tire size, it could help dial out a little understeer and give you more grip.

i know these cars are camber challenged (i could only get about -1.2 in the front of my old one) so you could use some offset bushings for the lower a-arms, but im not sure if you can run them in sp, check the rule book.

theres a lot more you can do (headers, intake, race seats, etc) but hopefully that gives you an ok start.

Solofast

At least get the 1984 Z51 springs, your springs are way too soft for a competitive stock class car. Bigger bars would help too, with the caveat that you can't go too much bigger on the rear bar without getting into a jacking problem.

Lower the car in the front by taking out the shims on top of the front springs, and in the back with longer bolts. Use slimmer under spring pads in the front or replace with a piece of teflon so it won't damage the control arm. Cut the height of the bump stops in the back or you will be bottoming on them. This also defines the practical limit on lowering back there.

The offset lower control arm bushings in the front are required, that will get you the -2 degrees of camber you will need in the front and there will be less loss of negative camber due to bushing deflection. Get as much caster as you can, your front suspension looses negative camber at high steering angles, so you need a lot of caster to overcome that. Try for more than 8 degrees. Guy Ankney had some home made upper control arm bushings that moved the upper control arm aft on the cross shafts and provided a lot more caster. It seemed to work for him.

The 315's all around are the minimum, you can use the ZR1 replica wheels since they are relatively inexpensive.

Most of the hot cars in the class are running Konis. Not to say QA1's are bad, but I have no experience with them.

The automatic is a disadvantage since you are limited in BSP as to how low a gear ratio you can put in the rear end. Six speeds come off of corners with almost TWICE the rear wheel torque when both cars are low in second gear, which is a big hit. Not that you can't be fast with an automatic, but generally speaking a stick will be faster. You can play games with the torque converter, and using a higher lockup converter will help you get off the corners faster, but the car will be harder to control since a throttle lift will let the car coast, and not help the front end point and turn in..

Serious tires are also going to be probably the biggest thing you can do. Hoosiers will make a big difference when compared to the BFG's.

In order of importance, get the Z51 springs and the offset control arm bushings first, since you need that stuff to keep your tires from self distructing. Then get the wheels and tires and shocks, probably in that order. That will get you to the limits of the present car. Before you do all that with the present car, you need to think hard about the automatic. A six speed is just a lot faster off of the corners, so you need to decide if you want to start modding the automatic or build from a six speed from the start...

ltborg

totally forgot about lowering the car. excellent advice.

steve40th

Thanks allot. Car is lowered, and I have the fattest sway bars GM made, 32S front, 26S rear. I will cut the stop bushings in the rear.
My engine is a 396 cu in LT1, and I have a 2800rpm Vigilante stall converter with 3.75 gears, so coming off the corners isnt too much of a problem, traction is though.
I will try to find some springs. I didnt know the 84's would fit in the 93 though. I tought they were different length.
Bushings , offset lowers are definitely on the table, and doable.
Thanks again for the advice. Steve

Solofast

You may be right about the 84 springs, our car was an 84 with a 96 rear suspension, so we used the 84 fronts. Look to an aftermarket spring with the same equivalent rate as the 84 for a starting point.

The bigger motor and gear aren't legal in BSP, you can't overbore that much legally and no C4 ever had 3:75 rear gears. The highest (numerically) gear that you can use in a BSP C4 is the 3:54...

BrianCunningham

You can change the spring rates in Street Prepared, they just have to mount the same way as stock.

Most national drivers run the competion springs from Vette Brakes.

Way stiffer than stock, which is needed since the cars are lowered so much.

Here's a national car I saw in California.
All the emissions equipment have been removed, so street prepared does not mean street legal. He was also running a custom intake and engine management system, headers, the permitted rear spoiler, and a full cage, which takes all the flex out of the car.

steve40th

Here in Hawaii, it is mostly safety and we are not out to stop people from running. Granted in a serious competetion arena, tey would reclassify me. But, since I was reclassified the first day and I bought the stickers, I am staying in BSP.
But, besides tires the suspension needs upgrading repairs etc as the bushings , ball joints etc are old.
And of course, seat time is the biggie, which I am trying to get done and time out there.

RAFTeRACER

VB&P springs are the way to go. You can research and figure out the exact rates you want and they will build the springs for you rather than just using the extreme or comp springs. You can definately use the offset lower control arm bushings, a must on a C-4. Koni makes a decent adjustable shock for a reasonable price.

astock165

Steve: the VBP springs are a great way to go and I have read nothing but good things about them.

However, a less expensive way to go is to buy the early C4 (87-90) Z51 spring setup. They should fit your car. I just bought a set for my 93 from user indianavette and can't wait to put them on. He seemed to have quite a few from an old development program and they look to be in good shape. Some already have the bumps shaved to lower the front of the car. Prices are reasonable as well.

If you want more info on the research I did just drop me a PM, I'll be happy to share.

steve40th

PM sent

VBP

We have actually added two new spring styles to our 88-96 group just for racing applications. We have taken customer feedback and designed two new styles to help get more performance and also keep you in class.

We have all of our springs on sale through Sept. 30, at 30% off. This is our way of saying thanks for our customer for 30 years of support. We are having a Special Thank You for 30 Years Sale. We have 20 to 30% off many products for 30 days.

Please feel free to call me toll free at 1-800-237-9991 or email me directly at Pattie@VBandP.com to discuss your application. We can get you in just the right style, arch style and spring rate to accomplish your performance goals.

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

www.VBandP.com