biggrizzly

I'm in the market for some new shocks for my C4 which will mostly be used for autocross events this summer. I'm also new to autocross with only a few events completed to date.

I am also on a very tight budget, and am on the fence about which way to go for buying shocks (coilovers are out of the equation at this time). I have done the research here and on the SCCA forums and there seems to be a split between the Koni Sport single adjustable and the Bilstien HD autocross shocks.

I am also considering putting a 32mm hollow sway bar on the front with heim jointed end links. The sway bar and end links will cost about $400 and the shocks will add to that. I can get the Konis for about $600 shipped and the Bilstiens for about $325 shipped.

So do you think the Biltiens Sport shocks will do for my first full season of autocross racing or should I spend the other $300 for the Konis and not feed my family for a month?

BrianCunningham

1st thing to do is figure out what class you want to run in

The simplest mod can have. You running with the heavy hitters

1st year it's best to leave it stock

biggrizzly

Ha Ha... It will be running in SSM for SCCA and Group 3 for NCCC

RacePro Engineering

Hi Don,

Like the prices you have found indicate, the Konis and Bilsteins are completely "different animals". While the adjustable characteristics of the Konis may not be as useful to you while you are learning the tricks of the trade, good shocks last a long time. If you continue to autocross, that extra capability will pay big dividends as your driving skill and suspension tuning improve.

The only "down-side" is that the rear shocks will need to be partially removed from the C4 in order to adjust them. Nevertheless, they are worth every penny!

Ed LoPresti

jwt1603

Call Paul at Van Steel to discuss your shock / suspension needs. They're a supporting vendor on here. He's helped me out a lot and won't sell you things you don't need at this point. He'll help you progress as far and as fast as you want to with your suspension set up.

They're number is 800-418-5397. Tell Paul Joe T out of Jacksonville sent you.

Solofast

The Koni's are your best choice. You can adjust the fronts between runs and you don't really need to adjust the rears. Set the rears a close to full soft and don't worry about them. Being able to get rid of a bit of push or looseness is a good thing, and you will learn how much to tweak the shocks as you learn what you like in terms of handling.

Not having some adjustment is like having your feet stuck in mud, you know what you want to do, but the car just won't do it. Being able to adjust things makes the learning process a lot less frustrating and a lot more fun.

Kubs

This is true if you know what to adjust and why, if you dont the adjustables will make it worse. For beginners its best to focus on driving and not adjusting.

Call Randy at DRM, he can make a custom valved set of Bilsteins that match your suspension setup. Its like having the right setup all the time. I agree that "off the shelf" non-adjustable shocks are like having your feet in mud, but custom shocks are way better.

Solofast

The problem is, with autocross, the setup changes a small bit, from day to day because you are seldom on the same surface. One day you are on sealcoat, the next you are on toothy Air Force Concrete, and the time after that you are on gray asphalt. Part of learning is figuring out what the car needs as you are driving it. If you have a bit of push, you can wind back an adjustable shock a bit and have the car dialed in. If you don't have any adjustability, sometimes the car will work great and you will be fine, but the next three events it will be a pig. You will often end up learning bad habits to try to compensate for a car that doesn't work right, or you will just be slow and that tends to make it a lot less fun.

Like I said, part of learning to drive is learning to adjust the car, and once you learn that getting it into the sweet spot only takes a few seconds. If the only adjustment you have is the front shocks, even for a newbie, it's pretty easy.... To fix push, soften the front shocks, and to fix looseness, tighten them.... Pretty stratight forward, and not too tough.

ScaryFast

LG posted a quote here years ago that I've always kept in mind when thinking about things like this. I don't remember verbatim, but the point is that with a 10 way adjustable anything, for any given track or course you have one setting that's right and 9 that are wrong. So you have a 90% chance of being in the wrong setting...

If you had the time and money to test and take data with all 10 settings then adjustability is the way to go, but most of us don't...

Take that as you wil.

Rob31

I like to play with dials and shims , and guages .. Made the mistake of making a change after the first run . The track is cold and green and the car always seems better the second time around .

RacePro Engineering

And quite some time before Lou's statement, the venerable AJ Foyt once quipped: "Early in May each year, we arrive [at Indy] with a pretty nice car; and by race day, we have adjusted it into a pile of junk!" (paraphrased)

But with both of these very successful racers, let us ask, "Do these sentiments mean they do not adjust their handling?" The answer is obvious.

We test. Not everyone does, and we recognize that. Even when we are not formally testing, we treat EVERY SINGLE SESSION as an opportunity to improve the car. We are constantly asking, "What does IT want?" So, while this may not yet apply to Don specifically, due to his relative newness to the sport, if he stays at it for very long, he will soon be "over-driving" his completely out-of-the-box setup. Autocross, track days, time trials, racing - all the same. And when the driver's capability exceeds the car's, the driver (or his engineer) needs the ability to "create" more capability WITHIN the car. Adjustable components (motor, suspension, aero) allow for this.

It is the driver's job to drive faster, AND to make his car so IT can be driven faster. That is how we think about it.

Ed

Solofast

Autocross is like any other kind of racing, you have a baseline setup, you look at the layout of the course, scuff your shoes on the surface to estimate the grip, and you decide what you are going to run that day.

Once you get some experience, you will most often be very close on what the car needs so that you can drive it the way you want to drive it. With experience you will learn that the front tires heat up faster than the rears, so the balance will shift from the start of the first run to the middle and towards the end of the first run (as the back tires start to come on and get warm), and it will be different on the start of the second, where it will finally calm down and work right so that it's great on the third run, and you might make a slight tweak in a setting between each run.

The trick is to not be chasing the setup of the car, but to anticipate what the car is going to need on the next run and not the run you just finished.

And face it, your learning curve might be just a bit steeper with some adjustability like being able to turn the shocks or front bar up or down a bit, but a year or two later you will want and need that to be competitive. If you don't buy the adjustable shocks now, you will shell out that much more in a year or so.

And if you really want to dumb it down, and don't want to mess with shocks, you don't have to. Take the car to a test and tune, get somebody who knows what they are doing to drive the car and help you get it dialed in, and then just leave them alone for the first year. That's just what you get with the non-adjustable shocks, but at least you can get the car closer to what you want from the get-go and the car will be better handling from the start.

Crepitus

One thing that catches my attention about the Konis, The only ones I have found are the red ones, Classics? When i had a 951 the red shocks were a soft ride street setup. For a more aggressive trackable set up the yellow body Sport was the entry level starting point. Is this different for Vettes?

Livermore Performance is offering these Bilsteins for 92$ each. Does anybody know what the Z51 valving is? How would these compare to off the shelf Bilstein Z51s? Or to custom valve setups from a couple of our favorite vendors? particularly on a moderate to rough road course.


Bilstein RR


Corvette SSGT 84 - 87 Front Conventional Body r360 c135 AK1030 $92
Corvette SSGT 84 - 87 Rear Conventional Body r540 c160 AK1031 $92
Corvette SSGT 84 - 87 Front Conventional Body r410 c145 AK1040 $92
Corvette SSGT 84 - 87 Rear Conventional Body r620 c120 AK1041 $92
$92 ea


Thanks!

RacePro Engineering

No - no different for Corvettes - the Reds are still high performance street, and the Yellows are track, with ratio-ed valving. It appears that Don has a 1994, and the Yellows will fit just fine.

But, at the risk of hijacking Don's thread, Koni offers every imaginable variation and permutation of racing dampers, from the fairly simple single adjustable Yellows to which you refer; to enhanced Yellows individually adjustable for bump resistance and rebound resistance; to Triples and Quads, allowing fine tuning of shaft velocity, as well as simple resistance, in both bump and rebound. Multiply these varities by a nearly infinite combination of custom valving, and it is understandable why the subject appears daunting.

Fortunately, with heavier cars, and for club racing, the single- or double-adjustable dampers are plenty capable. For special applications, Koni knows how to valve them based on your car's weight and spring rates (well, wheel-rate, actually.)

Ed

c4cruiser

Seat time will probably be the best investment you can make right now. There are enough variables in equipment that putting the wrong stuff (or not adjusting it properly) can make you slower and the car less responsive. But if the car needs shocks, then I would start with the Bilstein HD shocks.

You didn't mention what suspension is on the car now. A 32mm front bar can be an improvement but for now I would hold off on Heim joint end-links. Van Steel sells a 32mm front solid bar that is made by ADDCO. That may be the biggest bar you can find for a C4 right now. You can go with the stock end link and use polyurethane bushing on the bar and the links. Then get some seat time.

Even playing with tire pressures can make a difference on street tires. A good alignment is something else to consider. Vette Brakes has a page with some good alignment starting points. Go to this page and click on "Alignment Specs". Start with the Advance Street setting and then you can start to figure out a good autocross-specific alignment from there along with more seat time. But be careful as some specs may make the car not fun to drive on the street.

Oh, and did I mention getting more seat time? If I didn't, then get some more seat time.

1991Z07

I had Bilstein re-valve my FX3 shocks to the Rippie specs and bought the Rippie-modified shock controller with new chip.

Completely different car once it was installed. Soft setting on the FX3 is like the Performance setting used to be on the stock shocks...and gets progressively stiffer from there.

I found those 3 settings to be more than sufficient to keep me in the hunt at an autocross event.

My Z07 already had all the sway bars from the factory...just needed better shocks to control the body roll.

Here's a shot from TWS going through the Carousel...

biggrizzly

All great replies guys.. Based on lots of input already and the great feedback here I'm really leaning towards the Konis since its not too much more money. However, I'm still toying with the idea of a 1-1/4" tubular front bar offered by Guldstrand Motorsports and their heim jointed end links solely for easy of installation at this point. Although since I have the base suspension I'm not sure if my springs are too light to go to the stouter front bar until I can change springs and bars next year. Too many things to think about and too little time to incorporate.

As far as seat time... I have so many opportunities this season. I'm starting right off on April 17 with a Evolution Performance Phase I class and then a few weeks later doing their Phase II class at Dover. My club will have three more dual NCCC autocross events this season and I joined SCCA to jump on some of the Washington DC Region SCCA Solo events which are only 30 minutes from home for me.

I'm not totally new to autocross but might as well say I am. I have spent much more time at the organizational end of the events than the driving part.

Solofast

You need to upgrade to the Z07 springs and/or equivalent bars. With the base suspension the car will be wallowing around and even good shocks aren't going to do much for you. If you start with the Z07 package the car will be balanced and then you can tune it just a bit with the shocks, but if you don't stiffen up the springs, you are just wasting your time, literally.....

Kubs

I have been on stock springs/anti-roll bars for awhile (hopefully upgrading soon) and the car is very slow to respond to inputs. not to mention the horrible body roll as seen in my signature.

biggrizzly

Any recommendations on where to get springs and bars to tighten this pig up?