I have to ask

[touring67]

It's about the intended purpose of the car and the builder I think. Sure vette stuff can be had without too much trouble, its easy to get replacement parts and the forged aluminum parts make it light relieving some unsprung weight but like said before it has to be mounted the same way with the same specs. I have a fairly good personal experience that involves form (looks) over function. I personally would rather have the car perform than look great. I have a certain car *82 camaro* that my best friend and cousin also has *85 camaro though*. At some point, I don't know when, I was struck with the idea to add to its performance. I built an engine, swapped transmissions and rear gears, added a strut tower brace and some bigger BFG KDW tires to help keep it planted. While the car didn't look any prettier, in fact it looked worse with time and no fancy dress up parts, it did perform much better. In the meantime my cousin who has the same love for cars did nothing to aid performance but rather added a stereo, did some fancy bodywork and repainted the whole car, restored the interior, got a steering wheel and added a big 'cat-back' 3 inch exhaust (no headers!) with some 4 inch tips. The latter may have added some to performance but it was more for sound appeal. He would scoff at my, by his standards, ugly car that was fast while I could not see why he would not do SOMETHING to aid in the performance despite spending over 10k on looks. While he is my best friend and has the same *nearly* car and interest in them I prefer function while he prefers form. I recall this story because he is always pressing me to use Corvette suspension for some reason and I cannot see why he would do this other than that he 'thinks' or has 'heard' that it will make your car perform better. For someone who hasn't looked at any other options he automatically comes up with corvette suspension. In this such case, it is ignorance that leads one to 'want' corvette suspension. This may not always be the case but it is one point that I thought I would bring up. This did get off-topic I know but I think it really shows how it is the builders/drivers preference and knowledge when it comes down to making the decisions.

[Steve Chryssos]

I will come clean.

When I bought one of the first C4 clips back in 1999, I was totally impressed by the thought of having cool forged aluminum A-Arms/spindles and rack & pinion steering in my 1st gen. I'd pick up an A-arm and wave it at my homies bragging "Forged aluminum baby!"

When I drove the car for the first time, it felt like all four wheels were pointing in different directions. As I am not a fabricator or a suspension expert, I used the blank check approach to fix the car--but still did not have a clue about suspensiond design. Money wasted.

In order to get the car right, I found another (and more expensive) fabricator and before I pulled out the checkbook (again), I stopped and researched as much as possible about front suspension design so that I could take an active role in the revisions. Clips have come a long way since then, but the logic is still sound:
For those who think that a "bolt-on" a clip and fancy C4/C5 parts will turn their ride into a supercar, I offer some advice:

1) Buy a Book or Two
Read and understand them before you spend the $$$. You CANNOT effectively comparison shop for a clip without a good working knowledge of suspension design. Start with the Herb Adams book.

2) 100% Bolt-on Bla Bla Bla
The clip that is the easiest to bolt-in may NOT be the best performing design! Compromises may be (are usually) necessary to make the frame, suspension and steering parts fit within the factory platform.

You are changing the frame on your car. It is a big decision and a big job. Take it seriously.

[Mean 69]

Very, very well put, Steve.

M

[Kenova]

At the risk of showing how little I know, I'll toss out my two cents (CDN). When I first heard of Wayne's sub frame (before the passing of Art), I was more interested in weight savings and bigger brakes. Being able to go to the nearest GM dealer and order replacement parts is a big plus. In this case, form follows function and looks good doing it. And I'd bet that Wayne has been trying to improve his suspension design, given the demanding nature of some of his customers.
Unfortunatly, I don't have the resources to test and tune a car on a proper race track. That pretty well leaves me at the mercy of whoever is building the sub frame that I choose. To complicate things even more, there is no way to subjectively compare the different suspension systems out there. I would hope that all such systems would come with a suggested starting point for suspension/shock/spring settings.
Before I lay down the cash for a new sub frame or suspension system, I will certainly have to do some serious reading and note takeing. It would be most interesting to hear what others have had to do to make their after market suspension perform properly, other than testing and tuning. How about it? Another thread perhaps about pleasant and unpleasant surprises when setting up after market suspensions and sub frames?
Ken

[Salt Racer]

...I would hope that all such systems would come with a suggested starting point for suspension/shock/spring settings...

EVERY suspension manufacturer needs to be able to do this IMO.


For those looking to buy an aftermarket subframe, take Steevo's words. I couldn't have said it any better.

What makes C5 suspension a great performer is how GM engineers arranged the pivot point locations. The fact that the parts are forged aluminum has very little to do with it. In fact, you could swap in stamped steel A-arms on a Z06 and lose very little performance, and quite possibly none at all on smooth race tracks, so long as factory pivot locations are maintained.

Let me put it in a little different way, since most people have better understanding on engines...

Suppose you have two nice aluminum intake manifolds of the same make and model. You send one out for porting job to a very experienced shop with in-house flowbench, dyno, etc, while some toothless Billy Backyard with no engine building experience offered to port the other one for $5. Which manifold produces better hp/torque curve? Probably the one ported by a good shop.

Both manifolds look the same externally, yet there is a significant difference. It's the exact same deal on suspension. You can have the look of C5 suspension, but you may in fact have a suspension worse than the stock suspension unless the pivot points are carefully designed and located. The shape, material and construction of A-arms and knuckles DO NOT determine the geometry (or kinematics) of suspension. Pivot locations define that.

Unfortunately moving pivot points around is inevitable when you try to adapt C5 (or C4 for that matter) suspension into a Camaro because back in mid '60s, GM engineers didn't design '67 Camaro to accept yet-to-be-born '97-'04 Corvette suspension.

If you want a subframe with C5/C4 components in the interest of improving performance, pick up few books and learn what makes suspension actually work well. Then, spend a couple of hundred bucks and visit the manufacturers if possible. Have them demonstrate simple tests such as bumpsteer and camber curve. Airplane tickets are much cheaper than $4K mistake. Narrow down your choices based on suspension kinematics first, then pick up the best subframe for your use/preference - frame rigidity/weight, aesthetics, or whatever.

You're swapping a major chassis component. Like Steevo said, it is a BIG deal. Take it VERY seriously.

[touring67]

As far as Kenova is getting and what we may be touching on is the thread I started about subframes. It was this thread that prompted me to start that other thread in fact. It is hard to choose in some cases what to do and what to use. In almost all cases it is far more important to get the pivot points and the geometry correct than the components themselves, otherwise we would see titanium parts all over the place despite the price.

And yes, quite often 'bolt-on' means 'modify' and I have seen this quite often, and I believe that in some cases the term is used just to sell the component. It is a huge part of the car's characteristics and it's very serious, I know that I would NOT go buy a sub without crawling all over it and trying to find out everything about it. Again, my reason for the other thread. I myself am not impressed if it's just corvette suspension, because my next question would be almost word for word "Ya, but does it work in your car?". In my case I am probably a year away from buying anything, my books are in the mail, and my education is starting so I don't make any mistakes or fall into the marketing traps.

[Tony@AirRideTech]

this thread to me is getting a little confusing.... lets dissect what we are really talking about here and lets more or less try to put a generic definition on "Pro Tour"....
The definition will very much resemble like mentioned above.... "Pro Tour" in alot of opnions refers to the vast grey area of cars that are being built and that are the most popular car to be built these days. They are not "Pro Street".... they are not "tour" cars.... they are not "Hot Rods" ...and they are not lead sled cruisers and they definitely aren't trailer queens. What they are by most definitions is everything in between. It would be a mid or full size car that does everything "well". A good representative of a good Pro Tour car is one that can turn a respectable quarter mile time, hold its own on an open road coarse, and give you quality, comfortable confines getting you there. A prime candidate would be a car like the Chicayne... although the horsepower in that example may be slightly overkill.... . Now I know some of you are going to have a different view of what a pro tour car is or should be and that is great! That is what its about because I think for the most part we can all agree that it is for those "grey" area cars.
Now that we have depicted a somewhat rough definition of "Pro-Tour"... we all need to sit back and take a blinderless look at what we are all attempting to catagorize as how a "pro tour" car should be built. Even though we are currently discussing the validity or practicality of Corvette suspension components it really boils down to how each of indepedently feel of what our interpretation of what a Pro-Tour car is.
Justifying the use of C-4 components or C-5 components is actually pretty easy. First off... when installed properly... it is pretty darn good geometry to work with. We all know here that in order to get it to work and perform how GM intended it to, that you will need to keep it in the Corvette. But if you take and compare it to the suspension geometry of alot of the cars it is being put on it is a far superior set up. Other major benifits are parts availability, and aesthetics. You can damn near find any brake package, gear ratio, and differential upgrade parts you could ever want. They are also affordable and obtainable by those that are of men of average means..... That says the most. Besides that... back to reality.... when it comes to what some peoples definition of what a "died in the wool" pro-tour car should be, it sounds like we should all be building complete, purpose built, tube chassis that could compete in the 24hrs of Daytona. And lets face it... that can be just as bad as anything else when not installed properly or set up properly. Keep in mind, there are compromises with any route we take. The importance of what you are compromising can only be determined by the owner and his intended use for the car.... Anyways... I will now retreat from my soapbox....

[nancejd]

I think one issue though is that everyone remembers the horror that became prostreet, where just about every car was made in the "style", but didn't have any performance to speak of it. Maybe there should be a "Pro-Showing" type of car.

[touring67]

I think that those are referred to as trailer queens already hehe.

[Ripper]

What makes C5 suspension a great performer is how GM engineers arranged the pivot point locations.

sorry for asking, but I'm used to Swedish litterature... Which one is the pivot point?

[Beige]

The pivot points would be the ball joint and control arm bushing locations.

[Norm Peterson]

sorry for asking, but I'm used to Swedish litterature... Which one is the pivot point?

I'm not sure I understand the "which one" part of your question. A pivot point is any connection between two locating parts that acts like a hinge in either 2-D or 3-D. Most (but not all) suspension components that locate either a wheel or an axle have two such points, typically involving bushings of some sort at chassis and stick axle attachments and balljoints or rod ends at steering knuckles and tie rods.

Norm

[Ripper]

Thanks!

NOW I understand why the "pivot points" are so important

[baz67]

Sorry for the late post, but VERY well put Steevo.

Brian