volkswagens-for-life

How is it the z51 c4's were some of the best handling cars in the world at the time if everybody compares the frame to a "wet noodle"? They cant have been THAT soft if they were crushing everybody in road racing and autocross right?

383vett

My frame has never been soft.

volkswagens-for-life

I hear people on here and lots of other websites always saying that the c4 frames suck and are as loose as a wet noodle. You dont support that statement?

vader86

Vibrational mode analysis shows it is quite poor compared to modern cars, and its flexible as hell with the top out, but for its time it was good. McLellan says as much, and other GM SAE technical articles say similar.

The rest of the suspension was tailored to make up for it in some ways back in the 80s. That plus the torque will get you a long way.

Race Prepared

Taking the top out of the car exposes some of the frame's structural deficiencies. The torque arm tends to flex during hard acceleration causing rear suspension deflections (addressed with torque tube on C5 & C6 Corvettes), the front a-arm mounts are weak and also flex significantly with "stickies" on the front. There are aftermarket products that can strengthen the C4 frame structure which are exposed as the horsepower is increased, better tires are installed, and with activities related to roadrace or autocross events.

383vett

My car has frame stregtheners.

BrianCunningham

Same here

a harness bar really help out

My 6pt rollbar made it REAL stiff

383vett

Brian, you're getting excited again.

dizwiz24

You mention the front a arm supports are weak.

I was amazed how flimsy the ends of the lower a arm bolt carriers were.

I was so disgusted by it, that i had some 1/8" reinforcing plates made to the dimensions and then welded them in.

maybe i can assume that the bolt carrier end plates were not deemed a high stress area? But i wasnt taking any chances, i want it to hold alignment during turns...

lt4obsesses

Exactly. The key phrase being, "for the time". Anyone who was familiar with driving cars, even Corvettes, from the 70's and early 80's could appreciate how much better the C4 was, at that time.

Now, compared to today's cars, especially Corvette's, yes, it feels 'soft'. But the advance of alloys and fastening systems have brought about much lighter, yet stiffer frames. However, if you look at the basic architecture of even the C7, you can clearly see that the C4 was the grandfather of the design.

DrDyno

I don't know what all the fuss is about. Sure, my '96 LT1 coupe has a few more shakes with the top off, but would still easily out handle any of the C1's, C2's and C3's I ever owned.

I recently drove a 2003 6-Speed C5 coupe and didn't feel nearly as comfortable with its handling as I do in my C4 when the top's in place.

My car has the Real Time Dampening option. I just leave it in "Sport" mode and I always find it impressive. But, even in "Tour" mode the car is rock solid in the twisties.

SnAkeDr

I'm not a racer but want to enjoy the top being off.

http://www.vette2vette.com/product/8...ner-bar-system

volkswagens-for-life

lol 383vett you dont count! A rollbar isn't stock :P

But thanks for the link to the frame stiffeners and the input guys.

how would a c4 handling/frame compare to new bmw, mercedes, mustangs etc?

vader86

Really depends on which models. In terms of driver confidence and feel, those will all exceed most C4s. Their chassis are better engineered for the most part and they'll feel more solid. Engines and vehicle mass will make up the differences, particularly a Merc that has a hefty chassis and a blunt-force engine that will cause snap oversteer quite a bit. That will make you lose confidence, but its not really the fault of the frame.

An early Z51 will probably beat most in the twisties but they'll get smoked in the straights with stock power.

volkswagens-for-life

Dont care about the "feel" of the car, only the performance. So are you saying a new merc or bmmer might "feel" better, but will still get trashed by an early z51 on the twisties?

vader86

As I said, depends on which model and the course.

An S-class would get beat by an 84 Z51 on a tight course where the Merc couldn't stretch its legs. Something like a C63 would beat the early Z51.

tombrammer

It's not just the frame strength of the c4 that made it handle so well, it is also other things like a near 50/50 weight distribution (notice how the engine is completely behind the front wheels, also the low center of gravity. There are very few cars with the center of gravity very near 14". Also the totally independent suspension, fat tires, forged aluminum suspension pieces all made a car that still compares well to modern cars and well above many others.

volkswagens-for-life

^ohh I see. Thank you for the explanation.

What do you mean 14" center of gravity.. you mean that the center of gravity for the c4 corvette is 14" off the pavement?

Tom400CFI

Yes^ According to John Heinricy in the C4 promotion video, the C4's CG is 14" above the ground.

If you don't care about the FEEL of the car, and all you care about is objective numbers, then the C4 frame is "good enough". The performance potential is there already, and frame rigidity is not the "limiting factor" for performance.

What frame rigidity gets you is driver confidence, and confidence is probably more important than ANY "limiting factor" that puts the C4 at a disadvantage to newer cars. It's actual handling numbers, from an objective stand point aren't off a modern cars number at all (except for acceleration).

To put a number to the difference in the C4 compared to a modern car, the C5 frame is 4 TIMES stiffer in torsion, than the C4 frame. That's not a percentage stiffer...that 4 times, stiffer.

volkswagens-for-life

But if you are a good driver, you should be able to see past the frame strength and realize the true potential, no? Or is the c4 more of a "will it do this, or will it do that" when pushed to the limit type of car?