handling
Drifting
Joined: Jul 2002
Posts: 1,254
Likes: 1
From: Edinburgh
Unless you make significant changes to the front end the steering goes very light above 140mph. Ask me how I know
As a minimum you need to lower the front end to change the angle of attack but even then you can get into serious trouble going over a hump or small rise in the road or track at that speed.
As a minimum you need to lower the front end to change the angle of attack but even then you can get into serious trouble going over a hump or small rise in the road or track at that speed.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
That light feeling is exactly that; aerodynamic lift is occurring. This lift can be countered to sufficiently stabilize a C3 for high speed handling (I'm talking about actually taking 100mph+ sweepers), but rake and lowering alone aren't quite enough. The solution, at a minimum, is installation of a legitimate air dam and spoiler (both, not one or the other), such as the factory PC (which must be properly braced), and I can personally attest that this makes a tremendous difference when you decide to turn the wheel north of 100 in a lowered rubber bumper C3.
Your results may vary.
Your results may vary.
Last edited by TheSkunkWorks; Mar 5, 2008 at 02:48 PM.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
I've seen a handful of such aero mods applied to some track C2's, but not familiar with just what's available off the shelf other than pieces such as the C2 "front spoiler" from Eckler's. I haven't looked, but some of the other houses such as Vanacor, Tracy Performance or Duntov might have or know where to look for a selection for the Sting Ray. Guldstrand may be able to point you in the right direction, too. Also, I'd say maybe some of the vintage racers might help on the aero front, but suspect not to many of them would be into mods not from the "correct" era. Wish I was more help.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
There's more, but most of all, don't push the limits until you safely establish and address the oversteer/understeer balance of your car. You may find that you need different bars and/or springs, so don't lock in to one setup and become afraid to change things. And, if one end is giving you trouble, do everything you can to improve that end before taking grip off the other one to compensate. What I mean is, if you're pushing try a smaller front bar instead of a bigger rear one.
BTW, a rear sway bar isn't always required to balance a C3.
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Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
The short answer is that it will make the car over steer badly.
My advise would be to get something less than the stiffest springs (this is a street car after all). Get something that will give a good ride quality. In my opinion anything over 440 lbs. per inch (on the front) is too heavy for good ride quality on the street. This is assuming you don't want to do a lot of late breaking. Keep the rear to about 320 lbs. per inch unless you have a lot of tire back there.
Get a 1.25" front sway bar, some good shocks and (probably) three rear sway bars. The reason you need three rear bars is because you are tuning to the front bar. The first rear bar you get will probably be too loose or too tight. The second rear bar you get will probably be too tight or too loose. The third rear bar you get will be between the other two and will be just about right. Then you get to sell the two bar you didn't use on eBay.
If you're really particular about your handling you'll be fiddling around with air pressures and alignment settings at about this point.
BigBlockk
Later.....
My advise would be to get something less than the stiffest springs (this is a street car after all). Get something that will give a good ride quality. In my opinion anything over 440 lbs. per inch (on the front) is too heavy for good ride quality on the street. This is assuming you don't want to do a lot of late breaking. Keep the rear to about 320 lbs. per inch unless you have a lot of tire back there.
Get a 1.25" front sway bar, some good shocks and (probably) three rear sway bars. The reason you need three rear bars is because you are tuning to the front bar. The first rear bar you get will probably be too loose or too tight. The second rear bar you get will probably be too tight or too loose. The third rear bar you get will be between the other two and will be just about right. Then you get to sell the two bar you didn't use on eBay.
If you're really particular about your handling you'll be fiddling around with air pressures and alignment settings at about this point.
BigBlockk
Later.....
Drifting
Joined: Jul 2002
Posts: 1,254
Likes: 1
From: Edinburgh
I agree with BigBlockk.
A rear sway bar will make the break away of the rear end (Oversteer) happen a lot more suddenly. The lack of a rear sway bar makes the breakaway much more progressive and therefore easier to cope with.
I ran 440 front springs (before fitting coil overs) and a 330 rear spring with an 1 1/4" front sway bar and for hard street driving the ride was just about right.
A rear sway bar will make the break away of the rear end (Oversteer) happen a lot more suddenly. The lack of a rear sway bar makes the breakaway much more progressive and therefore easier to cope with.
I ran 440 front springs (before fitting coil overs) and a 330 rear spring with an 1 1/4" front sway bar and for hard street driving the ride was just about right.
Last edited by Graemeinvette; Mar 6, 2008 at 06:54 AM.
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
Then I removed the 7/8" rear bar I added (thinking Bubba had removed it and forgot to put it back on).
Melting Slicks
Joined: Dec 1999
Posts: 2,116
Likes: 156
From: Mid West
Cruise-In III Veteran
Been there too. I had a 1 1/4" front and 7/8" rear bar. Talk about an unforgiving car. One minute your handling flat and feel in control, then all of a sudden your in a big spin
.Dropped those huge bars, and it became so much easier to predict. I only have a 1" up front and a 9/16" in the back. Soooo much nicer ... better ride too
.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
"Ride comfort" is a highly subjective issue. If pulling G's is a higher priority, then sacrificing a little comfort won't seem that much of a price while you're getting your kicks and grins. On the other hand, if comfort is more important, then you will be leaving a fair amount of potential performance on the table. Not all of us have the same perspective here, so you have to ask yourself, where do you stand?
As for spring rates, I wouldn't exactly refer to 550# coils as being stiff, rather intermediate. Personally, I've had few complaints about the 860#'s which were required to counter excessive bottoming at Chevy Power race prep heights on my street shark. And, even my Daytonas might be called moderate, as yet stiffer springs rates of over 1K# are available for C3's.
What about age old advice to run the softest springs? Now, I'm not saying go out and get the stiffest springs you can find, but just bear in mind that "softest" doesn't necessarily mean soft, as in some applications the softest practical spring can end up having a fairly high rate in order to deal with the increased loads which come with heavy braking and hard cornering.
As for spring rates, I wouldn't exactly refer to 550# coils as being stiff, rather intermediate. Personally, I've had few complaints about the 860#'s which were required to counter excessive bottoming at Chevy Power race prep heights on my street shark. And, even my Daytonas might be called moderate, as yet stiffer springs rates of over 1K# are available for C3's.
What about age old advice to run the softest springs? Now, I'm not saying go out and get the stiffest springs you can find, but just bear in mind that "softest" doesn't necessarily mean soft, as in some applications the softest practical spring can end up having a fairly high rate in order to deal with the increased loads which come with heavy braking and hard cornering.
Burning Brakes
Joined: Jun 2004
Posts: 872
Likes: 3
From: Cortlandt Manor New York
If you want to drive 200+MPH on 40 year old suspension you need a psychiatrist not a new suspension. At that rate of speed you need a racing expert to set up your car not a couple of guys on the Corvette Forum who have no experience driving at that speed. 200+MPH is for the pros one little mistake at that speed and they bury you and the car together because there will not be enough left of either one to fill a cemetary plot. If you are serious about speed you need to get real serious about equipment.
Burning Brakes
Joined: Jul 2006
Posts: 830
Likes: 1
buy a brand new Z06.
The C3 is a soggy frame by todays standards. The brakes, suspension, steering is all based on 1960's technology. While proven & effective, probably not a good idea to take a "backwoods C3" up to 200+ mph.
I've had my C3 on fast tracks like PIR and various autoX, it's NOT going to keep up with modern cars. Again, buy a brand new Z06.
The C3 is a soggy frame by todays standards. The brakes, suspension, steering is all based on 1960's technology. While proven & effective, probably not a good idea to take a "backwoods C3" up to 200+ mph.
I've had my C3 on fast tracks like PIR and various autoX, it's NOT going to keep up with modern cars. Again, buy a brand new Z06.
Drifting
Joined: Jun 2007
Posts: 1,478
Likes: 4
From: Formerly from the Great White North but now residing in the Desert Southwest NM (The Land of Dis-Enchantment?)
That 7/8" rear bar was the worst thing I ever put on or the best thing I ever took off (what was VBP thinking?). I'm running 1000# fronts and a 450# rear with a 1 1/8" front bar, with all the necessary bushings replaced and the smart strut rear. I have some custom Bilsteins, 17" wheels with 295's and 315's The car handles like it's on rails, it's extremely predictable, and the ride isn't really that bad. The factory 7/16" rear bar is hanging in the garage just in case I want to make a small adjustment. I'm using a pretty agressive track alignment, and the car is lowered to the PB specs. But in my wildest dreams, if this car could do 200mph, I wouldn't try because the aerodynamics aren't there. At 130 the front floats, so wings and cow catcher spoilers and a lot of testing are definitely a must.
This thread's getting interesting, anyone else want to divulge their hot set up?
Last edited by NMsharkracer; Mar 6, 2008 at 06:32 PM. Reason: typo
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
That 7/8" rear bar was the worst thing I ever put on or the best thing I ever took off (what was VBP thinking?). I'm running 1000# fronts and a 450# rear with a 1 1/8" front bar, with all the necessary bushings replaced and the smart strut rear. I have some custom Bilsteins, 17" wheels with 295's and 315's The car handles like it's on rails, it's extremely predictable, and the ride isn't really that bad. The factory 7/16" rear bar is hanging in the garage just in case I want to make a small adjustment. I'm using a pretty agressive track alignment, and the car is lowered to the PB specs. But in my wildest dreams, if this car could do 200mph, I wouldn't try because the aerodynamics aren't there. At 130 the front floats, so wings and cow catcher spoilers and a lot of testing are definitely a must.
This thread's getting interesting, anyone else want to divulge their hot set up?
I think I've posted at least once about each handling mod I've made on my '80, but I don't remember listing everything in one place, this is it.
Goals first - I wanted a nice balance between handling and ride for both tame and mildly aggressive driving. I think I found that sweet spot. Here's what I have:
- A 350# VBP rear composite spring (the Gymkhana-equivalent)
- VBP HD Camber Strut Rods
- Front mono-leaf front spring set to the Gymkhana-equivalent, lowered as far as possible without tires hitting anything on bumps
- Tubular upper A-arms
- KYB gas-charged shocks (you need GC shocks to handle the lower unsprung weight of composite springs)
- Steeroids power rack & pinion steering system
- VBP front spreader bar
- Fiberglass front "street sweeper" spoiler/deflector (adjustable) to reduce lift by reducing air flow under the car
- Custom traction bar to stop wheel hop
- Ceramic brake pads
If I had to do it all over again, the only thing I'd do differently is to put in the complete front mono-spring kit instead of the mono-spring adaptor kit so I would have tubular lower A-arms to match the tubular upper A-arms.
Other than that, I think I found a winning combo.
Yes, I know. I didn't post pictures. Let me know if you want to see something on my list.
Team Owner
Joined: Nov 2004
Posts: 20,715
Likes: 25
From: Sorrento Italy
It's going to be very hard to go anywhere carrying a full 3.500/3.600lbs on your car's shoulders...
First step: leave at home a good fraction of your weight then everything will develop smoother and by the numbers with less effort and more responsiveness..
C3's, specially the late ones, are not built to 'handle', they're built to be comfy...that's why nobody cared in GM of their weight...if you look closely at the details there is no one single piece made with its weight in mind (which means with handling performance in mind...)...from the defenses to seats (and their supports) brakes, suspensions, power garbage, look at the thikness of the windows and windshield! it's like taken streight from a big limo and made to fit in a streamed body...everything is big, fat and heavy...and i know very well because i've been through every detail.
So my humile 2 cents contribution to this thread is to start from the beginning reviewing those (important) details the builders didnt care at all when they developped C3's, otherwise it'll be like dressing a nice armani suit without getting a good shower first, a waste of hard earned money...
First step: leave at home a good fraction of your weight then everything will develop smoother and by the numbers with less effort and more responsiveness..
C3's, specially the late ones, are not built to 'handle', they're built to be comfy...that's why nobody cared in GM of their weight...if you look closely at the details there is no one single piece made with its weight in mind (which means with handling performance in mind...)...from the defenses to seats (and their supports
) brakes, suspensions, power garbage, look at the thikness of the windows and windshield! it's like taken streight from a big limo and made to fit in a streamed body...everything is big, fat and heavy...and i know very well because i've been through every detail.So my humile 2 cents contribution to this thread is to start from the beginning reviewing those (important) details the builders didnt care at all when they developped C3's, otherwise it'll be like dressing a nice armani suit without getting a good shower first, a waste of hard earned money...
Last edited by panic; Mar 7, 2008 at 11:00 AM.