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Can a C3 compete with a C6 Z06? Video added 8/10/12

44K views 205 replies 32 participants last post by  phantomjock 
#1 ·
Can a C3 compete with a C6 Z06? That was the question some one ask a year or so ago. And if yes at what cost.

So I set out to find out. Including the cost of the car I set myself a budget of 30K and I am well below that figure.

Here is what I have so far.



1971 Corvette coupe
383 ci sbc
Eagle rotating Assembly
KB 18cc dished pistons
Comp forced induction cam
MSD 6AL ignition
MSD boost timing control
Edelbrock 750 CFM carb.
Holly 144 blower
AFR heads
Oil cooler
Long tube headers
3" collectors
2.5" exhaust



NV3500 5 speed trans.
3.08 rear end
C5 rims and tires.



Front suspension VB&P
Rack and pinion steering with hydro boost
Dual mount 8 pt. adj. transverse spiring
1.125" anti sway bar
Tubular off set A arms
QA1 single adj. shocks
Ploy Bushings
C5 rotors and calipers
Hawk pads



Rear suspension VB&P
Dual mount 8 pt. adj. transverse spiring
No sway bar
Off set trailing arms
Adj. smart struts
QA1 single adj. shocks
Ploy Bushings
Rear brake bias adj. valve
C3 calipers and rotors
Hawk pads



Holly 14 lb. 95 GPH fuel pump
fuel pressure regulator.



Hand built Cold air cowl induction hood.
Aux. elect. fan
HEI distributor



Custom built Dash
Sparco seat
5 pt harness.



Roll Cage. Coming as soon as I complete my TIG welding class.:D


 
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#105 ·
To keep this "on thread" and you fed, here is a "no cost approach you may have seen before (maybe not):
http://www.hotrod.com/projectbuild/hrdp_1011_corvette_hack_track_test/viewall.html its Hot Rod Magazine from Nov 2010 -- "Corvette Hack"

While NOT a C3 - it's a C4, they dropped 3 seconds per mile by dropping weight by about 1/3! Now I'll admit - it's not configured for passing TECH, but it does show the contribution power to weight really is. Note -- no aero tricks, no engine massaging, just weight.

I'll admit 'm being a bit fast and loose with the maths, like not precisely 1/3 weight and the 3 seconds per mile is an extrapolation too ( was run on a 1/3 mile oval), but you can CHECK THE FACTS FOR YOURSELF! (No political overtones implied or intended - but it is that season):laughing:

Cheers - Jim
 
#110 ·
There is a c3 that ran 2.25 flat at RA on bias ply treaded hooiser. Running GM j56 calipers and a slightly modified GM suspension. No coil overs, no special springs and no power steering. Most zo6's are running in the 2.30 with dotr R6.

So it can be done.:thumbsup:
Is RA Road America or Road Atlanta?

I've been to Elkhart Lake a couple times. It's a horsepower track so I can see a C3 with a boatload of motor doing well there versus a C6.

I don't have any useful experience with Road Atlanta.
 
#112 ·
OK so lets talk about Camber... What is every ones opinion as to where to start front and rear on a 3000 lb car that is striving for 50/50 weight distribution? I am now set 1 1/2 deg neg. all the way around.
 
#115 ·
Never ran more than a 1/2 deg neg in the rear. Anything more would over heat the inside of the tires. Could be the cause of your oversteer?
VB&P recommends 1 to 2 pos front and 3/4 to 1 1/2 rear to start???

My tires are running with in 3 degs across the tread?

OOPS that should read Neg...
 
#114 ·
after doing the tubular a-arms and wilwood calipers, I'm looking into doing the Wilwood alum front hub conversion and found a good thread on another forum. Thought this quote was interesting in regards to the C3 vs Z06 question:

"when I converted my C3 to aluminum hat rotors from wilwood the hat offset was 1.41", and with an Ultralight 32 rotor, the weight savings was 8.5lbs. Combined with the DB-4 wilwood alum caliper, this was an additional 6 lbs savings. Looking at the hub, I stand by the 4-5 lbs savings per hub. That would be about 18 lbs per wheel. It's huge, you really feel it when you drive the car. Some people claim that it is 6:1 for weight savings of unsprung weight. In other words, the car feels 6x18 lbs lighter (over 200 lbs lighter considering both wheels).

Taijtusu, I have done both front and rear wheels with this setup plus, fiberglass springs front and rear, park brake removal, aluminum steering tie rod tubes, brake shield removal, tube a-arms, wheels/tires, tubular sway bar, in short everything I could. Overall, I think I removed about 35 lbs per wheel, which made a staggering improvement on the ride of the car, far smoother over bumps, and around a corner, the car changes directions with such speed and poise, it's inspiring (yes, I am talking about a C3). Around an AX course and giving away a lot of HP, it takes a highly prepared vette to beat my old C3. And I am speaking of the Z06 machines. In the last AX in May, IN THE RAIN!, I beat all 11 Z06 cars. The corvettes that are trouble are the race prepared C4 and C5 machines. To answer your question directly, Taijutsu, the reason for the success is primarily the unsprung weight. Even though I re-engined, my new power is actually not much more than the original L48 (and I am totally bummed about this).
"
 
#126 ·
Needs more If you are using it on the track only. Not suggesting more for the street. :thud: At the track and at xcrosses, most people compensate for lack of camber on a street tire by raising tire pressures. Sidewall stiffness on a street is less than than on a race tire. Rolls over more. You lose you foot print. We had to change chamber setting each time we changed brands. Hooiser radials needed more camber, Goodyear bias used less. The V700 didnt need as much as the R6.
I can understand a need for variation in camber settings between brands of DOT-R or slicks. As an example, Hoosier recommends 3.0 degrees of camber for the A6/R6. Given the considerably diminished grip level of a street tire I can't imagine imagine you'd get good performance on a street tire at 3.0 degrees. Regardless of sidewall stiffness, you're not able to achieve the lateral G's on a street tire that you can on a slick or DOT race tire. Thus you have less body roll and need less initial camber.

I'm less familiar with a C3 on the track than a C5 or C6, so perhaps there's a fundamental difference, but to say that a street tire needs more camber on track than a DOT race tire or slick certainly isn't universal.

Have you done anything to reduce the camber gain and toe-out in the rear in bump travel? Or does you class not allow it? If not, I wonder how much less static camber you'd need if you reduced the camber gain.

That's certainly something to keep in mind, Ivan. I realize you were just looking for a good starting point, but keep in mind what works for one car may not work at all for another based on the suspension setup. Best thing to do is monitor tire temps and pressures and adjust accordingly.
 
#125 ·
We did it the old way, disconnecting the spring. And running the suspension from full extension to full compression.. While using a Longacre's camber and caster garage. We also checked for toe change the same way, but using a bump steer gauge.
With the ease of disconnecting the springs on my car. I think I will do that on all four tires to get a base line.

I'm finding that building horse power is a lot easier than getting it to the ground.
 
#129 ·
I said "generally" needs more. Didnt say anything thing about being universal.

Do you race now?
Unfortunately, no. My 'vette is still short a front clip. However, I am lucky enough out be involved with some racing via my job. We worked quite a bit with a team in Grand Am ST and World Challenge GTS this year. Doesn't get me any seat time, but at least I get to be involved in the setup and development phases.
 
#140 ·
I was going to ask you if you were going to do a Miller track day next year? Not those frozen March, april, May events. We were over for a historic event and the snow wasn't that high up on the mountains yet. I don't think that it was 62 degrees that weekend with the wind blowing:down:
I'm out there periodically. Any time you're in the area drop me a line. I'd love to get together for a beer (yep, they do serve that out here in Utah :laughing:) or meet up at the track. :thumbsup:
 
#143 ·
The first thing that really helps is: To get your front end completely mangeled, smashed, tore up while you are stand behind your Vette filling it at a gas station when you are dressed up and going out for a nice dinner meeting up with friends.

.............................
I'm not sure I'm talented enough to duplicate all that activity. :laughing:
 
#148 ·
It was actually sickening because i had just had a custom paint job done. This flat bed toe truck comes in and parks off the side of the building. I watch the youg guy come out and hop in. He reverses it at a high rate and takes off my front end while I have the gas filler in my hand.

I had only One out of four head lights left. I had left my lights on while filling it. I cancelled dinner and drove home
Man, that had to be depressing.

Just curious, what weight range is your car?
 
#147 ·
Since this thread is on c3 racing, I thought I'd throw this out.

You will notice most c3 racecars were convertible hard tops. Like greenwoods (most anyways) BFG cars. I read somewhere the vert hard top had a lower aero drag than the coupe with the abrupt flat back window. Just looking at it makes sense as the coupe flow would really separate. I haven't seen actual Cd numbers.
 
#150 ·
There - you had to go and mention Cd.
So I had to go looking. You'll have to wait until they "Load" but here is a comparison of various generations.

Corvette Fever:
http://www.corvettefever.com/techarticles/corp_0905_corvette_wind_tunnel_testing/viewall.html for more details.

Some straight "numbers:"
Cd 1980 Vette 0.350 Frontal Area 19.20 sqft
Cd 1968 L-88 0.360 Frontal Area 19.50 sqft

So it's more than just Drag Coefficient - but also Area. ANd yes, there would be a significant pressure differential between the "Flying Butresses."

Cheers - Jim
 

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#164 ·
I've been trying to do a similar thing.

Aluminum radiator support: test fit



And a coat of semi-gloss black to keep it NCRS compliant: ;)



The crossmember under the radiator is aluminum, and similarly painted black. There's a couple other aluminum/lightweight items too.
 
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