Forum: I've posted a few times about aero questions. Seems the PC aero kit gets 50lbs of downforce. Is that at 70mph or 140 mph? I would think that something taller in the rear would be an improvement.
Something along the lines of the circle track cars. They have a front spoiler about the same size and angle on both ends.

What does the high buck project car know that we don't know?

R

http://bangshift.com/wp-content/uplo...19-685x456.jpg

I really like the rear spoiler, who has it?

 

I was hoping someone had some good pics of C3 rear spoilers? There has to be something better than stock?

R

 

OK I'll ask the question.....do you go fast enough to need the spoiler, or is it just for looks?
I don't really have any answers for you, but Im sure that the downforce you mentioned would be at high speed, not highway speed.

 

If a person asks that kind of question here, then it's just for looks. Anyone seriously NEEDING a rear wing would be working with others in some racing venue to figure out what really needed to be done.

 

My goal is to run the SS in the 135 touring car class. I don't think that qualifies me as a poser. Having 300 rwhp should get me close to 160? Anyway, C3 has a tendency to Trailing Throttle Oversteer and a few other less than endearing habits compared to something newer. So, I have a real reason to improve the aeros.
Check this out. He has a real spoiler!

https://www.flickr.com/photos/123721...4/14259974257/

 

Hey to Stockton! I drove this one to work there for ten years. Have you got data on hp vs speed for C3s? I'm guessing later cars are noticeably aerodynamically efficient. My '69 made 327rwhp with the last engine (383). I would not have expected it to pull 160. It should be up by another 75HP when the LS swap is done and then I'd like to see what it would do.

Good luck running yours, sounds like fun no matter what top speed it reaches.

 

A few years ago the forum weighed in on the topic. While there is always some disagreement on details, there was a general consensus on a few things.
If it takes 600 rwhp to go 200 mph.
300 rwhp should get you to 160 mph.
The PC aero kit is excellent, wouldn't try high speed w/o it.
Most agreed that 160 was the limit for stock chassis.

The wind tunnel tests showed some very poor aeros w/o PC kit.
That is where the 50 lbs of downforce come from.

R

 

I would concentrate on a front splitter air dam to control air underneath the front of the car and to Aid Cooling on the rear I would use minimal Wing or spoiler and concentrate on a diffuser

 

George: I'm guessing that a nice splitter has to be custom made? That would make them a big $ item?
Oh well, speed costs, how fast can I afford to go.

We need to talk about my getting coil overs for the adj factor. Street to open road.

R

 

Other than a spoiler, have you swapped out the camber rods with rubber for solid joints, replaced the rear control arm bushings for metal spherical joints. Taking all the rubber out will reduce the trailing throttle oversteer at all speeds.

 

Simple 1/8 aluminum. A fab shop could make it pretty easy. I thought about how to have my mufflers in the diffuser.




To work the best they need to be near the ground like this IMSA car

 

The front QA-1dual adjust coil overs are under $1000 with three sets of springs from Speed Direct. I have a lite weight front end and 650# for the street and 700# for the track days.

I have the rear dual adjust shocks. They are from Summit and with tax they are $500 something for two rears. It was kind of a dumb move. I should have just done rear dual adjust coil overs, but i had already spent a bunch on custom steel and and two mono leafs.


My advice to anybody is to pull the front A-arms off. Then inspect the frame in the mounting areas for flex cracks. i ended up welding and fish plating both sides on lower arm mounting points. Rebuild them with poly bushings and long slot cross bar to get the castor up to 6.5 or so.

Front bar of 1 1/8th with spring end links

Castor of 6.5 camber of about .42 neg. (you can only really set camber with a heat gun for even tire temp or tire ware) Zero toe. I get perfectly even tire ware with those settings. I've had sticky front treaded DOT tires race tires and they were worn completely smooth in one day. Same thing with slicks the ware dots are always even depth.

Rear is .5 neg camber and i have tried zero toe and settled in on 1/8th toe in for some rear self correction factor.

 

Can I assume that the rears will cost 1K? What other costs are involved? How much fabrication will be required? I want to ease into this addiction! lol

 

You have to add up the rear VB&P smart struts and the custom 520# mono leaf. I have the rear dual adjust shocks. They are from Summit and with tax they are $500 something for two rears

Total Tom's Rear end with Richmond or my other rear end with US gears with custom yokes and HD trailing arms with tom's outer spindles

Welded up and reinforced frame rails.............. Solid mounts for the diff. Front solid mounts for the motor. drive line hoops............

Every time something broke I went better and stronger

You start putting big HP and going fast something breaks.

295 front slicks and 335 rears put lots of TQ to the frame



From street to slicks with 4 inch exhaust tips. Your imagined snap rear end swinging around then make the rear heavier than the front end like real race cars. Loose does not happen with enough tire under the rear! Kind of dumb excuse of " I don't want a rear sway because I make the rear tail happy statement"