ScaryFast

Can anyone point me to a place that sells aerodynamics for the old cars? I have to be very careful with class restrictions, but I'd like to weigh the cost vs benefit vs penalty of some better airflow around my vehicle.

The biggest problem area seems to be the gaping hole under the gas tank area. Has anyone seen a diffuser that covers that hole?

Slalom4me

From Greenwood Corvettes

What rules do you need to comply with?

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Slalom4me

Some information here about the car below. I installed 2DIN NAVI for my C4





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Slalom4me

I suspect that the parts are all hand made, one-off pieces, but the
photos of this car ought to stimulate some thought about C4 aero.



Here is a link to more photos. See where the radiator ducting exits?

CF Member Nuvolari offered it for sale in the following thread. There
is contact info if you wanted to approach him for more info.

Edit: Correction - Looks like he didn't want approaches about parts
F/S Corvette Lightweight GT Racecar

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ScaryFast

Are you kidding with the Greenwood stuff? Isn't it simply cosmetic?

I'm complying with NASA TT rules. I have to re-calculate my current point penalty and see how much wiggle room I have, but for comparison sake, here are some numbers:

Front splitter / spoilier = +2
Add rear wing = +2
Add flat bottom / belly tray = +5
Rear diffuser = +2
Side skirts = +2

Based purely on speculation, I would think that a rear wing or a diffuser would offer me the most bang for the least penalty. I'd like to hear some experiences with a front splitter as well, as I'll be modifying mine to add better brake ducts, anyway. Plus it's still a little "uglified" from a tire wall incident last season

I am currently running the risk of being forced into the unlimited class due to the recent decline in my lb / HP ratio, so the points may become moot. However, the issue then becomes effectiveness vs. $$ cost.

Mojave

I am getting a rear lexan spoiler made for my 96 that I'm setting up as a track car.

More info here: http://www.frrax.com/rrforum/index.php?showtopic=8603

Slalom4me

Is this more like what you had in mind?



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BrianCunningham

Try talking with these guys.
http://www.tccracing.com/main.htm
Alot of the run ex SpeedGT cars.

ScaryFast

Yes, thanks

XPC5R

I would trade the rear diffuser for the front splitter. The splitter is a guaranteed front downforce generator if set up well. So is the rear wing.

The rear diffuser can help generate some downforce with the underbody, but is dependent on the flow under the car, and probably really needs a flat bottom/bellypan to be really effective.

ScaryFast

How much of a difference do you notice with a front splitter? I'm thinking it will be most effective providing downforce at turn in, but that's typically your slowest speed on a track. Can you get enough downforce at 30-60 mph to help, yet not be a hindrance at 100+ mph?

Once in a corner my car is quite balanced. I have some push on very slow, tight hairpins, but on 80% of the turns I take I have plenty of bite at turn in.

KB Aero Biscuit

What about engine cooling airflow?

ScaryFast

Not sure what you're asking - how is mine currently, or what will a splitter do to it?

Currently it's fine, I don't know the answer to question 2.

KB Aero Biscuit

C4 relies on an airdam and a bottom breather inlet. How would the splitter change the airflow to the bottom breather?

BrianCunningham

A properly setup splitter would feed MORE air to the radiator.

You need to be careful with undertrays, you could overheat the trans and diff. Sideskirts are a better bet.

KB Aero Biscuit

More air to the radiator than needed will create unnecessary front lift and drag. Undertrays properly designed will create tremendous suction/downforce.

BrianCunningham

Correct, it works, with all the area we have under our cars, all you need to pull is 2psi vacuum and you could run the car upsidedown, but you need a place for the air entering the radiator to go, otherwise it's still going to go under the car, the side vent's help a little, Callaway really opened them up for their LeMans C4.


The hood of the C5R and C6R ( and Tazio_Nuvolari's car, later pics )are really what's needed. Actually Duntov used that trick on his prototypes.

You'll also notice a bunch of NACA ducts in the back of the C5R and C6R to cool the diff and trans.

ScaryFast

So where do I get that rear diffuser and the heat extractor hood?

Slalom4me

Home Depot - You can do it, we can help.

Seriously though, if you mean the Callaway diffuser then you could try
contacting them. While I am unsure of the answer, you do not know
if you do not try.

If you mean the f-body diffuser, I believe the Camaro belongs to the
fellow known as Blainefab in the thread that Mojave provided a link to
earlier. The picture comes from a second thread Blainefab provided in
the one Mojave posted.

Blainefab comments about the diffuser in post #8 (Aug/05)
Contact info is in the thread. He may be familiar with the C4 ...

Time spent reading through Alan's threads could be worthwhile. There
are some remarks about results noticed from the splitter and other work.

As for the Nuvolari hood - my take is that this started as a lightweight
hood (Toledo Pro carbon fiber?) and at some point, they added the
sheetmetal ducting from the radiator and opened up the hood.

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speedjohnson

I had high speed stability problems with mine that were solved with the addition of a rear spoiler and rear diffuser.

The rear spoiler is merely a six inch high piece of 1/8" clear lexan set at 45 degrees... clear so that you can see out the rear mirror.

The diffuser was more difficult and entailed rerouting the exhaust out the pass side door and having FuelSafe manufacture a fuel tank to fit beind the rear diff and sweep up to meet the underside of the rear bumper cover... the bottom surface of the tank is the top surface of the diffuser.

The results were quite noticable... not as much insecurity at high speeds, especially in the braking zone.