windtunnel
09-15-04, 11:09 AM
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windtunnel
does any one have and pics or videos of a stock fd3s in a windtunnal or does any one know where to find them? i have tried searching for them a few time but i have not had any luck. and i was wondering what kind mods for the body would help beside just a front lip
09-15-04, 11:44 AM
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i am looking at making my rx7 as a autocross or a highway race car and i want it to be stable at high speeds but still look stock. if any one has any ideas on how to do that it would help.
09-15-04, 11:47 AM
#4
Originally Posted by tedsmith26
i am looking at making my rx7 as a autocross or a highway race car and i want it to be stable at high speeds but still look stock. if any one has any ideas on how to do that it would help.
The '99 Spec Rear Wing is very popular with the road racers as it's adjustable and adds downforce for high speed handling.
09-15-04, 12:54 PM
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Autocross (at least SCCA Solo I and similar varieties) is run "at or below highway speeds," so aerodynamics are not typically much of an issue. If you want to add enough aerodynamic elements to actually be effective at those speeds, you would be moving into the modified classes - take a look at the size of the wings on the A-Mod cars to see what I mean.
Some forum participants did provide me some aero data recently that you might want to review:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/aero-data-fd-311143/
Some forum participants did provide me some aero data recently that you might want to review:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/aero-data-fd-311143/
09-15-04, 01:42 PM
#7
First off: adding downforce is good, but removing lift is just as good, and can usually be accomplished without adding drag.
For starters, the suspension: you should be able to adjust that already if you race competitively. Put the car as low as you can without rubbing, scraping, hitting the bumpstops or wreaking havoc on suspension geometry / alignment. The less air under the car, the better. Also, add some rake: put the front slightly lower than the rear, this will help make the car more stable at high speeds. This will affect your corner weights, so be aware of that. At all but the highest cornering speeds, your cornerweights will usually be more important; it's difficult to drive a car that has two different personalities depending on whether there's downforce or not. If you don't already know what cornerweights are, go learn about suspension, alignment and chassis setup before you do any more research into aerodynamics.
Do the sealed undertray thing, that will help reduce drag & lift from the underside of the car, which is really not too bad to start with, the underside of these cars are pretty smooth from the factory. If you're planning on moving the fuel tank, that will allow you room to make some underbody channels, which will decrease lift.
Front lip, sideskirts and a vented hood will help, again less air flowing under the car. Don't go overboard with the size of the hood vents, you don't want your hood creating tons of turbulence. For instance, I would probably not recommend the Scoot hood, those vents are a bit too extreme in size and angle of attack. Don't add any lips or skirts to the rear bumper, it will add drag: imagine a teardrop shape, or a droplet of rain. This is the ideal shape you're shooting for: the rear should not be disrupting airflow at all.
If very high speeds are your goal (120+mph), get rid of your side-view mirrors while you're at it, remove them completely and add mirrors inside the car.
As mentioned above, if you're doing this for SCCA Solo II / Autocross competition, you're wasting your time. What you need is a lightweight car with wide sticky tires, good suspension, and plenty of low and mid-range power. Autocross events rarely get you into third gear, aerodynamics are not an issue and even if they were you're doing too much turning for most aero aids to make a significant difference.
-s-
For starters, the suspension: you should be able to adjust that already if you race competitively. Put the car as low as you can without rubbing, scraping, hitting the bumpstops or wreaking havoc on suspension geometry / alignment. The less air under the car, the better. Also, add some rake: put the front slightly lower than the rear, this will help make the car more stable at high speeds. This will affect your corner weights, so be aware of that. At all but the highest cornering speeds, your cornerweights will usually be more important; it's difficult to drive a car that has two different personalities depending on whether there's downforce or not. If you don't already know what cornerweights are, go learn about suspension, alignment and chassis setup before you do any more research into aerodynamics.
Do the sealed undertray thing, that will help reduce drag & lift from the underside of the car, which is really not too bad to start with, the underside of these cars are pretty smooth from the factory. If you're planning on moving the fuel tank, that will allow you room to make some underbody channels, which will decrease lift.
Front lip, sideskirts and a vented hood will help, again less air flowing under the car. Don't go overboard with the size of the hood vents, you don't want your hood creating tons of turbulence. For instance, I would probably not recommend the Scoot hood, those vents are a bit too extreme in size and angle of attack. Don't add any lips or skirts to the rear bumper, it will add drag: imagine a teardrop shape, or a droplet of rain. This is the ideal shape you're shooting for: the rear should not be disrupting airflow at all.
If very high speeds are your goal (120+mph), get rid of your side-view mirrors while you're at it, remove them completely and add mirrors inside the car.
As mentioned above, if you're doing this for SCCA Solo II / Autocross competition, you're wasting your time. What you need is a lightweight car with wide sticky tires, good suspension, and plenty of low and mid-range power. Autocross events rarely get you into third gear, aerodynamics are not an issue and even if they were you're doing too much turning for most aero aids to make a significant difference.
-s-
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