AFAccord

I'm looking to start a discussion on aero modifications to make my car more stable at high speeds. I've seen some good discussions out there about standing mile/half-mile and such, but many people aren't using aerodynamics to their advantage, and you can see their cars dancing around over the asphalt.

I don't fully understand most aspects of a good aero setup yet, but from what I've been reading, creating a flat bottom to the car and maybe a rear diffuser sounds like something I could study and build on my own and achieve tangible results.

The primary question I have is how to best start/stop a rear diffuser. Obviously you don't want the diffuser 'scooping up' air and creating a parachute with the rear bumper. If the car already had a flat bottom, I'd imagine you could tuck the rear diffuser above it to prevent this from happening, but what about folding the leading edges upwards?

Any help with this?

88cr-rex

Check the bonneville cars . . .

a belly pan helps a great deal as well as sitting the car down as low as you feel comfortable on whatever surface you are going to run.

You can also try taping the seams of the car . . . they do this in roundy-round qualifying as well as restricting the size of the grille into the radiator.

rudebwoy

iTrader: (1)

been in Germany since 1998, never had no aero mods. focus on your suspension and tires, all those ricer **** that evo and subi owners install on their cars is just waste of time and "rice mods" you don't need it. Tire/suspension/brakes is all you need if I can use a stock body civic to take down some extremely fast cars while boosting at 620whp I know you don't need any of that madness. all I have is holes in my rear bumper using a GE diffuser. now I will attempt this with a 670whp del sol, and for that DE2K event I may push it to 800hp. Honda will be represented.

AFAccord

Thanks for the responses. I do need to get my suspension aligned and setup right, maybe toy with my dampening. By far, my biggest concern is hitting a slight hump or dip, and the *** end of the car catching air. It seems to be a bit too eager to do that already, but I don't want to end up with one of those FnF wings on the back.

Brakes have already been addressed, but I do need to educate myself about dampening and suspension in general.

gringotegra

I have and will be doing some Aero mods in my 94 integra this year and will be running more 1/2 mile events.

I can tell you this. Taping up my headlights was worth 3mph alone..






From one pull to the next. That was seriously all i changed.


This year, im making a front splitter/air dam. Doing the Kiwi 5" Sideskirts and a rear diffuser. So i will be making a thread here soon talking about the changes i plan on doing and what they do in the 1/2 mile event.

Right now i am fighting traction on a street tire, so Aero mods are my friend!

m4xwellmurd3r

I saw your 1/2 mile runs on youtube. That thing moves! Definitely do an airdam and front splitter/belly pan. Get as much air out from under the car and get it above the car. Get rid of the rear wing too. The stock wing is just for looks imo

gringotegra

I honestly don't mind the stock wing as the car moves alot up top after 140+. I kinda feel like the wing has to do something there lol.

But i plan on doing a back to back without the wing and with the wing there!

gringotegra

double post edit!

m4xwellmurd3r

Ya never know. At those speeds that wing could be producing lift instead of downforce! From what ive seen they dont have any sort of airfoil shape to them and are more or less a pretty slab of plastic.

The trunk spoiler I have on my 4 door would create downforce but thats because its a lip spoiler. Im tempted to buy myself an r32 gtr/gt t25 rear wing. Theyre true functional wings for downforce.

Anyways ill be looking forwards to seeing the back to back results when you get the chance

EddieCRX

Follow on from another thread, this car had simple aero mods and managed 181mph in the wet with no drama, the addition of the rear spoiler helped the back end a lot.

2 vids first is standing shot of car with back ground noise of run so you see the car and it's aero, second is the in car and you see the stability and all in the wet.

http://www.youtube.com/watch?v=2crAalXz4kI#t=0

AFAccord

I've read through your thread on this before, and was wondering how well the car was holding up at those speeds sitting so high!

I agree that a functional rear wing would probably be all I need to keep the back end down, but I even removed my stock spoiler because it was 'too much' for my taste. My best bet may be to have a second trunk lid with a wing on it for the days when I know I'll be going out just to run the car hard.

I'm still interested in options for 'sealing' off the space under the rear bumper since I rarely need to access anything in that area, and it could potentially be left in place and functional year round. I need to get back under the car for a look to see if something like a flat bottom is a viable option. Besides spending hundreds on a large sheet of CF for the rear, what would be the best rigid but light-weight material to use beneath the car?

tepid1

I've had good luck with 1/16" AL sheet in 6061. It's pretty ridgid and requires minimal fastening.

m4xwellmurd3r

Hey tepid, whats a good place to pick up some aluminum sheet? I kind of want to make a bellypan/splitter for my da, just no clue where anyone picks up this kind of stuff.

tepid1

I used a local metal supply shop.

ohsnapzafingcu

iTrader: (2)

how do you keep that 5th gear from shredding apart!? nice runs!

Steeve_Civic

Nice thread

rudebwoy

iTrader: (1)

I am currently considering some type of drag wing like CCC racing uses, but trying to find reasoning behind its purpose on FWD cars.

AFAccord

That style surely wouldn't provide any down-force for high speeds. I would imagine it reduces turbulence where the clean air meets the vacuum area, and might even increase vacuum at the rear of the car, helping to 'suck' the car to the road for stability.

rudebwoy

iTrader: (1)

that's what I figure, it would create some type of lift to the rear end.

AFAccord

Found this interesting...

redboost10

as mentioned, the wings are not meant for down force, but to get the air out from the rear of the car. air will always take the pathway of least resistance, meaning it will get sucked in under the rear of the car, lifting the car and creating instability. A pro stock wing is a prime example, i believe they extend about 18" off the trunk of the car and are basically parallel to the ground.

Steeve_Civic

Lindsay, here is my wind (not CCC)

I don't know if there is anything measurable at 1/4... perhaps stability, but goal is to get air out from the rear of the car as mentionned by redboost10.

m4xwellmurd3r

I think those wings work by disrupting the laminar flow going over the hatch. The air sticks to the hatch and creates lift. By extending the wing out, the air is able to seperate off the roofline and creates a zone of turbulence under the wing, pulling the car to the ground rather than pulling the car upwards and back.

tepid1

I use my wing for downforce, but it's nothing like the CCC wing.

I have so much weight in the front of the car (drag car) that the rear will get loose. My car us really stable at the end of a run, which is exactly what I wanted.

AFAccord

So basically, the effect I'm looking for is exactly what a GT wing provides, only I'm not ready to put a wing on the car.