splitter experts

[billyboy]

I got to thinking that maybe I got carried away with the homemade splitter. Should I taper in the side more? It follows the bumper shape but 3" out then curves up about 4".

[wastintime]

what spoiler setup do you have on the rear?

[billyboy]

Duck tail

[wastintime]

yeah, i'd tone those down a bit, that would make for one seriously unbalanced car, it looks like you've already got the Stype splitter to start out with, but i can't really tell from the pic.

[Jack Olsen]

I'm no aerodynamic genius, but I guess is that you're hurting more than helping going out laterally beyond the edges of the car. I'd cut it off so it tapers in to the point where it ends on the sides.

And from the picture, it looks like you're not putting any splitter across the middle 'cleft' in the front valance. This also seems like a bad idea, since you'll be essentially forcing air under the car right in the center. I'd have the spiltter run all the way across the front. As I understand it, the cleft is there for a tow line more than it is for any aerodynamic benefit.

[billyboy]

Thanks for the reply. I'll do those change and see how it looks.Do you think the 3" is too much, should I pull it back in a little also?

[RSBob]

I fabbed a piece of aluminum that fits inside the splitter that helps smooth the airflow behind the splitter to the pan. It also helps channel the air from the horn grills better to the oil cooler instead of dumping the air directly to the ground. I also created a raised tunnel in the middle to preserve the stock look, so its totally stealth. I figure it's worth a whopping 1/4 horse gain, or perhaps a little more! If you go with what you have created so far, I would recommend cutting the width by 1/2 in front and quickly taper the edges to the fenders or else you might be actually counter productive. I like Jack's idea of blocking the center cleft - by the backside. Keep us posted

[cstreit]

THat's definitely too agressive for a duck tail. THe RSR style splitter sticks out only 1.5". The the trick setup is to make it adjustable in and out.

I'll try and find a picture of mine. I bought an RSR splitter and slowly modified it (reducing the area) untill it felt more balanced. Ended up with the center section in front of the spoiler basically gone.

[cstreit]

Ahhh... here we go. This is a factory style splitter that I modified to balance out with the duck tail.

You can see the sides have "wings" but the center is removed.

[jluetjen]

If you check out the recent Racecar Engineering articles on splitters, I believe that the overwhelming majority of the downforce comes from the front of the splitter. Having it stick out the side just creates a lot of drag. Note that the F1 teams may do that when they shape the front wing end plates, but they are trying to create vortices and route the air around the front wheels, etc.

The idea behind a splitter appears to be that the blunt front end of the car creates a high-pressure area in front of it. If you put a splitter on the car, the high pressure area pushes down on the the area of the splitter creating downforce. Around the side of the car you want the airflow to be smooth.

[project 911]

Here are a couple of styles. Not your type of bumper, but it might give you an idea.


Upturned wing at the end:



Tapered into the side:

[Lukesportsman]

So the glue on carbon fiber winglets that the Civics stick on their bumper corners aren't working? There goes my birthday list.

I really have thought of going with plate Al with slotted holes to adjust for balance. You could in theory, adjust for slow (autocross) tracks or long tracks and or remove for street curbs. Does anyone think that struts (clevis/heim supports) are useful at our speeds and relatively small splitters?

[Chuck Moreland]

Originally posted by Lukesportsman
So the glue on carbon fiber winglets that the Civics stick on their bumper corners aren't working?

On many cars including 996 CUP, those little cantilevers are there to create a low pressure zone to draw air through radiators mounted on the extemity of the front bumper. Not for downforce.

You could in theory, adjust for slow (autocross) tracks or long tracks and or remove for street curbs.

The splitter isn't doing anything on slow tracks (less than 100 mph) anyway, so tune for speed.

The Racecar Engineering series John referenced above has some really good info on this.

[CBRacerX]

Trim the sides, fill in the front, make sure the whole assembly is well supported. 3" is not to far out front, but you have to watch the support aspect. If the material is not attached to the car body proper, support it with safety wire (ask me how I know).

With these rules, it will work well enough to support a serious rear wing. If you don't have a serious rear wing, soften that rear spring rate and swaybar!

Chris