Has anyone had any success at creating additional downforce or reducing front end lift at high speeds in a second gen? I've consistently fought this issue at speeds exceeding 120 mph, where the front of the car feels as if it lifts and gets rather floaty. I know that a well designed splitter should help (I do have the factory undertray installed), but I would like to avoid anything extremely gaudy or large. Anyone found the same issue and came up with some unique and successful solutions?

 

This is probably something to ask in the race-car section of the forum. The easiest small thing I can think of is canards.

 

we've done some stuff on the race cars, and it works, but its hard to test so no idea why it works.

plywood works great. you want it solid, but not so much that if you hit a curb it bends the frame

 

I've checked the race car section and it looks like that section of the forum has had zero activity in several months, so I figured I'd try here lol. I'm skeptical of the amount of downforce canards can provide, but I'm not totally against the idea. My thought is the splitter would likely have a larger effect, especially if you can alter the dive angle?

 

Do you have a rear wing or something you are trying to balance?

Because the stock front coefficient of lift is .08 and the stock rear coefficient of lift is almost double that at .14.

So, the rear should get floaty on a stock body FC, not the front.
And I can tell you from experience that my stock body FC never felt floaty in front with its midnightly trips 160-180mph.

The factory sport aero halves the rear coefficient of lift to .07 for more balanced aero, but I never had that.


If you are stock body FC and the car doesnt feel solid at only 120mph you need to go through the suspension in my experience. It was a loose bolt in the triaxial hub for me.

 

Years ago I ran a corksport front lip on a s5 bumper. Didn’t think anything about it for 2 years until I sold it at seven stock. While on the 2 hour drive home from sevenstock, the front end did feel lighter and awkward. I may have been running the RE wing that looks like a sti wing, and that did push the rear down.

just my .02

 

what are the ride heights set to? if you change the rake of the car it could change the aero too

 

I do not have a rear wing, but I will be installing one shortly (RE Type IV). This will only exascerbate the issue I'm experiencing.

Aside from my aftermarket front bumper, the car has all factory body panels. I've gone through the suspension several times and found nothing loose; however, the coilovers are much stiffer than I'd prefer (old stance GR's). Another thought I had is maybe it could be my steering rack? I have a manual rack and it seems like it has some play in it. Maybe this is causing the sensation of lift/float at high speeds?



The car is relatively low (not slammed) and is set to have a slight bit of rake (rear higher than the front).

 

When rack bushings went out in my FD it didnt feel floaty. I imagine this is because both front wheels are tied together tightly to the rack.

My loose rack bushings made the car feel like steering was numb on center and then didnt want to stop turning when I was done turning.

Numb on center might be your floaty, but when I think floaty front I think of a front that wants to change direction without input instead of one that doesnt want to change direction with input.

 

https://www.facebook.com/james.s.wood.7

 

Checked the steering while the car was parked... definitely seems numb on center. The more I think about it, the more I don't remember this being an issue with my old de-powered rack. However, I could be remembering incorrectly. I'm wondering if it's the bushings or the rack itself. At the very least, rack bushings are simple enough to change.

I do believe I'll still make a modest splitter with an adjustable attack angle in the future.



@FührerTüner

I've seen that guys build. Are you referring to the splitter he built?

 

Yeah pretty much, but now that I reread your first post I'm realizing that you dont want to install a splitter.

You could try to create an air dam behind the front fascia, but other than diffusers, wings, splitters, or dams, not really sure what other options are out there.

 

Ah, gotcha. If I do make a splitter, it will be functional and actually have a support frame like that one. Just not nearly as big.

The more and more I ponder what @BLUE TII said, the more I think the instability I'm sensing may be steering related. Control arms already have all new bushings, and I've got brand new wheel bearings installed (not directly related). The only thing that leaves is my coil-overs and the steering rack.

 

i'm failing at pictures, but we've done a few race car ones, and usually its just plywood. the race car ones are disposable, they hit stuff, stuff hits them. the trick is to make it solid enough to work, but not bend the frame when you hit a parking block...

the miata ones kind of look like this, where you just wrap a flat thing around the front, and put a piece of wood under it, it works

 

What is your wheel offset?

My experience with FCs is you have to run pretty close to stock +40 offset or camber thrust/bump steer starts to jerk the car to different sides over uneven road surfaces.

Friend had 17x9 +35 with 20mm bolt on spacer for 17x9 +15 offset and I thought the car was scary as hell. Moved top hub mounting ear of strut out with crash bolts and was able to clear 17x9 +35 and car drove nice.

I ran 16x7.5 +30 and later 17x8.5 +30 wheels.

 

For sure. Those are definitely more effective, but I don't plan on going to that extreme for my street car. Plywood is a good material though. I also have access to some aluminum core material that could work.

Wheels are 16x8 +12

 

You mentioned deadzone in the steering wheel. Adjust yoke plug tension on the steering rack itself.

I just did that on my fc and it tightened up the steering. I am running PS rack but I’d think a manual rack would also have a yoke plug.

 

I've heard that can be adjusted. I just need a huge socket, as I've tried getting that nut off to no avail. Maybe I'll just buy the damn socket already.

EDIT: Adjusted the rack. While it helped, it didn't alleviate the issue.