Downforce for an FR-S?

[HachiRo]

I'm still pretty noob when it comes to aerodynamics in general. I know the FRS has a very low drag coefficient which means it doesn't get affected by cosmetic drag, etc much. My question is, will putting a splitter or wing, in this case adding drag, make a big difference for street/daily driving?
I understand down-force will help is turns and cornering, but also increases grip which can cause the car's top speed to be lowered (?).
Would it be best to stay away from any parts that could cause drag? Or would cosmetic ones like an APR Splitter and or wing be too small to make a big difference?

[NWFRS]

It won't matter at the speeds a stock FA20 are capable of, certainly not on the street.

Maybe if you bumped it to 400hp and did drag races with it, and even then tires will matter more.

Personally, I don't think the extra drag from aftermarket aero parts will matter one way or another. Just be sure everything's fastened on good and tight or you'll look like a Civic and we'll laugh at you. :-)

[aznatama]

None of this will matter at legal highway speeds. The change is really negligible, unless you drive between LA and SF or Vegas on a weekly basis in no traffic on cruise control the entire way.

From what I hear, most rear wings and spoilers don't even do anything until above 80mph.

FWIW, BRZ factory has a cd of 0.28, with full STi aero parts and underbody panels, it gets lowered to 0.27, same as a VW Passat Wagon! LOL

[HachiRo]

Originally Posted by aznatama

None of this will matter at legal highway speeds. The change is really negligible, unless you drive between LA and SF or Vegas on a weekly basis in no traffic on cruise control the entire way.

From what I hear, most rear wings and spoilers don't even do anything until above 80mph.

FWIW, BRZ factory has a cd of 0.28, with full STi aero parts and underbody panels, it gets lowered to 0.27, same as a VW Passat Wagon! LOL

Ah, I plan to get an APR Front splitter and possibly a wing, not sure which, but yeah, I like the look of aero parts (sorry if I'm too ricer for ya guys).
I drive SoCal > NorCal and back every now and then. Hopefully that won't be trouble :\
But yeah, as you mentioned and as I've heard, aftermarket parts that aren't in the thousands range don't really affect drag much. But I wanted to have that clarified.

[Gunman]

Wings, splitters, diffusers, all start to work once you're moving. Their effect increases as speed increases, but it's not linear, meaning as a general rule, you double the speed, and the aero effect is 4X.

Splitters and diffusers have a low drag penalty, the downforce gain is worth more than the drag induced by them, and done right a diffuser can lower drag.

Wing's will induce drag, they are up in the free stream air, but how much drag will depend on the angle of attack, and the wing profile. For efficiency look at the L/D of the wing, not just the amount of downforce, or drag it induces.

[Wonderbar]

Aero works at all speeds, but it scales exponentially the faster you go. Physics be crazy.

Horsepower is completely irrelevant when discussing aero. You should always try and maximize your mechanical grip first; but functional aero will always benefit you from both added stability and grip, to a bump in MPG when you reduce your drag at highway speeds.

[aznatama]

Yes, aero works at all speeds, but at legal speeds, there's not much difference. We can even get into the discussion of how using paint sealer reduces drag, or how orange peel in the paint reduces drag... Is all this really relevant in the real world considering OP's DD/street use situation? Nope.

Gunman and Wonderbra, you're both have valid points, but are speaking from a track-use perspective, which is not what OP was asking.

For street/DD use, a splitter and wing are not going to make a big difference, provided the wing is property installed and not at some absurd angle.

[PHLonomenal]

I'm actually chuckling at this thread because the rear spoiler on my last car was believe it or not FUNCTIONAL...at like 130mph. No, I could not tell if it was working. 😉Wink wink


Sent from my StarTrek communicator using Tapatalk

[Wonderbar]

I'm not talking a wing, but a front splitter and rear diffuser are absolutely noticeable at legal speeds. So would be underbody panels.

A wing doesn't fall into the same category of aero as diffuser, splitters and underbody.

A good rear diffuser can add 10% mpg at 50-70mph and make the care feel night and day different. I daily drive my car more than I track it, it's completely relevant even for spirited driving.
@Ammonia can attest. Plus many others who didn't think it true until they actually felt it.


Again though, I would absolutely max out mechanical grip before doing aero.

[aznatama]

^ agree, but op only asked about APR front and a wing.

This is like someone asking about an intake, and turbos being suggested.

Personally, I have/will have a combination of Sti and ts aero s well as the jdm underpanels.

[Wonderbar]

Well, he asked general questions, by my interpretation of his post. So I'm doing my best to answer his questions and give him a bump in knowledge based on my own experience.
@Gunman builds aero for nascar, Gt cup cars, etc; so I'd take what he says to heart. Lots of people on here that can pass a ridiculous amount info and experience. I'm a nobody.

[aznatama]

All valid posts and good info. =)

[gramicci101]

Originally Posted by Wonderbar

Well, he asked general questions, by my interpretation of his post. So I'm doing my best to answer his questions and give him a bump in knowledge based on my own experience.
@Gunman builds aero for nascar, Gt cup cars, etc; so I'd take what he says to heart. Lots of people on here that can pass a ridiculous amount info and experience. I'm a nobody.

[cough]bullshit![/cough]

[Gunman]

Wings can definitely help at street legal speeds, look at some of the FSAE cars being built, with big aero, and they run 60 mph and less. You just have to go with a big wing, to work at low speed. Of course then people that don't know any better will make fun of you for being a "ricer", while you out brake them into, and carry more speed out of that on ramp.