Benefits of large rear wings for track use

[kenjiMR]

I'm in the process of considering installing the Marga Hills rear tall wing and the decklid spoiler that my friend is selling. He currently is using the large Kawagen wing and has noticed a significant improvement in stability during certain crucial turns on the racetrack.

I'm pretty sure that the Marga Hills spoiler is designed pretty well, but at this point, I'm not really trying to compare the downforce efficiency with the other wings. I would be interested to know what other mods should be made in conjunction with increasing the rear traction at the high speeds. Should the front undertray and front hood scoop also be incorporated at the same time to increase front grip as well?

If you have experience with the big airfoils for the NSX, I'd be interested to know your opinions and advice.

 

[ncdogdoc]

I am sure Supercharged will chime in here as he has done many of these things. The big wings really do help, but they also take some of your top end speed. I prefer to be planted and lose 5 mph at the end of the straight. I also find that the 25mm spacers in the rear help a lot. Finally, R compound Kuhmos will make for permanent grins

I do think the vented hood helps, but at higher speeds than the rear wing. But to contradict that statement, I do feel that the hood helps with braking and turn in on faster sweepers or fast uphill turns (like turn one at Road Atlanta and turn one through three plus eleven on VIR's full course and turn seven on VIR's north course). I have a CF front splitter, but am still working on my underbody tray and rear tray, which I hope will help me stick like glue.

 

[supercharged]

Yes I agree with the above if done correctly. Some wing designs or to much rake just serve as a brake (as opposed to just a little drag). A few points to consider:

1. The rear wing should be in clean air for best effect (this is higher than most people expect, even on an NSX).

2. The best down force/drag ratio comes just before seperation of the airflow over the wing.

3. Gurney flaps on the top trailing edge of the wing and rear trunk edge increase overall down force.

4. I really only felt the difference in medium to high speed corners (i.e. > 70 mph)

5. You can get 2-3x the downforce AND braking from an active wing but these are illegal in most race circuits (see Pulp Files for the S2000 example, good for about 5 seconds at TH).

6. A front splitter need not be used at the same time but it really helps with understeer if of the proper size (downside: it is the first thing to suffer if you miss your mark )

My personal order of preference would be:
Sway bars, rubber, suspension, rear wing, front splitter.
(no brake or power mods listed above to keep it simple).

 

[ncdogdoc]

My personal order of preference would be:
Sway bars, rubber, suspension, rear wing, front splitter.
(no brake or power mods listed above to keep it simple).

I would agree to a point. Obviously I am the only NSX track driver in America (except Ken) who has not done the sway bar swap. I think the bars are more seat of the pants than real (JMHO) as they do not allow the suspension its full travel. Now this is someone who is still running stock suspension on my track car (almost 400# lighter). Yes the car leans like a Cadillac, but I am as fast or faster than many on the tracks I know. The stock suspension is wonderful with a lighter car.

That being said, I do have Dali race bars (1") for the front, will either leave the rears stock or remove totally. I plan to do a straight bar with adjustable knives for the front someday, but will wait until Rob Morrison has the kinks worked out. I also have the Competition Konis from Comptech with 1000# front and 600# rear springs. Hopefully all of these will get installed over the next couple of weeks before I have to deliver the car to Atlanta for transport to Infineon.

 

[kenjiMR]

Good info guys.

Here is my current set up relavent to our discussion.

- TEIN-RA suspension 10kg/10kg lowered the car 1.5" at least
- Dali track/street sway bar. full stiff up front full soft in the rear.
- SOS CF replica front splitter 3/4" lower than stock
- Taitec rear diffuser and center exit exhaust

I also have a bunch of other small weight reduction items such as
Recaro seats and steering wheel. The car is pretty light, but there has
been no engine modifications at all.

I am running 17x7.5 front and 18x9 TE37 rims with stock brakes with Carbotech P+ and ATE Super Blue.

If I had my choice, my next mod would be Stoptech brakes, but the wing is tempting due to this opportunity.

 

[supercharged]

"I think the bars are more seat of the pants than real (JMHO) as they do not allow the suspension its full travel."

Not to get to far off topic but I agree with you until you start lowering the car then sways (at least front) are a must.

PS - I'm running the same Koni's you mention and love it, see ya at Expo!

 

[2slow2speed]

I am sure Supercharged will chime in here as he has done many of these things. The big wings really do help, but they also take some of your top end speed. I prefer to be planted and lose 5 mph at the end of the straight. I also find that the 25mm spacers in the rear help a lot. Finally, R compound Kuhmos will make for permanent grins

I do think the vented hood helps, but at higher speeds than the rear wing. But to contradict that statement, I do feel that the hood helps with braking and turn in on faster sweepers or fast uphill turns (like turn one at Road Atlanta and turn one through three plus eleven on VIR's full course and turn seven on VIR's north course). I have a CF front splitter, but am still working on my underbody tray and rear tray, which I hope will help me stick like glue.

Hi Gary,

Are you working on a underbody tray for the stock front bumper?
If so I would be interested in finding if you are planning to
produce a one-off or perhaps more?? (hint, hint..)

I've considered the Taitec one but that one requires the Taitec
front bumper, so it's a no go for me.

BTW: The vented hood does wonders for cooling too, here in
CA where we have 100+ degrees days at the track (air temp).
It really helps in keeping the car cooler and planted too

Safe driving..

Ken

 

[NSXGOD]

I plan to do a straight bar with adjustable knives for the front someday, but will wait until Rob Morrison has the kinks worked out.

I have one but I'm not sharing yet.

 

[Andrie Hartanto]

Kenji,

does big wing helps? Of course it helps downforce on rear of your car. Will it help laptime wise? This has to be tested.

In general you want a car that balance. Too much rear downforce can generate understeer. Resulting higher lap time. too big of a wing for a given power can mean too much drag. thus slower lap time.

However, if that wing helps you take turns faster, and won't cause too much drag so you don't suffer on the straights, than it can mean lower lap time.

So far the only kit that really tested wind tunnel wise are the one that used by realtime. Theirs were built by a company in England, and were used in NSX that competed in LeMans a while back.

I believe Dali has one as well, ex-Norcini car.

The problem is their front kit require relocation of the radiator.

The latest Japanese kits, that were used in the race also perform well. One thing to keep in mind is to have an aero kit that work well with your vehicle power. What I mean is don't look on the JGTC 500 kit for your less than 300HP car. Maybe closer if you look at their GT300 kit.

I believe SoS have quite selection of this kit.

 

[kenjiMR]

Makes total sense. Once the NSX is track worthy again, I will test with both configurations in the same day, that should provide some info on whether it is usefull for that particular track and suspension configuration.

Kenji,

does big wing helps? Of course it helps downforce on rear of your car. Will it help laptime wise? This has to be tested.

In general you want a car that balance. Too much rear downforce can generate understeer. Resulting higher lap time. too big of a wing for a given power can mean too much drag. thus slower lap time.

However, if that wing helps you take turns faster, and won't cause too much drag so you don't suffer on the straights, than it can mean lower lap time.

So far the only kit that really tested wind tunnel wise are the one that used by realtime. Theirs were built by a company in England, and were used in NSX that competed in LeMans a while back.

I believe Dali has one as well, ex-Norcini car.

The problem is their front kit require relocation of the radiator.

The latest Japanese kits, that were used in the race also perform well. One thing to keep in mind is to have an aero kit that work well with your vehicle power. What I mean is don't look on the JGTC 500 kit for your less than 300HP car. Maybe closer if you look at their GT300 kit.

I believe SoS have quite selection of this kit.

 

[cojones]

more info on GT300 aero ??

The latest Japanese kits, that were used in the race also perform well. One thing to keep in mind is to have an aero kit that work well with your vehicle power. What I mean is don't look on the JGTC 500 kit for your less than 300HP car. Maybe closer if you look at their GT300 kit.

I believe SoS have quite selection of this kit.

Is there more info on available GT300 replica aero packages ??

 

[ncdogdoc]

Hi Gary,

Are you working on a underbody tray for the stock front bumper?
If so I would be interested in finding if you are planning to
produce a one-off or perhaps more?? (hint, hint..)

Ken

Ken,

Sorry, but I had not checked this thread in several days
I do plan to make this for the stock bumper, and yes, if all goes well and I can do it cheap enough, I will make them available. Someday

 

[2slow2speed]

Ken,

Sorry, but I had not checked this thread in several days
I do plan to make this for the stock bumper, and yes, if all goes well and I can do it cheap enough, I will make them available. Someday

Hi Gary,

Thanks for the update, looking forward to seeing you and the Track Rat at Sears .

Ken