picture request (spoilers)

[Jayhall]

Ive been toying with the idea of removing the 3 peice spoiler, and replacing it with something a little larger. Before you start flaming, hear me out. The one im looking at sits 5 inches off the hatch. A little higher than stock, but I dont want something much larger than that. So I guess Im looking for 2 things here.
First off can anyone provide me with some pictures of MKIII's with a larger, LOW SITTING after market spoiler?

The second peice of informatio im looking for might be a little more difficult to come by:

How high off the rear hatch deck does the clean air flow? I do not want to spend alot of money on a functional spoiler, and render it useless by mounting it in the vaccume that the car puts off. The hatch back design will allow for a lower mounted, functional spoiler BUT if its going to be much more than 6 inches, im not really that intrested in going through with this whole idea. Ive been searching google for local wind tunnels, but I figured asking here would be worth a shot first.

 

[supramad77]

Have a look at my regulus rear wing. Sounds like you are looking for something like this.

 

[Freshmaker]

That picture(in first post) makes me lol. Its such a simplification it does more confusing than help.

The answer to your question is not a number, but an equation. While I have only taken a basic fluid dynamics class I will take a stab at some possible useful information for you. The only place on our car that likely has vacuum is right about the rear bumper and below the taillights.
The air that runs down the hatch and over the stock spoiler might be under an effect called "separation"(depending on velocity) which is basically disturbed/turbulent air. That air might not be perfect, but it can still be used for down force.

This is heresay from a couple years back: The coefficient for the Turbo supra is .33 and the non turbo is .34. Since the difference is the spoiler, one could assume the stock spoiler is functioning at its current height.

 

[foreverpsycotic]

The only spoilers that I would put on a MKIII would be from APR. Unfortunately, their GTC series has the lowest height of 10". Its just a little higher than what you wanted.

 

[92nsx]

IIRC Kaminari and regulus are the only rear wings that look like the OEM one only a little higher / wider.

Search for pics of the Kaminari one, it has been posted a couple times

 

[suprarx7nut]

That regulus wing is sexy.

 

[JDMMA70]

That picture(in first post) makes me lol. Its such a simplification it does more confusing than help.

The answer to your question is not a number, but an equation. While I have only taken a basic fluid dynamics class I will take a stab at some possible useful information for you. The only place on our car that likely has vacuum is right about the rear bumper and below the taillights.
The air that runs down the hatch and over the stock spoiler might be under an effect called "separation"(depending on velocity) which is basically disturbed/turbulent air. That air might not be perfect, but it can still be used for down force.

This is heresay from a couple years back: The coefficient for the Turbo supra is .33 and the non turbo is .34. Since the difference is the spoiler, one could assume the stock spoiler is functioning at its current height.

IIRC Pre89's spoilers provide a lower drag coefficient than 89+ with spoilers.
I believe it was .32 for Pre89 Spoilers, .33 wingless, and .34 89+ Spoilers

 

[Poodles]

Think he has the numbers reversed... Spoiler has more drag, and the different front made a difference as well.

Regardless, I can tell you the spoiler works. Went on a drive with some locals a few years back. We all had our cars spotless before the drive and after the drive (was dusty out and a few dirt roads), the turbo cars had tons of dust on their rear bumpers, the NAs didn't.

 

[honestabe]

If you want a pre-89 wing Daryl, you can have mine for free.

 

[JDMMA70]

Wonder how well the Pre89 Spoiler works? It looks like the 89+ spoiler works really good but i wonder about Pre89's. I also wonder if the door mirrors have any affect. If so i wonder which is more aerodynamic. The Pre89, 89+, or the folding mirrors.

 

[Jayhall]

That picture(in first post) makes me lol. Its such a simplification it does more confusing than help.

The answer to your question is not a number, but an equation. While I have only taken a basic fluid dynamics class I will take a stab at some possible useful information for you. The only place on our car that likely has vacuum is right about the rear bumper and below the taillights.

this is what the hatch back is designed to do, correct?

The air that runs down the hatch and over the stock spoiler might be under an effect called "separation"(depending on velocity) which is basically disturbed/turbulent air. That air might not be perfect, but it can still be used for down force.

This is heresay from a couple years back: The coefficient for the Turbo supra is .33 and the non turbo is .34. Since the difference is the spoiler, one could assume the stock spoiler is functioning at its current height.

So, if I were to put a better designed spoiler at the same height as the stock spoiler, it should catch this turbulent "separation" air flow, and make an improvment in downforce? And if the spoiler were just above the turbulent air flow, it would be in the clean air flow and working at its best?

What Id prefer to do, is keep the front under sideof the spoiler at the same height as the stock spoilers front under side. So ideally the only differance in actual height will be becasue of a bigger better designed spoiler.

Im going to have to look at that regulus spoiler a few times before I decide if thats too high, or just right.First impressions Im alright with it

 

[Freshmaker]

So, if I were to put a better designed spoiler at the same height as the stock spoiler, it should catch this turbulent "separation" air flow, and make an improvment in downforce? And if the spoiler were just above the turbulent air flow, it would be in the clean air flow and working at its best?

What Id prefer to do, is keep the front under sideof the spoiler at the same height as the stock spoilers front under side. So ideally the only differance in actual height will be becasue of a bigger better designed spoiler.

Im going to have to look at that regulus spoiler a few times before I decide if thats too high, or just right.First impressions Im alright with it

Correct. A spoiler at stock height will produce downforce. The same spoiler will produce more downforce at a higher height. To what extend the height change will be noticeable, one can only guess/test.

 

[supramad77]

Think he has the numbers reversed... Spoiler has more drag, and the different front made a difference as well.

Regardless, I can tell you the spoiler works. Went on a drive with some locals a few years back. We all had our cars spotless before the drive and after the drive (was dusty out and a few dirt roads), the turbo cars had tons of dust on their rear bumpers, the NAs didn't.

I concur on the dust thing, my rear bumper is always dusty after a drive no matter how clean and dry the car and road is.

 

[Jayhall]

I would like to test in a wind tunnel, but I dont know what kind of money thats worth. Im guessing a whole lot

 

[honestabe]

Very, very expensive. Indy cars do this and it costs them upwards of $100,000 for tests. You could make your own wind tunnel and use a scale model of the Supra as your test though and that would be cost effective. Just make sure everything is to scale properly. Mythbusters has done this a few times with highly successful results.

 

[Freshmaker]

How about: Buy a wing you like. Make adjustable mounts(height wise) for strain gage mounting. Mount up the wing and strain gages. Set it to the lowest height and start doing some data logging. Pick a couple speeds you want the wing to be effective at and record the strain. Then, raise the wing incrementally to test the effect of height. When you find the height you want, make a permanent mount. Not only will you have proven what height is the best to mount at, you can also calculate the exact down force your wing is giving you.

The same method could be used if the wing has an attack angle adjustment.

 

[Jayhall]

so maybe a 1:18 scale model of a wingless supra would work with a shoe box and a hair dryer? I was hoping I could flip someone a couple hundred bucks for a few minutes of their time on a weekend or something. And buying the wing and testing it myself would be time consuming, but atleast it would be perfect, just the way I want it. My big concern was buying an expensive spoiler and having it be usless at the low height I want it at. Thanks for all the input. MORE PICS PLEASE!!!!