Ray S

Does anyone know where I can purchase the little black stick on Gurney flap for the lower element of the GT3 rear spoiler? I believe these were more commonly seen on the MK I's

Ray S

Found it....

PN 996 512 988 00

RayGT3

Is it long enough to be used on the RS wing, needs to be about 44-45" long? Is it shown in the PET?

05gt-3jeff

have a picture ?

JasonAndreas

Has anyone looked into just buying a piece of pultruded carbon fiber rectangular rod or a slightly shinier piece of 90 degree carbon fiber angle strip? The dimensions required are around ~1/4"x1/4"x40ish so it should cost less than $30 compared to the $278.19USD that Porsche is asking.

RayGT3

If you want the verticle edge to be 90 deg to the ground you will need something like 100 deg angle as the rear edge of the wing tips up slightly at the last 3/4" or so. A 90 deg will look as though it is tipped forward a bit

JasonAndreas

The flap is mounted perpendicular to the trailing edge of the wing. THESE might work but I'm not sure of the attachment method other than adhesive or double-sided tape?




the 90 degree angle is visible on this Audi R10.

RayGT3

Jason,

Not sure of the aero result of having a thick edge vs. the thin edge. I've never seen a thick deflector used. You just want something to disturb the air at the very back edge of the wing. What happens is the air flowing across the bottom of the wing seperates from the surface about 3-4" from the back edge and you loose downforce in this area and drag is increased because of the lower area turbulance. The gurny disturbs the upper air, a bit, pulling the lower airstream up to the wing surface again, restoring the down force in this area. The gurny does introduce some drag but it also reduces the drag on the lower side, so in regard to total drag it is a net wash.

Talked to my CF guy and he will be making two pieces in different heights. Don't know about delivery, it's one of those "when I get a chance" things. But he seemed enthused about trying it. Will let you know as things progress.

I'm thinking double back tape will be more than adequate as I've seen some on race cars held on with racing tape. I may give 3M product engineering a call and ask their recomendations. I've been sucessful, in the past, doing this. If you sound real needy they'll send out a sample, usually enough to do you what want.

In the pic of the wing you show, which is typical of most wings, the rear surface is flat to the very back edge. If you look at the RS wing it turns slightly upward for the last 3/4 to 1". Which would result in the 90 deg gurny being tipped slightly foreward relative to the rest of the upper surface. I'm again, not sure, what effect this might have aero wise. If you were to open the angle up to account for the change in the wing surface the verticle angle component would return to verticle again.

Holger B

If there was some advantage to doing this, why wouldn't the factory have done it on the MK2 like they did on the MK1?

RayGT3

The advantage being: increased downforce with no increase in drag. No trade-offs here, it's all good. Whats really hapening is you are using the wing at its full potiental.

I can't answer as to why the factory does anything. Dual mass flywheel, sun roofs, etc.?

Z06

Corvette Speed WC testing found an advantage in rear end grip.. the Porsche Motorsports Crawford Carbon wing has one that slides on/off, the corvette bolts on.

va122

The 997 gt3 has it! It's to reduce turbulance.

RayGT3

Yes, the 997 does have one but not to reduce turbulance. It actually produces turbulance, a low pressure area behind the strip that pulls the lower air stream up. Which in turn reduces the turbulance in the lower air stream so, indirectly does reduce overall turbulance.

Cory M

You can buy preffabbed carbon fiber angle stock from a number of suppliers, google it, it is always priced way too high for what it is. Lots of mechatronics and robotics shops sell it but it will be cheaper if you buy direct from a composites shop. I have used a simple and cheap piece of aluminum sheetmetal sheared to size and bent on a brake, not as pretty as carbon but just as effective. You can also use aluminum angle stock but it is thicker and heavier than the sheetmetal. Quality double sided tape, like 3M autobody emblem tape, will hold it on - just make sure to clean the surfaces well before applying.

Jean

Might be surprising, but the 997 Supercup cars last year were losing on average 3mph vs. the 996 Supercup cars as a result of the gurney lip (160mph straight), but the incremental downforce more than compensates for that loss with lap times. Seen and checked on the Motec datalogs.