I apologize if this has been covered, I have been searching for a bit and haven't found anything. Like the title says, is this something anyone here has done? I don't see any aftermarket options available or if this is even possible for that matter. If this isn't something being done, what does everyone do to get more front grip besides sticky tires, adjustable toe rods, and camber?

 

In SCCA autocross a front splitter (and rear air dam) is more or less required in Street Prepared and up for srsbzns competition. It is not allowed in Street or Street Touring unless stock OEM. In PCA I'm not sure of the groups, but basically anywhere it is allowed it will be a requirement to be fully competitive. Pretty sure GT-racing has 997 front splitters.

Most people make their own front splitters in order to fully conform to the rules in the most aerodynamically advantageous way possible. (If it isn't banging the ground over the bigger bumps it isn't low enough.) A friend of mine just made one for his 993 in BSP, though it was basically a clone of the Porsche racing item to spare the real thing from cone damage.

 

This is awesome information. Do you or anyone you know have any examples of how they made theirs and mounted it to the chassis?

 

The only one I know about is Stan Whitney from Texas who ran a 2008 911 Turbo in SSP for several years. The car was totally awesome. I found his thread for his previous 2007 ASP Cayman build, http://93cayman.blogspot.com/?m=0 but couldn't immediately find anything for the 911.

 

I am surprised to hear that aerodynamics is even considered a factor in autocross.

I always thought that aerodynamic effects are not significant until you get > 60 mph. Even at that, wouldn't the biggest gain for downforce be in high-speed the turns?

 

While I posted in the Autox page, I really just mean in general/road course racing. I would have posted elsewhere but it doesn't really seem like other 'performance' sections of rennlist are very active.

 

This is a common misconception. Aerodynamic gains can be significant at autocross speeds in the 45mph to 65mph range.

I'm no expert by any means, but the simple air dams used on the back of street prepared autocross cars can essentially eliminate the natural lift that is usually there and the splitters do the same on the front by limiting air getting packed under the car which creates a high pressure area (lift). It doesn't take many pounds of force added (by not being lost) on the tires to make significant differences in a sport where small margins are significant. These elements are highly constrained in size and sophistication in Street Prepared. If they were allowed more freedom (primarily length under the car) even greater gains could be had with additional venturi (diffuser) effects.

And then when you allow wings and canards and such you start producing real down-force. A highly developed A-mod car with triple-element front and rear wing assemblies is a sight to behold as it goes around corners at incredible speed.

 

Are you referring to rear diffusers? Do you have any pictures of what you are talking about? Appreciate your input

 

I was referring to using the front splitter to become a diffuser as well. I'm pretty sure that rear diffusers are not allowed in SP. And the rules within SP, I'm told, make it nearly impossible to achieve effective diffusion in the front due to limited length. Some disagree and think it is a matter of money and development for any particular car. Got a wind tunnel?

Any combination front splitters/diffusers that would be used in, say a Cup car, would likely be illegal in SP. But, if you aren't interested in autocross, then you should be able to find front splitter/diffusers, rear diffusers, canards, wings, etc. from the racing 997s that will make a lot of difference on the track, or at least copy them. I know some of it is available on gt-racing.com as I previously noted.

 

Sounds good I will check some of those out and do some more research. I did find a very informative article overall on how to make an effective splitter which includes testing by using a ton of small lengths of yarn taped to the car and driving the car while having a GoPro or another vehicle record how the yarn reacts to the air.

 

Unfortunately, all the tracks I've run are 60 seconds or less with maximum speeds under 60 mph, which is a short straight run, then hard on the brakes for the next turn. No one is close to 45 mph in any turn we do (where downforce would really help), so we are probably not seeing any aerodynamics impacts.

 

Biggest gains would be in fast sweepers for sure. If you don't have any... no gains there.
Gains are also to be had when braking down for slow, tight corners. Aero will assist initial bite and allow later braking.
Also, there can be significant gains in fast transitions.

 

Thanks. Makes sense. We do have some fast slaloms.