bamf

Just curious if anybodies knows of a company that sells a full underbody tray and rear diffuser kit for a 2001 Mustang? I have found one place that does the diffuser and they have made some ridiculous claims about gas mileage savings (3 MPG). I’m looking for a full kit to improve handling during road course racing. In other words, a pan under the engine all the way to the rear of the vehicle.

Novanutcase

I don't think you'll be going fast enough for a belly pan to really make all that much difference. Not sure of the level of driver that you are but it may be better to use the money for HPDE rather than putting something on that won't do a whole lot.

John

bamf

I’ve already run (2) HPDE around Mosport International (Ontario, Canada) and about (3) events at smaller scale tracks. This year I would like to take my 2001 Bullitt to Mosport and see what kind of lap times I can post. The events are time trials (No passing) and I ran a 1:54 in a Mazda RX-7 TII, which isn’t that slow, but I don’t expect any professional race teams to give me a ride with those times. The Mazda had a front chin spoiler, underbelly pan for the engine and a rear wing.

The average speed works out to about 129 km/hr (80mph), with the back straight getting up to 200 km/hr (124 mph). My Bullitt is up 65 hp and 100 ft-lb torque over the Mazda which should drop times at Mosport.

Basically the Bullitt doesn’t come with a rear spoiler and I don’t think it is proper to put one on, so I’m looking for alternatives. With that said the car came with the front chin spoiler (AM), which I think looks sharp. Regardless I get nervous about doing 200 km/hr and have the rear potentially get loose.

Alternatively I could purchase a set of racing slicks, but I’m only looking to run one or two events this year and a set of slick will cost be about $900 CDN. Where the rear diffuser and under belly pan can be kept on and maybe I even get 1 mpg better fuel economy driving on the highway.

Novanutcase

If you're worried about keeping the rear end stable I would get a rear wing for more downforce before I would get a belly pan.
I'm not a aerodynamics engineer by any means but from what I've seen, been told by knowledgable people, and have experienced a belly pan won't really do all that much until you're running around 140mph and up. That's why a lot of the guys that run the American Iron series for NASA run big Cobra wings for better downforce. As far as I know none of them run a belly pan/rear diffuser.

John