aerodynamic drag and body style

[Mike Rietow]

Originally Posted by Jackie McCracken

On a 79 Malibu wagon the factory rear spoiler is worth almost 3mph on car that runs just at 100 without it in the quarter.. and the reason for it is that it pulls air from the roof and routes it down the back window (to keep it clean in civilian life) which fills in the vacuum hole behind the car. and if you're wondering how big and powerful that "vacuum hole" is, it is what the cars that make turns use to create their ground effects downforce in sufficient quantities to be able to drive one across the ceiling upside down. The "vacuum hole" is also the reason behind drafting in nascar, if you can get in close enough it will damn near pull you along... need proof of what good aero can do? How about 174 on a bicycle...peddling.

what you really want to do with the front of the car is to smooth the air and keep it out from under the car, along the sides and roof you need to keep it flowing smoothly, and a the back you need to eliminate the "vacuum hole"...


Jackie

Wow, excellent post.

This Chevy II has a All Pro RR 427 sbc we're getting ready to race with a 300hp NOS cheater plate per the rules of DXP Street, the car will be around 140mph 1/8 mile. We have the bumpers off for chroming but we still gotta ad a splitter under the front bumper. I'm more curious about the wake behind the car. Do you know anyone who has added a rear deck spoiler? This is a leafspring 275 radial car with a set of shocks on the back with a two way adjuster on rebound the azz of the car is up at the stripe to keep the nose down, you may have seen this on radial tire cars, not real conventional for drag racing but the shocks help get the power in the car early no wheely bar allowed by rules.

I'm just fishing around for Ideas, I think we can keep the air from under the car fairly easily.with a chin spoiler under the front bumper.

Are these chevy II's known for wake issues? the rear deck is long relatively speaking. I was thinking rear deck spoiler, not sure, looking around for experience with these cars. Would rather no spoiler.

Thanks ahead of time

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