aerodynamic drag and body style

[gsa612]

Back in the day a few stock and S/S cars ran a vinyl roof claiming the pebble on the texture was worth some MPH,however small the gain was.FWIW,Jason Line's Buick GS has a vinyl roof...gsa612

[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

.

[Adger Smith]

Larry, you have e-mail.
Sorry couldn't get the excel to post here
are you still using the "Woodfinlarry" mail?

[Adger Smith]

This car was pretty aero..

[Adger Smith]

Sorry no chart

[GTX JOHN]

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

ON my Aspen Wagon = a similar class to the Malibu
Wagon.....It slow the car down a MPH with the rear
factory spoiler!

[Billy Nees]

Just for discussion purposes.

[Dwight Southerland]

Billy, that's just a justification for not doing body work.

[Chris Hill]

Originally Posted by Steve Polhill

Hey Larry watch this video. in this case the front end was a disaster for drag but the most gains were picked up with work done on the rear of the car.

Great video and thanks for sharing.

[FED 387]

Looking at that RMS pic notice the ground hugging stance that the vehicle has---Air going underneath a car is "dirty air" and its trapped in all the nooks and crannies---better off getting the air to go over or around rather than UNDER for this reason---Why do you think NHRA has a blurb in the rule book about no underbody streamlining??? Just for that reason. FED 387