[Jack Blum]

Not sure where to post this so i put it here in Race.

After seeing pictures of my 68 GTO running in the Silver State Classic in the 130MPH class I know I really need a front spoiler. The car at 130 is about 6" nose in the air. And we intend on going up to the unlimited class and possibly running at Bonneville salt flats. After the garage fire (just burnt up the paint and killed the tires) we have completely torn the car apart and are rebuilding it again. I found some pictures online like this one:

I was thinking something like that with a 4" strip of tire rubber on the bottom as well.

Anybody have any others that they have seen?

Also the car has all of the Hotchkis front and rear including springs and sway bars. Car handles great on the road racing track. we are going to get rid of the 69 rear spoiler and go with a more NASCAR style type. Something that's adjustable.

Basically I don't want this thing to become airborne.

Thanks, Jack.

[twooldgoats]

I made one for my '63 Tempest (shown in sig pic). It worked fine (at 175 mph), but just make sure you can load it on your trailer. My tire pressures, ramps, etc. had to be set just so or it would hit while loading, especially. I finally tore half of it off (by accident) the last time out and decided to try without it next time.

Jim

[Bigger is Better]

Hi Jack,

I dont do the really high speed stuff but on the track and hillclimb (before I crashed that is) I did run a front spoiler extension and splitter on my 80 TA. While it was seat of the pants the front end was really more grounded above 100Mph, I used to say at 115 Mps it felt like it was doing 70 without the splitter.

The science is pretty solid, there is a great basic book if you want to read it, "Competition Car Downforce" by Simon McBeath, they are at least edition 2 now.

I think in your case you want to get your spoiler as low as you can get it to the ground but you will need to think about the car at full suspension compression and not have it hit. What you really dont want is the spoiler to break at speed, it could cut a tire or really upset the balance of the car if you are in a corner. So you want to build it strong with some bracing.

A lot of guys will build them out of Aluminum and on a road course let them grind to fit them selves but I would try to keep it higher. I dont thing a rubber extension on the front will do much unless it is braced well, there is a lot of air force and I think it would bend over.

You might also want to consider some side skirts, you can attach them to the rocker/floor board flange. I never did that as my rules didnt allow it but it also helps from keeping air from coming under the car from the sides and increasing lift.

I dont have any specific suggestions for your car as I dont know them well enough to make any mounting suggestions.

Good luck at the race, thats on my bucket list and would love to come do it one day!

Johnny

[Tom Vaught]

Originally Posted by Bigger is Better

Hi Jack,

You might also want to consider some side skirts, you can attach them to the rocker/floor board flange. I never did that as my rules didnt allow it but it also helps from keeping air from coming under the car from the sides and increasing lift.

Johnny

If you could copy some Trans Am Skirts (before the rear axle opening) as was said that would keep some air from getting under the back end of the car.

The spoiler you have shown in the picture has no visible outward angle change to keep air from not entering the front wheel opening. Rodney Butler and Travis Q built a front spoiler based on my suggestions and their fab skills that was good enough for 227 mph quarter mile passes. There are pics in old threads of the 63 Tempest body work and the front spoiler.

Tom V.

[Pearlbluebird]

I started making one yesterday for my 79 Firebird fiberglass front clip. From the bottom of my front clip to the ground I measured over 11 inches. My fastest MPH was 156 and the car was feeling really loose.
The biggest I could go in my application was 6" without causing loading issues. I'm using .080 aluminum and bracing to the frame. I'll post pics tomorrow should have it finished. Hopefully I'll see improvement.

[Jack Blum]

Thanks for all the great suggestions. I will look online for that book "Competition Car Downforce". Sounds like a good read. Jack.