[Mike S]

I am wondering If a front air dam would help the aerodynamics of a 67 GTO at 135 mph. I like the look without it but hell if I pick mph I could deal with it.
Anyone have pic's of a front air dam on their car?

[1965gp]

I was going to put a 69 Camaro chin spoiler on my 66 but haven’t done it yet.

I put one on my 69 Charger and it just kind of blends in.

[TinInjun]

Unless you can get the front end low enough to make it aerodynamically useful, it will be just added weight.

[Tom Vaught]

The idea is to keep the air out from under the chassis of the vehicle.

Air banging around on lower control arms, the bellhousing and the oil pan, the transmission, and in some cases the exhaust system/Mufflers created aero drag.

I did a bunch of aero work for Travis Quillen and Rodney Butler on their 63 Tempest.
(Both the front of the car and the rear of the car (WING Design) as well as the sides of the car (wheel openings).
It worked as he went 6.20s at 228 mph in the quarter.

The other thing is to get the air that does pass thru the grill/radiator away from the firewall as quickly as possible with air extractors like a Trans Am has but honestly would screw up the looks of the body.

John Cleeg did none of those things and still ran 194 mph in the Texas Mile with his 64 Supercharged Pontiac engine.

https://www.youtube.com/watch?v=tWJKqWCspWI

Just saying.

Not worth the bang for the buck with your vehicle.

Tom V.

[cgeise]

a well designed splitter would help also

[242177P]

Originally Posted by Mike S

I am wondering If a front air dam would help the aerodynamics of a 67 GTO at 135 mph. I like the look without it but hell if I pick mph I could deal with it.
Anyone have pic's of a front air dam on their car?

If it's low enough, it may change how you stage and even affect your RT? I was under the impression some classes didn't allow it??

[Keith Seymore]

My answer would be: it depends.

Aero is a funny thing. It's not always intuitive and you really never know unless you "smoke it" in a wind tunnel, or in some other way test so that you can visualize it.

We decided one time to remove the parking lamp on truck and replace it with a cold air inlet for the engine. Didn't work at all.

When we smoked it in the tunnel we immediately saw the air was hitting the inboard side of the inlet, shooting across the surface and coming right back out the outboard side of the inlet. No air was going IN the tube. Totally not intuitive.

Similarly, on the Volt program, we would add all these little "skegs" that could be worth one, two, three, five "counts". The problem was that while you were consciously making changes on one end of the vehicle you could be unconsciously making changes on the other end of the vehicle of similar or greater magnitude, polluting your results.

My summary is the same as Tom's: if you add a small air dam that forces air through the radiator and into the engine compartment = worse. Better for cooling, but worse for aero, because all that air is getting trapped like a parachute in the engine compartment and would need to be adequately vented.

If you added a large air dam, under the bumper, that forces air around the vehicle instead of under it: better. It would be similar to adding smooth body pans to streamline the underside of the vehicle.

K

[Keith Seymore]

This might also not be totally intuitive but "as low as possible" is best.

The drag is a function of the frontal area. But the frontal area is not just the "front of the car": it includes all of that area extrapolated down to the ground.

So lowering the vehicle reduces the frontal area and therefore reduces the aerodynamic drag. This is a well known fact and has totally been borne out in NASCAR racing.

The bigger the area the more there is to be gained. We lowered our 5th wheel travel trailer 2" and picked up several MPG on the open road.

And - here again, this has the added benefit of less air going underneath the vehicle.

It's free (or can be) and a variable within your control.

K

[johnta1]

If it's low enough, it may change how you stage and even affect your RT? I was under the impression some classes didn't allow it??

The spoiler would have to be 3" above the ground.(the staging lights are lower than 3")
Most tracks don't allow the extended 'thingie' on front of the car to trigger the finish line lights.
(like on most of the street outlaw cars on TV)

[nas t eh]

[QUOTE=johnta1;6388621
Most tracks don't allow the extended 'thingie' on front of the car to trigger the finish line lights.

[/QUOTE]

Is there a rule preventing someone from changing the wheel base or length of the car or how much front overhang you can have?

Make the whole car longer by 2 ft keep the rear wheels where they are and shorten the wheel base 6inches. Gain 2.5’ on the competition till they copy you.

I don’t need an answer, just thinking crazy ideas out loud.

[Keith Seymore]

Originally Posted by nas t eh

Is there a rule preventing someone from changing the wheel base or length of the car or how much front overhang you can have?

Make the whole car longer by 2 ft keep the rear wheels where they are and shorten the wheel base 6inches. Gain 2.5’ on the competition till they copy you.

I don’t need an answer, just thinking crazy ideas out loud.

What does that gain you?

You trip the starting beam with the front wheels, and you trip the finish line beams with the front wheels.

K

[Tom Vaught]

Originally Posted by nas t eh

Is there a rule preventing someone from changing the wheel base or length of the car or how much front overhang you can have?

Make the whole car longer by 2 ft keep the rear wheels where they are and shorten the wheel base 6inches. Gain 2.5’ on the competition till they copy you.

I don’t need an answer, just thinking crazy ideas out loud.

AERO is a function of many variables. The 67 GTO is not a AERO shape that travels smoothly thru the air.

OP, Instead of butchering a 67 A-Body Vehicle (it would look nothing like the original vehicle) if you are really after AERO improvements put the drivetrain in a much newer GM body where lots of GM $$$$ went into the aero design.

Thanks Keith for the great Aero Example.

Tom V.

[Stuart]

Originally Posted by Mike S

I am wondering If a front air dam would help the aerodynamics of a 67 GTO at 135 mph.

I assume this is purely for drag racing? Would adding aero components to the car put it into a different class?

[johnta1]

Is there a rule preventing someone from changing the wheel base or length of the car or how much front overhang you can have?

Actually, I think there is. Can't think of what it is right now.
On my dragster, when building it, the front nose can only extend so far in front of the tire/spindle mount. (2 feet seems to come to mind on that)
Also the nose had to be 3" above ground (or more).

Also dangling chickens aren't allowed.
(story for another time)

[Tom Vaught]

Originally Posted by Stuart

I assume this is purely for drag racing? Would adding aero components to the car put it into a different class?

Not sure about classes.

The Quillen/Butler 63 Tempest (with lots of aero improvements) allowed that body/chassis to run 6.27 in the quarter
at 228 mph years ago.

It had a proper wing on the back, windshield angle changes (I believe).
A front spoiler that was very low to the ground and had proper flares to keep the outside air away from the inner wheel wells.

The Turbo Exhaust outlets faced upward to apply more down force on the front of the body/chassis.

All of the aero modifications were based off of Lockheed Wind Tunnel studies on other vehicles tested at that location.
Smoke Wand information helps show & explain aero patterns.

Tom V.

[Keith Seymore]

Originally Posted by Stuart

I assume this is purely for drag racing? Would adding aero components to the car put it into a different class?

Bracket class rules are pretty liberal.

For heads up class racing it would depend on those specific sets of rules.

K

[Keith Seymore]

Originally Posted by nas t eh

Is there a rule preventing someone from changing the wheel base or length of the car or how much front overhang you can have?

Make the whole car longer by 2 ft keep the rear wheels where they are and shorten the wheel base 6inches. Gain 2.5’ on the competition till they copy you.

I don’t need an answer, just thinking crazy ideas out loud.

You break the starting beam with the front wheels, whether they go forward, or up.

Some cars trip the 60' clocks with the rear wheels.

If you trip the finish line clocks with the rear wheels you are either (a) driving a AA/FA, or (b) in big trouble.

K