comparing air dams and looking at cold air ducting

[magicv8]

I stopped at the shop that painted my car and Mike was painting a 69 Camaro air dam, so I got a chance to compare it to the air dam on my 66. First I put the Camaro air dam in the mold made from my air dam, then I put the Camaro dam next to a dam made from the mold. The camaro dam has a deeperV, less height, and doesn't fit the valence.

Mike also got in a 67 to restore, and I got a chance to take a pic of the l88 style cold air insert he made from a mold that fits a 67 BB hood. Those of you with 67 hoods - the line forms on the right

 

[Kid_Again]

...i added the L-88 cold air chamber to my '67 hood...got it from Eckler's


....as JohnZ will tell you, one of the highest pressure points is at the base of the windshield...the air on the surface is a layer of turbulent air known as the boundary layer..........what worked real well for me is the L-88 cold air chamber AND cutting holes in the back of the frame to allow the cold air to reach the top of the carb...i also added a k&n top filter and the top of the filter stayed cold to the touch into June on the East Coast

 

[Viet Nam Vett]

...i added the L-88 cold air chamber to my '67 hood...got it from Eckler's


....as JohnZ will tell you, one of the highest pressure points is at the base of the windshield...the air on the surface is a layer of turbulent air known as the boundary layer..........what worked real well for me is the L-88 cold air chamber AND cutting holes in the back of the frame to allow the cold air to reach the top of the carb...i also added a k&n top filter and the top of the filter stayed cold to the touch into June on the East Coast

And at what speed does that forced air actully add Power ..and What would be th HP gain?

Is there a chart that shows speed Vs Air Pressure to HP Gain. I would be interested in seeing just how much is gained per $1.00 spent for Labor and Materials.

 

[JohnZ]

And at what speed does that forced air actully add Power ..and What would be th HP gain?

Is there a chart that shows speed Vs Air Pressure to HP Gain. I would be interested in seeing just how much is gained per $1.00 spent for Labor and Materials.

There is virtually no gain at all from a hood scoop under about 150mph, assuming it's properly located; "properly located" means like a Pro-Stocker, with the inlet about 18" above the hood surface, well clear of the boundary layer airflow. The real gain is cooler intake air vs. underhood air; rule of thumb is a 1% power increase for every 10*F reduction in intake air temperature.

 

[Viet Nam Vett]

There is virtually no gain at all from a hood scoop under about 150mph, assuming it's properly located; "properly located" means like a Pro-Stocker, with the inlet about 18" above the hood surface, well clear of the boundary layer airflow. The real gain is cooler intake air vs. underhood air; rule of thumb is a 1% power increase for every 10*F reduction in intake air temperature.

Yeah..... I can see me running around with a Pro Stock scoop sitt-en 18" on top of my 66 BB hood.... Heh dude, I just picked up 5 HP....
otfl

 

[cbernhardt]

Speaking of air dams and air flow - I am thinking of adding a front spoiler/air dam to my '59 project. My questions for the airflow experts are:
1) Is the purpose of the spoiler to move air smoothly around to the sides of the car, thus lessening air flow underneath the car?
2) Or is the purpose to create down force at the front of the car?
3) or perhaps all of the above?

What I am looking for is the optimal design for a C1 body traveling at speeds above 120mph. Should the spoiler/air dam be sort of a continuation of the front body lines down to a few inches above the road surface (which I would assume would provide smooth air flow around to the sides of the car) or should it be angled forward at the bottom to perhaps provide some downforce, or perhaps a combination of both configurations?

Charles

 

[JohnZ]

Speaking of air dams and air flow - I am thinking of adding a front spoiler/air dam to my '59 project. My questions for the airflow experts are:
1) Is the purpose of the spoiler to move air smoothly around to the sides of the car, thus lessening air flow underneath the car?
2) Or is the purpose to create down force at the front of the car?
3) or perhaps all of the above?

What I am looking for is the optimal design for a C1 body traveling at speeds above 120mph. Should the spoiler/air dam be sort of a continuation of the front body lines down to a few inches above the road surface (which I would assume would provide smooth air flow around to the sides of the car) or should it be angled forward at the bottom to perhaps provide some downforce, or perhaps a combination of both configurations?

Charles

Ideally, an air dam 1)Spills air around the side of the car, 2) Creates a low-pressure area under the car, 3) Diverts airflow into the radiator, and 4) Creates downforce.

1) Reduces aero drag from the section width of the tires and reduces turbulence created by air flowing under the chassis and underbody.
2) Assists highway-speed cooling, as it increases airflow through the radiator.
3) Same as 2)
4) Not really significant under 100 mph, and is prone to damage if it's close enough to the road surface to be effective (2"-3" or less).

 

[bluestripe67]

When I made the fresh air induction on my '67 with the big block hood (drawing from the base of the windshield as in NASCAR) the carb went lean (plugs were very white). I recalibrated the carb, adjusted the timing. The low end torque was significantly increased to the extent that I couldn't get the car to hook up with street tires despite serveral try at the track. So something happened with this change, be it HP or TQ. It improved!!!!

 

[Ken Anderson]

Years ago I put a similar air dam on a 65 Corvette. After a couple of 120+ runs I quickly took it off. It felt like the front tires weren't touching the ground, and this was a frame off resto-so the suspension was right!. With no air dam, it handled great. Good luck in your project, sometimes stock is hard to beat.

 

[cbernhardt]

Years ago I put a similar air dam on a 65 Corvette. After a couple of 120+ runs I quickly took it off. It felt like the front tires weren't touching the ground, and this was a frame off resto-so the suspension was right!. With no air dam, it handled great. Good luck in your project, sometimes stock is hard to beat.

Did your air dam extend out far enough to cover the front tires?
How much space did you have between the bottom of the air dam and the road surface?

Charles

 

[Ken Anderson]

Covered the tires & about 8 inches aboe the road