How much percent H.P. increse with a cold air set up such as a "Shaker" or A12 type hood scoop? Thanks.

The A12 scoop is better than the shaker, it's up in the air more.

think I have an old DC racing manual where they compared ET's with other setups and the 70 T/A fresh air setup was the best, the A12 was second , and the shaker was 3rd with the AAR - but any fresh air is better than none - don't remember a HP # increase per set up though...Joe

It's been my experience that the fresh air systems don't make any extra horsepower. But they allow the engine to make it's best horsepower more often. For an example, my Cuda will run the same numbers the first pass of the day with and without the Shaker. BUT, it will loose about a .1 if I make another run rather soon without fresh air. And will loose about another .1 if I make yet another run fairly soon without fresh air.

It's the temp of the air that the carb gets that is the key to fresh air systems. Until the underhood temps exceed the outside air, there is not much advantage to fresh air systems. But as the underhood temps climb and the difference between that air and the outside air widens, so does the advantage of the fresh air system.

The biggest difference I have seen with my car with and without outside air has been about .25 in the 1/8. Well worth the effort since I often need to make back to back runs.

On a similar note, my electric cut-outs pick the car up about the same. Except the cut-outs increase the performance that much. Not just maintain what it is already doing.

Yup, shakers don't do squat for power. The only scoop that even barely got above the boundary layer of air was the A12 scoop on 69 RR and Bee. The boundary layer of air is a turbulent area of air that sits on the surface of the hood and causes fast moving air to flow over it. So the air doesn't actually "flow" into the scoop.

But it looks cool, that's about it.

Ryan

Well even though the shaker doesn't "ram" im air like many like to believe, it does provide a source of fresh outside air instead of breathing in hot under-hood air. I would agree that it helps to maintain power, instead of losing to to heat soak/hot air under the hood.

Was a noticable seat of the pants difference on my 71 demon when i sealed the carb to the hood. BUT do block your heat crossover or whats the point.

I've never had one, so I can't say from experience, but I did remember running across this 1970 Rapid Transit Authority ad on the Hamtramck website that touts that the shaker option boosts quarter mile time:

"Aside from the fact that it looks tough and girls dig it, it's good for .15 to .20 of a second in the quarter."

I can't say if it's true or not, but it's still a cool ad...

In 1976 my pal Wayne Hyland and me raced his 71 Cuda 340 shaker billboard orange 4 speed at the local dragstrip all summer long--it ran a tenth better in the 1/8 with the shaker on his front porch--we came home one day and the garbage man had taken the shaker with the other stuff his mom left out for them Oh well........
that was one heck of a car for a couple of thousand $$. I can't quite remember how many clutch sets it took to do that.

I dynod my cuda with it open and closed, didnt make a difference on peak numbers, it did however move the curve a little bit...

I have heard of people running the shaker on a really fast car and actually having a VACUUM at the scoop opening.....

I actually tested this, i was curious too on how much effect a fresh air sytem has.

My Coronet has a 440 4bbl, with a six pack hood on it, no sealing for the air cleaner though.

I went to a swap meet to pick up a ramcharger underhood set up for a buddie who has a 6 pack road runner.

i installed it on my hood as my trunk was full of stuff, sealed up the gaps with a towel, and drove 30 miles on the freeway. Took it off and on the way back i plugged my hood scoop with the towel and drove home.

I didnt notice any difference between running my car normally, running with the ramcharger set up and running with the scoop plugged, the car ran a tick warmer with the hood scoop plugged though.

Carb has to be jetted when running a sealed ram air system, otherwise the back to back test is useless.