Ram Air

[Phantom]

I was thinking about the Pontiac WS-6 and other cars over the years that have ram air induction and the resultant horsepower increases. Then I added in the data I collected in my senior level lab I did on ram induction and they correlated.

Back in the early '70's Ford was touting a ram air system(shaker hood) that added about 15 HP to their Mustangs and Torinos. Pontiacs system took the T/A from 305 HP to 320 HP. In each case the net HP increase was about 5%. My study indicated that the ram effect didn't become apparent until speeds in excess of 90 MPH - BUT - a 100°F reduction in intake air temperature was worth about 5% due to the incresed density. That is about the difference between underhood air drawn from behind the radiator and cold air drawn from in front of the radiator or above the hood.

Bottom line - a cheap way to increase HP by around 5% is to get an unrestricted intake that draws fresh, cool air rather than the heated underhood air. This is intuitively obvious but how many guys out there are running carburated cars that are sucking their air from right above the engine exhaust manifolds?

[Guest greimann]

I know from my Holley TBI data interface that the intake air is routinely 140 deg. F. I have seen it as high as 156 degrees. When I was running a carburetor, there would be times where the fuel would boil in the bowl and stall out the motor. That is one reason I went with TBI. I have always had a fresh air induction project in the back of my mind, but for me, it has to be an unobtrousive well engineered solution. A hood scoop is not out of the picture, and some members here have some very elegant solutions for this. I think I want to go with something totally under hood, that is more than a tangle of sheetmetal and hoses. A project for another day, because the car runs fine right now with out it.

[Phantom]

Lone Star 1 has a nice "dual snorkel" set-up for his LS-1 that draws air from either side of the radiator just behind the grill.

[Guest Anonymous]

Oldsmobile had the slickest factory ram-air system; two scoops mounted below the front bumper with 4" hoses running to the air filter.

[Guest Ziggy Vulcan]

Why not just put in a hood scoop?

[Guest greimann]

I prefer to preserve the asthetics of the original hood profile. I also want a clean underhood appearance. I have an idea for a rigid plenum style cold air duct that takes air from the underside of the front of the hood. I am willing to put in the extra effort to create something that no one else has done. Maybe this winter.....

[opie]

Olds did have the idea right. Pontiac Ram-Air from the 60's didn't really ram much until they pushed the intakes to the front of the hood in 71 for the GTO and 70 for the Formula Firechicken. The lower temp of the air did make a diff though. You're correct. You can get the same ram effect that the '96 and up Pontiac's get on the Z hood due to the slope up front.

[Kevin Shasteen]

This came up in another thread. I too like the later Firechicken's hood scopps. I have also been a long time Olds fan-owned a few 442's and liked the aggressiveness of the Olds W-25 scoops (1970-73) and the later Pontiac F-Bodies.

 

I came across these in a Summit Catalogue-under the Truck/SUV section. With the exception that they are only 3M taped on-not graphed into the actual hood I think they look pretty good.

 

http://www.weathers.com/Lund/Hood%20Scoops.htm

 

BTW: Year One sells the Olds under the front bumper Ram Air Duct set up for the 66-67: 68 may have even used that system prior to the 69 Hurst Olds. But be careful of water puddles-too large of a puddle and your engine is toast.

 

Air compresses-water doesnt...Bad Bad Water-Bad Water

 

Kevin,

(Yea,Still an Inliner)

[Guest pvtkary]

Sorry ther spelling is bad. Im not a rocket scientist, I just play one on tv. I am currently working on this problem. I am trying to ram a large volume of air into the motor. The plan is to use the area under the front lower valence panel. This should provide suficient area to produce a posative manifold pressure in a V8. It should also induce a negative pressure differential under the car to help me with top end handeling charistics. I Am cuently working on the math to gauge the propper size, and come up with a mas airflow sensor to keep the mixture correct. So far this seems like the main stumbeling block. Most fuel delivery systems are gauged to engine RPM. This obviously will not work with this system. If I work out the bugs Ill share it with anyone who wants it. The other thing that is still a problem is keeping out water.

[blueovalz]

I was under the impression that the typical "hot wire" used in AFMs had the capability to meter the air intake under a wide variety of pressures (densities), which would make them ideal for this.

[Phantom]

Hood scoop location can greatly affect "ram" air. There are spots on a hood that actually have negative pressure because of the aerodynamics of the particular vehicle. That is why the Firebird moved their scoop inlets so close to the nose. The mid-hood locations will give you "cold air intake" but won't ram. To get pressurized air you need to be in front of the radiator or right at the base of the windshield.

Remember - ram air effect is measured in inches of water pressure (27.7" = 1 psi) so this doesn't even resemble boosting an engine. 5% vs 40+%. A fuel injection system should be able to adjust for this no problem. It's about like driving the car from Denver to Houston.