69CutlassAlex

Hello all, What is the benifit of the OAI Ram air compared to just the seal and having the air always being ramed into the aircleaner/carb. Why not just do away with the flapper lid and just do the seal against the hood to the aircleaner. Thanks

stevengerard

I'm sure it has to do with cold start-ups and emmisions. I met an engineer at Lansing this summer who said he worked on the original 70 hood starting in 68 he was far removed from it by the time 70 came around, he said it definitely helped but only at higher speeds.

firefrost gold

http://image.highperformancepontiac...._air_setup.jpg pontiac used this in the early stage's
noise was a resin for the door. and it helps with water intake on rainy days
and foul weather. if the vacuum door was a performance upgrade than race car's would have them.

allyolds68

They call it "Outside Air Induction" and not "Ram Air" for a reason. The primary benefit is cooler air, not any ram air effect.

The 68 under bumper OAI supposedly had the best "Ram Air" effect of the 68-69 body styles . In 69 the ram air effect was reduced due to the bumper configuration. 67 W30 was probably the best.....

I don't know much about the 70 OAI hoods

I've always been told the Chevelle Cowl hoods benefit from higher pressure air at the base of the windshield.

firefrost gold

http://image.superchevy.com/f/111955...lle_engine.jpg

good old smokey in 1966 Id take my car to the best damb garage in town

jensenracing77

i always believed that the flapper was just a neat gizmo to make it look cool for marketing but that is only my opinion. i think for functionality it may be more for cold temps like stevengerard said, it has to block the cold air from the hood to let the heat from the manifold work on warm up. in high school i thought i was something when i unhooked it and zip tied a bag over the cleaner snorkel. i thought that all the pressure was going out the snorkel. i never thought to much on the reality side. if it had that much pressure it would brake the plastic OAI breather top.

1969w3155

Was the bumper configuration the reason for the smaller scoops in '69, or was there another reason.

allyolds68

I've heard a couple of stories about guys doing this but I'd never seen a picture of it done before. I'm working on something similar for my mine

kjr442

I have always thought that the coolest air was at the cowl. If I am wrong, please let me know.

bccan

Street car has to operate smoothly vast majority of the time. Flap closed engine draws warm air, helps w/ warm up, general drivability, probably better for emissions & mileage too. Likely to help prevent carb icing under the right conditions too. When vac drops under high demand, power becomes the priority, flap opens drawing cooler outside air which should be denser helping provide better performance. Mostly pretty marginal but valid.

Even if it did nothing it still looks cool & helps those secondaries sound the charge!

1969w3155

Isn't that what the '68 Z/28's had as an option, but using one scoop towards the passenger side, basically eliminating the drivers side one shown there on Smokey's car?

stevengerard

somewhere I have read an article about how the 70-72 OIA hoods were actually one of the best at bringing in air (farther forward and just high enough). Yes the low pressure near the cowl helped the Checvy's. Also read the Buick's scoop was too low and too far back to do much at all - (though that's nice looking hood as well)

firefrost gold

Have read that the only scoop that work is the snorkel scoop on the t/a challenger's ??

Rickman48

Early '67 Z's got that 1 scoop system, yes, on the pass side.
Cowl hood came along, and eliminated it!
Had a cowl hood on a '65 chevelle - straight in, and never had a problem.
Kept the snow cleared in the winter, though!

wmachine

The "flaps" were far from exclusive to Olds. Chevy and Mopars come to mind. Open under heavy throttle, closed otherwise when it wouldn't do any good anyway. No magic there.

Olds did indeed pretty much stick with the OAI label, but they did make occasional references to "ram air".
None of the manufacturers were using wind tunnel technology to design their air intake in the '60s. I recall seeing tests in the '80s that determined that pretty much none of the intake configurations yielded much of a ram effect. At best, only at higher speeds, but not enough to be very effective regardless. No matter where, from bumper to windshield, though some spots are marginally better than others. What it really amounts to is that in order to get anything appreciable, the intake would have to be well above the hood. Too high for a production vehicle.
So what we're left with is much more of a "cool image" factor than something really functional.