nelsontj

Does the W25 hood actually do what it was designed to do and add more horsepower? Have there been any legitimate "scientific" tests, over the years, that attempted to measure the results, if any? Obviously, the long hood scoops look threatening and a lot of thought went into the vacuum controlled air cleaner design. I'm under the impression that they did not give a whole lot of bang for the buck. But, they do look cool and a few aftermarket vendors have been able to sell quite a few reproductions.

Bobsw32

This isn't scientific BUT I ran mine without the stock air cleaner because I put a high rise intake on the motor, and at 60 miles per hour it pressurized the engine compartment enough that the air couldn't get through the radiator and the car overheated. I put two pieces of foam in the inlets and the problem went away........The rest of the story is I spent weeks and bucks chasing the overheating problem to find out it was the ram air hood causing the problem... Those two little openings would overpower the big openings of the grill.......Now is that going to work around town...probably not much though it does let cool in which helps but at 60 MPH I think it does

My442

I added a W25 set up to my 70 442.

No scientific data, but you can feel a difference when you floor it, and it is most noticeable above 50 MPH.

My "butt dyno" says it probably adds 5%.

joe_padavano

Most factory hood scoops from the 1960s were more for show than performance. In particular, scoops like the Ford and Chrysler shaker scoops cleverly placed the inlet in a LOW pressure area, probably hurting HP.

The Olds O.A.I. systems have always been engineered to have inlets in the high pressure area. That's why the 66-69 systems had scoops under the bumper or at the headlights. The 69 H/O similarly had scoops with inlets at the leading edge of the hood to maximize high pressure air inlet, however if you've ever looked at the installation of the scoop in a 69 H/O, it's less than "professional". In particular, the rough-edged rectangular hole in the hood and lack of sealing between the scoop and the hood probably caused more flow disruption than good. The W-25 hood was similarly designed with the scoops right at the leading edge of the hood and has a nicely-formed air box under it. Period advertising from Olds claimed that the design was wind tunnel tested.

rocketraider

The only "shakers" that really worked were Pontiac's, and that's because they faced REARWARD at the base of the windshield. That area may actually be a little higher pressure aerodynamically than the grille area or leading edge of the hood, but it doesn't look as intimidating. Pontiac built them both ways- shaker for TransAM, hood leading edge for Formula. The trick to either of those is to find a shaker scoop or hood that has the ductwork opened up to get the benefit of the ram air effect. Early Formula hoods had open scoops. Later ones had slots cut out on the underside between the grille opening and radiator. It worked, and was great for keeping snow and rain out of the carb, but I don't think it was quite as effective as the open scoops.

Chevrolet's Cowl Induction worked well too, and their NASCAR package that actually tapped into the cowl plenum at the firewall was really good. Buick's Ram Air, like Ford/Chrysler, was in a fairly low aerodynamic pressure area that always looked like it would have created a venturi vacuum across the scoop inlet instead of funneling cold air to the engine.

Later Ford/Chrysler setups repositioned the scoops closer to the hood leading edge, and 71-73 Mustang NACA styled scoops were supposedly very effective too.

joe_padavano

Which is exactly why I didn't include them in the list.

As you correctly point out, the two high pressure areas are the grille or leading edge of the hood and the base of the windshield.

mugzilla

What does N A C A stand for .."

The predecessor to NASA ...

w-30dreamin

How much horsepower can the stock W-25 OAI system with factory aluminum intake support?

I guess I'm trying to ask,at what power level does the stock system become a restriction to the engine?

thanks

BIGJERR

I wouldnt say the W25 hood adds HP but allows the motor to make more HP with fresh air and or the ramair system,Its sure better than a stock hood.......I auctual lost ET racing my car going to the sealed system of the w25 hood to the unsealed cowl Iam running now............Jerr

joe_padavano

National Advisory Committee on Aeronautics. Eisenhower used NACA as the basis for NASA when he created that organization in 1958.

mugzilla

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