OAI OR RAM AIR??

[BosMobile]

Hey guys, Ive got a 72 cutlass supreme,always wanted a factory scooped hood,don't have the money now either,but i'm curious.Whats the difference between the two?Was the ram air hood non-functional?What years [72]were they offered?Again,just curious,BO

[Bobsw32]

Outside air is cooler than under hood air while ram air creates high pressure much like a supercharger..... Now for a quick story....Many years ago I installed a 1970 ram air hood on my 1970 convertible. I was running a high rise intake so I did not use the ram air air cleaner..... I immediately began experiencing over heating with the car at speed (60 Miles per hour)... It would cruise around town all day in 90 degree heat and never overheat........After replacing everything in the cooling system an old timer said just block off the ram air hood and see what happens.......It turns out the ram air hood created sooo much pressure in the engine compartment the air could not get through the radiator..... Lesson learned THOSE HOODS WORK!

[jensenracing77]

Originally Posted by Bobsw32

Outside air is cooler than under hood air while ram air creates high pressure much like a supercharger..... Now for a quick story....Many years ago I installed a 1970 ram air hood on my 1970 convertible. I was running a high rise intake so I did not use the ram air air cleaner..... I immediately began experiencing over heating with the car at speed (60 Miles per hour)... It would cruise around town all day in 90 degree heat and never overheat........After replacing everything in the cooling system an old timer said just block off the ram air hood and see what happens.......It turns out the ram air hood created sooo much pressure in the engine compartment the air could not get through the radiator..... Lesson learned THOSE HOODS WORK!

that is funny. i had the same thing happen to me a long time ago. i told dad i thought that was what it was and he did not believe me. i never heard of it again till now.

[jensenracing77]

are you asking what the difference is? in oldsmobile it is called OAI or outside air induction. people have adopted the term rem air over the years for the OAI hood. there is just 2 hoods, the OAI and the standard.

[BosMobile]

OK,thats cool ,thanks.WOW,so if i ever get one i'll have to block off the scoops,or run snorkels [dual ] to the air cleaner to keep from overheating?Thats a neat story, too. thank yall,BO

[joe_padavano]

Originally Posted by BosMobile

Hey guys, Ive got a 72 cutlass supreme,always wanted a factory scooped hood,don't have the money now either,but i'm curious.Whats the difference between the two?Was the ram air hood non-functional?What years [72]were they offered?Again,just curious,BO

The difference between the two is that Ram Air is a Pontiac marketing term and Outside Air Induction (O.A.I.) is an Oldsmobile marketing term. Both refer to an air inlet system that allows the air cleaner to access cold outside air instead of hot underhood air for a slight HP increase.

Olds used under-bumper scoops in 1966-1969 (actually, through-the-grille for 1967) and the fiberglass hood with scoops for 1970-72. There was never a non-functional "ram air" hood offered by Olds.

[BosMobile]

Thanks JOE,so the correct hood on 72 would have used the intakes to air cleaner through the openings in the bumper.ok thanks,BO

[BosMobile]

I'm sorry,had to read your post again.The 72 used the OAI air cleaner.If your car is correct it will have the OAI air cleaner.Only aftermarket hoods are non-functional,probably because of the formentioned overheating problem.BO

[Wasted]

Originally Posted by BosMobile

I'm sorry,had to read your post again.The 72 used the OAI air cleaner.If your car is correct it will have the OAI air cleaner.Only aftermarket hoods are non-functional,probably because of the formentioned overheating problem.BO

Someone correct me if Im wrong, but I believe that even the aftermarket ones are functional.

[BosMobile]

HEY,i've seen some at the drag races that arent cut-out.Those hoods also looked ''mickey mouse''to me.I think you cut some of them yourself,i would never thought of the overheat problem through,who eles has seen this?just curious,BO

[joe_padavano]

Originally Posted by BosMobile

HEY,i've seen some at the drag races that arent cut-out.Those hoods also looked ''mickey mouse''to me.I think you cut some of them yourself,i would never thought of the overheat problem through,who eles has seen this?just curious,BO

There are a bunch of aftermarket 70-72 hoods. These range from very accurate copies of the factory hoods (with the correct metal frame), to less expensive all-fiberglass versions, to relatively inexpensive copies that don't have the air box underneath. The latter still have openings at the front of the hood, but won't be "functional" without the airbox. I have one of those in the barn. I have also seen the VFN one-piece fiberglass front end for these cars that do come with the scoops molded shut. You need to cut them out.

[Run to Rund]

In 66, the air intake "bezels" in cooling slots in the bumper fed the "ducts" behind the bumper. Not under the bumper until 68. The 66 factory W30s window stickers called it Force-Air Induction, and GMPD used O.A.I. or outside air induction. The six-page instruction sheets in 66 called it Outside Air Induction system. The Olds letter (June 3, 1966) from G. A. Hirshman, Asst Admin. Engineer to W. E. Dismuke of NHRA began: "Oldsmobile has released an induction forced air system for its 1966 4-4-2 models (W30 option)." the letter then went on to describe engine, induction, battery, and rear axle changes pertinent to the W30 option. As noted above in this thread, Olds did not use the "ram air" term. Olds also did not use the Pontiac "Tri-power" term, rather "Tri-Carbs" was used for the three two-barrel carb option in 66.

[Bluevista]

Originally Posted by jensenracing77

are you asking what the difference is? in oldsmobile it is called OAI or outside air induction. people have adopted the term rem air over the years for the OAI hood. there is just 2 hoods, the OAI and the standard.

There were three hoods in '72. The standard, the louvered and the O.A.I. type. Pontiac also used "Ram-Air" to designate their high performance engines followed by the respective Roman numeral.
I've heard that the cowl induction type hoods actually function better than front scoops.

[joe_padavano]

Originally Posted by Run to Rund

In 66, the air intake "bezels" in cooling slots in the bumper fed the "ducts" behind the bumper. Not under the bumper until 68.

Yeah, you got me. I was being lazy with my prior post.

Originally Posted by Bluevista

There were three hoods in '72. The standard, the louvered and the O.A.I. type.

Actually, there were FIVE.

The metal hoods (with and without chrome louvers) each came either with or without the slots at the base of the windshield. Slots for non-A/C cars, no slots for A/C cars. Of course, the "louvers" were never intended to be anything other than decorative.

[BosMobile]

WOW,thanks for all the input.If a man were to buy one which brands were built right?I'd want an ''OAI'' reproduction.Also ,anyone know about the wieght differences?From what i've read ,i think a reproduction would be as heavy as a plain steel hood.
I have a friend who cut a stock steel hood at the front,welded up some scoops and made one,he could've spent a little more time and it would've looked really good.Hmmmm... I've got an extra,THANX,BO

[mugzilla]

You have two things going...

Outside (cooler) air is routed to engine and improves performance at all speeds ...

The effects of "Ramming" (pressurizing) air are noticed at speeds over 150 miles per hour ...

I've thought about the pressure effect on radiator air flow but since the scoops are in the wrong area and really don't work ( At least the whiners say they don't) I've never worried about it .

[mugzilla]

Originally Posted by BosMobile

WOW,thanks for all the input.If a man were to buy one which brands were built right?I'd want an ''OAI'' reproduction.Also ,anyone know about the wieght differences?From what i've read ,i think a reproduction would be as heavy as a plain steel hood.
I have a friend who cut a stock steel hood at the front,welded up some scoops and made one,he could've spent a little more time and it would've looked really good.Hmmmm... I've got an extra,THANX,BO

I would think that you would put the lightest hood on which would be an all glass one ...

[joe_padavano]

Originally Posted by mugzilla

You have two things going...

Outside (cooler) air is routed to engine and improves performance at all speeds ...

The effects of "Ramming" (pressurizing) air are noticed at speeds over 150 miles per hour ...

I've thought about the pressure effect on radiator air flow but since the scoops are in the wrong area and really don't work ( At least the whiners say they don't) I've never worried about it .

You are correct. I've seen published numbers that claim a one HP increase for each 7-10 degree drop in inlet air temp. Also, in magazine ads from 1970, Olds claimed that the W-25 hood was tested in a wind tunnel. I have no documentation to prove that it either did or did not help, I just present that information. I do agree that the cold air effect is far more important than any ram effect at normal speeds. That's why Olds called it Outside Air Induction and not ram air.

[mugzilla]

Originally Posted by Bobsw32

Outside air is cooler than under hood air while ram air creates high pressure much like a supercharger..... Now for a quick story....Many years ago I installed a 1970 ram air hood on my 1970 convertible. I was running a high rise intake so I did not use the ram air air cleaner..... I immediately began experiencing over heating with the car at speed (60 Miles per hour)... It would cruise around town all day in 90 degree heat and never overheat........After replacing everything in the cooling system an old timer said just block off the ram air hood and see what happens.......It turns out the ram air hood created sooo much pressure in the engine compartment the air could not get through the radiator..... Lesson learned THOSE HOODS WORK!

I've driven in pouring rain with no problem so that indicates low air flow ...

Enough though, to add to engine compartment pressure and if the carb is sucking huge amounts of air it would seem likely that it would access the "cold" air provided by the scoop ...

I'm going to make some scoop blocks and see what's up ...

[BosMobile]

Hey man,yeah that would interesting.I'd love to have one ,they just look mean.Some guys on ''realoldspower'' are building taller ones ,for hood clearence.Do the factory ''OAI''s add any additional clearence?What about the wieght?Thanks for any input,some of you guys know a TON!! Hungry for knowledge! Later,BO

[442much]

Originally Posted by BosMobile

I'm sorry,had to read your post again.The 72 used the OAI air cleaner.If your car is correct it will have the OAI air cleaner.Only aftermarket hoods are non-functional,probably because of the formentioned overheating problem.BO

Not in every case...

[BosMobile]

Hey 442,I really dig your car!I've always liked OLDS cause there a little different,so when i see a really rare olds its extra sweet !Looks good!

I have 72 cutlass ,does the company where you got yours make funcional hoods for other models?WHO?HOW MUCH? Also did you like the ''fit'' of it?Thanks for the input,later,BO

[442much]

Originally Posted by BosMobile

Hey 442,I really dig your car!I've always liked OLDS cause there a little different,so when i see a really rare olds its extra sweet !Looks good!

I have 72 cutlass ,does the company where you got yours make funcional hoods for other models?WHO?HOW MUCH? Also did you like the ''fit'' of it?Thanks for the input,later,BO

Thanks. My car is in the shop and will be out in a week or so. Have the original being painted as well. Here is the link for the place I got my hood. They make them for your car. You have options. You can get a bolt on like mine or if money's tight they also have a "pin on". You can get an "air box" where it's functional or just for looks. Mine fit great. Check it out.

http://www.vfnfiberglass.com/site.htm

[carl1775]

To answer your question, there are only two hoods that I know of, (I'm no expert by any means) that are functional and CORRECT. The first being an OEM Oldsmobile OAI (outside air induction) W-25 hood and the second, being a repro. by Thornton.
The OAI hood weighs more than a "flat" hood, I think?
If you go with an all fiberglass (no metal frame/ i.e. all other repro. Olds OAI hoods) and have the stainless trim running across the cowel, you'll have fitment issuses lining up the trim. Also, many all fiberglass hoods are prone to warping, IF not properly layed and cured. The two functional and "correct" hoods are glued to a frame to take away any warping.
So, long story short, if you like the (W-25) dual scoop on the hood look, save your money and do it once correctly with an original Olds piece or Thornton aftermarket. Parts have been coming down a bit in price, so you may be able to luck upon a relatively easy fixer original. That being said I would recommend, for reasons already metioned, to go ahead and get the "correct" base, top plate, filter, and foam, in order to make it functional.
If you simply want one, buy the cheapest pin on hood you can find, with the outside ports blocked off from the engine compartment and slap'er on. It's just a decision you have to make. If your looking for a performance advantage, you may consider an aftermarket under-bumper oai application, which "ducts" the air to an aftermarket air cleaner assembly. The fitment would be correct for years earlier than you car, but will function just as good. Any way, hope that helps.

[wolfman98]

This is a question i have been wondering about for a while now , so to go slightly off topic (stiill about hood scoops) I was told and have heard that the 1969 Olds 98 convertible had an option with a hood scoop. Any of you heard or know if the 1969 convertible came with this option or not because i have not seen one as of yet that was original.

[joe_padavano]

Originally Posted by wolfman98

This is a question i have been wondering about for a while now , so to go slightly off topic (stiill about hood scoops) I was told and have heard that the 1969 Olds 98 convertible had an option with a hood scoop. Any of you heard or know if the 1969 convertible came with this option or not because i have not seen one as of yet that was original.

Yeah, "they" say a lot of things that are incorrect. No such hood scoop. There was W-34 O.A.I. package for the Toro, but that was ducted from the core support, not hood scoops.

[wmachine]

Originally Posted by wolfman98

This is a question i have been wondering about for a while now , so to go slightly off topic (stiill about hood scoops) I was told and have heard that the 1969 Olds 98 convertible had an option with a hood scoop. Any of you heard or know if the 1969 convertible came with this option or not because i have not seen one as of yet that was original.

Not heard of such a thing, if you can be more specific, maybe we can find something?
There may be some confusion with "OAI" here. In '68, Olds introduced the W-34 Toronado with "OAI" (Outside Air Induction). That was simply an under the hood "scoop" behind the grill with a hose routed into the air cleaner snorkel. (This arrangement showed up many years later in most all of the models with little fanfare and was not called OAI!)
That arrangement was discontinued for the '69 and '70 W-34s, though Olds still referred to the W-34 option as "OAI".

[BosMobile]

Hey guys,Thanks for the input!That company seems to have some of the better quality hoods i've seen.{good pictures helped!] CARL,i agree ,only buy it once,i'll cheak out the''thortons'' as well.A functional bolt on hood is about 600,thats what i'd expect to pay.Fitment is an issue,i'd want my chrome trim,front and rear,to fit nicely.
Any one else have hood from VFM ,71-72 ??thanks again,this site is great!!later,BO

[wolfman98]

I thought as much but was confused when I saw a pic of a 69-88 convertible with a hood scoop. I did not know if it was original , but now I do.

[mugzilla]

I have a nicely built aftermarket hood and when I painted it I used "The Right Stuff" at any contact point between hood and frame ...

It cut the squeeks out and opens and closes nicely ...

I also reinforced the area around the hinge mounts where it usually bends ...

[BosMobile]

Hey,yeah what brand is yours?What year,71?I dont mind doing some minor modification,like you.I've seen some that just dont fit at all!! That''VFN'' hoods finish looks nice and check out the body lines,they look tight as well.Just guessing,but 442MUCH doesnt strike me as somone who would have ''junk''.Anyway thanks for reply,and dont forget tell me who made yours as well.just looking for quality,thanks,BO

[anthonyP]

The '71 "flat" hoods had the openings at the rear, while the '72 "flat" hoods did not. It did not matter if it had A/C or not, it was by the year. Also, the louvered hood can be made functional, if done properly, something Oldsmobile should had done from the factory, but probably didn't due to the OAI option. The same as why Oldsmobile did not make the 15" Super Stock rims optional after the '70 model year, not unlike Chevy, Pontiac, and Buick, with the wide 60 series tires, especially since they used them on the '69 H/O.

[carl1775]

Totally incorrect on your statement that the '72 flat hoods did not come with cowel openings (My Supreme Convt. for one is proof). Maybe only the supreme was available with the cowel slots only (horizontal to the hood and not vertical W/ louvres), a greater expert than I can fill the crowd in. All I know is that my hood is original to the car and it has the 2 open cowel slots that run from fender to fender.

[442much]

Originally Posted by anthonyP

The '71 "flat" hoods had the openings at the rear, while the '72 "flat" hoods did not. It did not matter if it had A/C or not, it was by the year. Also, the louvered hood can be made functional, if done properly, something Oldsmobile should had done from the factory, but probably didn't due to the OAI option. The same as why Oldsmobile did not make the 15" Super Stock rims optional after the '70 model year, not unlike Chevy, Pontiac, and Buick, with the wide 60 series tires, especially since they used them on the '69 H/O.

Oldsmobile DID make 15" Super Stock rims after the 69 H/O. My car was ordered with 15" x 7" SSII wheels.

[BosMobile]

Hey,yeah my 72 s,has a plain flat hood,factory big block ,bucket seats.Oldsmobile's must of had lots of options.Thier the best cars,thats why.Any one you got's a good one.I've learned no matter what the part is,somebody is gonna want it,so PLEASE dont scrap nothing.Just my 02,later,BO

[joades]

Like BosMobile I too have a 1972 Cutlass that I want to put the W-25 hood on. I have some questions to add.....

1. What is correct for a 1972 W-25...Pin on or Bolt on? I assume that bolt on means that it will work with the stock hood latch with no pins. Is this correct?

2. What is the end all be all best fitting W-25 bolt on hood? I have seen references to several suppliers including thornton and Parts Place. Parts place indicates that they have a new steel frame version, but have "call" for the price. Thornton looks to be incredibly expensive. Which is best for a functional system that will give the car an original look?

3. Here is the stupid one... Since I don't have this set up and have no car to look at closely....how does the functional setup handle water? I doubt my car will ever see anything wetter than a humid summer day, but you never know. I assume that the airbox has a drain in it..?? Where does this drain to?

If anyone has and would be willing to photograph a functional OE OAI setup from 71-72 on a 350 I would very much appreciate seeing the photos. I really want my setup to be as original as possible. My email is jaymgb@aol.com

Thanks.

[carl1775]

1) The OEM hoods bolted to the hood springs, used the safety latch, and had two pins in the front. Most aftermarket Pin-on hoods require 4 pins two font and back, no safty latch
2) As I mentioned OEM, or Thornton. I have no idea about parts place, probably same as Thornton (parts-wise). Expect to pay 1,500 on up for a decent one, or an oem that needs work (depending on severity of damage) 6-700 and up
3)short of a hail mary down poor, don't worry about it, or the good ol' KS 60 miles per hour sideways rain, in which case find a bridge/carwash/strangers garage, you'll be fine. The drain is the exhaust pipes.
4)see 442much's engine pic, that's pretty dang good.

[joades]

Thanks for the scoop. I will check with Parts Place on Monday to see what they are wanting for one. With a little luck and some advance planning I hope to never have to test the rain theory!

[Allan R]

Originally Posted by joades

Thanks for the scoop. I will check with Parts Place on Monday to see what they are wanting for one. With a little luck and some advance planning I hope to never have to test the rain theory!

Parts Place and Tamraz both claim to have a "functional" W25 hood that is ALL fibreglass. They say you can't tell the difference from 5 feet away. Ok, and they also don't have the mesh screen attached under the hood either. Not bonded to metal as GM and Thorntons are. The repro fibreglass ones run about 600 bucks. You also need to change your hood springs to light duty ones (that they will be happy to sell you), and they don't have the hood latch for the T44 security lock. The pictures they provide do look impressive. I'd say from the pictures that they both get their hoods from the same supplier.

I've asked both places if they're planning to put out a "proper" w-25 hood like Thorntons, and they both say that those projects are in the works (like for the past couple of years).

I've heard that the repro hoods do not fit the greatest, and they have issues with accepting the stainless steel reveal at the back of the hood.

[mugzilla]

Originally Posted by BosMobile

Hey,yeah what brand is yours?What year,71?I dont mind doing some minor modification,like you.I've seen some that just dont fit at all!! That''VFN'' hoods finish looks nice and check out the body lines,they look tight as well.Just guessing,but 442MUCH doesnt strike me as somone who would have ''junk''.Anyway thanks for reply,and dont forget tell me who made yours as well.just looking for quality,thanks,BO

I'm not sure who you are talking to ...

I have no Idea what brand mine is, it does have mesh. ...

As far as fitment I've noticed most glass hoods either line up in the front or the back , not both ...

I went for lining up the front. I plan on getting some cherry nos hinges and I will try for both ...