I'm adding an OAI hood this winter. I've read that I should block off the air passages if I don't install the OAI air cleaner assembly.

I would PREFER to add the OAI Air cleaner assembly but i have an Edelbrock performer intake and it sounds like alot of messing around to get things to fit properly under the hood...... so instead I'll keep my stock air cleaner assembly in place and spend that $500 on other goodies.

SO...... how are people blocking those passages off to avoid cooling issues?

 

I can't imagine an issue with a little extra air blowing down around your engine as you drive around. Some extra cooling effect is never a bad thing unless you are in sub zero climates to begin with.

 

As noted, I don't think the extra air would cause a problem unless you're in the frozen tundra. When I drove my OAI-equipped '72 Cutlass to shows, I stuck a piece of soft foam in the scoop opening to keep the bugs and stuff out.

 

Hmm.... I had read a few posts where travelling at highway speeds causes enough pressure in the engine bay to reduce air flow through the radiator and causes over heating

 

If true, that would only apply in hot weather. In a Minnesota winter, that would never apply. If you are of sufficient age, you will recall that Minnesota winter drivers put covers over the radiator openings to maintain heater output.

 

I will look for the posts I read on this forum. One member described that at 60+ mph speeds he was over heating. He plugged the hood scoops and problem solved. Another member confirmed the same experience after adding the W25 hood. Perhaps it only happens on long interstate trips. My car always runs cool so it may not be an issue for me, I just wanted to know how others might be blocking the passages off for ideas in case I choose to do so.

 

The solution to that problem is straight-forward. The following measurements assume you have a 455:

• The Performer 455 carb-mounting pad is 1.65" taller than on a Cutlass intake.
• If you put a Chevelle Cowl Induction adapter on your non-OAI air cleaner body you will drop the foam-mounting surface by 2" compared to an OAI air cleaner.

If you buy W-31 foam (taller than W-30 foam), you will make up the difference and your total bill will be under $100.

 

Gary, thank you for that information! Very interesting. So I'll use my existing base and a combination of chevelle and OAI components to make it work? I'm away from my office right now so I cant look up parts at the moment

 

Exactly. Don't forget to put some sort of drain from the space outside the air filter. And then add a hose that will keep any rain water away from the top of the engine.

 

exactly as Gary said above, the ss chevelle air induction metal ring, on your original air cleaner base, with a w30 short foam, or w31 tall foam , can add pics if you need, Tim

 

Gee, with the entire bottom side of the engine bay open, I can't imagine the inflow volume of air required to increased the PSI of the engine compartment even one (1) psi. I doubt seriously that measly foam spacer ring would not blow apart with that same volume of air in a normal functioning OAI system.

Call me skeptical, but I don't think there will be a measurable difference in engine bay air pressure with the hood opening blocked or not.

tc

 

this is one of the threads that got me thinking about the overheating:

https://classicoldsmobile.com/forums...ram-air-12205/

 

OK Guys,

I REALLY appreciate this guidance. Sorry to have to ask for more clarification but I don't have any experience with the OAI system yet.

I am looking at the "kit" for $500-ish that comes with the vacuum valve, air filter top, vacuum lines, flapper door, springs and valve cover spring retainers. Am i following this correctly that if i use the Chevelle ring/adaptor along with this kit and the W31 foam i should be in business with an operation OAI system that fits between the Performer intake and the W25 hood?

 

X 2 Oldsmobile designed these cars to be used 12 months each year. If people are having cooling problems in the winter, there is something else going on.
........Just my two cents worth.

 

Maybe I created some confusion with the original post. I never said anyone had any winter cooling problems.

 

Does anyone know if the only difference between the OAI top air cleaner "kits" for the 350 and 455 is the height of the foam seal on top? I figured I can save a few bucks by purchasing the 350 kit that has the taller foam since I would need to order that separately anyway if the rest of the components are the same

 

Jeff, you don't need the $500 "kit." You only need your original air cleaner base, the Chevelle Cowl Induction adapter, and the W-31 foam. You can use the full size air filter that is already in your air cleaner base and a filter top which you probably have stashed somewhere (this is the top that comes on HP Chevs that you see with the open element). If you don't have one of those tops already, you can buy a used one for little $. Or buy the smaller OAI filter and air filter top. The smaller OAI filter top is around $40. Either one will work without obstructing air flow. The larger filter will have slightly less pressure drop.

The Cowl Induction ring fits tightly inside your air cleaner base and provides a surface upon which you mount the W-31 foam. The foam will be tall enough to seal against the OAI hood.

This provides a sealed OAI system with an air cleaner that is always open to the scoops. You will not have the flapper and operator. Some air will blow out the snorkel; however, the power advantage of the OAI is cool air, not ram air. You will not have the advantage of uniformly heated carb air. But if you do not drive in winter, this is less important.

 

Thanks for explaining that Gary - I was slowly arriving at that conclusion on my own as i pieced this together. I appreciate you taking the time.

 

Those scoops are only open at heavy throttle.

 

green1972 "exactly as Gary said above, the ss chevelle air induction metal ring, on your original air cleaner base, with a w30 short foam, or w31 tall foam , can add pics if you need"

I'd be interested in the pics......Thanks in advance

 

In high school I had a Rallye 350 and if I took the top off the OAI air cleaner the car would get hot at speed. This was repeatable and the problem went away when I put the top back on. Before I stopped driving it as a daily driver the radiator got a leak and replaced the core. The problem never happened again. All I could figure was that the scoops were taking just enough air flow off a border line bad radiator that it cause a problem. I have no idea really the why or how but I did experience this problem.

 

I had an open element air cleaner on my 442 with an OAI hood and never had an issue with over heating, and I drove that thing all over in any weather.

 

I have owned my 70 W30 for 35 years. Shortly after I purchased it I noticed while out and about my hood pins would be popped. Eventually somebody helped themselves to my OAI air cleaner top. Luckily a had a second original. So from then on I would chain the hood closed. I got tired of that fast and just removed the air cleaner assembly altogether and installed an aftermarket open air. This car was my daily driver for the first 5-6 years. At the time I lived in New York and drove this car down South and out West 1/2 dozen times. All without the OAI top and an open Ram Air hood. NEVER ONCE DID I HAVE A HEATING PROBLEM ON THE HIGHWAY. I now live in Florida and drive this car frequently in 90 + degree weather. The air cleaner top has never went back on the car and I still never experienced any overheating from it's absence.
On another note, when this car was my daily driver up north I did close off the the Ram Air scoops in nasty weather. I used dense seat cushion foam and it worked perfectly. Still never had an overheat issue on the highway

 

Back in the 80’s, I had a 72 H/O with the ram air hood, and no OAI setup. Down here in South Florida, it can get awfully hot in summer but I never had the issue your mentioned.

 

I was looking at my 1972 Olds “Illustrated Facts & Feature Manual. Under the Force-Air Induction System (W25) it states: “It is specifically intended for use where performance is demanded, BUT IS NOT RECOMMENDED FOR CONTINUOUS HIGHWAY OR FREEWAY USE”.

So is GM implying that sustained WOT can contribute to cooling issues? Some people on this thread seem to have identified a problem, while others have not noticed any long freeway driving issues.

I was researching it because my car stays around 195 degrees in hot temps, but if I get on a freeway, the temp will ultimately run around 220 degrees. One issue may be that with the turbo 350 and 3.23 gears, I’m turning a strong 3000 rpms.

So is the OAI a factor? Guess I should plug the air intakes and see if it has any effect. Must be a reason that GM printed the warning.

 

Like said earlier, the OAI, in factory form, was usually off. A vacuum motor holds a flapper up to block flow. I drove one 700 miles this weekend in the summer heat at usually 60 mph and, while I did have some minor issues, heat was not one of them.

 

I have a aftermarket OAI hood on my Cutlass with just the stock air cleaner. I have never overheated on highway or anywhere else. This is a interesting thread and this is the first I even thought about it. I had a 65 Dodge Coronet that I added a Super Stock type hood scoop on and it was a bear to cool, even with a new pricey aluminum radiator, I no longer have that car but I wonder if that scoop screwed up the airflow thru the radiator?? maybe.....