iuhoops83

I own a 71 Cutlass S. The car came with an Edelbrock aluminum intake manifold, 4 bbl Edelbrock carb and a performance style chrome aftermarket air cleaner. Other than that, the car is all original. To maintain originality I purchased an original factory air cleaner and replaced the chrome aftermarket one. Unfortunately, the car isn't as peppy with the original air cleaner, but proper look is more important to me than performance. I have two questions.

1. I see many pictures of Cutlass' with these performance style chrome air cleaners. Was this an original sytle air cleaner offered by Olds, or is it purely aftermarket?

2. Which sytle would give me better fuel economy, the aftermarket open chrome style or the original factory style?

Any other comments on this topic are appreciated.

Thanks,

Larry

Oldsguy

1. Not to my knowledge, and for sure, not the open to the under hood air type.

2. Probably original because you would not be burying your foot so often. I think the real change, if one were able to conduct a controlled scientific test comparison, would be negligible.

If you are looking for a more performance appearance that is also original, though probably was not available for your car, you could convert to the O.A.I system.

88 coupe

If those tests included jet changes, to compensate for the differences in air flow, I think you would be right.

Norm

joe_padavano

It was only factory offered on the 66-67 4 speed 442s.

While the difference is likely not measurable, the factory air cleaner housings are designed to reduce noise as well as filter air, so there is some small additional restriction.

Danny Wiseley

Do you mean that there would be enough extra flow through the open air cleaner that it would lean out the mixture sufficiently to increase the fuel mileage if the jets are not changed? Would this apply at part-throttle?
DW

88 coupe

Jet changes are decided on an “as needed” basis. If it was slightly rich, going in, and the intake was made less restrictive, one might see a slight power gain without altering the fuel supply.

Or, as in this case, if it was slightly lean, going in, one might see small loss in power.

As in the above illustration, it would depend on the existing mixtures.

Since, at part throttle, vacuum is higher, there is less airflow, vacuum advance is added, and the carb runs leaner, the main jets will probably have little effect on fuel consumption.

Thanks for the opportunity to clarify my “off topic” statement.

Norm

Allan R

Olds did have dual snorkel air cleaners I believe on the higher performance engines. Some of them might have come with the chrome top, but most were black. I suspect the look you're describing is the billet look most rodders are after on their car.

As far as economy and breathability, I saw this on an Olds test track for the 68 Hurst Olds. Flip the can lid and let the air cleaner suck in more air. You can always flip it back over for when you want it looking original at the show and shines.

Other than that listen to the wisdom of Norm and Joe.

joe_padavano

On a car like the 68 H/O, this is actually the wrong thing to do. Flipping the lid negates the functioning of the O.A.I. system and allows the engine to ingest hot underhood air instead of cold outside air. A rule of thumb is about a one HP increase for every seven degree reduction in inlet air temp. Going from 70 deg outside air to 180 deg underhood air results in a 15 HP loss.

Of course, flipping the air cleaner lid makes more noise, so it MUST be faster...

Allan R

Ha ha Joe. Noisier is just noiser.

Didn't know about the reduction in HP. Guess someone should have told the designer of the 68 Hurst Olds that one. Honest to God, it's just like I described. It's in one of the threads on this site.

Also, there was no mention of an OAI on the original post, so I'm assuming that you are talking about the OAI on the 68.

So lowering the outside temperature increases HP? That would explain why I can spin my tires easier in the winter!! NRN

Jamesbo

Here's the thread and the discussion of the flipped top on the air cleaner. The 68 H/O was not designed to have the top lid inverted. The only answer I can come up with is that it was a test and they were trying different things.

https://classicoldsmobile.com/forums...90-68-h-o.html

joe_padavano

Actually, it explains why turbocharged and supercharged cars run intercoolers. Compressing the air increased the inlet temp significantly.