Air Cleaner Cut out through hood!

[FDNY340]

Greetings all! Need to make a hole in my hood for a 14" round air cleaner. I already know the obvious answer, BUT...... is there any science behind the airflow that says the hole needs to be a specific diameter larger than the actual air cleaner? Once its cut the top of the air cleaner will be about 3/4" above the hood. Thank you in advance!!

 

[TT5.9mag]

Tape a pen to the air cleaner and shut the hood to a point where the marker will leave a line on the bottom side. Start engine, rev a few times. The length of the line will tell you how much the engine rocks on the mounts. I’d probably add a little bit for a saftey margin.

 

[FDNY340]

Tape a pen to the air cleaner and shut the hood to a point where the marker will leave a line on the bottom side. Start engine, rev a few times. The length of the line will tell you how much the engine rocks on the mounts. I’d probably add a little bit for a saftey margin.

Thank you.
Motor mounted with engine plate and mid plate so not moving too much. Question is more or less about airflow. Thanks again.

 

[TT5.9mag]

Thank you.
Motor mounted with engine plate and mid plate so not moving too much. Question is more or less about airflow. Thanks again.

The engine won’t care much how much gap is around a 14” dia air cleaner. The smallest of gap will offer a ton of surface area open.

 

[Dana67Dart]

If you want science....

Bet a ball of yarn and tape 4" pieces every 4 inches left to right and every 4 inches front to back.

Drive the car at various speeds and note what the yarn is doing.

You could also get a magnahelic (very sensitive pressure meter) and run a tube to various points on the hood.

You may be surprised to find that under the hood might be a high pressure zone and at the cowl typically is a high pressure zone.

Other places on the hood might actually be a low pressure zone and the engine will have to fight against the low pressure to get air in.

Think aerodynamics if the air is going up before it goes back over the hood then there is a low pressure zone under it.

Fun stuff


Now if all you want to do is get cooler air to the intake through the hood or cowl or core support plumbing will work

 

[4mulas]

3/4" an inch above. Do you have a high rise intake and this is unavoidable? Ie: major drop base air cleaner?

 

[marksmopars]

Put a “6 pac” scoop on it and be happy.

 

[AJ/FormS]

I Didn't know the answer either/ still don't;
so what I did was ;
I cut the hole in the hood, dead-enter between the fenders, then I sealed and bolted an aftermarket aluminum oval air filter housing on the hood/over the hole, then sealed the airhorn to the hood; Badboom!
Oh yeah, then I stacked a second filter on it for a total height close to 4 inches.
I run a KnN all week then, on the weekend , I stick a paper element on top, unless it's raining........ It doesn't run any different with the Second filter, but it looks intimidating.
I got no more issues running 87E10.

The filter housing was a Mr. Gasket.

 

[junkyardhero]

I Didn't know the answer either/ still don't;
so what I did was ;
I cut the hole in the hood, dead-enter between the fenders, then I sealed and bolted an aftermarket aluminum oval air filter housing on the hood/over the hole, then sealed the airhorn to the hood; Badboom!
Oh yeah, then I stacked a second filter on it for a total height close to 4 inches.
I run a KnN all week then, on the weekend , I stick a paper element on top, unless it's raining........ It doesn't run any different with the Second filter, but it looks intimidating.
I got no more issues running 87E10.

The filter housing was a Mr. Gasket.

i'd love to see pictures of this...

 

[FDNY340]

Put a “6 pac” scoop on it and be happy.

Actually gonna be a hemi scoop!

 

[furrystump]

So your total filter height is what? 3/4” above the hood, leaving 2”ish below? For the absolute best flow, I would treat the top of the hood as where you want the bottom of the filter. Then I would use the new space below it to make an ideal velocity stack into the carb. I mean you already have a hole in the hood, why not use the height to your advantage.

 

[Yunick13]

Are you planning on sealing the air cleaner to the hood?

 

[RustyRatRod]

Ask @66340SEDAN Keith how he did his. It came out pretty good.

 

[memike]

Ask @66340SEDAN Keith how he did his. It came out pretty good.

It did turn out good, has a good look and cool air making it threw his carburetor., show us a picture @66340SEDAN

 

[toolmanmike]

You can't drive in the rain or shouldn't though.

 

[RustyRatRod]

You can't drive in the rain or shouldn't though.

Meh. Cheap water injection. LOL

 

[memike]

You can't drive in the rain or shouldn't though.

Agree, I watched 66340SEDAN do it on a 40 or so mile trip, dizzy got wet and pulled over twice, now that's dedication