Opening OEM Grille Cells With Router Technique — For Maximum Air Intake Flow

[ShadesOfBloo]

Sometimes air flow is better than air access. If there’s not enough negative pressure at the back of the hood then the hot air just gets stuck in the engine bay.

I agree with this part.

The cowl hood popular with hot rods know about this and they suck out a lot of air.

No, cowl induction hoods don't suck out air. They take in air because the base of the windshield creates a high-pressure zone, and pushes air into your carburetor (as mavisky explained on the previous page).
They're as popular as they are because Chevy made them look cool in the 1960s, and because it gives you clearance for a tall intake.

The hoods designed to let hot air out look more like this:

Not saying this is the answer for you but for example...

If my Mustang was overheating the first thing I'd do would be to remove the little drip trays under my vents. I'd give the air a lot more outlet area before I tried to scoop up more of it.

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[rubyredponycar]

I agree with this part.


No, that's not how cowl induction works. It works because the base of the windshield creates a high-pressure zone, and pushes air into your carburetor (as mavisky explained on the previous page).
They're as popular as they are because Chevy made them look cool in the 1960s (while Buick, Olds, Pontiac and others put forward-facing scoops in their hoods).

The hoods designed to let hot air out look more like this:

Yes, Cowl “induction” works for carburetors but on every thing else it’s for heat extraction. It’s gonna depend on the hood design. If you look at the gap of the windshield the hood will make a low pressure zone immediately after the cowl because its much higher pressure above the cowl and against the windshield. Depending on the hood design it will either pull air from the engine or act as an intake.

 

[mavisky]

Yes, Cowl “induction” works for carburetors but on every thing else it’s for heat extraction. It’s gonna depend on the hood design. If you look at the gap of the windshield the hood will make a low pressure zone immediately after the cowl because its much higher pressure above the cowl and against the windshield. Depending on the hood design it will either pull air from the engine or act as an intake.

Physics doesn't change depending on whether or not your car has fuel injection or not.

The only time heat will come out of a cowl induction hood is while it's sitting still. This has been proven on many different cars with basic string tests.

 

[rubyredponycar]

I agree with this part.


No, that's not how cowl induction works. It works because the base of the windshield creates a high-pressure zone, and pushes air into your carburetor (as mavisky explained on the previous page).
They're as popular as they are because Chevy made them look cool in the 1960s (while Buick, Olds, Pontiac and others put forward-facing scoops in their hoods).

The hoods designed to let hot air out look more like this:

Yes, Cowl “induction works for carburetors but on every thing else it’s for heat extraction. It’s gonna depend on the hood design. If you look at the gap of the windshield the hood will make a low pressure zone immediately after the cowl because its much higher pressure above the cowl and against the windshield. Depending on the hood design it will either pull air from the engine or act as an intake.

Physics doesn't change depending on whether or not your car has fuel injection or not.

The only time heat will come out of a cowl induction hood is while it's sitting still. This has been proven on many different cars with basic string tests.

according to the guys who run them it still cools the engine at higher speeds maybe increased air volume? There’s probably more going on that causes this like hot engine air creating low pressure that’s enough of a difference to bring slow moving air into the engine.

I know the stock hoods for 15-17 have a small cowl shape and the hood will pull up at the back at higher speeds.

 

[mavisky]

according to the guys who run them it still cools the engine at higher speeds maybe increased air volume? There’s probably more going on that causes this like hot engine air creating low pressure that’s enough of a difference to bring slow moving air into the engine.

Would LOVE to see those datalogs.

 

[GTP]

...
If my Mustang was overheating the first thing I'd do would be to remove the little drip trays under my vents. I'd give the air a lot more outlet area before I tried to scoop up more of it.

I already did that. I decided to design my own louver vents to replace the factory ones.

Also, bear in mind that GT350's and 500's have functional grilles at the ends of the bumper. My GT does not, and so I opened all the cells. Again, my radiator, condenser, two trans coolers, and oil cooler are all behind the two central grilles.

I emphasized cooling before aero. I will work on aero next.

 

[rubyredponycar]

I already did that. I decided to design my own louver vents to replace the factory ones.


Also, bear in mind that GT350's and 500's have functional grilles at the ends of the bumper. My GT does not, and so I opened all the cells. Again, my radiator, condenser, two trans coolers, and oil cooler are all behind the two central grilles.

I emphasized cooling before aero. I will work on aero next.

On the gt350/500 Are you talking about the ones in the lower grills on each side right below the headlights?

 

[GTP]

On the gt350/500 Are you talking about the ones in the lower grills on each side right below the headlights?

Yes. One side is for oil cooler and the other for trans cooler.
My coolers handle more BTU. 228F steady CHT on track, and 205F A10 trans.

 

[rubyredponycar]

Yes. One side is for oil cooler and the other for trans cooler.
My coolers handle more BTU. 228F steady CHT on track, and 205F A10 trans.

That makes sense because they are in line with the fan so they will have more consistent airflow. The ones on the right and left will have less CFM passing through.

 

[mavisky]

That makes sense because they are in line with the fan so they will have more consistent airflow. The ones on the right and left will have less CFM passing through.

True when sitting still, but at speed the fan actually serves as a restriction to airflow. This is why most modern cars have a radiator shroud with flaps that blow open to allow extra airflow through.

 

[DougS550]

Amazon was even quicker

@op looks good. I would have done the same but I don't have the patience.

Did you buy new grills on Amazon? Or the router.

 

[stannypack]

I got this instead of dremeling
https://www.americanmuscle.com/mp-concepts-upper-grille-1819-gt-ecoboost.html
looks cooler too

 

[Pistol_91]

I got this instead of dremeling
https://www.americanmuscle.com/mp-concepts-upper-grille-1819-gt-ecoboost.html
looks cooler too

Same, this is what I run. With the JLT intake, though, this grille will create MAF turbulence. Most won't notice it. I use cruise control quite a bit and noticed it while cruising on the highway.

 

[DougS550]

I got this instead of dremeling
https://www.americanmuscle.com/mp-concepts-upper-grille-1819-gt-ecoboost.html
looks cooler too

It does look nice but way more restrictive?

 

[stannypack]

It does look nice but way more restrictive?

Not sure but I'm getting an ESS put on this week so it's changing to a fenderwell intake anyways lol

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