Hood Scoop Functionality

[Theshandman]

Definitely newbie questions, but I'm wondering about the hood scoop as I close in on getting the body ready and what others have done. The hood scoop is of course a significant part to the looks of a 'Roadster', but at what point does it become functionally necessary based on a given engine's breathing requirements? I presume it becomes more effective at higher speeds than say, idling along. Can too much air via the scoop be a bad thing? And, if it is a necessary part to the breathing equation, how big should the port in the hood be? FWIW, I'm installing a BPE FI 347.
Art

[Hoooper]

Are you going to have it sealed to your intake? Most of them are just for looks and actually function as an underhood pressure generator to help stall the flow of air across the radiator.

[Theshandman]

Are you going to have it sealed to your intake?
Wasn't planning on it. Actually, not sure what to do... If just for looks then I guess I wouldn't need to cut a hole in the hood under the scoop.

[Jim1855]

They do a great job of letting hot air out when you're not moving.
There are more efficient and effective ways to get fresh air into the carb just none have the "look".
Jim

[Derald Rice]

Once upon a time, someone did the tape and yarn thing to the scoop and found out that air was actually bowing out of the scoop at speed.

But I can't remember who is was, maybe someone else remembers the discussion.

[Jeff Kleiner]

Once upon a time, someone did the tape and yarn thing to the scoop and found out that air was actually bowing out of the scoop at speed.

But I can't remember who is was, maybe someone else remembers the discussion.

I think it was Nice Guy Eddie, about 12 or so years ago.

Jeff

[john42]

Ya the air certainly blows out of the hood scoop at speed. This past Sunday I had a power steering line spring a leak unto the headers and the smoke came out of the hood scoop at 70mph...

[Railroad]

Ya the air certainly blows out of the hood scoop at speed. This past Sunday I had a power steering line spring a leak unto the headers and the smoke came out of the hood scoop at 70mph...

More reason to cut a hole in the hood, LOL.

[Derald Rice]

Ya the air certainly blows out of the hood scoop at speed. This past Sunday I had a power steering line spring a leak unto the headers and the smoke came out of the hood scoop at 70mph...

John, I have done the smoke test for leaks, and I think that you may have used the wrong set of instructions.. ...

[Hoooper]

Once upon a time, someone did the tape and yarn thing to the scoop and found out that air was actually bowing out of the scoop at speed.

But I can't remember who is was, maybe someone else remembers the discussion.

Interesting, Im surprised even with the bottom of the engine bay wide open theres still enough pressure under the hood to be forcing air through the scoop

[john42]

John, I have done the smoke test for leaks, and I think that you may have used the wrong set of instructions.. ...

lol! HAHHA

[facultyofmusic]

I'm planning to put a hidden dashcam under the scoop. Don't want dashcam wires cluttering the already tiny windshield! :rolleyes: :rolleyes: :rolleyes:

[Nigel Allen]

I'm planning to put a hidden dashcam under the scoop. Don't want dashcam wires cluttering the already tiny windshield! :rolleyes: :rolleyes: :rolleyes:

That is a totally cool idea.

[Blitzboy54]

I'm planning to put a hidden dashcam under the scoop. Don't want dashcam wires cluttering the already tiny windshield! :rolleyes: :rolleyes: :rolleyes:

Holy cow that’s a great idea. As long as the heat isn’t an issue

[GoDadGo]

This has been one hilarious thread, but quite enlightening to say the least.

In the attached video you can see John George's hood lift up as the speeds increase.
https://youtu.be/o4MIZyfDqic

In this video he's running a hood that has louvers in it which lets the air escape.
https://youtu.be/J6_OtvVB91o

Thank You All For Posting & Participating In This Thread!

[facultyofmusic]

Holy cow that’s a great idea. As long as the heat isn’t an issue

Yeah, I'm also a little worried about the FOV. Only one way to find out!

[GTBradley]

This has been one hilarious thread, but quite enlightening to say the least.

In the attached video you can see John George's hood lift up as the speeds increase.
https://youtu.be/o4MIZyfDqic

In this video he's running a hood that has louvers in it which lets the air escape.
https://youtu.be/J6_OtvVB91o

Thank You All For Posting & Participating In This Thread!
I think that is lift or negative pressure going over the hood that causes John’s hood to lift up. Totally awesome video, by the way!
It lifts at about 68mph with no cars immediately in front, when drafting another car you can see it lift and shut repeatedly or even stay down even above 100mph.

In the second video he appears to have the hood nailed down pretty tight and appears to have pins rather than the cobra latches.

I would guess this is the reason they turned the hood scoop, or shaker, around backwards in the 70s like on the Firebird. If I remember right it took advantage of the positive pressure created by the windscreen. Not that that would help John as he doesn’t have one.

The negative pressure created on the hood could be part of the reason the airflow reverses at high speed through the cobra scoop.

[Jeff Kleiner]

The backward facing scoop is to let the air OUT! When I was competing at RunN’Gun at Gateway in 2008 I watched as Tony Martin’s Backdraft launched the hood about 60 feet in the air while going 160+ on the main straight! It ripped the hinges and latches completely through the fiberglass. The BDR team guys turned their scoops around afterward!

Jeff

[GTBradley]

166820That would be a bad thing on a shaker:p

[Avalanche325]

I'm planning to put a hidden dashcam under the scoop. Don't want dashcam wires cluttering the already tiny windshield! :rolleyes: :rolleyes: :rolleyes:

You better make sure it can take heat and vibration and is weather proof.

My air cleaner is up into my scoop. But there are a million combinations.