Hood scoops and boundary layer airflow

[Ghoste]

As many well know today, Dodge engineers determined that
a hoodscoop opening was more effective an inch above the hood.  My question is twofold.  First, does this mean only that the opening should be an inch above the hood panel at large?  Would a scoop with the opening off the hood but a ramp on the base of the scoop like the old Mopar Pro Stock style from the early 70's lose effectiveness?  Secondly, what about scoops mounted directly to the hood but with an opening that goes well above the one inch mark in it's total opening height?

[b5blue]

I thought I read somewhere on an engineering level most scoops were mostly a marketing gimmick as at speed the air rushing into the grill area would give greater flow if diverted from going through the radiator and getting heated up. (more like 70 Olds. 442 positioning) If not sealed off properly the air from the front would push up and raise all heck with the flow out of the radiator and the scoop screwing up designed under hood airflow characteristics with one over riding the other at different speeds. This is on a street car, not a purpose built drag car. This being said....I still think scoops are cool if the are functional. NASCAR used the air pressure that builds up in front of the windshield I believe.     

[Ghoste]

I know what you're saying but wouldn't that also depend greatly on whether or not the carbs were sealed to the hoodscoop?

[b5blue]

Yea that's what I meant.  I think I was reading about why 2nd gens never came with a hood scoop......

[flyinlow]

I copied the olds 442 concept. Engine  likes the cooler air.

[flyinlow]

pic,  DANGER ,Wil Robinson

[Cooter]

Here in Va. we can't have anything over 2 1/4" above the hood line on 1990 and back cars/trucks and no more than 1 3/4" 1990 and up....Something bout "Line of sight" ....

Course, this does not aplly to "Antique registered" cars for "Show only" purposes...(READ: My '68 Dart, with over the top 6" cowl hood)

[flyinlow]

Point of stagnation.   ?

The spot on a  aircraft , high performance car, or well indowed woman where the airstream must divide to go around the object.

Highest ram pressure. Normally the lower center of the grill....of the car.

http://autospeed.com/cms/A_1023/article.html?popularArticle

[b5blue]

The whole front of a 2nd gen. is a scoop anyway! Flyinlow yours is ideal an set-up, well done! (Hat's off to B-9 Robot) 

[Mike DC]

In case you're not aware, most of the benefits from any of the front end scoops at street speeds is simply the colder air.  The ram effect is negligible until you're way over 100mph.



As for the question about whether 1" above the hood is better or 1" above the hood with a ramp to it . . .  good question.  I might guess that the ramp would not be an improvement but I really don't know. 

If you aren't using a ramp then the area below the scoop (in the 1") should probably have a bit of a bullet-nose and fall back at the sides like the windshield does.