Hood scoop size/placement

[jacksoni]

There have been a few posts here about hood scoops and their effect (Hotrod Larry, Maxracesoftware Larry and others). I have an '86 Firebird Bonneville car running a 4cyl, 2 liter engine (runs but no dyno yet). Looking for about 160mph. For slight ram effect and to get cooler intake air am interested in a scoop but it does disturb aerodynamics too. Maxracesoftware's ET predictor shows some ET and MPH benefit in pretty much any car with a scoop. (good efficiency)

My question is about placement absent a wind tunnel or lot of track time testing stuff. Anybody have any rules of thumb, suggestions or theories? The scoop would be offset to the right in front of a theoretical passenger. Basically question is how far forward (as far as possible or set back) and how high off the hood (low and forward or higher and set back). I am looking at, for instance, a Harwood style mini Aero 3162 or 3163. Depending on the box around the intake (IR injection) I have some leeway for and aft placement.

Thanks for any thoughts.

Jack

[Ed-vancedEngines]

There is a scoop stle hood that is made to fit your car that looks like the Gen 4 FireBird scoop that catches air at the front of the car and there is also an airbox kit for it too. That is my suggestion. I think it will both cut the air and catch the air, if that makes any sense to you. To make it even better thay also offer a front nose pice with air dam that looks like the later FireBird or Vette.

I will have to dig to look, but I think I can find the pics af a few or at least one car with it. It looks great and is very low but still functional and catches the air for the scoop right as it breaks over the nose.

Ed

[jacksoni]

Thanks Ed. That might work. Don't think I can legally change the nose but the hood is ok. Look forward to see a picture or if you can find the manufacturer or web site that'd be great.

Jack

[Cobra]

A NACA style air intake should be considered. Anything sticking up into the air has to be a liability. Side-winds have to be taken into account. If car gets out of shape a scoop can limit vision. Go to the LSR sites and check out vehicle photos. Check what others in your class are using. Your body style is one of the best for cheating the wind. Build a small model wind tunnel to check your ideas. A scale model of your car can be used in wind tunnel! Best of luck on your project!

[maxracesoftware]

There have been a few posts here about hood scoops and their effect (Hotrod Larry, Maxracesoftware Larry and others). I have an '86 Firebird Bonneville car running a 4cyl, 2 liter engine (runs but no dyno yet). Looking for about 160mph. For slight ram effect and to get cooler intake air am interested in a scoop but it does disturb aerodynamics too. Maxracesoftware's ET predictor shows some ET and MPH benefit in pretty much any car with a scoop. (good efficiency)

My question is about placement absent a wind tunnel or lot of track time testing stuff. Anybody have any rules of thumb, suggestions or theories? The scoop would be offset to the right in front of a theoretical passenger. Basically question is how far forward (as far as possible or set back) and how high off the hood (low and forward or higher and set back). I am looking at, for instance, a Harwood style mini Aero 3162 or 3163. Depending on the box around the intake (IR injection) I have some leeway for and aft placement.

Thanks for any thoughts.

Jack

There is a bunch of ET/MPH gains or rather potential LOSSES
in a HoodScoop.

back around 1976 with my 1968 CSM Camaro 331cid
i got my first Lesson in Ram-Air and/or HoodScoops,
i used the then popular Velocity Stacks
mounted on a Flat plate that sealed against the HoodScoop,
this ended up a disaster in ET/MPH,
the Car ran much faster without it,
i learned then and there a Carb also likes to breathe around its sides
as well as directly ontop.

i did away with that Velocity/Plate setup,
went with a flat plate directly around the 750 Holley,
and gained 2 tenths and 3 mph

don't do this =>
http://i123.photobucket.com/albums/o287 ... 24x735.jpg



later on,
we set the B/FX Record in Fremont, CA with this Camaro=>
http://i123.photobucket.com/albums/o287 ... Johns_.jpg

Larry Tores of T&D Rockers was there with his new Buick V6 Opel,
he saw the B/FX launch and set the Record,
i guess he liked what he saw enough to Ship his V6 Engine
so we could install it Johns B/FX Camaro,
go to Moroso DragStrip in Florida and set the Record in D/FX
with the Buick V6, as Buick at that time wanted more exposure
in Drag Racing .

Went all the way to Florida,
unloaded the RaceCar and it barely ran the Index
much less set any Record

Came back home,
went to Baton Rouge DragStrip made a few Runs
and went just about identical Times,
completly removed the carb's underhood Scoop's sealing pan,
and the Car picked up a few Tenths ET,
then blocked the HoodScoop opening,
let the Engine just suck the underhood air
and first Run was about a Tenth ET under the National Record !!

later John had the Scoop redesigned just for V6
and that solved that problem

i think the worst HoodScoop problem i ever saw was
Johnny Martin's Monza ,
when it had a SBC Engine with 2-4 it flew,
put a Big Block Chevy Engine in it , it died,
removed the Scoop sealing pan + blocked off the HoodScoop Entry,
let it suck underhood air like a SS Car,
it picked up 11 MPH

Martin also changed HoodScoop design , placement, and angle,
and that solved his problem also.


if everythings correct..you should see exactly the Gains in ET/MPH
ETA predicts with a HoodScoop input at 100.0 %

here's "text" part of Help Window in old ETA version=>

http://i123.photobucket.com/albums/o287 ... p_Help.jpg

just look at Help Text
"3 Methods to Test HoodScoop's Efficiency"