Hood Scoop Opinions....

[Dynoroom]

Yes we all know there are formulas for calculating hood scoop openings, but there is a tradeoff in aero vs. hp in pressure recovery. Not to mention airflow needed at lower speeds but higher power output.
Given you need a hood scoop on your car what made you choose the type you run and show us any pictures you might have of the development of your inlet system.

Lets see where this leads us....

[Stainless1]

Hey Mike, I'll start
We use a NACA Duct on the side of the car.  Goes into the airbox at the bottom, through a filter and into the TBs.
No  aero drag, very efficient scoop, pressure in the box.

[bvillercr]

When we built the car with the twin centrifugals we really didn't have much choice of where we could put the air intake.  We did have someone build a hood for us and it blew off the car at about 265.  The next year we built one ourselves.  We took a pro stock scoop and cut in half long ways, and then only used about the first six inches off the front.  Here is a couple pictures.

first the air intake



you can see the resemblance of the pro stock front

[Dynoroom]

Stainless, I've seen some of the posts you've made regarding the NACA duct on your lakester. Can/would you share some of the development you went through to make it work for you. Most NACA ducts don't work very well in low speed automotive use. I know NACA ducts require very sharp edges & very specific ratio changes in depth vs. width. This is a great option if you can use it on your car but I'm also looking for information on scoops that protrude into the airstream.

[Stainless1]

Boeing did all the R and D on the scoop  and its transition to a 3 inch duct.  It came from a burned engine pylon that was being repaired.  Since it was surrounded by burned skin, it could not be reused and was condemned into my trash can.  We built a panel to put it on the car, just trying to put fresh air in the motor area. It was almost impossible to paint, any time paint was sprayed across it the paint would just shoot out the back.  We decided we needed to build a closed induction system.  While most believe the NACA is ineffective at low speeds, we have recorded pressure in the airbox at WOT starting about 190 MPH.  The pressure rises with speed.  We had attempted to double the air by using 2 ducts, thinking we could get more pressure, lost all the pressure, guessed it was running out the other side.  The key to the duct efficiency is the wing, stop by to look at it at WoS. 

Sorry, it an innie not an outie

[Bville701]

When we built the car with the twin centrifugals we really didn't have much choice of where we could put the air intake.  We did have someone build a hood for us and it blew off the car at about 265.  The next year we built one ourselves.  We took a pro stock scoop and cut in half long ways, and then only used about the first six inches off the front.  Here is a couple pictures.

first the air intake



you can see the resemblance of the pro stock front

That's a good idea. Did it take a lot of work/ time to make?

[jl222]

  We and Procharger also believe that we get ram air from the 222 cars front scoop.
  All the latest prostock cars have giant scoops along with nitro dragsters and unblown nitro dragsters.
  It seems that air being sucked into the engine would take some of the drag away from the protrusion especialy if it was part of the frontal area anyhow.
 
  JL222

[jl222]

Bville701
 
  It was'nt easy but not to hard and a lot easier than for the twin blowers. Look in build diarys starting about pg 6 under [getting ready for Bonneville] to see assembly.

       JL222

[Bville701]

Thanks I will take a look.

[bvillercr]

Bville701
 
  It was'nt easy but not to hard and a lot easier than for the twin blowers. Look in build diarys starting about pg 6 under [getting ready for Bonneville] to see assembly.

       JL222

page 4 you can see how much room the twins took, page 7 shows the single blower intake build.

[Bville701]

I guess no one else runs any hood scoops?           

[836dstr]

"Dyno"

I had thought about running a NACA duct on my Roadster but in talking to some guys very knowledgible in aerodynamics I learned that they are only effective on long flat surfaces like on Stainless' car.

Last lear at Bonneville I was going to test 2 different air intakes. One a hoodscoop with a bellmouth that extended in front of the grill shell. The other ducted air throught the radiator (actually picked up the air in back of the one core radiator) into a plenum. Best laid plans, lost the transmission on the first run. Well, there's always this year!

I'll look for some pictures.

Tom

[WZ JUNK]

Here is a link showing how I built the one for the Studebaker.   http://purplesagetradingpost.com/sumner/hooley/hooley-construction-2005-1.html   I always say that it is the ugliest piece I ever made but it works.  It fits directly to the Enderle injector when the front end is on the car.

John

[maguromic]

Michael, Have you looked at any of the SAE papers on air inlets?  Just for fun I typed in"Air Inlet' and got about 200 hits. Most local library's can get them for you.
Tony

[Dynoroom]

Actually I was trying to get more people involved with some tech conversations. Hood scoop ideas seemed like a good topic. I've got a couple more too. Just wanted to get so ideas flowing.

Thanks for the library idea Tony. Thats one I hadn't thought of.