Hood Scoop

[836dstr]

Rex,

I've got the front part of the Air Intake figured out thanks to your advice. What about the rear part? The object is to turn the air into the carb with the least amount of turbulence.

I'm running a single 4 Barrel with a 2" air horn that seals to the bottom surface of the hood. Should the back of the Intake/Plenum direct all the air flow into the carb (your "turning vane"), or have an opening that allows some bypass air?

I guess you will always have some reversion of air with a sealed system. Maybe I'm overthinking this too much.

It would sure be nice to have an Air Flow facility to see how the air reacts to different designs. Way beyond my budget and expertise.

Thanks for any advise!

Tom

[Rex Schimmer]

Tom,
As I have said the F1 teams are in a continous development program on their engine air inlet scoops and they can and probably do anything you might even consider that could affect the scoop efficiency.

As far as having a "vent" hole in the scoop I am against this approach for two reasons. 1. You are probably bleeding pressure (air) out of the inlet which is exactly why you went to all the work to build the thing in the first place. 2. A vent hole promptes air flow thru the scoop which will cause an increase on drag, now that would need to be balanced against the drag that could happen if you made the scoop inlet to large for the engine requirement and you would then have air, and probably turbulant air, bleeding out of the front of the scoop. Probably a good place for some testing at your "Air Flow facility".

I do think that you need some sort of guide vanes on the inside of the scoop to get the air pointed into the carb. Another thought is providing some sort of "dampening" material inside the scoop, like a good high flow air filter, to help reduce and any interior pressure pulsations. I have always wanted to try lining the large volume section of the scoop with some very porus foam, like fuel cell foam, to provide internal dampening. Another thing to test at your "Air Flow facility". Build a scoop with your best thoughts and then put a Magnallic pressure gage connected to the inside and see if you get good pressure recovery, make changes and see if you can get it better.  For us guys without unlimited budgets the old "cut and try" method is probably our only way.

Good luck, Rex


                           

[bbarn]

Something I have considered for a while. This is a "general" video (not a ton of scientific information, just an overview of how to accomplish it) of the idea that water can have improved laminar flow and how to accomplish it, air and water are not that much different.

I saw a very large scale professional installation at the Bellagio and the work they did to improve the flow of water for their fountains. In the back of my mind, I'm thinking there may be some benefit to looking at what they have done and how it may apply to air flow/intakes.

http://www.youtube.com/watch?v=OV-IazRk0sU

[wolcottjl]

Here is an image of the air intake on a 1994 Formula 1 car showing the large increase in size after the scoop opening.

[836dstr]

Thanks Rex!

I'll definitely work on some type of turning device. Good idea on low density foam.

Tom

[wolcottjl]

I have seen few of the guys that build their own flowbench use bundles of drinking straws and or egg crate covers from fluorescent light fixtures to straighten out flow. 

[836dstr]

I was thinking of making a full scale mockup with viewing ports using a leaf blower and a smoke generator to get some ideas. My redneck flow bench.

[jl222]

  You might look at Pro Stock intakes and how much room on sides of carbs also, you know they have the latest tech.

                      JL222

[Kato Engineering]

...


...        N.A.C.A.  DUCT.

find a photo of my 85' t-bird and you will understand.

 find a photo of the Kibler D-C / STR and you will understand.
  ( the one that did not have the 9 gallon fuel tank in front)