Mike Wood

My son has asked me a question that has got me thinking, I hope someone can help. My Vette's BB hood has a 4" open cowl toward the windshield with no opening in the front although with the fiberglass rise it certainly could be open as well. Why isn't it? If the idea is to introduce as much fresh air as possible to the intake why not have it open as the Pro Stockers do? Quite easily I could Roto-Zip into the front of the hood and seemingly offer my engine more of a good thing. What do you think? :confused:

flynhi

Above about 40 mph, there is a high pressure area in front of the windshield. Locating the intake at the rear reduces water intake in the rain.
Locating the intake high reduces dirt intake.

zwede

Look at a NASCAR. Notice how they all take air from the base of the windshield. I hear Smokey Yunick was the first to use it back in the 60's???

When the air hits the windshield it builds a high pressure area, like the previos poster said.

73 LS-4

Back with my old truck I ran a ram air setup on it first and later I went with a nice cowl hood and setup, didn't notice any power difference between the two, the biggest difference was with the cowl setup the filter element stayed cleaner much longer. Also think the cowl setup is probably cleaner aerodynamically then most scoops.

:cheers:
Pat Kunz

Juliet

Mike - I just e-mailed a very very cool thread from a few years ago about the cowl induction setup. It was a loooong thread with lots of great data - even someone modifying their setup & taking temperature measurements at the track under the hood before & after etc... It's really way to long to post here, but if anyone want's it I'll be happy to e-mail it to you - LMK at Juliet@annapolis.net. It's no longer in the archives that I've been able to find unfortunately. :( I'm glad I saved it to disk! :) ~Juliet

Mike Wood

Thanks for the excellent information Flynhi, Marcus, Pat & Juliet. I get it. If anyone else has similar questions regarding cowl induction, Juliet's download is the ultimate. Offering Expert analogy and testing. Thanks guys! :seeya

JD/76-ZZ4

Reading Juliet's comments reminded me of when I started that particular thread on cowl induction....I recall taking various meausurements around the air cleaner and on the MSD box located to the right of the booster and saw a considerable drop in temp. I took the readings on the highway at various speeds...I finally cut all the obstructions which kept me from having a straight shot of air to the carb cleaner....My work was crude but even though I had no way of meausuring power, I know the temps under the hood dropped....And unless you know what to look for or if the hood is open, one will never know the mod I made to the hood....

shawn_cake

I built a cowl induction hood by hand - because my fuelie big block wouldnt fit under the stock hood. I also built a sheet-metal air-box around the air cleaner. The airbox has 1" flanges which seal to the hood with self adhesive foam tape. While monitoring the ECU with my computer, I've seen 35 degree dops in intake charge temperature. The EFI allowed me to program in air charge temperature enrichment - and make more power! Cowl induction does work!

:cheers:


[Modified by shawn_cake, 8:09 PM 1/19/2002]