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Author Topic: Cowl Intake  (Read 2762 times)

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Offline CTX-SLPR

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Cowl Intake
« on: November 12, 2016, 10:23:20 PM »
Howdy Y'all,

Have a question for you.  I see lots of cowl induction feeding off of the high pressure area at the base of the windshield and I see front mounted intakes.  Is there a reason why people don't feed air from what used to be the HVAC cowl intake area?  It's already built into the body on most cars and is feeding off of the same effect as the cowl hood does.  I think the original Z/28's had something similar?


Thoughts?
Central TEXAS Sleeper
USAF Physicist

1964 Buick Riviera T-type (4.1L Turbo6, 4L80E, L67 EFI system)

ROA# 9790

Offline jimmy six

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Re: Cowl Intake
« Reply #1 on: November 15, 2016, 05:30:41 PM »
I don't think u can get much positive pressure from the cowl/windshield split.
First GMC 6 powered Fuel roadster over 200, with 2 red hats. Pit crew for Patrick Tone's Super Stock #49 Camaro

Offline manta22

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Re: Cowl Intake
« Reply #2 on: November 15, 2016, 06:11:14 PM »
Any positive pressure is a help but on LSR cars the windshields are usually raked back at a less-abrupt angle than "street" cars so the pressure gain is probably nil. Some class rules don't allow windshield modifications, of course.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline CTX-SLPR

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Re: Cowl Intake
« Reply #3 on: November 15, 2016, 10:02:52 PM »
I'm planning on running classic production so I can't really rake the windshield back any farther than GM did on the G-body.  Here's the panel area that would be missing (the welded in plate on the cowl:

Here's the heater box that was deleted from the above pictures (needing the bare metal panel and the black welded in piece):


I'd basically convert that screen section to the intake.

Looking at old NASCAR flow diagrams, it still looks like the base of the windshield is still a high pressure zone:


Now the one thing that makes me wonder is that since the car has a gap between the hood and the windshield, will that recess be under positive or negative pressure?  This image I found, in which I'm assuming that the car has a similar windshield to hood gap like most modern vehicles, shows a much lower pressure area at the base of the windshield:


Someone borrowed my rulebook but I remember something in there about you can't put the air intake any lower than it was from the factory.  Am I remembering correctly?

Any further discussion?
Central TEXAS Sleeper
USAF Physicist

1964 Buick Riviera T-type (4.1L Turbo6, 4L80E, L67 EFI system)

ROA# 9790