Chris Lockhart's
1989 Porsche 928 GT
Cowl Induction Project
From
Date Monday, April 15, 2002 9:26 pm
To "928" <928@rennlist.org>
Subject [928] Cowl induction hood-- update (longish)
The hood project is finished minus paint. Had a few "minor" engineering
setbacks with the pin mounts on the front of the hood that delayed things a
bit. All is well now, and I have new pics showing the mount sytem and the
installed hood. Would really love it if one of the guys would like to post
some pics on their webpage since I'm clueless as to how to build one myself.
(any generous parties interested?????) Any rate, I'm no scientist, and I
don't know all this fluid dynamics stuff, but I do like to tinker, and I
think that this set-up may work out. My whole reason for doing this is to
get a good source of cold air into the intake, not pressurized air. The base
of the windshield has been talked about alot as a good source of air, and my
recent mileage in the rain indicates that this is possibly true. Now my
findings may be more vacuum effect related, but here goes: when driving in
the rain(stock airbox installed to prevent water ingestion) the water runs
up the cowl and then makes a turn back towards the front of the car and into
the hole in the hood for the filter to come through. The water behaves as if
it's being sucked back forward. Like I said this may just be vacuum effect
from the air passing under the car, but I still found it interesting
nonetheless. My only problem at the moment with completing the cold air
pipe, is to find a cheap source of 4" OD aluminum pipe with a 45 degree
bend. If anyone knows a good source please let me know. Burns Stainless only
has it with a 90 degree bend, and it's basically a hundred bucks!!!!!!!!! I
could cut 45 degrees out of the 90, but that's alot of money for an 8" long
piece of pipe.I have a flange set-up to seal against the underside of the
hood to prevent hot underhood air from getting to the filter. This will
allow only ambient air to flow into the K&N low profile cone filter and
straight down the 4" pipe to the MAF. Should be very little restriction, and
hopefully better overall breathing. (in theory) Does anyone know how many
cubic feet per minute of air a 5.0 liter 928 engine requires????? I know
this was discussed awhile back, but i don't remember the thread topic. I
want to make sure that the filter can flow enough air to satisfy the engine
needs and not choke it down. Kinda defeats the purpose huh??? LOL. Oh well,
I'll quit rambling. I'm just happy to be able to post again. (thanks for all
your help JD) TIA for any info on piping or air flow.
Chris Lockhart
'89 928 GT
April 15, 2002
http://members.rennlist.com/pirtle