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