bcdavis

I'd think that the best way to make this work the best, and keep the stock stuff intact, is to fabricate tubing, or some sort of rectangular ducting, that exactly matches the shape of the intake holes, right above the radiator. The oval shaped holes.

Then run that tubing, or ducting, right out to the front of the car, in the gills. That would be smaller than the tubing that is used on Steve's setup, so it would not interfere with the flow to the radiator as much. And it might help to keep up the air velocity. You can still have bell-shaped intakes at the front, but taper them into the oval or rectangular ducting. The advantage would be in being able to flow the air directly from the front of the car, into the intake tubes, without any turbulence or drastic change in direction.

Adam C

Out of rain gutters!

bcdavis

Dammit! I couldn't find a picture of some cool-looking rectangular plastic tubing!

Grrrrr!

Well, you get the idea...

Normy

-I'll see if I can find some information on 1/2 ounce fiberglass cloth model airplane construction. It isn't hard...and if you make wooden forms, then you can re-use them. Meaning...volume production-

Do you have any pictures of your airbox complete with the water heater insulation?

N-

Steve Cattaneo

Steve,

Just an observation, I would think air flow, thru the blue corrugated intake tubes would be turbulent, stalled. Would there be any benefit in fabricating two smooth light gauge steel square air ducts, routed down thru the grill or spoiler then up thru the belly pan feeding the intake tubes.

bcdavis

That was sort of my idea. Rectangular tubing, directly from the inake tubes out to the front of the car...
But no bends, etc. Just a slight downward angle. Which would help to eliminate any water intake...

pappy92651

Hello Normy, Thank you. I have the blanket off right now to make one that looks pretty. I will post a picture once I get the new one finished.

pappy92651

Hello Steve, The corrugations do create slight boundary layer turbulence. Good or bad laminar boundary flow? I need to calculate this. The interior of the GTS tubes are the same.

Yes. I think BC was hinting about the same thing. If you could create ducts that had the right volume they might be extremely effective. You eliminate as many bends as possible but a custom bell mouth would be required to smooth the air at the entrance. To be effective the ducts would have to be slightly wider that the bell mouths on the fan shroud. Because of the width of the duct you would loose some velocity before it enters the fan shroud bell mouth. At higher speeds this factor might be less significant.

Steve Cattaneo

Great minds think alike

Tony

Well, your times are , thats for sure...either NA or S/C'd
Your probably the quickest NA 928 out there!
You using a GTECH with the PASS software?

The custom converter was a pretty good idea

Once i get in a final state of tune ill have to send my dyno chart and specs to the shop you had it done to see if anything should be altered?

pappy92651

Tony, I did it all with my Junghans precision stop watch. I will be buying a GTECH so that I might log data without the human error associated. When I hit third it feels like the drive train is going to come through the bottom of the car. Really strange to drive an AT 928 that lifts the nose in 3 gears. The car just squats and pulls. I'm taking bets on which rear axle will give up first (bet you know or will find out).

heinrich

Ken had an idea sometime ago about ducting inside the hood.

pappy92651

Heinrich, If you are referring to the hood braces, they lack sufficient volume to feed the engine.

The other concept that I saw was a barrier sheet layed over the top of the engine. This would reduce the air box pressure. Most of the air box heat build up comes from the radiator at idle. Longer term you get a heat soak in the air box from the heads, exhaust, and headers, but the primary delta t is from the radiator. It was an interesting idea.

It is good that people are exploring new approaches and sharing them.

BTW: If you look at the 928 S4 forward hood braces you will see 2 ventrals on either side. Water would be carried up against the hood and sheet under pressure. That water is forced to the outside and drains to the ventrals which are behind seals. If the water is deep enough nothing will save the engine.

rob rossitto

just a thought, but if it's heat build up that's the enemy, would bigger fans help? ie just blast more air under there to keep the whole compartment cooler, and there would be less build up in front, hence cooler air for the intake tubes...

IcemanG17

Steve
Awesome work!!! Once you get a new hood with complete 3" tubes should be a noticeable improvement.