vented air box
#16
Drifting
Join Date: Jul 2002
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I think it's an equal tradeoff.
If you just take the top off the airbox, you have very little restriction.
You get a lot better airflow. The downside, is that it is hot air.
If you duct air from the front of the car, with the stock setup,
you get cold air, but that air has to travel a long distance through
twists and turns. So you get some restriction of flow.
I think it's a tradeoff.
And none of these mods gets you huge gains.
If you just take the top off the airbox, you have very little restriction.
You get a lot better airflow. The downside, is that it is hot air.
If you duct air from the front of the car, with the stock setup,
you get cold air, but that air has to travel a long distance through
twists and turns. So you get some restriction of flow.
I think it's a tradeoff.
And none of these mods gets you huge gains.
#17
Burning Brakes
Join Date: Oct 2004
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Originally Posted by Jim bailey - 928 International
Ah, OK ; engine and fan running car hot try putting your hand in front of the radiator then putting it behind the radiator which is cooler ? As I recall Louis Ott has done numerous temperature studies which confirm that the cold air system works pretty well .
#18
Nordschleife Master
Cripes, guys...
I made a open top air cleaner and tested in on the dyno:
5 more HP with the tube setup.
I tried it at the track, too:
No noticible performance improvement.
BUT, I may go back to it because it sounds good, looks cool and is fun. I swap filters at the track anyways. Once you're doing 50, 60, 140 the underhood air isn't overly hot and it shouldn't hurt performance.
Here's the thread and pics:
https://rennlist.com/forums/928-forum/146484-race-air-cleaner-top-project-2-a.html
I made a open top air cleaner and tested in on the dyno:
5 more HP with the tube setup.
I tried it at the track, too:
No noticible performance improvement.
BUT, I may go back to it because it sounds good, looks cool and is fun. I swap filters at the track anyways. Once you're doing 50, 60, 140 the underhood air isn't overly hot and it shouldn't hurt performance.
Here's the thread and pics:
https://rennlist.com/forums/928-forum/146484-race-air-cleaner-top-project-2-a.html
#20
Addict
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Thie is nothing new to the 968/944 guys. All you need is a holesaw and an adapter kit ($5 four holes). Don't know if it improves the preformance but it does sound nice...just another sucking sound to some.
HH
HH
#22
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Erich I agree the heat off the exhaust manifolds which are far far hotter than the radiator will tend to rise and collect under the hood. Nearly all the racers cut down the top of the firewall and try to get high pressure air off the windshield cowl area since the heater box is long gone and they block off the rest to avoid the heated air off the engine.
#23
Inventor
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In summer, you can remove the rubber hood seal along the back of the firewall. (Rainy and cold = steamy windows inside)
#24
Burning Brakes
Join Date: Oct 2004
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Originally Posted by ErnestSw
OOPS!! We're getting into religion here. Jeff, you go right ahead and worship whatever diety floats yer boat.
#27
Burning Brakes
Join Date: Oct 2004
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OK...I'm sorry for venting . It isn't a big deal to me one way or the other...I just want to feel uninhibited, about posting this or that most likely "hair-brained" idea I might have (once and a while I have an idea)...without fear of a group crucifixion for thinking out loud...(Oh god Ernest...I see what you meant now)...Peace and love to you all...
#28
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If I trepan corresponding holes in the hood and cover them with a scoop will that give forced cool air.
Maybe thats the answer.
There's no religion under my hood!
Maybe thats the answer.
There's no religion under my hood!
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
#29
928 Collector
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Originally Posted by BrendanC
Porken swears by his non-topped box.
#30
928 Collector
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Originally Posted by ROG100
If I trepan corresponding holes in the hood and cover them with a scoop will that give forced cool air.
Maybe thats the answer.
There's no religion under my hood!
Maybe thats the answer.
There's no religion under my hood!