Which direction, I want to put some fans in the engine bay to exhaust heat and to keep the intake manifold temps down.

I believe the air flows in from the top. I think there is a low pressure area there.

won't work.

air flows out the engine lid. IIRC.

In at the top (thru the engine grill) out at the bottom!


To lower the intake manifold temps build a snorkle to catch some clean cool air.

Yes in the top and out the bottom. But it is an air pump, taking air from the low at the engine lid and forcing it out the bottom.
Snorkle it.
:PERMAGRIN: Joe

How about an example?

I take it you are running a non-Porsche engine? If thats the case, then there isn't an 'active' air pump like there is with a Porsche motor. With the air cooled motors, you have a huge air pump to do the cooling.

I have read through many threads here and no one seems to have a really decisive answer as to which way the air really flows in a 914 where the engine tin has been removed.

For my Subaru conversion I am planning on doing two things to force air into the engine bay from the top. First, I'm building a deployable flap that will sit just past the trailing edge of the roof. At speed, this will force air down when its needed. Secondly, I'm going to build a special fiberglass plate to cover the entire bottom of te engine bay from the fire wall tot he rear bumper where a large diffuser will help accelerate air from beneath the car. A vent in the plate will allow hot air form the radiator to be suckd through.

So you could try one or both of these to get some air pushed into the engine bay if you find that you can't force air through with a fan. Probably the easiest thing to do is measure the temperature with no fan, and then with the fan and see what kind of cooling you get. From there you could decide if aerodynamic aides are needed.

-Tony

Like this

And it might help if you say what you're doing/running.

Air curls around the back of the roof and hits the back window, I don't know if it is truely a low pressure zone.

This curl effect is why you see MB verts with those little pop-up windows behind the front seats. It's so this curl effect doesn't mess up their doo.

sorry about details,

I have a V-8 car and although the coolant temps stay down the intake air temps can get a little high. This may just be at low speeds thus the odd air currents may not apply. My wish would to force air on the intake directly from the engine lid. I have an "air-gap" intake and could pipe it in directly. That would likely lower temps where I would like to see them. I don't like to see them over 130 but maybe thats too much to ask. Driving at speed they stay well below that.

S N O R K E L

130F is damn cool under hood temp. Enjoy. Here's the setup on my V8. They blow down, not suck up

As a point of reference for you, the IAT on my '96 Impala ranges from 80-120dF depending on variables such as idle, (tends to climb) cruise, time and temp.

After I've driven it, let it sit for 10-20 minutes, and come back out, I've seen it as high as 150+. After starting the engine, it'll creep back down to 120.

(My coolant temp, BTW, sits at a very steady 195-197 dF)

All readings are done via the ScanGauge connected to the ALDL, so read direct from ECM inputs.

Thats a nice peace of information, its been a long time since I have read a data stream of a GM system. I was a tune-up and drive-ability specialist (GM products) from 1980 to 2001. I am using an Edelbrock EFI which is based on an mid 80s GM PCM. It too has a scanner / programmer interface which can be viewed from the driver seat.

Howard,
I like your fan setup, I will likely do something much like that.

Aaron,
Thats a mad Max look, wow it may work great but man looks goofy

Ceramic the headers and drop like 300F off the top.

I bet your whole car gets hotter than hell once your driving right? I'd put some intakes on each side of the engine on the fenders so air is forced in under way. Keeping all the tin and engine bay cool and suck cool air down into the engine bay would keep things cooler also and there are some kickass 12 volt fans out there. I'd ceramic the headers and even heat tape the whole thing front to back.