Forcing Air into the Engine Compartment, Engine Cooling ??? Options

[Highland]

I'm guessing it's been tried, but is there a downside to forcing fresh oncoming air into the engine compartment? I've read that removing the rain tray does not help cooling which tells me the 2 engine compartment side vents are more than adequate to feed the centrifugal cooling fan; so perhaps increasing engine compartment air pressure and reducing relative air temperature would help.

So don't laugh too hard at the pictures (IMG:style_emoticons/default/av-943.gif) It's a first pass attempt.

I did a couple of runs on my normal joy ride and am qualitatively seeing about a 5 to 10 degree head temp reduction and quicker cooling to normal temps after an uphill grade. Also cruising at 65mph in 5th I'm seeing about a 10 degree reduction in steady state temperature. I have a big hole in the back due to a 3D print problem and my duct tape keeps on flying loose so not getting full duct air. I just have a VDO head temp gauge on #3 plug. As many of you know the VDO has 50 degree hash marks; so not real accurate reads.

So is it correct that head temps are not affected by outside air temp, that's an oil temp thing?

Has anyone tried this? The stock grating is still in place. Can I be doing any harm?

[JeffBowlsby]

Read these 914 aerodynamics papers:

[wonkipop]

Read these 914 aerodynamics papers:

good stuff mr. b. you have some good gear/research you have accumulated.

air flow along flanks of 914 confirms vw thinking on the old type 3.
the long louvre vents on rear guard flanks of those were into plenums that then fully seal ducted cooling air and induction air into the engine. they never had any tin-ware separating lower engine from upper engine. just a separated ducted cooling intake.

you want to keep your cooling air intake as far from your heated air exhaust as possible in everyday conditions of stop start go slow traffic. i reckon porsche got it right for the 914 as an everyday car (except when it comes to something like death valley/and or/australia). fortunately you don't get caught in traffic jams in death valley?

(IMG:style_emoticons/default/beerchug.gif)

as an aside, 917s just had a dirty big hole in the top and the fan sucked it straight in.
and they were going at 230mph. no ram tube etc for cooling. they might have been trying to ram induction air in later on.