Radiator venting options: hood, wheels, under car... Options

[MichiganMat]

Gents,

Im working on putting together my 914-wrx and Im exploring venting options for the front radiator. Im trying to think about it from a performance perspective and Id love some feedback to see if my assumptions are correct.

Up and out of the hood: Needs venting of some kind. Either louvres or a big hole, but seems like the most efficient way not only get air through the radiator but also the best solution aerodynamically. True?

Wheel-Wells: It looks like a common option is to vent out of the wheel-wells. Cut a huge hole, put some mesh on it, done. This seems bad as its blowing hot air onto the brakes, but maybe the temp difference doesn't matter. Its tempting though because I don't have to cut holes in my brand new hood, but aerodynamically speaking is it not efficient? Pushing air into the front wheel-wells... seems bad, no?

Under car: I know this bad for a variety of reasons, so its really not an option Im considering


Yeah, so what Im really wondering is, if you were building a track-focused 914, would you vent to the wheels or out of the hood?

[914forme]

Hood, GT500 hood vent would work. In reality the key is good duct work on the front and back side. Seal the front well to create a high pressure area to force air through the rad. Create a low pressure area in the back to draw the air out.

After that you get into things like angle of attack, and linear flow, etc.... Do not make the front opening to big, and the rest becomes a lot easier. 1.7 to 2x opening on the back side is the rule of thumb, as hot air will expand. This is also where other items come into play, oil coolers, radiators for your intercooler (heat exchanger) and the your radiator.

Also not sure if the subie 4 has this issue, but our -6 capitate the water pump at high RPM, and require a huge amount of potential flow to over come this issue. I am thinking about going with an electric water pump, and removing the implies on the engine pump. That way I can control the flow of the water, and the speed, tailoring it to the exact needs of the system.

Hope that helps