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?

Track focused? The hood is the best option.

A big hole with a diffuser in front of it to allow for air to create a vacuum to pull the air through the radiator. (Think cowl hood).

Shroud it as well and you actually have yourself a makeshift front spoiler as well.

It was MUCH easier for me to cool my big v8 when I had the big hole in the hood and a cowl.

i remember from reading about the rod simpson v8 kits that on the track, the air coming from the radiator was cooler than the air in the fender wells, heated by the brakes.

i have one of those kits for my long stalled v8 conversion project...

I'd go strictly through the hood from a performance perspective. I have both the hood and the wheel wells but I taped off 90% of the wells after the first session.

T

My Suby conversion vented through the hood. Exit hot air on top of the car, not under it.

I agree. I think a lot of the through-hood vents looks pretty bad though, ill proportioned, tacked on... I was initially thinking of going 911-style by diving the hood down into the radiator but I may have changed my mind. Im thinking louvres are the way to go visually speaking. Going to experiment a bit, we'll see...

I am not a fan of most methods used to attempt to "hood vents"...not really a fan of most louvered efforts as well - some are ok. Very few cars had "appendages" sticking on or out of them - clean and simple - kind of like the mid-2000's Ford GT. Pull that off and that would be cool as Hell (I've thought about that!).

The previous owner did something really simple with mine. He literally cut three sides of the hood where he wanted the vent. Bent it down and blocked and glassed it in. It does have a screen at the opening too. It flows nicely with the hood; isn't' the absolute best with rigidity but that's mainly due to the light weight fiberglass hood.

Overall, it was one of the main things that attracted me to this chassis. Good luck.



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Its a good look man, the car looks great.

Im in a similar situation, I've got a lightweight Rennspeed fiberglass hood without headlight openings. It would be great to not have to deal wth building and fabricating fiberglass though. Im looking at some "universal" options on eBay but I haven't pulled the trigger, Im with you, many of them look not so great. Hoping something will pop up.

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

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Has anyone done a dual radiator set up. Like the 996's?

I did in our 912 STi project, but it was really tough, and we had to include a 3rd rad in the front opening of our RS bumper. The 911 fenders give a lot more room to work with too, so I don't see how it would be possible in a 914 even with GT fenders.

Neo914 did the tripple radiator setup ala boxster S. That being said the car has never ran.

Huey and Papa Smurf have totally opposite methods to address this:

Huey vents below, however, not in the 'normal' sense. instead of mounting the cooler on the front, its a flatter, square unit that is mounted on the floor. The air flows through the shroud than over the cooler on its way out. This allowed us to install a flatter shroud making the front compartment more usable (its still a street car). Plus, this way the shroud area (and thus the interior of the front trunk) does not get hot.

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For Papa Smurf, we have it vented out the top:

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Kinda OT, but is that a Sheridan front spoiler? It looks great!

For Papa Smurf, we have it vented out the top:

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I see you've got a Gurney flap in front of your venting too!

Early stages still cutting and trimming we ave not started the fiberglassing yet but you can get the over all look and function I'm going for. Hopefully done in a week Click to view attachment Click to view attachmentClick to view attachment

Looks cool. How does it look with the hood up? Like to see the engineering you have going on in there.

Excellent observation I need to build something from the bottom up to meet where the hood stops underneath. It's about 6 inches from the bottom which I need to fill. I will post more pics later this week.

Ya gotta be careful. The SCCA very specific hood venting rules. Read the book before ya start hacking.

This is a legal job of it.
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Are those hood vents custom? Is there a build thread on this car? Is that OT??

I no longer own the car.
Off the top of my head......

The vents were purchased.
Last build thread I saw was on the Subie site....it was extensive.
The car is owned by Britain Smith......who is a member here, I think.
The Logo on the trailer is his outfit......a good contact point.

Where do u find those louvers? do you make them or is there a place to buy them? just a general question even if this isnt ur car

byndbad914's old racer:

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heading for paint.Click to view attachment Click to view attachmentClick to view attachment