Heat soak - vented hood options that are not "louvered"
 

Edit: Just want to clarify I'm looking for venting options due to my FI build. I'm looking for solutions that take the intercooler into account.

I'm not really sure whether this thread belongs in here or in the "body/exterior" forum but I figured I'd start here as I suspect I'm not alone. If a mod thinks this belongs elsewhere, please feel free to move it.

So unsurprisingly, I'm having radiant heat/heat soak issues especially when the car is pushed hard and I'm looking at more engine bay venting before I look into a bigger oil cooler/radiator/other cooling options whatever. I already have the vented fender liner from GTM so a hood scoop would be a nice way to get some air circulation going.

Thing is, I'm not crazy about the vented hood options I've seen posted here (carbon signal, seibon etc). I really don't like those diagonal vents as it kinda ruins the lines of the car - no offense intended, just my opinion.

I ran across this on my facebook feed (not my car):

http://i.imgur.com/XgYgGwe.jpg

...and it turns out this is a non-functional scoop - ugh. Is there a hood that looks like this or the old 350z vented hood style? I've been told modifying the stock hood (even with a fantastic metalworker) is a bad idea for several reasons.

Any ideas?

What are these vented fender liners you speak of?

I remember seeing a DIY for it a while back, but I didn't know there was a commercially available option

GTM sells one if you don't feel like DIYing it.

OP, I'm with you. I'd love some venting that isn't quite as noticeable as the options that are out there.

Lol, I see that, I want more info, maybe an installed pic

:facepalm: Chuck... :gtfo2:

Well this came up yesterday because apparently sticking hood scoops all over mustangs is all the rage ;)

Would be tough to take a picture of because of where the vents are. I'm sure you can google the GTM stock picture.

... Got it... Lol

And yessir, that good scoop is a stick on

I'm surprised there aren't more understated options. Oh well.

Some NACA ducts like the gtr would work if we knew where to put them. I'm not convinced any of the aftermarket hood makers have done any more testing beyond "the vent looks cool right there". I'd hate to put the vent in the wrong place and make the situation worse.

I doubt that scoop would do much good even if it was "functional". Most cars have a low pressure, "dead" area close to the hood. The area at the bottom of the windshield is usually higher pressure, hence the "reverse" inlets/scoops that you sometimes see.

If you have a scoop to hide the hole, it doesn't have to look real pretty. ;)

With the way the Z is shaped, I don't know if NACA ducts on the hood would actually pull air in or whether air would just flow right over them.

I was warned by several people not to modify the stock hood because it "wasn't safe" but I'm not sure why that would be short of possible (?) hood latch issues.

Would it be possible to have a custom scoop like the one pictured above fabricated and attached and a hole cut into the hood by a really good body shop?

Sure, you could have a good shop make some kind of scoop. I think the one in the pic is too far back. My guess is that the best solution from a function standpoint would be a vent with an extractor/louvers in front of the motor to give the air coming out the back of the radiator a place to go.

You can do like Synolimit did here & heat will pour out of the hood. http://www.the370z.com/exterior-inte...d-vents-2.html

http://i39.photobucket.com/albums/e1...ps5bdee05f.jpg

Lipstick on a pig (er..pony...er Tony pony).

I like that concept and placement but I still think I'd want a scoop or something on top of that so that if I get caught in weather, the engine bay isn't directly exposed.

I wouldn't do a scoop only because I think a vent is better. Instead on bringing in ambient temps into the engine bay, I'd want the heat to get out of the engine bay faster/better.

Well, I'd be leery about having the engine bay directly exposed to weather/debris/whatever even with that mesh there. I think I'd feel better with a combination of scoop/mesh.

Also, with my vented fender liners, a scoop would generate air circulation where a hole in the hood covered with mesh might not. Not an expert here or anything but I think I'll give my guys at D&V a call and see what they think.

From my testing and experience on mine, as far forward as possible! I don't know how the gtr works being so far back but I don't think they're a heat thing. I think they're a stabilizer or something because if you watch the making of the gtr on youtube they're insane with aerodynamics and drag etc etc.

Bingo. New vette, all the evos, all up front before the motor to pull the radiator heat. It works for the same reason a bigger radiator will drop oil temps.

Evos have done this forever, no issues with them year round. An engine bay is basically water tight. Nothing will happen but surface rust or corrosion on aluminium parts. And that happens even with closed hoods.

The problem on the Z is how little room there is between the motor and radiator. The air almost has to make a 90 degree turn to go out a vent placed there on the hood. A deflector on the timing cover to split the airflow to either side and two vents basically over where the intake pipes run may be more useful. Until we get some guys willing to tape yarn all over their hoods to check airflow at speed, we're just guessing.

How is the fender vented? Behind fenders isn't the engine bay, it's normally the side of the fire wall and the reenforced impact rails the motor sits in between. If there is I direct link, adding a scoop doesn't mean air will enter and leave. Unless you can wind tunnel test, you'll have no idea whats going on and you could be killing your aero.

Heat soak - vented hood options that are not "louvered"
 

The fender vents aren't going to address the main issue, which is getting the hot air passing out of the intercooler/radiator out of the engine bay. The only thing the fender vent does is give the air exiting your oil cooler a place to go.

The scoop may also make things worse. If you're pressurizing the engine bay through the scoop, you may stall the air coming through the radiator.

This is likely a problem I will have to wait until spring to tackle. Kinda hoping a vendor figures this out and offers a solution that isn't a gaudy CF louvered hood before then.

yeah that's what I was thinking. Scoop forcing air downward over the engine means better airflow over the oil cooler and out the fender vents. That said, I'm not sure it would actually work but it would make sense.

Maybe some kind of extractor setup on the under panel? Bring the air out the bottom?

Doesn't matter, it works same way the air hits the motor and has to 90* down under the car. Airs light, it can change direction fast just like a stillen CAI bends. Heat rises and the hot air hitting the engine has no place to go but up or down and under the car. Both of which get the heat moving and out with a properly placed vent. And I did the yarn test on mine.

Airflow in that direction may interfere with the airflow through the radiator. You want air being pulled out of the engine bay, not going in.

Zspeed nismo undershroud would probably do that - it's vented but I'd be sacrificing downforce.

The gentler the change of direction, the better the flow.

It makes no noticeable difference in temps. The vent is under the oil pan. You could cut a vent further up.

Correct.

Wait the fender thing is the vents installed in front of the tires? Then a modded fender in the back? Yeah that's going to do nothing for engine bay heat even with a hood vent/scoop.

The scoop is pretty much a non-starter. The potential for messing up airflow is too high without a ton of research. OEMs that use scoops have wind tunnels to use. Since we don't, were stuck with vents. Even if the vent isn't 100% dead on in the right place, it will still make a positive difference as long as its placed as far forward as you can get it.

True. But like you said, it's really all we have to work with, with the little room we have. I haven't done scientific testing but the yarn seems to flow how I want and I haven't been able to exceed 218 degrees on the oil with hard driving for like an hour straight on fast twisty country roads in the middle of summer . Next summer when the tracks open we'll see whats what. But I'm hoping Mitsubishi and Chevy did the work for us and hell the evo doesn't have much room either...

That and when stopped the heat pours out like a volcano!!! Its insane how fast and how much comes out. So in traffic you'll be much cooler.

My guess would be a vent in front of the motor and upgraded radiator and fans are going to be about all you can do.

I think I'd go look for bigger radiator fans before I try to upgrade the radiator itself. Space comes at a premium under there these days.

I did the radiator, and before next summer ill swap out the fans. At least in TX it seems like you need to do both. If that's not enough its time to start cutting into the hood.

I know my hood displaces a ton of heat during the summer.

I'm sure they do but I don't like those louvered vents on the Z.