What happened with GTM?

They're a forum sponsor. Not worth getting into. PM me if you're really interested but it's probably nothing you haven't heard before.

Unless there is somewhere for the air to go, upping the pressure from the fan won't do much good. It sounds to me that the engine compartment is pretty well sealed (not totally or the engine would overheat all the time).

Where does the air vent from the engine compartment? I just made a look around the engine compartment and underneath and didn't see any vents. They've got to be there somewhere. It might help to enlarge them.

I'd assume that the air exits underneath the car behind the undertray. There's really nowhere else it could go, right?

Yeah that has been my assessment, that it gets pulled out under the car.

Achieved... thanks to Aero Jacket:

If I end up with a vented hood, that's the one.

Sounds reasonable to me. I'll jack the car up later and take a closer look.

The vent closest to the windshield works great. The other one doesn't do much. Another drawback is weight. With the reinforcements put in place the hood is several pounds heavier than the stock hood. I could care less, though. It's functional and easy on the eyes.

That was a wild-*** guess, so I may be completely wrong. It just seems like the only place that air can go.

So is this hood available now? I think it's a great design with looks & function. But I'm happy with my GTR vents ;)

So that's available from Aerojacket, or did you have a shop make it for you?

They have to cut one up. The result is nasty and requires lots of prep from the body shop if they're willing to work on it. I basically spent $1300 or so, and that includes the hood, mods from Aero Jacket, and the labor from the body shop to clean up the work, reinforce, and paint.

Well I think the science behind it is that Heat flows from hot to cold. Heat will draw to cold like a magnet. As colder air running under the car also creates a draft/ suction effect pulling some of the hot air out when the vehicle is at speed.

So it's basically a custom hood. Damn, I was hoping for something off-the-shelf where I just needed to have it painted.

Maybe someone can have it fabricated with vents of this style. I prefer OEM aluminum hood.

There's definitely a market for that hood if someone wants to buy OEM hoods and install the vents.

Understood. We're all making guesses at this point. ;)

It does seem to be the most likely place. The hood seems to be well sealed and it's not going through the firewall. Out the bottom or through the wheel wells sounds like the only other options. I'm interested enough to check it out.

BTW, I like that hood with the louvers at the bottom of the creases. Very subtle.

Possibly. Shipping is expensive. It's about $200. I had Aero Jacket find one locally and ship it to me, so I only pay one way.

I'm thinking with these vents, it can definitely melt ice on the windshield at some point. Weather is crazy here. It can snow or get icy by the time I leave work. [shrugs]

I'd happily pay shipping to avoid being a local shop's guinea pig on cutting the hood.

Damn. I too would buy that hood if it were available.

Haha someone messaged me wanting to buy/trade the hood since my car is up for sale. It's too much of a hassle, so I keep hood ;)

What's funny is that I was just thinking about doing the same thing. :rofl2:

Perhaps AeroJacket or CarbonSignal would be willing to make these... since AeroJacket has already made at least a couple they could make a mold and start pulling FRP and carbon replicas. I'd prefer a full FRP hood to a stock hood with FRP vents molded into it.

This is the hood I would love to have. It's about perfect for removing heat from the radiator. If you could make duct work from the radiator to these vents without letting too much air into the engine compartment. The Z would never overheat. If you look at the new vette, Viper, and some other high end 2 seaters. you will see the same set-up.

On the other question about where does the air excape on the Z. To goes through the radiator, around the engine, to the back of it. Down the firewall, and out along the tranny.

Thanks

If you drive with your fuel pump access covers off, you will generally feel very warm air coming in. This is because the air under the car is the air that came in through the radiator and around the engine.

I think that a scoop on a hood is a bad idea unless it is used to feed the air intake filters in a sealed manner. Vents will relieve pressure in the engine bay, allowing heat to escape out the top, hopefully allowing more air through the bumper/coolers while reducing air pressure under the car. A scoop will just try and cram more air in, and if it does, it will probably only serve to increase engine bay pressure, possibly reducing radiator flow, and putting more air under the car.

I also think that louvers are used rather than just openings in attempt to create a venturi effect. Seeing as how most louver designs actually bulge up just before the vent, then the dip down for the opening... creating a little high pressure area that transitions quickly to a low pressure air with an opening... well that's the formula for a venturi. If successful, these louvered vents at speed should be pulling air out quite well.

How technical it gets after that is probably the type of stuff that would hurt the brain. My personal belief is that further spaced gradual louvers like the Siebon TS will have a more effective venturi effect, and that steeper more rapid louvers will have superior airflow volume with less venturi effect. I have really good reasons for thinking that, but I dont want to say it aloud and then have someone who is way smarter come in here and make me look like an idiot :)

At this point, I think you've earned the right to say pretty much whatever you want without someone calling you an idiot. We're spitballing here, so let the unfounded beliefs and wild-*** guesses fly.

would it be wise to check out what nissan did to the GTR? im not saying they are super similar but the basic ideas are the same. twin turbos placed in almost the same location as a TT 370z. both have a radiator and IC mounted in front..... maybe something like they did on the GT3 car. albeit ugly...

http://www.the370z.com/members/beema...60-gtr-gt3.jpg

That hood looks godawful. Perfectly fine for a race car but there's way too much "stuff" going on there.

Man I sure opened a can of worms. My initial question was innocent enough!

i agree, but im also sure its full of R&D with wind tunnel testing.

Well... I think that each vent in a steep louver will hurt the venturi effect of the louver in front of it by putting another high pressure area too close. But, if you think about it... you may not need a venturi effect anyway.

I think that it depends on the scenario. If your car has a problem with too much air pressure in the engine bay and under the car, then you dont even need a venturi to get the air to leave that hood vent... its going to just leave because of the pressure differential. Aggressive venting would be fine for that.

But if your car doesnt really have an issue with pressure in the bay and forcing pressure under the car... then mass hood vents may not even do anything at all... there is pressure on the hood already, so the pressure in your bay better be higher than the pressure on the hood otherwise air is not going to be leaving hood vents without a vacuum effect from a venturi.

I think the GTr posted above sort of supports my theory. I am willing to bet that the steep louvers in front are ducted from the radiator allowing mass airflow... so there is minimal pressure in the engine bay because of this, and then behind that ducting they use the venturi louvers to pull air out above the intake manifold to reduce pressure under the car and reduce underhood temps.

maybe???

There is this hood on some of the 370z in Japan racing:
http://www.zclub.com.au/forums/uploa...497_200046.jpg
http://www.zclub.com.au/forums/uploa...497_331605.jpg
http://www.zclub.com.au/forums/uploa...497_234608.jpg

I'd also assume there's ducting under the hood to make full use of all of those vents.

and I wouldnt be surprised to see those front NACA ducts possibly headed straight to the exhaust manifolds to help them get fresh airflow cooling even though that air will just end up under the car.

Doing more digging on those hoods from Japan. Here is the best underside shot:
http://stat.ameba.jp/user_images/201...2743489338.jpg

Go for it. So far, I've seen no true experts respond. A few with some very good practical knowledge, but no PhDs. I was an Instrument Tech many years ago and have some familiarity with gas flow but I'm certainly no expert. If we can test your theories, we'll see how good of a guesser you are. :)

lol funny you mention this.

There's a few mounting holes on the tranny tunnel near the shifter area that blow air up into my forearm at speed. Freaked me the **** out the first few times I drove it at speed hahaha.