So I already have an oil cooler on my '13 G37S sedan, but I am starting to think about hood/fender vents or a new hood with vents. I swear I saw someone on here with a sedan with fender vents and I would love to hear if they work and how much they cost to do.

I see some universal hood vents that I might be able to make work, but I would want to cover them up inside the hood somehow when not on track to keep water out of the engine. I am worried that hot air coming out of the hood may fog up the windshield on track. The other option is a Seibon carbon hood with built in vents, but I am not sure if I can cover those up when not in use to keep water out.

Would a different radiator be a more effective and cheaper solution to vents?

Let me know your thoughts/experience. Thanks!

 

I am of the personal belief (based purely on anecdotal evidence and speculation) that hood vents would make the most sense. While a radiator would provide improved efficiency and cooling, that hot air still has to go somewhere, so it makes sense (to me at least) to give it the easiest way out - up. If you have the vents in the first third of the hood (i.e., slightly after the radiator), aero forces should also suck air out of the engine bay.

It's also probably the cheapest to do.

 

Are you referring to the GT-R vents? I've seen one member add those. BP mentioned Radiator upgrade which is your next best bet for heat reduction.

 

I ordered some vented fenders to try and see what they do before I start on the hood (mainly because of the look I wanted, but also to see if it would vent any hot air). I agree the hood is the best and most logical area to vent. I was thinking of 3D printing up some actual exhaust vents that mimic the shape and look of the GTR vent, as I find them appealing. It should be noted that the actual GTR vents are intake ducts, not exhaust ports. An other idea was a strip vent near the back center of the hood, but I think addressing the area above the headers would be more advantageous. If I wasn't in limbo about this Whipple SC and what might need to be done to our hood to make it fit I would have pulled the trigger on some vents in the hood first, to be honest.

 

I am not sure if the radiator or vents would be more effective, but both would be good. The vents initially are cheaper than a new hood and a radiator, but by the time I get the hood cut up and the vents painted and installed I bet it will be close in price to the radiator.

I was thinking the same thing about the air travelling over the hood sucking the air out of the engine. It might even create a little downforce at speed and pull more air past the air filters, radiator, oil cooler, etc.

Now if I could just find some that you can close up when you are not on track...

No- GT-R vents are naca ducts that bring air into the engine bay to cool the turbos. I want vents that let air out of the engine.

When I mentioned a different radiator in the initial post I was unsure if that would be a better idea than vents. Both would probably be best, but maybe vents would be enough. Hmmm...

 

I agree about the vent near the back of the hood. Logically I would think that is where the most hot air would be trapped as it is up high and probably pushed to the back of the engine bay by air coming in from the grille. However, I would worry that the heat would get pushed onto the windshield and cause it to fog up.

Then again, old muscle cars used to have cowl induction at the back of the hood near the windshield based on the idea that air bouncing off the windshield would be forced back into that vent. I doubt that would work with a newer and more aerodynamic car though. Usually, when you see wind tunnel testing the air moves in a pretty straight line over the hood and windshield.

 

This is a pretty generic flow graph of a car - but the idea is similar.



There's usually a stagnant area right at the base of the hood - which is why it makes sense to use a cowl intake to draw air in from there. But if you're looking at flow velocity to draw air out of the engine bay, the first third is where you want to be for cooling vents. Incidentally, it's also the immediate path of exit of air being pushed through the radiator.

 

OP are you trying to stay cooler for the track? What are you trying to achieve?
The VVEL system on these cars make the engine run real hot but I have yet to see any kind of overheating unless your FI and running the track.

 

Also - as an FYI, fender vents do nothing for heat. They're to relieve pressure built up from the rotating tire within the fender. That's the other reason why you see the huge cutouts after the front and rear tires in the fenders.

 

I agree about vents toward the front of the hood to help pull air through the radiator better like I was talking about 2 posts up, but is that the best place to pull heat from the engine? It seems like the vents would be mostly in front of the engine and pulling the air from out of the radiator more than from above the engine. (I'm only asking because I do not know for sure)

Yes, for the track. As I mentioned in the 1st post, I would like to be able to close the vents up when not at the track, because the car will see more days on the street.

Without an oil cooler this car will overheat and go into limp mode pretty easily on track. The power steering overheats as well. The last time I was at Road America the engine bay got so hot that the Infiniti badge on the engine cover melted off and the radiator started spitting a bit of fluid. So yes, heat is definitely an issue on track with these cars.

Some cars do and some don't. There are many different fender vents. I have not looked inside our fenders close enough yet to see if I could get venting from the engine to help with the heat. If anyone has had success with this on our cars, please let me know.

 

I like the discussion! This is an area that's not really agreed upon, especially not with these cars. Anything helps.

I was looking at these - Large Angular Universal Hood Louvers - Hood Louvers - SHOP BY PART

Maybe instead of riveting them in, bolt them instead? That way you can make a blank plate out of a sheet or aluminum or something so you can just pop them out when you're not at the track?

I'm in socal, so these would probably be on 24/7 since I essentially don't get rain here, but for your purposes it may be a better idea.

 

I will take a closer look at the underside of the hood to see about airflow and location.

Are those louvers steel? I like the idea, but unbolting and rebolting something to an aluminum hood is a bad idea. Plus, the filler plates would look pretty ghetto.

I had a Subaru 2.5RS that had functional hood vents with plates on the back so you could open and close them. They even had a little drain hole so when it rained all the water would just go to one tiny area. Something like that would work well for my situation, but I am not sure how to go about it yet or if something like that even exists.

 

Hie thyself over to my370 board and peruse their track forum. All cooling issues have already been discovered and solutions discussed.

 

While the 370Z is essentially the same car and there are plenty of other resources online, there are still slight nuances between the platforms that can be discussed here. Just because I'm on miata.net, s2ki and the 370Z forums doesn't mean I can't replicate those discussions on this one.

 

Fender vents are typically for wheel well pressure relief but that doesn't mean you can't fabricate and route hoses so it also pulls air from the engine bay. I few stock cars came from the factory with air vents plumbed to the fender vents for just this reason. The RX-7's and RX-8's fender vents were used to vent air from their oil cooler, the BRZ/FRS has vent holes from the engine bay to their fender vents, the STi's vents also have plumbing from the engine bay routed to the fender vents.

Also, I have to agree with bPChaos, the chassis are similar but to give a blanket statement like that is bold in this situation i feel. I, out of curiosity, went over to the 370z site and went to the track forum and went 7 pages deep and found nothing useful on this subject; did a search of that forum and pulled up little as well. Does that mean it's not there? Nope. Does it mean the info found, once found, isn't useful? I'm sure it is. But it doesn't help this forum to say the answer for venting the G37's engine bay can be found on the 370z's track forum.