333pg333

Derek, you're right in that of course I can't see it at speed, but with a vented nose panel I'm confidant that what would normally be a stall zone (nose panel) is now acting correctly as a draw through with the hood vents...however this is all conjecture. As Adam points out...maybe an easy test is to try some wool tied to the louvres. The only thing that I think could prove inconclusive is that the wool would just get caught along with the overall air going up the bonnet due to forward movement. Worth a try nonetheless.

Duke, I also think that it should help with underhood temps, both at speed and rest. I think it will help dispel heat which can in turn become heat soak. Guess some sensors or maybe even a thermometer and swap hoods might be a basic test.

gt37vgt

tape the wool to the bonnet in front of the vent then thread it in to the vent so there is an inch or so off wool in the vent just a tail.. think you will find the tail is sucked out and on the top of the vent after a blast ..

Duke

It should help with underhood temps a bit, but I don't think the difference will be huge. But heat shields in the right places + vented hood = good stuff!

DrZ1

IC I was thinking getting the underhood temps down would help put less load on the cooling exchangers, but really all that is needed is to pull the hot air from behind them.

Would side venting of the hood in the same low pressure area as the center venting , have the similar effectiveness? Assuming the surface area's were similar? Or does the vent need to be directly behind the radiator?

I had thought about a 968 ducting style.


Steve

DDP

I hear you, Patrick. At this point, we're really all guessing. I just think my guess is way smarter than yours. lol.

alpinewhite951

If you removed the weather strip from the cowl area at the back of the engine compartment, would it allow hot air to flow out and over the windshield and reduce the amount of air going under the car? I know it is a small opening, but if it would work, maybe there would be a way to increase the opening to allow more hot air to flow out.

George D

Oh and they're made of some resinous material, not plastic Adam. [/QUOTE]

The original post didn't ask why some of us installed hood vents. If you are using the factory intercooler location, and factory ducting behind the factory intecooler, factory belly pan and batwing, hood vents are probably just cosmetic.

We used hood vents because I now have two oil coolers, one thermostat controlled fan driven, and one static next to my intercooler on each side mounted at an angle pointing slightly up towards the hood behind the factory bumper. We have a vented metal belly pan that was designed for this application, not the factory plastic piece. My intercooler is front mounted, and we are using a much larger radiator.

We custom built a new bumper with venting designed into the bumper for additional air flow and strength. We will be opening the front bumper cover to add flow to the intercooler, radiator, and both oil coolers where we feel will provide the best results for this particular application.

We also added custom heat shielding everywhere necessary in addition to all factory heat shielding in the engine bay. We also designed the 4" intake pipe to house the intake inside the driver fender behind the inside plastic cover. Wanted intake air out of the hot engine bay. We had to use fixed light buckets to allow this modification to work properly.

Venting the hood was part of the overall design to allow all this extra heat generated from the front of my car to flow out of the engine bay as best we could design based on what we had to work with.

These vents were reinforced with CF on the back side by us, as they didn't come this way. We wanted the hood vents to be as strong as the hood itself.

The D9 vent material is not plastic, and we talked with D9 extensively prior to just cutting vents into the hood. I don't particially like the look either way, but that was not the primary reason for venting the hood.

If you are using the factory intercooler location, the factory batwing and belly pan should be used in this application. I suppose some hood venting would help, but I've never had an issue with cooling with my 951's using the factory intercooler location. This includes a 2.5 with 425whp. No heating issues, ever.

I've seen some really well designed intercooler venting setups for the stock located intercoolers. Something like the 968TS hood setup on a few cars I've seen were very well done, and I'm sure allows better intercooler performance.

Based on our calculations, I'll never agree that hood venting for my particular application and it's location won't help evacuate heat, idling or at speed. We know it will work well based on my particular application. The metal belly pan vents and the ducting as done for the intercooler and front mounted oil coolers would not work as designed without proper hood venting.

I was simply out of options when running the car at the HP and TQ levels I was seeing on a consistent basis. The car would run too hot during some hard runs. Turning down the power (boost) solved the heating issues, but that's not what I wanted from this ride.

The proof of our build will be known as soon as we get the car back on the road.

333pg333

Looking forward to seeing the results George. Can't be too far away I hope.

Techno Duck

I am going to do those D9 vents also. Not so much for underhood temps at speed, but to reduce the heat soak when idling or after coming off the track and sitting in staging. On some occasions if i shut the car off for 1-2 minutes prior to opening the hood, the hood latch is hot enough to burn my fingers. Not to mention the turbo water pump practically runs indefinitely. I figure i dont be that guy that feels the need to pop the hood on the car every time i park it to aid in cool down .

I am hoping between the hood vents and having the headers / crossover coated by Swaintech it will reduce the heat buildup. I practically cant even lean over the passenger side fender after shutting the car off due to the heat radiating from the headers.

333pg333

Good point Jon, although I don't mind being one of those guys who lifts the hood between runs either.

George D

Imagine summer temps into the low 100's with the asphalt close to 115 degrees. Most of the track stuff I do is in the winter, spring, or fall. Tried a track day at Firebird one August......110 degrees outside. With your helmet and proper driving clothes, you are soaked. I won't do any more summer runs here unless they change the rules and let me run my AC with the windows closed...LOL.

D9 vents are positioned properly. One over the turbo and the other over the headers. They do let the hot air out, and your AC, radiator, and intercooler will probably get more flow at speed. This does make our condensors work better, and keep the AC colder.

DrZ1

What about something similar to the 968 style open vent w/o the side NACA ducts. Something like the following link.

http://www.bing.com/images/search?q=...eec2857e32.jpg

It looks to be in the low pressure zone. And should vent alot of the hot air from the IC and radiator.

Would I need a raised lip around the vent to help w/ ventalation, or could it be flush mounted, w/ directional mesh if even necessary.

Thanks
Steve

Lemming

Steve, I've been looking at the following vent for the car I am preparing with an FMIC in front of the radiator. Can be purchased in both fiberglass and CF.

http://www.carbontrix.com/store/inde...roducts_id=159

http://www.carbontrix.com/store/inde...products_id=91

ehall

That will work. It's worth considering a way to create an exit duct.

LS1Porch

A small cowl on the hood would look pretty nice on these cars IMO. It would obviously need to be shielded from the air inlet for the heater/AC, but that wouldn't be too hard.