Coconut

I've seen many pics of the wind tunnel pressures for hood vents on the C6, but I thought that some may be interested in this pic for a C6 with the center vent for radiator heat.

Plano76vette

I am planning on running an mcm hood that has a vent like that!!!

Nice!

sothpaw2

Wow, there's an idea--has anyone tried that in lieu of an oil cooler? Just venting the hood might do a lot to reduce both water and oil.

Solofast

1. Don't assume that cutting a hole in the hood of a street car will do anything remotely similar to what you see here. The CFD model likely has ducting that DIRECTLY routes the air to the hood vent. Cutting a hole in your car won't do that at all.

2. This model also has a splitter in front and that changes things too.

3. There have been a number of threads on this subject, do a search and you will learn a lot more than seeing one picture.

AU N EGL

The radiator is leaning forward

69427

Looks like tri-Y headers on this thing. I'm amazed how often this setup seems to come and go. Anybody ever see a decent technical write-up comparing these to conventional headers?

Regarding the hood vent (on a street car), keep in mind of where the interior (cabin) fresh air supply comes from, and will it get "polluted" with the heated (and possibly baked-bug stinky air) output from the radiator.

Aardwolf

There was a huge thread in C4 tech about the tri-y's. There is a company that manufactures them for the C4. Some installed them and there was talk of their benefits.

With the cabin input air, I sealed that off on my track car. It's recirc all the time. I kept the blower for clearing the occasional fogged up window.

BrianCunningham

If you don't vent and duct it right, it will draw air in instead of letting it out.

0Anthony @ LGMotorsports

Bingo....hence why our hoods are designed the way they are.

Jason

*putting the drill down*

Kubs

I am plainning to put an old L88 style scoop on my C4 to clear the air cleaner setup (not L98). That particular style has a vent in front of the cowl. Will that provide any help venting or will it hinder me in the long run?

LG Motorsports

We have tested the Tri Y headers and we use them on our ALMS car with single Side pipes because they help keep the power band broader.
But when we did the testing on headers that go under the car, into a typical X pipe, there was no gain over the normal 4 into 1 headers with a Y pipe.

Knowing that, we decided that the extra cost involved for the Tri-Y headers was not worth the extra money spent.

AND unless you step the headers and plan out the angles on the Y pipe, 2 into 1 collectors, you can actually lose power.

Again for side pipes they work well.


as for the louvers?, they are amazing in the wind tunnel. The Grand Am car can not run them and the wind tunnel shows how dramatic the loss is from not having them.

All the air that goes into the radiator, can not leave through the bottom of the car, so it creates lift on the hood.

The louvers allow the air pressure to leave the engine compartment and not create lift on the hood.



Thanks

Lou G

AU N EGL

So Lou Grand-Am Car ? :

Care to share some info and of course PICs?

davidfarmer

EVEN I am getting tired of this topic........seems like we discuss it monthly.

Flaming the fire however, my JC Whitney Louvers did a great job reducing hood lift and extracting heat. Can't speak to any aero gain (no splitter anyway), but a good gain nonethless.

Pumba

I had Jack Burns of Burns Stainless do a header design for a 427 inch motor with a 244 intake - 264 exhaust - 117 degree LSA - .630 inch lift cam:

He suggested that the primaries be make of three pipes segments 9 inches long:

- The first segment was 1 3/4 inch tube.

- The second segment was 1 7/8 inch tube.

- The third segment was 2 inch tube.


For a collector, he recommended a merge-megaphone collector.

jabrun

From what I've heard it won't vent because right in front of the windshield is a high pressure area. That's why a lot of the older musclecars with rear facing scoops used them for induction to feed the carburator. '70 Chevelle SS, early Pontiac Trans Ams, some of the plastic bumpered mid seventies Stingrays etc.

RedLS1GTO

This is about as un-scientific as it gets, but I had an oil line come loose and blow onto the pass side header at speed on the track. before I got slowed down I got a really good look at the smoke flow coming out of the vent on the hood. I am not an expert but I have some background with aero engineering and design and would say that I know what I am talking about with basic aerodynamic principles. The smoke that I saw coming out had a pretty perfect looking laminar flow coming up and out of the vent that by the eyeball test suggested a decent amount of downforce. The difference between mine and the center hood vents are that mine get a lot of air draw from the wheel wells instead of under the hood. Just my $.02 that nobody asked for.

Nimo

A video on the same topic. I pinched a radiator hose while working on an oil cooler tube.
- Nice even spray at 7 secs in to the video - doing 80-100mph, before seeing it.
Who needs a wind-tunnel ?

And it does give a less favorable smell in the coupe, but not really an issue.

/Nik

probably need to select HD and go to youtube to see it well.

Kubs

I plan on building a structure under the hood scoop to make sure all entering air from the rear goes into the air cleaner and any air in the engine bay already should be forced out the vent. That was my thinking anyway.