To the OP.....this mod is deffenitly a functional mod. Your use of the car will dictate how much "function" you get from the mod.

Go to the road race section are search hoods, downforce, louvered hoods ect.... There are lots of great threads from guys who race their cars. Who have "real world" experiance with this mod.

Thanks.....

 

What hood is recommended I thought about doing a carbon fiber hood with the louvers (or gills as I call them) on each side.

 

How well does that hood work in rain ? Does the engine take a shower ?

 

High cost and little or no benefit. For increased cooling a larger radiator and or oil cooler is a better course of action. If aerodynamic front-end lift is a problem for you, some duct tape over the screened air inlet louvers would prevent air from entering the under-hood area.

 

Another no value added post.

I HAVE a heat extractor hood and it WORKS.

 

ACP ( note NOT ACI ) saves about 12 lbs over normal hood

ACP = http://www.CorvetteRaceBodies.com


Web site has few pictures.

 

Agreed ^^^^^

ACP....makes real composite parts....for aircraft and vette panels also. He will build anything you ask....2 or 3 ply prepreg carbon with nomex core...the real stuff.

Thanks.....

 

Yup non of that fake weave. Comes primer gray over a very light weight epoxy resin. Ready for painting

 

No, not at all. In fact I was expecting quite a mess the first time I washed the car and after taking no special precautions at all it took just a couple seconds to wipe off the overflow and windshield washer tanks and that was it.

 

He is not fooling himself, he is speaking from experience, as will I.

The moment I put on the ACP hood my car ran cooler on the street.

Next.

 

Air that enters through those openings is channeled into the wheel wells. The source of pressure in this case is the bottom-feed cooling setup.

That said, even if there was ZERO airflow into the engine bay, the underhood pressure would be slightly higher because it's almost stagnant compared to the air above the hood.

 

Sorry but you either do not know what you are talking about or you unfamiliar with the air entry points on the Z06s. The air entering the brake cooling ducts is directed to the wheel wells. Radiator cooling air enters under the front bumper, is directed upwards by the center air dam into the cavity formed by the radiator shroud, it flows through the A/C condenser and radiator then enters the engine compartment and exits under the car. The air entering the screened inlet ducts enters the engine compartment outboard and above the radiator shroud cavity ending up in the space where the air cleaner housing is located.
Touting the aerodynamic and cooling characteristics of the C5-R hood design as a justification for purchasing a vented hood for the production car is one of the more ignorant comments I've read in this section.

As for me, I remain unconvinced that a vented hood on its own will provide the same benefit as a larger radiator and or oil cooler. Most people who autocross and participate in HPDEs that believe they need additional cooling go with a larger radiator and or oil cooler. I have both and have dropped by coolant and oil temepratures at the track significantly without the use of a vented hood. I sincerily doubt I would have gotten the same effect by just by installing a vented hood. As for the supposed increased downforce this hood provides, please produce the wind tunnel data (on a production Z06) that supports that claim.

 

Main reason for an air extractor hood, is aerodynamics. If your car runs a 4" front splitter with front under tray ( closes off the underside making your car a front breather) AND A 65" to 72" rear wing then YES you need an extractor hood, to prevent the parachute effect of the hood.

 

So which is it?

No impact, some impact, proven impact? Which position is your real position?

Perhaps you should call up the folks at ACP and tell them the product they sell (in your opinion) is useless rubbish

Do you have wind tunnel data that shows the vented hood offers no aeriodynamic advantage?

 

I can see where venting the top of the hood would have an effect under the conditions you describe. However, this is a far cry from the reported benefits in cooling and down force from just adding the vented hood to an otherwise unmodified production Z06.

 

Your original flipant dismissal of the hood was not qualified by any supporting condition:

I see your opinion is now tempered with "an otherwise unmodified production Z06".

Does this mean you now concead that the heat extractor hood is in fact a functional item?

 

Not as a stand alone modification on a production street vehicle. What AU N EGL described are some fairly radical aerodynamic modifications. The original discussion pertained to the suposed benefits of installing one of these hoods without the discussion of any race related aero modifications. One of the posters cited the C5-R as an example for its increased benefits. That was a ridiculous comparison.

My goal was to illustrate that if increased engine cooling and a little increased down force was the desired effect, there are much more effective and cheaper methods to achieve this on a street car that is used for either amateur autocross of HPDE type events.

Changing the location of the goal post mid discussion for the purpose of justifying a position serves no purpose other than maybe leading you to believe that I have somehow decided to ignore the facts and yield your point, no so.

You and every other corvette owner can choose to install whatever pointless modification you choose to purchase for your vehicles. This ignorance is what drives the majority of the aftermarket component sales. Sorry that you and several other posters have been offended my opinions of a mostly useless part, but don't shoot the messenger for pointing out the obvious.

 

I have no idea what I was thinking when I typed that, you are correct about the screens...although there is a Vararam on the C5Z sitting in the garage. I hope I haven't lessened my credibility.

Anyway, it seems like a radiator swap / oil coolers would make more of a difference than the hood as far as cooling...but it most definitely cools the engine compartment, which would improve the effectiveness of the heat exchangers you mentioned.

I myself have made a vented hood out of a spare, used for an event. The mirage coming out of the vents after a run was dramatic. Here is picture of that:




Here is a post where Jim Hall indicates a 20° temp reduction with his DRED hood: http://forums.corvetteforum.com/1578643414-post12.html

Another where he mentions "downforce": http://forums.corvetteforum.com/1578643414-post12.html

I will look for windtunnel data, I'm sure it exists.

 

http://forums.corvetteforum.com/pict...ictureid=70229

 

to get better cooling


1- clean out your radiator first.

2 - That should do it