That hood is Not anything like a real C5 R hood. it bares no resemblance to the vacuum processed Real C5R hood. its a replica. but it has no closed cowl area like a real C5R hood.
I suspect that hood is a hand lay up hood incapable of anything close to 180 mph.
A real C5R hood. note the cowl area is closed and not raised, the extractor is almost twice as wide and missing the center line aero vents and the placement and design of the out board vents are no where near the same design.



I mean no disrespect to you , but to say its the same hood used on a C5 R is just not true, it bares a slight resemblance but that's about it.

 

I want you to know that my suggestion here has no basis in fact, and without testing that hood I do not know how effective heat extraction would be. The OP feels his real world experience with this hood is a plus for him. as far as a factory hood, the hood itself is super strong, but if the hood is not aligned properly, air can lift the front of the hood creating an exponential ( ever increasing ) air scoop... to run at those speeds, proper alignment is very critical. A factory alignment of the hood is not always optimized from the factory. High speed applications require body tuning. if you notice we took two degrees off the rear fascia to reduce drag in an effort to resolve the gas guzzler tax. You wont read that in any book but look closely at the fascia, it doesn't look like a spoiler which is only designed to increase down force but at the expense of increasing drag. we dropped the fascia 2 degrees to reduce drag. People add a spoiler for the " Look" and never go over 80 mph, then wonder why they cant get 32 mpg on the highway. the 2 degrees came out of the wind tunnel body tuning.

 

Well ET, you're probably right, but until somebody comes up with a better hood, I'll stick with this one. Incidently, this hood has been in excess of 170 mph without a flinch.

 

If they testet. Then i wonder how.
I grilled my C5 by hunting up the swiss alps. i was driving behind a lotus elise (original) and two original 300zx nissans. they didnt drive away but my engineoil hits really fast the 130°C and so did my automatic transmission. On about 10°C Ambient temperature. And the other cars had really no problems with temperature.

Sorry the original cooling equippent of the C5 is far to low for her performance.
The one in the C6 may be better.

mfG René

 

And yet people cry when they raise the price tag... champagne on a beer budget it seems.

People want everything but not pay for it.

SAE stick together, keep at er E.T.

 

This thread was started with a title Hood aerodynamics and cooling.
I think the search and spirit of this thread is to find a hood that is capable of 180/200 mph. But not only capable of aerodynamic integrity, but in heat extraction. AS we all know more horse power can be pulled at cooler temps. At these speeds north of 180F, internal combustion temps and engine oil are being pushed to the limit. Even with external oil coolers these LSX motors are seeing 250/260 F oil temps. These engine can take a lot of heat, in fact they were designed around a high heat base. The question here is can you increase the aero ( reduce drag ) over the stock hood by enough to make it worth it.
Can you add an extractor that wont increase drag enough to offset any decrease in engine cooling. lets just say you can reduce engine temp by 20 degrees, potential hp gain would be roughly 3.6 Hp using the formula for corrected dyno numbers. Now if you increase drag by adding an extractor ( drag will reduce some of the gain ( 3.6 hp ) . the question is, will 2 horse power be enough to be more competitive than the guy you are chasing, or enough to keep the guy chasing you in your rear view mirror. Of course , everything you do in a positive manner, makes you more competitive. I'm just not sure , for most of the people in this forum, seeking a professional competitive edge, I think most would be chasing ghosts. Meaning, At what level of competition are you chasing. the difference we are talking here could be the difference in weight of one competitor over another , or the amount of fuel in the tank.
Just some discussion here, and some food for thought.

 

So using some 6" wide by 13" long vents, starting at about the 1/3 point coming from the front and installed in the middle of the silver stripes on my Z16 hood, will help with some heat extraction as well as possibly offsetting some potential lift issues at 180+mph? (Former owner says the real Z16 cf hood was damaged and what I have on the car is fg).

Just wanting to clarify here, as well as any potential negatives. I know that to really be sure of facts would take more $ in testing and time that I am not willing to spend, but it sounds as if the benefit may be worth doing for me if indeed it can drop underwood temps 20 degrees and remove some air wanting to make that hood not stay in place.

Just wanting to make sure what I'm hearing here.

 

I have an MCM hood like the one pictured,,,it seems removing the screen from the opening would reduce resistance for hot air to escape / be sucked out (scavenged)? What's your opinion ET? Any benefit or downside to removing screen?

 

Very poor information? It's pretty hard to miss the hood flapping on the freeway.

The hood might be able to hold up to 150+ mph pulls in milford, but why does it flap at 70mph?

 

I run my car every year in an 90 mile open road race with a target speed of 150 miles per hour average over the 90 miles and an maximum speed of 165 miles per hour at any given point along the course.

As far as aero goes my car is a bone stock coupe (not Z06).

Each time I've run this race I've noted a perceivable, and increasing with increasing MPH, "lightening" of the steering wheel once the car reaches around 125 mph. At 150 it's actually a bit un-nerving and variations in the road surface tend to exaggerate the feel (at least to me).

Other C5 racers I've spoken with quote the belief of air build-up as something they saw back in 98/99 when the 5's were brand new.

Does anyone else have experience with a "vented" (for heat or air-pressure or both) hood in this type of situation?

thanks all...

 

I've done quite a few top end pulls and noticed after installing the MCM extractor hood the front end seems to plant down above 120 mph.