What are cowl induction hoods good for?

[Guest bluex_v1]

I really want to get one of the wider, smoother contoured cowl induction hoods like Scottie-GNZ has, but that desire is purely based on looks, and I can't stomach the thought of spending money on something that doesn't have some real functional benefit. (I absolutely can not stand ornamental vents on cars)

I know the hood's opening would help exhaust the engine compartment when the fan is running when the vehicle is stopped in traffic and such, but what is its effectiveness at highway speeds?

I understand the transition from hood to the base of the windsheild is a high-pressure area at speed, so does this create a back flow into the engine compartment once the vehicle is moving at a high enough rate? If so, could this possibly add to front end instability at higher speeds because this additional air has to be exhausted out the bottom of the engine bay?

I was also thinking of just using the hood vent as my efi air intake. Has anyone done this yet? Any problems driving in the rain? Might there be the slightest bit of ram-air benefit? I'm sure it would be a pain to make a system that seals effectively for that, but man it would be neat.

Are there any other pros and cons to using the cowl hoods? (besides having to use hood pins )

[Guest Anonymous]

Because of carb or fuel plumbing the hood will not close without an extension ie: hood scoop. Nissan added those plastic lovered vents on the late 70's Z for cooling purposes to let hot air out

[Guest bluex_v1]

If everything goes right, I won't need the extra hood clearance with an efi 5.0.

Now, I have to admit near complete ignorance when it comes to airflow properties of the Z, but aren't the later Z vents far enough toward the front that they would actually be in a low pressure area where the flow has already split from the hood surface?

[CruxGNZ]

Blue,

Check out this link for Early Z Aerodynamics

 

!M!