Engine Compartment Venting

[nemo]

[jime57]

Originally Posted by freebeard

I can't find a good illustration of where the Saturn ventilator opening are; but maybe this could help. A generic fiberglass hood scoop that feeds into a spoiler in front of the wipers. If the opening was mid-hood, tall and narrow with a low, wide exit and your exhaust vents were in the back corners of the hood... Just crazy enough that it might work?

Maybe, but I've always thought that that area, right at the base of the windshield, was a high pressure area. That is the theory behind using those kinds of hoods, that the high pressure "forces" air into air cleaners and carbs. I may be wrong?

I think that the outlet on the hood top has to be farther forward. It would probably be tricky to select the fore/aft position for such a top exit. One would need to look at the local pressures as aerohead suggested. And, Hucho suggests that the under hood vent work must be smooth to get any advantage. That requirement alone is a big stumpling stone on most front engine cars as there is a lot of stuff in the way

I wouldn't do something just at random. It is a tricky problem even for those who want to live with the disadvantages. I like to do aeromods, but I've been slow to act on this one.

[freebeard]

In the cold light of day, it wasn't the best idea I ever had. I was thinking of an external duct on top of the hood, like a snorkel, to separate the vented air from the cabin intake. It would probably interfere with the wipers.

Depending on where the optimally-positioned vent and the intakes are, maybe vertical fences on the back of the hood would suffice.

[arcosine]

I think I an going to put the gill slits back on.

[radioranger]

67 Mustang had vents right behind the front edge of the hood for cooling , they help a lot over earlier no venting models, might be a problem with water entering if further back also helped to kill some of the lift those cars were famous for.

[YeahPete]

I believe the idea is to vent it to a low pessure area to better fill the void. Is there any way you can get it vented behind the car? Maybe by running some sort of vent inside your already made belly pan to the back of the car? Maybe 2 vents running along the exhaust. Hm.. Would that put too much pressure on your belly pan? Can someone comment on my ideas please.

[ConnClark]

Originally Posted by jime57

But wasn't this primarily due to the different configurations at the rear of the two vehicles, and the amount of wake they created. The differences due to the ventioning of cooling air were minor by comparison. Did I miss something?

That information I gave was for arcosine as he wondered about the Cd difference between the two configurations.

[arcosine]

Testing showed no center turbulence improvement with venting through tire clearance holes.

Originally Posted by YeahPete

I believe the idea is to vent it to a low pessure area to better fill the void. Is there any way you can get it vented behind the car? Maybe by running some sort of vent inside your already made belly pan to the back of the car? Maybe 2 vents running along the exhaust. Hm.. Would that put too much pressure on your belly pan? Can someone comment on my ideas please.

Why not put the radiator in the rear, or the whole engine.

[freebeard]

Can someone comment on my ideas please.

Why not put the radiator in the rear, or the whole engine.

There is one (a good one too)—here's another: skin friction. A duct the length of the car would have to have a cross section some multiple of the vent area to move sufficient air.

[radioranger]

I believe the famous shneider cup racing airplanes of the thirties , at least some of them used the skin of the plane and evaporative cooling or something along those lines, I think a vent right behind the radiator with maybe a sheild for rain would probably be the best, like and old fashioned cowl vent as used on fifties cars only right behind the rear edge of the radiator or close to it, the air here is going up and pulling a vacumn on the front of the hood on most cars I would think and this allows a bit of air to fill that and kill some lift as well.