New thought on cooling...

[MaineShark]

Alright, so the side vents are there to allow hot air from the engine compartment to escape.

But they are subject to the radiator fan, to accomplish that. And that fan is operating as a push fan, from their perspective... and one located a good distance away, at that. Not very efficient.

How about installing a fan inside the engine compartment, for each side vent? It would still be a push fan, but it would be located right there. It seems to me that would extract heat more efficiently. It would also reduce the backpressure on the radiator fan, allowing it to operate more efficiently, as we.

And, it would be possible to have a timer to run those small fans for a few minutes after the car is shut off, to reduce underhood temps (without killing the battery, like a large electric radiator fan would).

It would require some work, and some relocation of parts (there are some items that are close to the area where the vents open into, in the engine compartment). But it seems like it might help, particularly in getting that exhaust manifold heat out of the car.

Thoughts?

Joe

 

[Tom73]

Joe,
There is a product something like you describe on the market for C4s. Electric fans that exhaust the air out of the wheel wells.

The engine mounted fan has only one purpose, to pull air through the radiator. Where the air goes after that is a function of nature. It will build up a higher pressure in the engine compartment so will have to go somewhere. Most, probably 90% or more, will go out under the car. The rest will go out of gaps in the hood, fenders, and side vents. I really don't think a fan on those side vents would make much difference. Remember the 70-72 side vents were not even functional.

tom...

 

[Stallion]

Remember the 70-72 side vents were not even functional.

Really? I didn't even know that.

Joe, that sounds like a good idea in theory. Good luck with the cooling!

TR

 

[MaineShark]

Well, I'm basically thinking that it would extract exhaust heat, as the biggest benefit.

And, like I said, the smaller fans could be left running for a certain amount of time after the car is shut down, to reduce underhood temps, since that's the hottest time for the engine compartment.

I'm not sure exactly what would be involved. Some components would have to me relocated, and I'm not sure how that might affect the A/C system (right next to the passenger-side vent). I'm going to have to look it over.

I think it would be workable - I'm just not sure how much modification would be necessary, and whether it would blow too much dirt down the side of the car, near the vents.

If you ever blew a brake line at the master, I think you'd be able to kiss your driver's side paint goodbye. Of course, I think that's not a common thing to happen...

Joe

 

[biltogo]

72 side vents are functional. I can feel air moving out of them while the engine is idling.

 

[Stallion]

72 side vents are functional. I can feel air moving out of them while the engine is idling.

That sounds right. I can't imagine they wouldn't be useful. Even if just a little bit.

 

[biltogo]

You can get more air into the engine compartment by removing the A-arm covers.

 

[MaineShark]

You can get more air into the engine compartment by removing the A-arm covers.

I want to get air out of the engine compartment

Specifically, I think that moving air out the side vents would work well, since it would pull that hot air off the headers/manifolds and out of the engine compartment.

Joe

 

[Bob Chadwick]

I want to get air out of the engine compartment

Joe,

That is one of the posted problems with changing over to electric fans. The electric fans point down rather than back at the engine and do not move any of the hot air around the engine and under the hood out of the compartment.

I lost the pictures you sent me when my computer crashed and now have an electrical gremlin with the Vette so I am in no position to explore the use of your auxillary electric fan on my car. If you are getting rid of it for dirt cheap I would probably take it off your hands just to play with it later. Otherwise, I'll have to say no.

Thanks for the offer though.

Bob

 

[MaineShark]

That is one of the posted problems with changing over to electric fans. The electric fans point down rather than back at the engine and do not move any of the hot air around the engine and under the hood out of the compartment.

Yeah, I was thinking about that. I think that a piece of plastic between the lower radiator support and the front crossmember (or, partway to it, anyway) might be an interesting addition, to force the air over the engine (and keep the engine compartment cleaner, I'm sure.

If you are getting rid of it for dirt cheap I would probably take it off your hands just to play with it later. Otherwise, I'll have to say no.

Considering that it's used, and not in the greatest shape (functional, just not pretty)... pay shipping and it's yours. I'm not sure what shipping will cost, though, with the size. Probably $30 or so.

Joe

 

[Bob Chadwick]

Joe,

Tried to PM you but your mailbox is full. PM me your address and I'll send you a check.

Bob

 

[Bob Chadwick]

Yeah, I was thinking about that. I think that a piece of plastic between the lower radiator support and the front crossmember (or, partway to it, anyway) might be an interesting addition, to force the air over the engine (and keep the engine compartment cleaner, I'm sure.

I was wondering what it would take to mount these things perpendicular to the ground but if you did so the bottom would be away from the radiator and you would be back into the shroud issue all over again.

 

[biltogo]

I want to get air out of the engine compartment

Specifically, I think that moving air out the side vents would work well, since it would pull that hot air off the headers/manifolds and out of the engine compartment.

Joe

I understand, but by allowing more of cooler air to flow in, you'll push more air out. By putting fans at the vents, they'll only try to create a vacumm, (which of course they can't), so the fans will pull air out which is replaced by incoming air from the best available sources. Sooooo...forcing cool air in, creates addtional air pressure forcing heated air out, without the trials and tribulations of rigging the fans.

 

[greg454]

.
"Remember the 70-72 side vents were not even functional."
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Of course they are functional. I can look right through them and see my engine on my '72. Also I think I have read that the reason for the vents in the first place was not so much to let heat out of the engine compartment but to keep the front end from lifting so bad at speed. With that said, it's amazing how much heat pours out of them even at idle!.

 

[MaineShark]

I was wondering what it would take to mount these things perpendicular to the ground but if you did so the bottom would be away from the radiator and you would be back into the shroud issue all over again.

Plus, the fans will be most efficient when they are parallel to the radiator (perpendicular to the "chanels" formed by the fins). A big part of the poor cooling performance in C3's is the two bends that the air has to make to enter, and then leave, the core. Every bend slows the air, which reduced the overall mass airflow through the core. I'm looking into the deflector. It wouldn't be able to extend to both sides, but I think it could go partway across the center section, to force some air back up toward the engine.

I understand, but by allowing more of cooler air to flow in, you'll push more air out.

I have a feeling that the positive pressure created by the radiator fans would force air out through the suspension, rather than drawing air in.

By putting fans at the vents, they'll only try to create a vacumm, (which of course they can't), so the fans will pull air out which is replaced by incoming air from the best available sources.

The fans won't be able to create a true vacuum, but they will create a pressure differential, by lowering the local air pressure. Higher pressue air, aft of the radiator fans, will flow towards that area to replace the other air, flowing over the headers/manifolds, in the process.

Basically, the goal of putting the fans in the vents, (even compared to putting fans over the control-arm openings) would not be the quantity of air moved, but rather the direction of the airflow. Forcing more air in (with a more powerful radiator fan, or some other vent near the front) will end up sending much of that air out under the car. By putting the fans in the vents, it should draw air to that area, passing over the headers/manifolds in the process.

I am sort of curious about the control-arm covers. I think air will move out, but maybe not. I think I'm going to try popping one out, and seeing which way the air moves...

Joe