Better Engine Cooling. Aerodynamic principles.

[Leo B]

When the water circulation and the radiator are in order, think about how the air intake for the cooler works at the moment. Due to the vortex, only part of the cooling air reaches the radiator. If you put a non-rotating electric fan in front of this, the surface area will decrease even more. What about the possible license plate in front? Before you install other solutions, this thing is important and you also need to understand how the air flows and what is underpressure and overpressure. The solution can be done reasonably easily. I drew the plan to Stude Avanti as an attachment.
Thanks to aerodynamic engineer Eric Ahlstrom and George Smith.
Read more https://nasaspeed.news/tech/engine/rocket-science-achieving-better-engine-cooling-with-proper-aerodynamic-principles/

Edited October 17, 2023 by Leo B

[ronmanfredi]

That was a really cool article and makes all the sense in the world.  I recently removed the stock fan, leaking clutch, fan shroud and installed an electric fan with it's shroud.  I also replaced the old 67 amp alternator with a 125 amp one to cover the fan motor draw.  Now, when the fan comes on, you can feel the air flow coming out of the rear of the front fender on both sides.  Air flow has increased quite a bit. 

 

[Dwight FitzSimons]

Cool!

--Dwight

[tanda62]

Very interesting article and nice drawings for the Avanti.

Romanfredi - what fan did you install? I will be going the electric fan route myself and it looks like you found one that fits nicely. Thanks

Tom

[ronmanfredi]

4 hours ago, tanda62 said:

Very interesting article and nice drawings for the Avanti.

Romanfredi - what fan did you install? I will be going the electric fan route myself and it looks like you found one that fits nicely. Thanks

Tom

I did a LOT of research before buying this and it works really good. Fan assembly is Flex-a-lite #180. Control kit is Flex-a-lite 31165. The control kit is their heavy duty model and more expensive which includes a hard wired water temp sensor you can put in the thermostat housing or intake manifold. It also turns on all the time when the A/C is on, plus the fan starts up slow and then ramps up to max speed. The fan draws 18 amps at max speed, so I went ahead and replace the stock GM 67 amp alternator with a 125 amp PowerMaster 7127 alternator off Amazon. You can get the fan with their stock control unit but the reviews on it are not good. I called Flex-a-lite about that and they highly recommended getting the unit that I bought. You can also set the fan "on temperature" on the controller. Best price on the fan/controller is Summit Racing.

[tanda62]

Thank you for the great write up on the fan. I have a Holley Sniper EFI unit so I will compare how it controls the fan vs the Flex a lite unit.

Thanks again, Tom 

[Footer]

What did you use for a shroud?

[Leo B]

1 hour ago, Footer said:

What did you use for a shroud?

If you mean my drawing, I will do first measuring and testing. This will happens next spring. Im working now with desktop and interior.

[ronmanfredi]

2 hours ago, Footer said:

What did you use for a shroud?

If you are asking about the Flex-a-lite fan, it comes with the shroud and universal mounting brackets

 

[Kodjo]

It looks a lot smarter than an air dam!

Did anybody try this?

[Leo B]

20 hours ago, Kodjo said:

It looks a lot smarter than an air dam!

Did anybody try this?

If you ment this... The Air Dam is for a different purpose than the solution I drew and linked. The purpose of the Air Dam is to create a negative pressure under the car. My drawing and link presentation directs the flow better to the radiator.
If I have time, I will built this kind of solution. Before that lot to do.
BTW. Air Dam / Spoiler might also act as an air guide for the radiator if it's in the very front and directs air to the radiator as well. I personally don't like the way it looks in the Avanti.

Edited November 21, 2023 by Leo B
edit

[Kodjo]

6 hours ago, Leo B said:

If you ment this... The Air Dam is for a different purpose than the solution I drew and linked. The purpose of the Air Dam is to create a negative pressure under the car. My drawing and link presentation directs the flow better to the radiator.
If I have time, I will built this kind of solution. Before that lot to do.
BTW. Air Dam / Spoiler might also act as an air guide for the radiator if it's in the very front and directs air to the radiator as well. I personally don't like the way it looks in the Avanti.

I ment the solution you drew in the start post. I understand the function of the air dam. Both solutions increase airflow true the engine bay. But, if I had to choose one, it would be your suggestion and keeping the original design of the car. Combining the two would be the coolest solution 🙂

 

[Leo B]

13 hours ago, Kodjo said:

I ment the solution you drew in the start post. I understand the function of the air dam. Both solutions increase airflow true the engine bay. But, if I had to choose one, it would be your suggestion and keeping the original design of the car. Combining the two would be the coolest solution 🙂

 

👍 That's exactly what I think myself. I don't want to change the appearance, but improve the air flow to the radiator. Another thing that interests me is the so-called belly pan/undertray to avoid vortex under engine and gearbox.  Undertray creates a negative pressure under the engine and increases the flow from the radiator and the engine bay.
I need to buy this book: Modifying the Aerodynamics of Your Road Car written by Julian Edgar to understand more.

Edited November 22, 2023 by Leo B

[ronmanfredi]

One of the things that I noticed when adding the electric fan assembly as shown previously, was that when parked and the fan is running, I feel a constant blast of hot air hitting the floor behind each tire.  The air is coming through the radiator, across the top/sides of the engine and then downwards behind the front tires.  My 82 doesn't have the holes drilled into the upper inner fender like older models did.

 

[Geoff]

So I'll be going, oh let's just be accurate, "totally nuts" with my build. Here are some of the mods I will be doing:

Air extracting elements in the hood and front fenders
A skid plate (if I can fit one under the engine bay)
A belly pan
A rear diffuser
I'd love to recreate the 20th anniversary car's front fascia/bumper

Some of those necessitate other changes which I will make, and there are more changes I will make to my car. The preceding added to say, I don't mind doing exactly as your illustration shows, blocking space behind the fascia, especially if it means smoothing the incoming air.

[Leo B]

Recommended for anyone interested in aerodynamics and how the flow goes in the front of the car.

https://www.youtube.com/watch?v=MCXhU0IeyTg&t=485s

[Leo B]

4 hours ago, ronmanfredi said:

One of the things that I noticed when adding the electric fan assembly as shown previously, was that when parked and the fan is running, I feel a constant blast of hot air hitting the floor behind each tire.  The air is coming through the radiator, across the top/sides of the engine and then downwards behind the front tires.  My 82 doesn't have the holes drilled into the upper inner fender like older models did.

 

A negative pressure is also created in the wheel housing while driving and it "sucks" in air from the engine room and improves the flow through the radiator. I think that there is turbulence/vortex inside the wheel housing, so probably not quite optimal flow.

Edited November 23, 2023 by Leo B
adding text