Moving radiator to the rear?

[bert knip]

I am thinking of moving the radiator to the rear of the car.
When you put the radiator in the back, you will also suck air from around the engine, which should be good.
Advantage would be that the front compartment can be totaly used for luggage.
The rear luggage thing is not really usefull as it gets warm, due to the engine.
Also makes engine easier to acces
Advantage would also be weight reduction, because you do not need the pipes running through the chassis.
Has anyone already done this? Or does volantary quarantine make s me think to much?
Just curious

[jbcollier]

It's not a good idea.  Air flow recirculation is already a huge problem in the rear compartment with some areas have an air temp a good twenty degrees above ambient.

[Sandyman]

I agree with JB. If you look at the air flow it enters the back of the car and exits out the trunk lid. This area is also in a slight vacuum. The other minus is the change to the balance of the car. Lighter front could get very light at higher speeds.

[BDA]

What JB said. The cooling system is not over designed in the first place. Putting a radiator somewhere other than in a cool stream of air would require a large one. Besides the fact there is less air to go through a radiator if it's in the rear, the main flow is up through the vents in the boot and thus warmer.

I know this first hand. My oil cooler is vented out the rear of the car and the flow out of that duct in not strong but rather ambiguous (it seemed like a good idea at the time).

[bert knip]

I would think, when you remove the rear luggage tray, and put a radiator maybe with 2 fans, it would greatly improve the flow in the engine compartiment.
But I was just curious if someone has tried it.
As to weight distribution, I could consider to put the battery in front, but I do not think that the weight of th aluminum radiator will make a big difference.
As for the pipes , they run from back to front, so no weight disturbtion,

To BDA, I agree when you dont force the air through the engine compartment, probably like your oilcooler it will not work.
When you would put a fan on your cooler it will improve drasticly

My first car 45 years ago was a mini cooper, it had the radiator sideways, so no actual drivingwind going through, but engine itself was in the front catching some wind

[jbcollier]

Here's how the air flow works in a Europa S1/2.

Air flows in forward of the rear wheel, through where the radius arms work.  It then flows up, about the engine and exits out the vents in the cover.  That's all good.  Here's where it gets bad.  It flows back over the rear and a good portion of it flows back in through the open grill at the back.  Don't believe me?  Look at the back of a Europa after a run.  It's coated with exhaust residue.  Air recirculation and resulting heat build up is a major problem.  The intake air on a TC is a good 20° hotter than ambient.  There is a reason Lotus covered up the rear opening in the TC/S.  It helps but doesn't cure the problem.

What is needed are positive displacement air scoops.  The 47's NACA ducts don't really flow that much air.  You only have to look at later mid-engined vehicles to see that they are now festooned with such scoops.  The problem is that they would radically alter the Europa's clean lines.

So, everything you can do to get heat out of the rear area and vented elsewhere is well worth the effort.

[bert knip]

I do believe you,  but also think when you have serious fans, you could force the flow to get different.
Sucking in the air from under the car, blowing it out trough the radiator and the back vent (I have a  S2)
But I will rely on the expertise of this forum, like I said, just wondered if anyone tried

[BDA]

To BDA, I agree when you dont force the air through the engine compartment, probably like your oilcooler it will not work.
When you would put a fan on your cooler it will improve drasticly

Yeah, I thought about that but the truth is that I don't really need an oil cooler so I've left it the way it is.

Using fans makes it possible but I think the stock location or in the extreme where you have a radiator that exhausts out a big duct in the bonnet (a la Lotus Supplies ducted bonnet https://www.lotus-supplies.com/parts/bodywork/panels-bodywork/bonnet-ducted-isophthalic-47r-62s/ which for most of us isn't really necessary) is a better solution.

[EuropaTC]

I do believe you,  but also think when you have serious fans, you could force the flow to get different.
Sucking in the air from under the car, blowing it out trough the radiator and the back vent (I have a  S2)
But I will rely on the expertise of this forum, like I said, just wondered if anyone tried

The Hillman Imp in the UK had a rear mounted engine and radiator. The main problem was dirt being thrown up from the wheels but otherwise it worked ok in standard form and even for moderate tuning.   From what I remember, when the temperature gauge rose I'd either cooked the head gasket or the radiator needed cleaning !

If you're aiming to suck air from underneath with large fans then I'd imagine you'll have the same issues.

Apart from the other comments on here I'd look at paths already trodden.  IIRC the Imp racing boys used to move it to the front to get better airflow and most other manufacturers push the radiator at the front. The air flow gets clean air and there's a better ram effect.  Think about it - if a rear rad would work as well, Lotus could easily have done the same with the Elise and then had a small but usable front luggage compartment.  But the rad is at the front and the front of the car is useless for storing anything other than paperclips.

Having said all that, I'd encourage you to keep thinking outside the box, more folks ought to do so.   Not everything Lotus did was perfect, it was mostly dictated by the period so new ideas are always welcome.   

Blue sky thinking and discussions make everyone question the status quo, and that's a good thing.

Brian

[bert knip]

Thank you Brian, that is useful information.
Had not thought about the getting dirty part.
I was also thinking of making a vent through the chassis, so that Ram air reaches the engine, but thinking is not doing it right away!
But I agree discussions can be fun and sometimes helpfull
Bert

[jbcollier]

Flowing air through the chassis is a good idea and it moves a lot of air, but -- damn, why is there always a but -- it significantly reduces front plenum pressure which reduces flow through both the rad and the heat/ventilation system.  There are ways around this.  You could duct the existing front rad with smaller ducts for the air through the chassis and the ventilation.  Varying the duct sizes would control the amount of air flow each system received.  The only down side being that it would introduce significant amounts of moisture into the chassis if you drove on rainy days.