Go big or go home

[jbcollier]

The first rad I fitted was an aluminum rad from the group buy oh so many years ago.  It worked well until I hooked up the AC.  It still worked pretty well but it somewhat hesitated to cool down on really hot days.  Then temp stopped climbing once the rad fan came on full but it pretty much held it steady until road speeds picked up again.

Here’s what the set up looked like:

https://jbcollier.smugmug.com/Lotus-Europa/i-wS2KWM4/A

Pretty cosy in there.  Also, when the rad fan is on, some hot air goes sideways and heats the air in the plenum.  Not a huge deal; but noticeable.

So I was trolling through the Kelvedon website and spotted this item:

https://kelvedonlotus.co.uk/product/race-radiator-and-fan/

I enquired and got them to send me some photos.  It looked very nice indeed.  Peace of mind being precious above all, I took the plunge and ordered it.  It arrived quickly and looked even better in the flesh.  Bonus, it had a puller fan.

Here’s the two rads compared:

https://jbcollier.smugmug.com/Lotus-Europa/i-xmK8dBz/A

Getting the old one out was no mean feat:

https://jbcollier.smugmug.com/Lotus-Europa/i-k2sT2FG/A

As you can see, it is larger all round:

https://jbcollier.smugmug.com/Lotus-Europa/i-KVgkB5h/A

The puller fan makes a huge difference.  Much more red hot air coming through and none bleeding into the plenum:

https://jbcollier.smugmug.com/Lotus-Europa/i-924R9FQ/A

So far, so good but it’s early days yet.  I’m off to the Squamish B.C. Sunday week and we’ll see how much a difference it makes.

[BDA]

Very interesting, JB! That is a huge radiator! If it's too hot for that radiator, you are already dead and by now,  you've apparently made some serious mistakes in your life!

Good luck on your trip!

[dakazman]

Wow , You certainly went big.👍👍😀

 Very nice install .  I have been thinking about that since meeting Literymadness in Jupiter. He had a puller fan also installed and mentioned it ran cooler. It’s not like we race these a have to worry about cooling the brakes.
Dakazman

[BDA]

I looked up what Jensen Motors did for their racing Twin Cam wrt radiators. They didn't do that much:

Water Cooling
The standard radiator in conjunction with the engine oil coolers used was found to be adequate even when racing in ambient temperature as high as l15°F.
The electric fan was discarded and aluminum ducting fabricated to divert all airflow through the radiator. Aluminum tubing was substituted for the steel water tubes running through the chassis backbone. The 15 psi pressurized system-utilized an expansion tank and 50 percent Ethylene Glycol coolant with inhibitors. The system was filled through a threaded cap in the thermostat housing. The-capillary type temperature gauge sensing bulb was mounted in the top radiator tank. Care must be taken to ensure all air is evacuated from the system.

So the stock cooling system isn't as bad as we sometimes like to think.

[jbcollier]

True that but they didn't race in rush hour traffic with the AC on ;-)

[literarymadness]

When I first specced out my radiator, Ron from Ron Davis Racing Products http://www.rondavisradiators.com/
gave me a choice between a pusher and a puller fan.  And because of the unique location of the radiator in the Lotus, also a choice between which side of the radiator the fan would be mounted. Ron's expertise is desert racing. Both Ron and Steve from Twin Cam Racing in Sarasota, Fl (who was doing the install) both agreed while there was nothing wrong with the original set up, that a puller fan would be more efficient than a pusher. My decision to mount the fan on the wheel well  side was again to keep the plenum area maximum cooled. The cost was the same, so if I could improve the cooling system even a little, Why Not! After struggling before to keep, my water temperature down below a 100 degrees celsius on mid-90s South Florida summer days, she stays right at about 87 degrees on the hottest day. 

[BDA]

True that but they didn't race in rush hour traffic with the AC on ;-)

I certainly didn't mean to imply that the stock - or nearly stock - cooling system would be at all sufficient for your purposes. I meant it as evidence for D'man that serious modifications are really not needed for most of us.

Speaking of keeping the plenum cooler, I had a conversation with a guy at LOG a few years ago who said he was able to achieve similar goals by mounting a sheet metal "baffle" that covered the radiator except for where the fan is. He also claimed that his car ran cooler too.

As for using a puller fan instead of the standard push orientation, I missed the benefits of that completely. It seems like another good idea that I missed! Good for you guys!

[jbcollier]

No criticism implied or taken.  Racers go fast and get good air flow across the rad.  No need for fans.

A pusher fan pushes air against the rad.  Not all goes through.  It can escape out the sides needlessly heating the plenum and bypassing the rad.

A puller fan sucks air through the rad.  Properly housed, a puller is much more efficient.

This is especially true with an AC condenser fitted as air being pushed through the condenser makes for even more air evading the rad.

With the original set up, when the fan came on, you could feel a gentle flow of hot air out the rear of the rad.  Now, it burns your hand.

[BDA]

Your puller fan gave a bigger improvement than I would have expected! Great deal! 

[literarymadness]

Back atcha BDA    Your one of my fav's on the forum.

I posted this previously on another thread but here is what the back of my radiator looks like in the wheel well. I also have a switch under the dash to shut the fan on or off.

 

[BDA]

Thanks 'madness!

Your and JB's pull fan seem to be the trick. Before this thread, I don't believe I've ever heard of anybody doing that. Kudos to both of you for a very nice improvement!

[GavinT]

That looks really good, JB.

I wondered if the fan might be exposed to more water in the wheel well, but perhaps they’re sealed sufficiently anyway?

[jbcollier]

Some are, some aren't.  They need to be either completely sealed, or have the vent facing down.

[dakazman]

True that but they didn't race in rush hour traffic with the AC on ;-)

   I only brought up the heating up the brakes from most articles written by experts bashing the design of the Europa. I also think I saw a glimpse of the jay Leno/ garage build where they vented the radiator thru a hole in the bonnet. It was nice but not an Europa.
   Shrouding the fan increase its efficiency. I can safely vouch for that after removing the shroud on the vette after dropping in the zz4 motor with a serpentine belt that runs the fan anti-clockwise. So that is another study to look into. The car with A/C on ran hotter in traffic unshrouded. It’s now on my list of jobs to do is reinstall it but it needed the fan cut and recut to fit inside shroud. It also makes installing the fan nearly impossible . Sorry for the rant.
Dakazman

[literarymadness]

dakazman: That's why I had the on/off switch installed, so that at high speeds, I can shut the fan off if I want to. You are getting enough air from the front naturally, so at high speeds, the fan isn't necessary and with it off--no extra heat on the brakes. But with stop and go traffic, the brakes aren't being taxed, so the fan is stays on.  You are correct; the shroud is very efficient. Pfreen's Europa (the other one you saw in Jupiter) has a shroud with twin Spal fans.  He has A/C and his car runs very cool.  Our temperatures are about the same.  You saw his car; it's pretty amazing--all of the functional changes he has made.