Rad modifications?

[Howitzer]

What are the best ways of making a radiator more efficient?

My 500E has very little room and can happily run at 110°C without any problems but feels better running at between 80°C and 90°C. Pick up etc all better from a standstill and mainly, nicer for me as i'm always a bit dubious of it getting so high. It is pretty much designed to run at 98°C with the air-con on at all times but can take a while to recover to normal running temps after slow uphill drives or long periods in high temps.

So, I understand that sending my rad off to have a copy made from ali should give me better cooling, but is this guaranteed due to the material or is this generally because it has a greater capacity etc?

I wont be making any changes at all mechanically, still want to keep my viscous fan and air con rads etc all in the standard positions so want to know i'll get the benefits if I ask for an exact copy to be made.

Dave!

[Howitzer]

The fan is fully ducted and is working correctly as far as I can tell, I tested it engaging and it does.

It has 2 electric fans, one comes on at 98degrees, the other not till 105 degrees, these were both artificially lowered by fitting a resistor in paralell, a comoon mod to help low speed temps. With both fans going it sounds like a jet engine is stored under the bonnet but this has only happened a few times. 1 fan runs at low speed while the air-con is running and this is when I see it sit at 98 degrees when speeds are around the 30mph mark.

The price of a new radiator not far off the price of a custom one I had specced for a project of mine, but if it works better than the original i'm not so sure. Normally when i've seen someone have a custom rad made it is a larger size, greater volume etc.

This is the best picture I have of the front of the car where you can see any kind of fan, radiator assembly....



Dave!

[Howitzer]

leorest said:

I thought ali was used for race applications because it was a lot lighter than copper and the poorer conduction properties were compensated for with better design (bigger larger more etc). Not sure if a larger capacity ali rad saves you much weight though as waters weight is 1kg/liter.

IMHO best option is to fit a new standard rad, flush everything well and make sure everything is working as designed.

This was my fear about the ali rad.

Thanks for the help guys, new standard rad is looking like the best option then at the minute.

Dave!

[Howitzer]

GreenV8S said:

One advantage of a good alloy rad is that they are thinner for a given cooling capacity, which means that they have much less restriction on the air side. That might come in handy since you would seem to be short of air flow. I can't figure out why though, since this problem seems to be self inflicted. From your description you have fans capable of delivering ample air flow but chose to set them up so that they don't come on under the conditions where you want improved cooling.

In normal running, the air con fan comes on at 98°C, this is on low speed, at 105°C the second fan kicks in at low speed again, then when it hits 115°C they both go up to full.

I've dropped it so the fans come in at a lower temp to stop it going past 100 preferably, as when it gets past that you really need to be doing about 60mph for it to get back to less than 100.

Sadly there isn't any space without removing the cowling to put puller fans in.

I will enquire about the ali rad though, I didn't know they were more efficient for the same cooling power.

Dave!

[Howitzer]

SprintV8 said:

Is there a fan on the engine on this.

Sure the front fans are to aid cooling when it's getting to hot with the air con on.

Yeah I have a mechanically driven fan on the engine, it really does drag a fair amount of air through when spinning at 2000rpm plus.

Dave!

[Howitzer]

The car itself will stay completely standard in all other ways, also, dark car, black leather, air con is REALLY needed haha.

It does run noticeably warmer, especially on a run with the air con running, although the peak temperature is no higher.

Dave!