Where to fit an oil cooler?

[julians]

Where is the cooler fitted on those cars that have one, there doesent appear to be any space in front of the radiator, so I presume it goes behind it.

 

Any suggestions?

 

 

[Roger King]

The official position for the oil cooler is in front of the radiator on purpose made brackets.

 

This obviously reduces the cooling capacity of the water radiator and in my personal view is undesirable simply because water cooling can be marginal on a 7.

 

Our policy is to mount the oil cooler behind the water radiator. This reduces the efficiency of the oil cooler, but in most cases it is still adequate to reduce oil temperature to acceptable levels

[greg]

Roger,

 

I've a oil cooler infront of Rad thing, why would you favour cooling Water instead of Oil.

 

My car seems to stay arround 80c 90c in trafic, which seems Ok to me.

 

Q 990 RAE

[Red SLR]

Julian, let me know what results you get, I might need one as my oil temp got very high at Elvington about 2 or 3 times.

 

I would mount one behind the rad also, if needed could run a bit of duct to it.

 

Ur car back now for Saturday??

 

Simon.

 

X777CAT

[julians]

Simon ,What temp did you get?

 

My car is now sorted ready for saturday, how about yours?

 

 

[murph7355]

With K-series cars (road cars taken on track) there's a theory that getting the oil up to temp. and to stay there is the more tricky deal.

 

In traffic the water temp can rise pretty quickly in these cars so blocking off cooling capacity isn't ideal, hence putting the oil cooler behind the rad'. Not sure about other engines, and mode of use is likely to factor heavily but I'd imagine this situation to be similar.

 

I've opted for an oil/water heat exchanger instead of a typical oil cooler. This allows the oil to get up to temperature very quickly ( 50degC which I think is fairly quick) and maintains the oil temp at between 70degC-80degC [ish] when it's been running (hard) for a while. I was once told that this is a very nice temp for modern oils to operate at.

 

The other advantage it has is that you can put it more or less anywhere in the engine bay as it isn't reliant on airflow, just pipes for oil and water.

 

The disadvantages are that it's a bit heavier than a typical oil cooler (I think) and there is an argument that for best effect you really ought to keep the two systems separate to avoid one introducing heat into the other unnecessarily (which is a fair point, but with restricted air flow "slots" there's not much you can do short of having zero ground clearance or long pipe runs to the top of your roll bar [and a slot in the hood if you have one]).

 

One thing I have done to try and avoid the latter is to fit a big rad (ali' race spec' rad) which will hopefully keep water temps sensible more often (does this also give a bit of deformable crash structure at the front I wonder).

 

The jury's out at the moment as since having it fitted I've not taken the car in track. Nor have I subjected it to 30degC ambient temperatures in heavy traffic (the summer day has yet to arrive unless I missed it already). But it seems fine for "fast road use", such as you can get these days.

 

Towards the end of July I should be getting lots of intense track action and may even get hot weather to play with it. Only then will I definitely be able to tell that all the theories work properly. And only then if the rest of the upgraded engine hangs together smile.gif.

 

[Marius]

Last year fitted an oil-cooler to my 7 (modified VX), just behind the water-radiator. I machined two brackets from aluminium and mounted the cooler "hanging" down from the chassis-rail just behind the front ARB. Worked pretty well, water-temp didn´t get higher but the oil wasn´t getting warm anymore. Reason was that I fitted an external-dry-sump-tank (alloy) at the same time and this tank already brought the temperature down significantly. So no need anymore for the oil-cooler. But I got it still lying around in the garage with some aeroquip-quick-connections, so that I´m able to mount it within 10 minutes (hot track days for example).

 

Hope this helps.

 

Marius

[ashaughnessy]

I once heard at a talk by Len Unwin that he reckoned oil coolers weren't much use on a seven.

I used to have one (in my supersprint) mounted in the "official" place, in front of the radiator, and found that it significantly reduced my water cooling capacity (in other words, I overheated more often), especially when racing. Since I removed it the water temperature is more under control (though still a bit of a problem when racing).

I've no idea what my oil temperature is, though.

Anthony

[Roger King]

Greg,

 

To some extent, we are in an area of personal opinion on this one and there will definitely be people who express the opposite view.

 

However, have found that an engine that is highly tuned (more than Supersprint if we talk Crossflow), can run into water cooling problems when used on track on a warm day if the oil cooler is in front of the water radiator. It would seem that Anthony has encountered this problem.

 

If you overheat the coolant, death will follow fairly quickly for the engine, but oil temperatures have far more latitude before damage occurs. This is far from saying that oil temperature is not important though. We have found that the oil cooler behind the radiator solution keeps both temperatures under control.

 

Having said this, if you never go on track, you may well never encounter a problem, so I'm not necessarily suggesting that you change.

[greg]

Roger,

 

Thanks for the info, I was not aware that water temp is more critical than oil temp, but I'm not a specialist. I want to use my 7 for track / sprints, and will add moving the oil cooler to my upgraditis list (3d mapping, more engine tweaks, dry sumping etc...).

 

Greg

 

Q 990 RAE

[Red SLR]

Julain, I had to pit twice at 100c. Not sure how hot it should get, but 100c seemes a bit warm for my liking!

 

My 7 should be ready for Saturday, I will find out tomorrow how many BHP it has now got.

 

U fancy meeting up in the same place, same time?

 

Simon.

 

X777CAT

[Red SLR]

As for water, it never got over 85c, but as mentioned above the race rad can have a bit better cooling.

 

 

 

X777CAT

[SLR No.77]

Julian, my oil cooler was factory fitted from new, and is mounted low down behind the radiator - this I beleive is the normal fitment for the K-series race cars.

 

I'll be at the Lancashire meet in July (can't make June) if you want to have a good look, but I can e-mail some photos in the meantime if you wish?

 

Stu.

[Fleming Seven]

Good evening

With some years delay :-))) I would like to ad this design to the topic. I just turned the MOCAL brackets around (and had to bore some more holes and cut some materials away) to have the oil cooler fit between radiator and xflow.

7 regards

Mr. Fleming's driver

George

[7 wonders of the world]

Your mounting brackets for the front mounted fan cover a significant portion of the radiator area.... I would look to put these on a good diet

[Garth]

For others reading this thread is it worth considering a Laminova oil cooler? Have one on my modified Sigma after having problems with soaring oil temperatures on track days. Oil temp now pegged much closer to the water temp and does not overheat when pushing on. Think I am right in saying it also heats up the oil slightly more quickly from startup which also has benefits?

Trust this post is not out of order!

[JonT]

I've got a laminova on my K-series, which as you say works well as an oil warmer too. One thing to watch though is that you'll be dumping more heat into the cooling circuit, so you may want to increase the capacity of the radiator. I don't know if it's coincidence, but not long after fitting my laminova the end caps went on the rad - which was a good excuse to upgrade.

[7 wonders of the world]

The Laminova is good for warming the oil  however the inherent problem is they limit the oil temp to that of the water.... and the two fluids are designed to run at different temperatures.

Also where are you measureing the oil temp from too.

A better solution is a correctly sized oil cooler with a thermostat, in a DS system this would be in the scavenge hose 

 

[SLR No.77]

In the K-Series dry sump setup I wouldn't add anything that would restrict the scavenge ability in any way, it's already marginal even with the gold pump (as opposed to the original purple pump).

Stu.

[7 wonders of the world]

If the hose, unions and cooler are correctly sized there will be minimal back pressure. you need to be looking at -12 really.

Mocal do a high flow thermostat to with 2 stat options and a raft of fittings

This one can be ordered with a 95 degree stat too.

https://www.merlinmotorsport.co.uk/p/mocal-oil-thermostat-with-12jic-threads-m-ot-12jic?utm_source=Google&utm_medium=ShoppingUK&utm_campaign=ShoppingUK&vat=on&currency=GBP&gclid=EAIaIQobChMI6JSk897E6AIVWbvVCh3Thg7DEAQYAyABEgKfEvD_BwE