Oil cooler chat

[WR1 Bro]

Below is a an e-mail dicussion between Mark and myself...

I thought an oil cooler followed a simple princliple of cooling the oil as cooler oil makes more sense!! As per usual Marky Mark spends the rest of the day trying to explain these things to me!!

I thought it worth posting for discussion and also for other people who might know as little as me!!

Please read from the bottom!



-----Original Message-----
From: Mark Reynolds
Sent: 25 July 2007 15:05
To: Hughes, Stuart
Subject: RE: Oil cooler

Speaking to our oil bods at work, modern decent synthetics should be
fine at up to 150 degrees!

We do one engine that instead of having water cooling it is oil cooled.
It uses a radiator that the oil is pumped through and the same oil is
used as engine oil. Apparently normal running of this engine is in the
130-140 degree region, and they regularly get to 150.

On track I go to about 120 before I back off. My old engine let go at
about 125 but the P1 bearings are made of chocolate anyway! Lets wait
and see. I have to say that oil coolers are a bit 'funny' and I have
heard of so many bad stories about cars with them fitted (3 Bar oil
press under load, loads of air you can't get out of the pipework etc.)
that I would want to leave fitment to someone with a lot more
experience. That would be Zen performance probably. RCM are non -
believers in oil coolers by the way.

Note that with 15/50 oil in you will probably see higher temps than you
will with 5 or 10/40 with all other things being equal.

Oil and associated bits are one of them subjects that it's difficult to
get a handle on unless you understand the chemistry, specs, and EXACTLY
what is required from an oil etc. I don't, and I suspect a lot of people
don't either.



-----Original Message-----
From: Hughes, Stuart
Sent: 25 July 2007 14:10
To: Mark Reynolds
Subject: RE: Oil cooler

I regularly see temps of 110 when having a spirited road drive! To be
honest this really bugs me as you have to back off when the fun is just
starting.

Ooooo oil coolers aren't as simple as they sound!! I love to regularly
feel REALLY thick!



-----Original Message-----
From: Mark Reynolds
Sent: 25 July 2007 12:58
To: Hughes, Stuart
Subject: RE: Oil cooler

They are not pointless, but unless you suffer with high temps on the
road or do a lot of track work then I personally would not bother.

You re going to be creating similar heat to mine. I get 110 max on the
road so no problem, but I keep an eye on it if I am on track.

Lets do the conversion then see whats happening but I doubt you will
need it. There are lots of bad things about coolers as I state below.
Also listen to Ren who has been there and done it.

http://p1woc.co.uk/postnuke/index.php?n ... opic&t=177
56&highlight=oil+cooler

A Baffled sump is not required. This has no effect on heat. Yes you can
get big ones that carry more oil but they are mainly for track work or
really quick accelerating cars. The baffles stop the oil sloshing into
areas away from the pick up. If this happens you can get split seconds
where you suck air into the pump instead of oil.



-----Original Message-----
From: Hughes, Stuart
Sent: 25 July 2007 12:15
To: Mark Reynolds
Subject: Oil cooler

Hi ya matey... long time no hear...

Oil cooler - why did we not discuss these? Are they pointless at the
current power gain target?

Similarly, I remembered considering a baffled oil sump to allow better
cooling and more oil? Is this over kill too?

Your thoughts... probably something like "shut it fat boy"!

[marky mark]

mmmm.

maybe there are 1 or 2 things on there that i would have put differently - or elaborated on - if i knew it was for public consmption...'bearings made from chocolate' etc

You would think that i would know by now that nothing with Bro is confidential

[WR1 Bro]

You would think that i would know by now that nothing with Bro is confidential

I thought it was useful! Sorry!

I've Tipp-ex'd it out for you. Happy to remove if you prefer?

[marky mark]

No need mate.

PMSL @ the tippex gag.

[WR1 Bro]

No need mate.

PMSL @ the tippex gag.

Thats cos some of us are funny and you're just a dull slap!

[dynamix]

funny as but Marky Mark is spot on

So often people think oil coolers are the latest bit of bling, oooh got an oil cooler it must be a serious track car.....

Most good oil (i use Millers 10/60 CFS) will cope with 125C easily and possibly bursts above that on track. If anything these oils work better if hotter ! I am yet to see above 118C on track myself (my temp alarm is set at 120C too) and as such I dont feel the need for a cooler.

Having an oil cooler is another mass of oil and has several downsides, least of which is the fast that they can overcool the oil and create higher engine stress as a result.

I have also seen two occasions recently where oil cooler pipework has come lose (on very well prepped scoobies too) with the result of a complete engine fire on one and the other leaving oil on a TF day at Nurburgring with a biker falling off on it and ending up in hospital (as well as the scooby spinning).

Sorry if this is supposed to be a funny thread

[marky mark]

It's not meant to be funny Duncan but any thread that Bro posts on inevitably goes that way....You will get used to it.

If i was going to fit a cooler to my own car i would get the spec C item. That seems the sensible and safe way to do it. I have a spec C block in my car so it's pretty straightforward, not as easy in a WR1 though.

These people that have long lengths of pipework and put an oil cooler up in the position where an o.e TMIC normally resides are not quite grasping whats going on. Similiarly the remote oil filters sitting upside down somewhere in the engine bay is just asking for trouble.

[dynamix]

yeah, those remote filter kits are funny. It's not as if the filter could be anymore conveniently placed on the subaru

I am sure one may be required on mine once power levels get very high but at current modest levels i can think of better things to spend

[WR1 Bro]

See, it was worth posting our e-mail conversation!!

Thanks for the extra info Dynamite.

[danr55]

all very interesting.

At Cadwell, particularly in the afternoon when pushing a bit harder both myself and Fraser got the oil temp to 120 which is where the warning was set. Both had to back off for a lap and let it cool before pushing on again but it was then pretty quickly back up to 120 again...

[dynamix]

all very interesting.

At Cadwell, particularly in the afternoon when pushing a bit harder both myself and Fraser got the oil temp to 120 which is where the warning was set. Both had to back off for a lap and let it cool before pushing on again but it was then pretty quickly back up to 120 again...

was your oil level low?

I found with mine that when going round long right hand bends, a lot of oil would be dragged up through the breathers and into my catch tank. (With the std arrangement this would go into the inlet manifold and cause det) within a lap or 3 my catch tank would be full and oil temps would then rise a lot.

I changed that set up now and have a RCM catch tank with inputs from all of the breathers and a drain pipe back to the sump:

You cant really see the can that well here...


This is the drain pipe arrangement to the sump plug:


The breather pipe from the catch can:

[danr55]

Duncan, oil level was fine! not sure what oil I've got in there, normally on spirited road driving it would only go to 110 max 115.
maybe i was just driving faster than you

[marky mark]

Some good track prep there Dunc, identical to Bob Rawles set up i think.

[danr55]

Some good track prep there Dunc, identical to Bob Rawles set up i think.

Do I need one of these Mark?

[WR1 Bro]

Some good track prep there Dunc, identical to Bob Rawles set up i think.

Mark, am I right in the understanding that your catch can does not return to the sump? If not, why not? As it seems like a much lower maintenance system?

Also, can someone explain the breather pipe?

[marky mark]

Obviously i don't know the exact spec of your car (i will look under bonnet at weekend) but i would suspect your breather system is as o.e, so you will be venting back to the inlet pipe.

For high power or track applications i would recommend a catch tank for sure (i am putting one on Bro's). Dynamix has gone a litle bit further with the return to the sump because he has been suffering high oil loss. This could well be a bit more of a 2.5 thing than a 2.0L thing as breathing losses will be higher (same volume cranckases but bigger pistons and longer stroke pressurising)

I also suspect time attack rules (if they follow other motorsport guidelines) will stipulate you cant vent anything to atmosphere and the oil breather system needs to be closed.

I thought you wanted it to blow up?

[dynamix]

Duncan, oil level was fine! not sure what oil I've got in there, normally on spirited road driving it would only go to 110 max 115.
maybe i was just driving faster than you

that'll be it then ...... you must have been on a cool down lap etc etc

Yep - same set up as Bob's and a few of the other guys. Took me ages to understand what was going on with it as it would only dump oil if going quickly round sustained high g right handers. The guys on 22b came up with this solution - i wish I was clever enough

It has cured it though and didnt use a drop of oil at Cadwell.

Back to the topic of oil coolers, if you do fit one make sure you fit a thermostat so that the cooler only gets used when temps above 85C ish otherwise you will have probs with the oil never getting up to temp.

[WR1 Bro]

I thought you wanted it to blow up?

FPMSL... Seems like Dan needs to tackle a few more long right hand bends!

[marky mark]

Some good track prep there Dunc, identical to Bob Rawles set up i think.

Mark, am I right in the understanding that your catch can does not return to the sump? If not, why not? As it seems like a much lower maintenance system?

Also, can someone explain the breather pipe?

You are correct. I don't need too. Dynamix has found a big oil loss under track conditions. running at high RPM and boost all the time will fire off oil vapour, he is just returning it back to the sump.

Running on the road you won't get the same, and on the track it will be pretty much pure oil venting. On the road you get a watery/milky/oily mayonnaise type stuff that you would not want to return to the sump anyway.

With a fit engine it will be a couple of months minimum before you need to empty your tank Bro.

Are you still connected up to your PCV Dynamix?

[dynamix]

This image shows where the pipes come from. It stops oil vapour from feeding into the inlet manifold as OE (done for emissions) - this is not liked by the engine and can cause det. With the catch can arrangement, the mapper can be slightly more aggressive with the map.



The pipes from the engine breathers feed into the can where the oil vapour is separated from the air. Collected oil is then fed back into the sump for re-use and air vented through the breather pipe.

Normal catch can arrangements do not have the drain back to the sump and require emptying of the can ocasionally to stop it filling up. My prev catch can was like that but filled up on certain corners, Coram at Snetterton, Luffield at Silverstone and to a degree Galgenkopf at the ring. Once full it would then syphon the oil out of the back of the car... At snetterton in february, it lost about 2 litres of oil

This arrangement makes it closed loop so therefore zero maintenance.

fyi - For TA regs there are no rules preventing this venting to atmosphere.

[marky mark]

Bro, that is exactly the same as the tank i have at home to fit on your car.

[dynamix]

Some good track prep there Dunc, identical to Bob Rawles set up i think.

Mark, am I right in the understanding that your catch can does not return to the sump? If not, why not? As it seems like a much lower maintenance system?

Also, can someone explain the breather pipe?

You are correct. I don't need too. Dynamix has found a big oil loss under track conditions. running at high RPM and boost all the time will fire off oil vapour, he is just returning it back to the sump.

Running on the road you won't get the same, and on the track it will be pretty much pure oil venting. On the road you get a watery/milky/oily mayonnaise type stuff that you would not want to return to the sump anyway.

With a fit engine it will be a couple of months minimum before you need to empty your tank Bro.

Are you still connected up to your PCV Dynamix?

Road driving used to collect the Mayo you talk about - this is fed back in to the sump now and just burns off in the sump. The oil quality has been fine with about 1000 miles of daily driver stuff. (i was concerned about this, but it is only little bits and seems to cope with it easily)

PCV .... hmm i 'think' not but it was so long ago that the original can went on that I cant really remember.

[dynamix]

Bro, that is exactly the same as the tank i have at home to fit on your car.

it is the best on the market - RCM know their stuff

[marky mark]

Burns off in the sump?

It cant burn its water. It can evaporate obviously but you are still introducing back into the engine, not on the combustion side granted but it still can't be good.

Think i will stick with a set up i have to drain every now and again. As a track car your needs are different and you cant suffer the oil loss you have been doing so fair enough.

[dynamix]

Burns off in the sump?

It cant burn its water. It can evaporate obviously but you are still introducing back into the engine, not on the combustion side granted but it still can't be good.

Think i will stick with a set up i have to drain every now and again. As a track car your needs are different and you cant suffer the oil loss you have been doing so fair enough.

I felt the same way, but Pavlo, John Felstead, Bob Rawle, Andy F all assured me that the water vapour would leave the system... and judging by the oil quality, there is no evidence of sludge. I do most short daily driver type trips despite frequent track days.

[WR1 Bro]

Very interesting thread. Thanks for the pic too.

[marky mark]

Im not one to argue with any of them, but personally it's still not something i would do unless i really had too.

[marky mark]

If you want your breather system closed Bro it's pretty easy to do.

[WR1 Bro]

If you want your breather system closed Bro it's pretty easy to do.

Not sure. You point about putting Hellmans into the sump is a little worrying. I thought the catch can filled with oil so it seemed sensible to have a closed loop.

[marky mark]

No mate. If you could run arond everywhere at high RPM and boost it would be 99% oil.

Its probably false to call them oil catch cans. In reality they are just a can to contain anything that is forced out of the cam cover and crankcase breathers by pressure in the engine cases.

If you do short journeys etc you will get a very watery substance in there. This is just condensation getting blown out etc. I do 3 miles to work and 3 miles back along with more 'normal' driving and i would say my contents are round about 90% water.