Combined rad/oil cooler

John Fitzpatrick · 02-21-07, 07:23 PM

Is there any advantage, esp. in a rear-engine car, in using a NASCAR style radiator/oil cooler combination?
Thanks

Bill D · 02-21-07, 07:40 PM

No advantage due to the long run of the oil hose. It's common to put one in the engine bay near where the side scops direct ait to the engine

Bill Musarra · 02-22-07, 06:38 AM

John,
The original road cars had a small oil cooler mounted just behind the front radiator. The hoses that connected it were at leat an-12 of larger. Don't know about the racecars. Someone more in the know would have to chime in.

Bill

Jim c · 02-22-07, 06:58 AM

I have never fitted a cooler with hoses that long.
Would you get a pressure drop over that distance.?

Jim

Lynn · 02-22-07, 02:25 PM

Jim C,

Undoubtedly, which is, I am sure, why Bill put the emphasis on the -12 hoses at a minimum. Personally, I don't think the hassle of the extra plumbing really buys you anything though.

Lynn

CliffBeer · 02-22-07, 03:51 PM

Might not be a problem - porsche 911's rely on oil as the sole method of liquid cooling and the external oil cooler is located at the opposite end of the car. Incidentally, the long runs of the lines are expected to provide a significant amount of the cooling. The difference is that the lines are brass. There is also a thermostat plumbed into the system so that the cooler doesn't start to operate until about 190 degrees. I'm not aware of any pressure problems with such a system (the cooler is plumbed in on the low pressure/return side of the system) but perhaps it's somehow different for SBF...

One common oil cooler that is used as an auxiliary cooler by the air cooled crowd is the Mazda RX-7 aluminum cooler - very nicely made and highly efficient.

Fran Hall RCR · 02-22-07, 06:21 PM

The 911 is a dry sump system too dont forget...

rekab69 · 02-23-07, 04:43 PM

Hi,

am I right in thinking (guessing) the Ford GT runs it's oil cooler up front..?

db

Jac Mac · 02-24-07, 12:59 AM

Quote:

Originally Posted by toy264

Is there any advantage, esp. in a rear-engine car, in using a NASCAR style radiator/oil cooler combination?
Thanks

John , Only in that it would add weight to the front end. In this day & age I would suggest a water/oil heat exchanger mounted in the bottom coolant line close to the front of the motor would be the best solution. The extra cost of this unit would be largely offset by the reduced amount of hose etc required to fit in this area. This location would also keep it away from damage in the event of an off course excursion which always seem to find conventional type oil coolers.

Jac Mac

BruceLambo · 02-24-07, 04:28 PM

Just to note, my Lotus Esprit has 2 oil coolers mounted up the front. One on each side in front of the front wheels, plumbed in series.

Big-Foot · 02-24-07, 07:19 PM

There is another advantage of using an water/oil cooler - The engine coolant will help bring the engine oil up to temperature faster which will allow it (oil) to flow more freely and will also reduce the hp requirement to drive the oil pump.
These types of oil coolers are extremely efficient - much moreso than typical air/oil coolers..

John Fitzpatrick · 02-24-07, 11:14 PM

Quote:

Originally Posted by jac mac

John , Only in that it would add weight to the front end. In this day & age I would suggest a water/oil heat exchanger mounted in the bottom coolant line close to the front of the motor would be the best solution. The extra cost of this unit would be largely offset by the reduced amount of hose etc required to fit in this area. This location would also keep it away from damage in the event of an off course excursion which always seem to find conventional type oil coolers.

Jac Mac

Brilliant! Shorter lines, and oil/water transfer has got to be more efficient than oil/air. I might squeeze one in next to the accusump. I wonder if I ought to consider that for the transaxle oil cooling as well?

Big-Foot · 02-24-07, 11:24 PM

Here you go;

Jac Mac · 02-25-07, 04:45 PM

John, Randy,
A couple of seasons back after two near disasters as a result of conventional oil cooler failures I built a oil /water exchanger from scratch. This unit had the added benefit of being able to be dismantled completely for cleaning etc and was a lot more compact than those shown in the above post. Smaller units could be built for your T/A. The only commercially available unit's similar in size that I have seen are Laminova & Aeroquip. In the unit I made the Bottom Coolant pipe was only exposed to the exchanger element for 12" x 1.5" dia ( Simple plain bore- no fin's etc ) Temp drop of oil was approx 45 deg F.

Jac Mac

Russ Noble · 03-08-07, 12:01 AM

Quote:

Originally Posted by toy264

Brilliant! Shorter lines, and oil/water transfer has got to be more efficient than oil/air. I might squeeze one in next to the accusump. I wonder if I ought to consider that for the transaxle oil cooling as well?

I've been mulling over this concept for a week or so...... Sounds good in theory, but......

Ultimately you still have to get rid of the extra heat that is going into the coolant water. In a GT40, radiator size is somewhat limited up front. Is an existing radiator going to be capable of handling the extra heat dissapation now demanded of it? Or will the radiator need to be upgraded/enlarged? Possibly not an easy task?

I seem to remember reading once that 50% of the engine cooling is provided by the oil. That strikes me as quite a high figure, but if it's right that would then mean that the radiator would be required to dissipate twice as much heat. However I am a little sceptical of that 50% figure.

One benefit of running a water/oil exchanger is that it would totally free up the side scoops for ducting to the rear brakes, eliminating the drag of snorkels. Too bad, I think the snorkels look horny, but function over form any day!

Anyone care to comment?

Cheers

Jac Mac · 03-08-07, 12:25 AM

Yeh Russ, but in your case I would only be repeating myself!!!!

Jac Mac

Russ Noble · 03-08-07, 01:52 AM

Jac Mac, you're obviously trying to buy time before coming up with the reasoned and knowledgable technical comments that we all come to expect from you.

Or maybe you've just been at those tomato plants again?

I wait with baited breath.

Cheers

Russ Noble · 03-09-07, 03:05 AM

Still waiting.....

Can anyone confirm the approx % of engine cooling that is achieved by the oil on something like an SBF ?

Has anyone run a water/oil heat exchanger on a GT40 and what effect did it have on engine water temp? Did you need to upsize the radiator?

Failing that has anyone thought about doing it but discarded the idea? And why?

Thanks

Lynn · 03-09-07, 09:24 AM