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Strange Ebay Oil Cooler Design

SECURITY

By SECURITY,
in Engines & Forced Induction

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SECURITY Grand Master

SECURITY

Posted
Posted

I was trawling through ebay and found this: http://cgi.ebay.com.au/NEW-12-V8-RACE-EXTE...%3A1|240%3A1318

As im looking for an oil cooler i was trying to think how effective it would be and came up with this;

- the fins dont penetrate deep enough into the oil for it to be effective in transferring heat

- oil pressure on startup will take longer to generate depending on where it is located (the picture in there is showing it to be mounted up high).

looks like just another ebay cheapo item to me. What are your thoughts?

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https://www.sau.com.au/forums/topic/258200-strange-ebay-oil-cooler-design/
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QWK32 Veteran

QWK32

Posted
Posted

i think the normal tube/fin style coolers would be more efficient. the one you linked doesn't look like it would have the surface area contact to the cooling fins that a convertional oil cooler would. also i'd think the air flow through a tube/fin coller would be better at removing heat than a larger "solid" cooler would.

JMW Mentor

JMW

Posted
Posted

Yeah agree with you on looking cheap and possibly not doing a great job of cooling. Aluminium does transfer heat well, but it would really need to be mounted with fins running front to rear of the car to work the best. I'd stay clear of it.

BeEnAr Experienced

BeEnAr

Posted
Posted

I've actually seen something like that on a couple of race cars, looks like it works like a massive heatsink like on a PC. Would work better plumber in at the front of the car or somewhere it would get airflow I rekon.

**RB2530** Proficient

**RB2530**

Posted
Posted

My feeling is that these would not work very well at all when compared to more traditional oil coolers..These are the reasons why...

1. Although the oil is able to penetrate the cooling fins the main flow of oil would be through the core of the cooler as this is the path of least resistance. The oil penetrating the fins would stagnate in the fins as there is nothing to cause this oil to flow. So you would end up with most of the oil flowing through the centre of this thing and the cooled oil would remain in the fins.(just as if it was just a length of hose)..Oil has a much lower thermal conductivity than aluminium and therefore you could argue that the fins would be better off if they were solid.

2. The most efficient heat exchangers maximise the ratio of contact surface area vs fluid volume of the hot and the cool fluids..In this case the fluids are oil and air...The most inefficient cross section for doing this is circular...The most efficient is squat rectangular sections that are wide and short. This give the most surface contact between the two fluids. Just like traditional oil coolers...

3. Also for an air type cooler to be effective, free flowing air must flow over a large area to maximise the heat removed. With this design if you had air flowing at 90 degrees to the cooler, the fins themselves would trap air between them which once again would stagnate. At the back of the cooler (the side not facing the airflow) you would also get a low get a low pressure region. This would reduce the heat tranfer from the fins to the air.

So IMO these are worth every cent you pay for them...which is not much by the looks of it...They would be slightly better than no cooler at all but not worth the effort to fit one...

BeEnAr Experienced

BeEnAr

Posted
Posted

I wonder if it would work better if you mounted it longitudinal <--- is that right, rather than horizontal i.e with the opening at the front of car and the exit at the rear of car?? That would eliminate the airflow restriction but I agree traditional works for a reason so why do it differently if it's not as good

**RB2530** Proficient

**RB2530**

Posted
Posted
I wonder if it would work better if you mounted it longitudinal <--- is that right, rather than horizontal i.e with the opening at the front of car and the exit at the rear of car?? That would eliminate the airflow restriction but I agree traditional works for a reason so why do it differently if it's not as good

Changing the orientation so that the air travels along it fixes one shortcoming but creates another...What would happens is the air at ambient temperature would hit the front end of it and as it travels along the fins, the air would be heated...This happens in all coolers...the air traveling out is warmer than the air traveling in...this must happen for the cooler to be cooling...but as the air heats up less and less heat is transferred into it so it becomes less effective at removing heat..

Also the relatively small projected cross sectional area of the cooler that would be exposed to the airflow would be very limiting...If you consider the cooler functioning as follows it will become obvious...

The road speed air at ambient temperature flows over the cooler that is heated by the oil..heat is absorbed by the air as it is drawn out of the oil...Now if you consider the setup in 2D, and that the road speed air has the capacity to absorb only a certain amount of heat...It follows that as the projected area of the cooler increases, the ability of the cooler absorb heat increases directly proportional to its area...Eg If the diameter of this round cooler was say 50mm and it was compared to a standard cooler that was 100x100mm, the 100x100 would cool at least 4-5 times more...(yep couldn't be bothered working area of 50mm dia but you know what I mean)..

So this means that with coolers the projected area of the cooler is more important than the cooler depth. ..So no matter which way you orientate this cooler it wont work better than a conventional one because its projected area to the airflow is small...

hope this makes sense...

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