PC chip heat sinks on trombone cooler?

[Palmer1980]

Just a random idea...

After cleaning off the factory trombone cooler and adding the pelican air scoop, do you think something like this would do anything?

Swiftech MC21 Aluminum MOSFET Heatsinks - 4 pack

Ideally larger...

[daniel911T]

I have a better suggestion:
TRA3374 3374 Aluminum Heat Sink Velineon 380 Brushless Motor - Traxxas Motors

This is just an example for general idea, but for R/C boats, planes, cars, and helicopters, they make a wide array of round heatsinks that are made to attach after the fact. I would just measure the OD of your trombone cooler tubing, and buy some of the appropriate size from HobbyKing R/C Hobby Store : (out of hong kong, just about as cheap as you can get, and pretty good stuff)

Those MOSFET sinks are made for flat surfaces, to be stuck directly to the top of a microchip. They don't work very well due to the lack of clamping and the losses associated with the adhesive. I was going to add some to my video ram, but the general opinion on the net was that they weren't very effective.

If you are feeling punchy, here's a strange, yet professional looking way to repurpose a beer can: Heat Sink for electric motors

It has the benefit of being next to free, it is a great way to recycle, and you can make it as big as you want.

Cheers!
-Dan

[86 911 Targa]

Originally Posted by Palmer1980

Just a random idea...

After cleaning off the factory trombone cooler and adding the pelican air scoop, do you think something like this would do anything?

Swiftech MC21 Aluminum MOSFET Heatsinks - 4 pack

Ideally larger...

Go with the factory finned oil cooler & thermostatically (210F) controlled fan.

I did, and never regretted it.

Best,

Gerry

[wwest]

Originally Posted by Palmer1980

Just a random idea...

After cleaning off the factory trombone cooler and adding the pelican air scoop, do you think something like this would do anything?

Swiftech MC21 Aluminum MOSFET Heatsinks - 4 pack

Ideally larger...

First, what indication(s) do you have that the trombone cooler isn't efficient enough..?

If it ain't broke don't fix it.....

That being said affixing the heatsink to the round pipe such that you get a reasonable level of heat transfer accross the coupling might be a challenge.

[masraum]

Originally Posted by wwest

First, what indication(s) do you have that the trombone cooler isn't efficient enough..?

If it ain't broke don't fix it.....

That being said affixing the heatsink to the round pipe such that you get a reasonable level of heat transfer accross the coupling might be a challenge.

Obviously, the best way to accomplish that would be to hammer flat spots into the tubes!!

[daniel911T]

Originally Posted by masraum

Obviously, the best way to accomplish that would be to hammer flat spots into the tubes!!

There's a man after my own heart!

...As an alternative, you could just duct tape some beer cans to the trombone cooler, I'm sure that will give great redneck cooling! If you leave the beer in the cans, you can even get some alcohol to oil heat transfer! That would be super efficient.

-Dan

[HawgRyder]

Or...go down to the local HVAC store and grab a short length of the type of tubing they use for hot water heating in houses.
Those tubes have fins all along the length of them....and must conduct a fair amount of heat or they would have come up with a better design in all these years.
Have Fun
Bob

[911pcars]

While some heat is transferred out of the tube walls, maximum heat transfer relies on exposing the medium (oil) to a large surface area, like in a proper oil cooler.

On engines 2.7 or larger, and in warm ambient climates, the trombone cooler is usually insufficient.

Sherwood

[Joe Bob]

See #5....The euro 3.0s came with a brass row cooler in place of the trombone. They are relatively cheap and work well/easy install.

[Joe Bob]

The fan works only when in bumper to bumper traffic when airflow is low and temps are high.....it actually lessens cooling at speed by blocking fins.

[wwest]

Originally Posted by 911pcars

While some heat is transferred out of the tube walls, maximum heat transfer relies on exposing the medium (oil) to a large surface area, like in a proper oil cooler.

On engines 2.7 or larger, and in warm ambient climates, the trombone cooler is usually insufficient.

Sherwood

Sorry, but "proper" oil coolers do not expose the oil (itsself) to more cooling surface, instead they expose the fins/vanes to LOTS of airflow so that the heat that is transferred between the oil and the "pipe" wall is more quickly "wicked" away.

[wwest]

Originally Posted by Joe Bob

The fan works only when in bumper to bumper traffic when airflow is low and temps are high.....it actually lessens cooling at speed by blocking fins.

The oil cooler fan/blower in my '88 runs anytime the ignition is switched on. Was there a later mod that only ran it as needed...?

In any case those type of fan/blowers do not provide a significant level of blockage to airflow, instead they simply act as small electric generators as the force of airflow turns them. The liquid to metal heat transfer coefficient is quite high, acceptable. It the metal to air heat transfer coefficient that is lacking efficiency, therefore more metal/air "interface" is provided.

[911pcars]

Originally Posted by wwest

The oil cooler fan/blower in my '88 runs anytime the ignition is switched on. Was there a later mod that only ran it as needed...?

A thermostatic (thermo-) switch, as in the factory-supplied switch or an OEM BMW switch with a lower temperature ON threshold setting. Check the archives or the PParts catalog.

Originally Posted by wwest

In any case those type of fan/blowers do not provide a significant level of blockage to airflow, instead they simply act as small electric generators as the force of airflow turns them.

Depending on the fan assy. and the vehicle speed, it can block the airflow somewhat. The fender itself is the biggest impediment to adequate airflow to the cooler in the factory location.

IMO, the cooling fan motor as an electrical generator while idle is somewhat limited by the size of the fan blade and especially when the switch is in the OFF position.

Originally Posted by wwest

The liquid to metal heat transfer coefficient is quite high, acceptable. It the metal to air heat transfer coefficient that is lacking efficiency, therefore more metal/air "interface" is provided.

Please rephrase. Don't understand.

Sherwood

[wwest]

Originally Posted by 911pcars

A thermostatic (thermo-) switch, as in the factory-supplied switch or an OEM BMW switch with a lower temperature ON threshold setting. Check the archives or the PParts catalog.



Depending on the fan assy. and the vehicle speed, it can block the airflow somewhat. The fender itself is the biggest impediment to adequate airflow to the cooler in the factory location.

IMO, the cooling fan motor as an electrical generator while idle is somewhat limited by the size of the fan blade and especially when the switch is in the OFF position.



Please rephrase. Don't understand.

Sherwood

The HIGH MASS/density of the oil and the metal pipe result in a very HIGH heat transfer rate vs metal to low mass/density atmosphere.

[911pcars]

Originally Posted by wwest

The HIGH MASS/density of the oil and the metal pipe result in a very HIGH heat transfer rate vs metal to low mass/density atmosphere.

Agree (I think). Unfortunately, the tubes by themselves (w/engine size caveat) aren't good enough to serve as an adequate "oil cooler" in lieu of a real one.

Sherwood

[86 911 Targa]

Originally Posted by wwest

The oil cooler fan/blower in my '88 runs anytime the ignition is switched on. Was there a later mod that only ran it as needed...?

In any case those type of fan/blowers do not provide a significant level of blockage to airflow, instead they simply act as small electric generators as the force of airflow turns them. The liquid to metal heat transfer coefficient is quite high, acceptable. It the metal to air heat transfer coefficient that is lacking efficiency, therefore more metal/air "interface" is provided.

"As needed".

Your oil cooler fan should engage only when the oil temperature exceeds 210F.

However, the factory sensor does not engage prior to 248F.

The optimum operating oil temperatures for the 3.2 is 185-210F.

If the fan activates with a "cold" motor, perhaps the fan relay or the sensor is defective.

I installed a Nason sensor with "On" at 210F, and "Off" 197F.

The sensor can be custom made for various temperature requirements.

If you chose to replace your front oil cooler, be certain that there is a "bung" to accommodate the sensor.

You may pm me as needed.

See pics:

[Tidybuoy]

My '74 2.7 has the factory mounted oil cooler in the front fendor but does not have an electric fan. The temp gauge runs a consistant 180-185 and sometimes peaks above 200 in the summer traffic. It can easily get over 100 degrees here in the summer. That said, i think the factory fender mount cooler works pertty well - with or without the fan.

[911pcars]

Originally Posted by Tidybuoy

My '74 2.7 has the factory mounted oil cooler in the front fendor but does not have an electric fan. The temp gauge runs a consistant 180-185 and sometimes peaks above 200 in the summer traffic. It can easily get over 100 degrees here in the summer. That said, i think the factory fender mount cooler works pertty well - with or without the fan.

Perhaps I should have added, "YMMV".

"......sometimes peaks above 200 in the summer traffic..."

If it runs close to 200ºF, you're fine. Temps around 230ºF are borderline hot, especially on heat-sensitive 2.7 engines.

Sherwood

[Tidybuoy]

One thing I've wondered about....my car has both the factory front fender cooler as well as the behind-the-engine cooler. Is this normal? I don't see it in the diagram posted in post#3.

[gtc]

Originally Posted by Palmer1980

Just a random idea...

After cleaning off the factory trombone cooler and adding the pelican air scoop, do you think something like this would do anything?

Swiftech MC21 Aluminum MOSFET Heatsinks - 4 pack

Ideally larger...

Maybe you could stick a bunch of them to your oil filter...