E34 Large Case Diff Cooler

[M5W]

Hey guys Im rebuilding my diff right now and I wanna plumb in a cooler using a turbowerx oil sump pump and an aluminum oil cooler. My only concern is the size of the cooler. For packaging reasons I want to use a smaller cooler so I can tuck it in the wheelwell. Im thinking about using a 6.25x4.75.2 core for my diff. Any ideas as to if it will be enough for it ?

[m60b30530i]

um could i do this with a medium case, also how would the pump operate ,would it be electric

[M5W]

Im using this pump for it.

http://www.turbowerx.com/Scavenge_Pumps/Exa-Pump/Exa-Pump.html

You could do it with a medium case diff. The drain plug and fill holes are M22x1.5 threads, so im gunna use an adapter plug that has an AN flared thread on it and use the drain as a supply port and the fill hole as a return port. Im just curious if the small core has enough surface area to effectively cool the diff down. And also if the diff input shaft will be starved for oil by the sump sucking oil from the drain plug. That could be rectified by filling the diff slightly more than usual, just so the input shaft bearing always has a constant submersion with oil.

[moroza]

...Why?

[M5W]

I just had my factory diff go on me and I do beat on it alot, ex. hard launches, high speeds, rapid acceleration and hard braking, so its a good idea to have something to cool the fluid, I really dont want to have to go thru this again and I always love having peace of mind about my components. This is a peace of mind mod more than anything.

[xatlas0]

You would want to fill it with the system connected through the fill plug. I don't know if the pump goes before or after the cooler. You are going to want to figure out the additional volume the cooler+piping+pump allow into the diff system, as that will be how much extra fluid to add.

Any kind of cooler will help some, but you may want to consider an oil thermostat, too. If it is cold, then the oil needs to warm up ASAP, as when it is cold, it is not lubricating as effectively. Having the pump and cooler going all the time will significantly delay this process.

I'd be more concerned about the trans fluid.

[93FIM5]

:devillook

Give them a call at their US location they will help you size what you need or just look through their sites I remember them having the equations needed to properly size a core for heat transfer and pressure losses (more for engine coolers). Good luck and I have some news for you bolt and filter wise.

Cooler core: http://www.setrab.com/index.php?id=67
US Location: http://www.setrabusa.com/oilcoolers.htm

[CO535i]

Diffs expiring is not a result of the temp of the oil but the mechanical stress/shock you are putting it through.You just said that you :


I just had my factory diff go on me and I do beat on it alot, ex. hard launches, high speeds, rapid acceleration and hard braking,


Coolers were put on diffs because of the extended high speed cruising the diffs saw in Germany and unless you are driving the same way here (highly unlikely due to the speed limits) there really is no need for a cooler on the diff. I would put a temp gauge on it to verify that it really needs a cooler rather than go through all the expense of adding automotive jewelry 'just because.'

[m60b30530i]

is there any way to beef up our Diffs? my stock one went, the 4.10's are holding up pretty well but since they were put in i have had a whine on deceleration. i was thinking of changing the fluid because i do not know what viscosity fluid was in it before i got it so i went out and bought some 75w 90 hopfully this will quite her down.

[russiankid]

You could rig up a mechanical pump and mount it somewhere. Then get a cog onto the diff somehow on most likely the passenger side and run a belt or a chain.

[uk525td]

^^ im sorry thats just not a good idea

[5mall5nail5]

A lot of teams use mechanical pumps but...

Why? You are not going to get the diff up to a temperature that requires cooling beyond the housings ambient radiation. There is such a thing as too much cooling.

[M5W]

Well logically the factory diff does a good job as is, I see what you guys are saying. I wont put it on.

[russiankid]

^^ im sorry thats just not a good idea
I remember seeing an older M5 having this setup, not sure if it was factory but it worked well.

[uk525td]

oh i agree a mech pump may be good
but running a chain on sprockets in the harsh environment under the car? if it were a sealed drive lubricated with diff oil it would probably be ok