[4doorbmwpower]

Okay, so update is as follows.

I will still be pursuing this however, I can not for the life of my find the dimensions of the stock oil pan. If if i werent deployed i would have had mine off and been fitting under my car daily. But i can not for the life of my find a document that conclusively has the dimensions of the stock pan. That being said i have two on order for testing purposes, when i get home (3 months) i will be able to get dimensions and even scan in the stock part IOT get the exact gasket size everything after that will be custom. it also will help to know clearance from the stock plastic underbody so i know if i should keep it above that or say screw it and cut out a chunk of it for fitment.

All that being said if someone can find me a doccument that has the info i may be able to start testing from here. the prototype part is the issue. The filter i have engineered will flow more fluid with less pressure than the stock one and should eliminate even finer debris from the oil. So i have plans... just need the numbers

[135Pats]

ZF's own documents don't even have dimensions

https://www.automaticchoice.com/uplo...ue/zf6hp21.pdf

Are they the OE for the actual plastic pan? If so i'll call them on Monday.

[4doorbmwpower]

ZF probably makes the "genuine BMW" one and yes they make one and so does VAICO, i would say its a good start. Im talking in millimeters if possible! thanks man, i cant call from on ship.

[4doorbmwpower]

while i got you since when i get back i forsee me using a lot of tranny fluid. anyone used Redline's D4 ATF? they sell it on ECS and they say it meets the specs for shell Shell M1375.4 .. looking for a cheap fluid that works for our tranny...

[rooringhusky]

Originally Posted by 4doorbmwpower

while i got you since when i get back i forsee me using a lot of tranny fluid. anyone used Redline's D4 ATF? they sell it on ECS and they say it meets the specs for shell Shell M1375.4 .. looking for a cheap fluid that works for our tranny...

Redline are good fluids that a lot of people use in the stock AT. D6 is closest to the stock spec and D4 is slightly thicker viscosity. Hope that helps.

I swapped in a new pan and flushed my trans fluid with D4 a couple weeks ago, then reset transmission adaptations through INPA afterwards. Between that and the OEM E46 M3 trans mounts, my trans is shifting smoother/faster than it ever has since I owned it! Great stuff!!

[ajsalida]

Like the ideas here esp larger pan.

But I am still not seeing why replacing the stock heat exchanger, plugging the rad, mounting a large cooler off the existing lines, would put any more strain on the pump, or if it did that it would be significant enough to cause problems. It should be no harder to pump fluid through a, say, 25 row cooler mounted in the left front brake duct than it is to pump it through the OEM heat exchanger in the radiator. Heck you could even do it all OEM with the 1M/335is left radiator (just with trans oil instead of engine oil).

You could even mount a long linear cooler closer to the tranny under the car, duct the belly pan to get some air flow. Completely remove the circuit to the front of the car, and end up with less strain on the pump than stock. Not arguing here just not seeing how the internal pump is so weak or the various new fluid line configurations would be that stressful. Nobody worries about this with extra oil coolers for example. Help me understand this issue.

[135Pats]

Originally Posted by ajsalida

Like the ideas here esp larger pan.

But I am still not seeing why replacing the stock heat exchanger, plugging the rad, mounting a large cooler off the existing lines, would put any more strain on the pump, or if it did that it would be significant enough to cause problems. It should be no harder to pump fluid through a, say, 25 row cooler mounted in the left front brake duct than it is to pump it through the OEM heat exchanger in the radiator. Heck you could even do it all OEM with the 1M/335is left radiator (just with trans oil instead of engine oil).

You could even mount a long linear cooler closer to the tranny under the car, duct the belly pan to get some air flow. Completely remove the circuit to the front of the car, and end up with less strain on the pump than stock. Not arguing here just not seeing how the internal pump is so weak or the various new fluid line configurations would be that stressful. Nobody worries about this with extra oil coolers for example. Help me understand this issue.

I believe you'd need to add a dedicated pump to keep line pressure up, when it was tested pressure at the pan nosedived even with very modest changes to line routing and orientation. I can't speak for those who have cooked up DIY units, but i'm confident they haven't actually tested anything. It's just a more complicated project than it would initially seem, to all our dismay.

But we'll get it done.

[135Pats]

Originally Posted by 4doorbmwpower

while i got you since when i get back i forsee me using a lot of tranny fluid. anyone used Redline's D4 ATF? they sell it on ECS and they say it meets the specs for shell Shell M1375.4 .. looking for a cheap fluid that works for our tranny...

Originally Posted by rooringhusky

Redline are good fluids that a lot of people use in the stock AT. D6 is closest to the stock spec and D4 is slightly thicker viscosity. Hope that helps.

Originally Posted by FCobra94

I swapped in a new pan and flushed my trans fluid with D4 a couple weeks ago, then reset transmission adaptations through INPA afterwards. Between that and the OEM E46 M3 trans mounts, my trans is shifting smoother/faster than it ever has since I owned it! Great stuff!!

D4 FTW. I've run it in both my 6HP cars for a long time now, no issues in any manner. It's impossible to quantify but on paper it should be appreciably better than OE under high load, high heat situations. More viscous, more shear resistant.

[ajsalida]

Originally Posted by 135Pats

I believe you'd need to add a dedicated pump to keep line pressure up, when it was tested pressure at the pan nosedived even with very modest changes to line routing and orientation. I can't speak for those who have cooked up DIY units, but i'm confident they haven't actually tested anything. It's just a more complicated project than it would initially seem, to all our dismay.

But we'll get it done.

Thanks for the reply. Thinking out loud here. I am wondering if whatever configuration was tested had an obstruction in the lines, or they were too small diameter piping in the cooler, or something. IOW maybe what was tested was bad but that may not mean every similar configuration is bad. Because adding a couple of feet of line with no elevation or restrictions should not be enough to alter pressure characteristics.

As a basic thought experiment, just add a loop of line to the existing lines, no cooler. Is that enough to cause a big pressure restriction? No, should be no difference. Now remove the factory heat exchanger and swap with a cooler, same idea.

Tranny coolers are so basic an add-on it would amaze me if the pump in the ZF 6HP21 is so close to being maxed out that such a small change in load had such a big downside.

Would be nice to hear from others who added a cooler if they're seeing tranny temps much lower and they had any mysterious shifting issues that might be traced to this pressure drop.

[135Pats]

Originally Posted by ajsalida

Thanks for the reply. Thinking out loud here. I am wondering if whatever configuration was tested had an obstruction in the lines, or they were too small diameter piping in the cooler, or something. IOW maybe what was tested was bad but that may not mean every similar configuration is bad. Because adding a couple of feet of line with no elevation or restrictions should not be enough to alter pressure characteristics.

As a basic thought experiment, just add a loop of line to the existing lines, no cooler. Is that enough to cause a big pressure restriction? No, should be no difference. Now remove the factory heat exchanger and swap with a cooler, same idea.

Tranny coolers are so basic an add-on it would amaze me if the pump in the ZF 6HP21 is so close to being maxed out that such a small change in load had such a big downside.

Would be nice to hear from others who added a cooler if they're seeing tranny temps much lower and they had any mysterious shifting issues that might be traced to this pressure drop.

The problem is I have NEVER seen data of any type from anyone who has attempted it, everyone puts in a larger core and assumes improvements have been made (which is reasonable). I'll talk to Alex but this type of work for his shop is so easy, they do stroker builds and all that jazz. And it was pretty clear from them that it was not a viable project to do right unless big time $ was dropped.

[Ingeniator]

Originally Posted by ajsalida

Thanks for the reply. Thinking out loud here. I am wondering if whatever configuration was tested had an obstruction in the lines, or they were too small diameter piping in the cooler, or something. IOW maybe what was tested was bad but that may not mean every similar configuration is bad. Because adding a couple of feet of line with no elevation or restrictions should not be enough to alter pressure characteristics.

As a basic thought experiment, just add a loop of line to the existing lines, no cooler. Is that enough to cause a big pressure restriction? No, should be no difference. Now remove the factory heat exchanger and swap with a cooler, same idea.

Tranny coolers are so basic an add-on it would amaze me if the pump in the ZF 6HP21 is so close to being maxed out that such a small change in load had such a big downside.

Would be nice to hear from others who added a cooler if they're seeing tranny temps much lower and they had any mysterious shifting issues that might be traced to this pressure drop.

Originally Posted by 135Pats

The problem is I have NEVER seen data of any type from anyone who has attempted it, everyone puts in a larger core and assumes improvements have been made (which is reasonable). I'll talk to Alex but this type of work for his shop is so easy, they do stroker builds and all that jazz. And it was pretty clear from them that it was not a viable project to do right unless big time $ was dropped.

Pats real world data is correct. If you look at piping system design theory. Any additional length in piping fittings and exchangers will add pressure drop as the drag coefficients on the fittings will compound into equivalent length. If the pump doesn't have enough NPSHA line pressure will drop.

Some basic info.

[4doorbmwpower]

about the oil cooler debate. The problem lies in the fact that the stock setup with the heat exchanger doesn't change the VOLUME like adding >6ft of -6AN lines and a 19 row core. Trust me i got all the parts. people run larger OC off the stock pump because the car was INTENDED to and the OC ideas most people have are actually easier than the stock ridiculously bent frankly poor setup, and for people like me they dont even have one in the first place. The problem with adding to the tranny is how sensitive that system is; it doesnt like change. And Pat is correct in saying anyone who has done this has not actually logged any real data. why... because its hard to. SO my entire thought process branched off into engineering a new pan that will increase fluid capacity and to compensate for the increase in psi requirements i am going to engineer a new way to get the fluid UP into the tranny. This is where we stand now. I am forward deployed so R&D is hard BUT, its working slowly but surely. and when i get home it will go much faster. cause i can Frankenstein my own vehicle

[4doorbmwpower]

Everyone that was involved. I wanted to revitalize this thread. I have found a partner. We will be starting on the process of designing my pan. Hopefully we will have it available by Easter timeframe.