and some updates! our own design dct oil pan
you can think, "why we can't just go and buy one of the dct pans, which already sells enough on market?". i'll return to this question after typing some info
.
first time we thought about custom pan in summer, when swapped dct on our e82, but those time we had no time for this.
anyway, after some dct usage on track we have a lot of experience with it and we saw some weak spots.
one of the main problems on track - oil starvation. it happens when you have high G on lateral acceleration and after hard braking. dct trying to get right oil pressure, to make some of the operations, like working with clutch or gear shifting, and it can't build enough pressure, cause oil goes away from suction pipe. in that moment you can get some short delay, or, if you'll continue to push acceleration pedal - fault code on dash and transmission warning light.
easiest solution - raise oil level. this way chose bmw on their track oriented M3 GTS- it has additional liter in transmission.
this solution helps a lot, but not totally - on stock oil level we can get some transmission warnings every track session and after raising the level like on gts, only 1-2 times per day (about 8-10 sessions). thanks to huge grip of 275 square setup hankook semi slick
.
so we decided to close this issue totally with changing stock dct pan. in our own design pan we added some huge partitions all over bottom surface. another way - lowering bottom of the pan. but it wouldn't have any real effect, if suction pipe will stay on same height as stock. so, we also make some spacer, to lower suction pipe to the lowest point of our new pan.
another weak spot - dct overheating. in some cases we had up to 185c degrees in some points of the transmission (oil ramp over forks and hubs).
main solution (and most effective) - uprated oil cooler. we also use it, but if we making custom piece of aluminum, we can make anything we want
. so we must to use all possibilities - and we add some real cooling fins all over bottom surface.
another additional function of new pan - add some stiffness to transmission case. oem dct pan made from plastic, which also bends on high temperatures - to compensate this, bmw (or getrag) use thick rubber seal.
in our case we don't need to compensate bended flange surface of the pan (cause it has excellent smooth surface), and if we will continue to use rubber, we can't get hard connection between oil pan and main case. so, designing oil pan flange without rubber seal, to fit it with sealing compound.
and another one condition - oem dct oil pan has a little slope from the front to the end. this was made to compensate transmission angle, when it installed on the car. this slope on the pan gives horizontal position for the bottom of the pan. we had repeated same slope on our pan.
also, we have some limits in the height - most of the track oriented cars has low ride height and smallest ground clearance, so we can't add height a lot.
so we have tried to make max height, which will not make our pan - lowest point (around transmission location).
so, why just don't go and buy?
because i've spent a lot of time, looking through the internet, and i saw most of them and... i don't like any of them
.
all of them has some real minuses. a lot of them were made with huge savings in manufacturing - small cooling fins, which i don't understand how to call "cooling fins" (real fins takes a lot of cnc time). bottom without any slope - huge cnc time economy (if you work on 3-axles machine).
most of the pans has simplest design inside, without any partitions. best i saw - some small partitions on the bottom, which doesn't make any real difference.
and a lot of deep pans - one deeper than another
but no one of them thought about suction pipe height.
and another "why?" because we can
ps this one was made for our M3F80. second copy, for our e82, will be done after new year vacations.
i'll post some pics, fitted on the car later.
