M50B25TU - G220 vs G240 + LSD

[N-Gen]

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The issue at the moment is the gearbox. The engine came with a G220 and I can only assume the one I have on the 316i is a G240 (will have to verify).

The LSD is 3.91 and I need to pick a gearbox before I choose what ring and pinion to drop into it and change the ratio.



Cleared on 25th Feb 2014 - I just received shipment of the parts needed for the engine swap.

I was lead to believe I bought a M50B25, however it has a VANOS unit, if I'm correct. I matched the cylinder head serial and it is a VANOS cylinder head.

I can't seem to find the engine number, so help on that would be very much appreciated.

Apart from that, is it correct to assume all M50s are OBD-I?

Don't know if the photo is of much help.

[tytypetersen]

Looks like an obd1 m50b25tu. I can tell by the oil fill cap is in the back and it has the obd1 intake manifold. As for the vanos the m50s from 93-95 came with it. That is what the tu in the engine code is from, it stands for technological update. The engines serial number should be on the block on the intake side, right underneath where the motor arm would go. Hope that helps!

[N-Gen]

Wouldn't that be M50TUB25? :P

Nice to know what TU stands for though, never bothered looking it up. I did read some stuff about the oil cap and so on but I've never really checked into the different technicalities on M50 engines so your conclusion was very helpful. Glad it's OBD1, saves me lots of hassle.

Now, to sort out what tranny it has...a whole new can of worms there. I know it's a Getrag, numbers on it are 226, 023 and 2200.0225.98

Ideas?

[Varinn]

I'm not well versed on the exact details of e36 transmissions but I believe it will be a Getrag 250. Same gearing as a ZF but weaker, came on e36 318/325's.

[N-Gen]

The problem is, the VIN on the ECU shows the car being an auto. This is a manual, so I have to figure out what stuff is one by one.

[Nick_S]

Def an M50TU. Do you know what car is came from? E36 or E34? I've read the E36 harness is much more swap friendly to use. If the harness is in fact from an auto car it should have some extra connections. As far as the transmission. Is likely a G250 and would be just fine behind an M50. Although depending on your rear dif it can be a r3v happy setup.

Read this if you haven't.

http://www.e30dohc.com/wiki/index.php?title=DOHC_Swap_Basics

Then read it again. And again for good measures. And then maybe once more. There is so much info on these swaps on here. It's quite easy if you take your time and know what you're doing.

[N-Gen]

That's a good read, I'll keep it handy, thanks.

Engine and gearbox came with all the correct conversion parts as the person/company I bought them from deal with conversions themselves, so I'm pretty confident I have everything. Including the E36 steering rack.

Engine came off a 325i Sport. ECU has a sticker over the label, but I'm told it's blank so I'll need to flash it.


Edit: Also includes E30 3.46 (I believe 3.46) LSD.

[franky2fingaz]

3.45, but that was for the 318is, if your diff came from an E36 325i then it should be a 3.15, which should be perfect with the G250 and no OD

http://www.bokchoys.com/differential/GearRatios.htm

[N-Gen]

The diff should have come from an E30, I sourced parts from different cars.

[franky2fingaz]

I thought you were going to do a double ear fabrication :P , well bottom line is there is no 3.4X in E30s, just make sure it didn't come from a 318 or anything shorter than presumed ratio, with the G250 your car would make a good farm tractor with such ratios

http://www.e30tech.com/forum/showthread.php?t=1863

Edit: Malta? nice place, this changes things, what market E30/36 are you dealing with? you might be right if Euro markets had such diff

[N-Gen]

Yup, all Euro stuff here. To be specific, the same as any UK version, so we have RHD E30s.

http://en.wikipedia.org/wiki/BMW_3_Series_(E30)#Differentials

3.46 does exist, but it might be a 3.64 since they seem more common. I'm sure there's a place I could identify what diff it is, right?

Edit: Engine and parts were sourced from the UK and shipped here, so it was a UK spec E36.

[N-Gen]

A bit of research later and it seems to be a Getrag 220 which was featured in Euro spec E36 318 and 325 models and seems to have almost identical ratios to the 250.

Thinking I'd have to probably change it if I turbo later.

[franky2fingaz]

If your diff is a 3.64 along with this transmission, you will be revving past 4K at 110KPH, 1st gear is for pulling tree stumps, just so you know before mating it all up, some like this combo but I can't live it..

[N-Gen]

110kph on 1st gear? And in the case it's a 3.46?

Edit: Never mind, final gear. I should have a Getrag 240 in the car right now (will have to verify), assuming that will work better?

[franky2fingaz]

no 5th at 110kph, I was also adding that 1st will be useless, like a creeper gear...will be shifting quickly out of 1st or start in 2nd...

G250, ZF and other same ratio transmissions need something like 2.93 to 3.23 diffs for good highway cruising and daily driving, any diffs with lower ratios (numerically higher) means overall RPM will be higher in all gears.

G240 will work, but it's the same ratios so no point...