M20 with ZF Possible?

[Hatch]

Hello all, I'm a noob on the forums, a semi-noob to BMW, and a dated technician.

I currently have a M20 Auto ETA and was wondering if anyone has done (or seen) a successful m20 engine mated to a e36 ZF trans.

I ask this because I got a free ZF that had a issue going into 5th and reverse from a friend and did the 5th gear pin TSB on it, so I'ma take my chances.

I know that you can put a M5x into the e30 using the getrag transmission, but can it be done the other way around, like I want too?

[Herr Faust Schinken]

you will need a custom trans brace a different drive shaft a bent selector rod its not worth it for a stock m20 , it drops in with m5x motors because the zf doesn't sit at an angle like the getrags do but if you put a zf in with an m20 it will be at an angle so you would have some work to make it fit

[Hatch]

Thanks for the fast reply!

I have a M50 on the engine stand waiting to go in. I was just curious as to why noone ever did a ZF swap for it's higher hp rating over the Getrag.

Time to start a swap!

[akorcovelos]

Jordan has a euro zf 6spd in his e30. I think the biggest reason peopke dont do it is there is no real benefit when using a US spec zf since the final ratio is the same as the getrag. So you end up just having to shift more for the same performance as the 5spd. The euro zf has a higher final ratio and better ratios for the other gears, so it more beneficial. Im just regurgitating what ive read on the forums, so take it for what its worth.

[Herr Faust Schinken]

Thanks for the fast reply!

I have a M50 on the engine stand waiting to go in. I was just curious as to why noone ever did a ZF swap for it's higher hp rating over the Getrag.

Time to start a swap!

yeah the m50 with the zf320 will be excellent just you will want a lower final drive ratio to compensate

[Hatch]

yeah the m50 with the zf320 will be excellent just you will want a lower final drive ratio to compensate

I got a 2.79 out back. I am slowing turning this e30 into my daily. I drive my 95 m3 alot and gas gets expensive with a 3.45 out back...:D

[Wanganstyle]

I got a 2.79 out back. I am slowing turning this e30 into my daily. I drive my 95 m3 alot and gas gets expensive with a 3.45 out back...:D

ZF 5 speed is a great idea for a e30 with M20 stock engine: I put a ZF 6 speed with my M20 engine and it was great.
ZF 6 speed is = ZF 5 speed but has overdrive #6. 5 speed is much easier to mate up to E30 also; you can modify original shifting parts slightly to work and use an original E30 5 speed driveshaft as well.


ZF5 will bolt right up and you can use either E36 complete clutch&flywheel setup or E30 complete clutch/fly setup (ideal if you have a spare from your e36M)

if you have fabrication ability for a crossmember and to bend the shift carrier+ selector (and weld it up) then this costs you almost nothing.

the ZF 5 speed is more modern and efficient than the Getrag G260's.
Gearing is also very close ratio and does not have overdrive; G260 has a ~.83 or .81 overdrive.


M20b25 "i" engine with G260 and 2.93/2.79 final is a DOG; so slow. with a ZF5 speed it would be nice around town and also cruise decent.

[Wh33lhop]

ZF 5 speed is a great idea for a e30 with M20 stock engine: I put a ZF 6 speed with my M20 engine and it was great.
ZF 6 speed is = ZF 5 speed but has overdrive #6. 5 speed is much easier to mate up to E30 also; you can modify original shifting parts slightly to work and use an original E30 5 speed driveshaft as well.


ZF5 will bolt right up and you can use either E36 complete clutch&flywheel setup or E30 complete clutch/fly setup (ideal if you have a spare from your e36M)

if you have fabrication ability for a crossmember and to bend the shift carrier+ selector (and weld it up) then this costs you almost nothing.

the ZF 5 speed is more modern and efficient than the Getrag G260's.
Gearing is also very close ratio and does not have overdrive; G260 has a ~.83 or .81 overdrive.


M20b25 "i" engine with G260 and 2.93/2.79 final is a DOG; so slow. with a ZF5 speed it would be nice around town and also cruise decent.

If you normalize the ratios, the G260 is very very close to the ZF5 with the exception of first gear, which is ~10% longer (closer to second) in the ZF. All other gear spacing is within a few percent between the two.

The main performance benefit of the ZF is the higher torque rating (I think the G260 has stoll been proven suitable for higher hp applications), the fact that it's newer and that you do not have to run a very high rear end to get shorter gearing. The drawbacks are cost, not a direct fit and you may have to deal with fifth gear lean; a problem the Getrag lacks. Also, if you want to be able to cruise at 80 without going insane an overdrive trans is nice, although again it will depend on your choice of final drive.

[e30m20TurbO7]

[ThatOneEuroE30]

completely possible the m20b20 n my car was paired to a zf tranny but the zf i have was out of a e9 or something like that haha euro cars are f'ing wierd

[Wanganstyle]

I had a zf 6 speed bolted to my m20. Works happily

[snowboarder2587]

I am about to do a similar swap as well. I'm swaping out my g260 with a ZF310 in my 1986 325es (turbo build in progress). My first gear in the g260 is completely shot (car wont move and trans just grinds in gear). I was looking for a 260 but locally they are hard to find and I found a really good deal ($240) on the ZF trans. The fact that I am a manufacturing engineer for ZF transmissions may have also uped the cool factor for me.

Did you finish your swap? I like to know how it turned out. Also which starter/flywheel/clutch set up did you go with? I plan on using the starter/flywheel/clutch from my m20. I read that the flywheel has to be shaved down but I haven't seen a confirmation of that and how much needs to be shaved off. Also did you modify your trans crossmember yourself or did you buy an already modified one?

[Wanganstyle]

If you normalize the ratios, the G260 is very very close to the ZF5 with the exception of first gear, which is ~10% longer (closer to second) in the ZF. All other gear spacing is within a few percent between the two.

The main performance benefit of the ZF is the higher torque rating (I think the G260 has stoll been proven suitable for higher hp applications), the fact that it's newer and that you do not have to run a very high rear end to get shorter gearing. The drawbacks are cost, not a direct fit and you may have to deal with fifth gear lean; a problem the Getrag lacks. Also, if you want to be able to cruise at 80 without going insane an overdrive trans is nice, although again it will depend on your choice of final drive.

if playing apples to apples the 2.79 rear with no overdrive will be alot LONGER than the stock G260 e30 setup


original setups:

E30 G260 (0.83 5th) + 3.73 -
e36 (325i): G250 (1:1 5th) + 3,15
e36 95 m3 ZF5 (1:1 5th) + 3,15

5th gear top speed calculation is within 3 mph for same RPM


G260-5 of e30 is also subject to case flexing and alot older internals;
g260-6 in the m30b35 cars seems to be the same gears but a different and stiffer transmission case; this one does not seem to have as much flexing issues

[GunMetalGrey]

I have supplied a lot of braces for odd engine/trans/chassis combos. From e21 to e30, ranging with all of the common transmissions.

[Nisse Järnet]

If u find a diesel ZF 525tds E34 for example its bolt on with stock gearbox mounts etc.
A M3 E36 3.2 6 speed 420g fits just as good as a ZF 320 btw.