E36: 325i engine with M3 gearbox??

[mybmmer318]

Hi guys.Anyone using this set up now? A M50B25 engine with a a m3 manual 3 litre gearbox? If using the m3 gearbox do i have to replaced the drive shaft and rear differential too??Currently driving a 318is manual but intend to swop out the M42B18 to a M50B25. Hers a few setup that i have in mind: Option1.M50B25 engine with Manual M3 3litre gearbox. Option2.M50B25 engine with my current manual M42 gearbox. Option3.S50M30(M3) engine with Manual M3 3 litre gearbox. For Option1: do i have to replace my current long shaft and rear differential? For Option2: i have read that this set up i can still use back my orginal gearbox, ecu, drive shaft and differential?? Correct me if i am wrong. For Option3: I know quite diffcult to find but still possible but can be very costly. i already have lobang to secure the S50 manual gearbox and rear differential and i need advices whether which set up will be the most effective in terms of cost and power output as i understand changing into a M3 engine is not as simple as putting it in.If Option 2 is affordable and not so complicated with increase in power i will ditch the m3 gearbox and rear differential idea and concentrate on looking for a B25 then.Many help appreciated. Thanks for reading

 

[ALBundy]

Your current differential ratio is 3.46. If you swap to M3 LSD differential, the ratio is likely to be 3.15, much better in my opinion. You would also need to change your rear subframe together with the driveshafts.

As for the swapping gearboxes, your could use back your existing long shaft.

Hope this helps.

 

[mybmmer318]

Your current differential ratio is 3.46. If you swap to M3 LSD differential, the ratio is likely to be 3.15, much better in my opinion. You would also need to change your rear subframe together with the driveshafts.

As for the swapping gearboxes, your could use back your existing long shaft.

Hope this helps.

Hi ALBundy, thks for sharing.btw where is the rear subframe u mention? Isit the piece where u mount the differential together? Are the subframe and drive shaft diffcult to find in our local chop shops?

 

[Lionel_Koh]

Hi guys.Anyone using this set up now? A M50B25 engine with a a m3 manual 3 litre gearbox? If using the m3 gearbox do i have to replaced the and rear differential too??Currently driving a 318is manual but intend to swop out the M42B18 to a M50B25. Hers a few setup that i have in mind:

Option1.M50B25 engine with Manual M3 3litre gearbox.
-A bit wast if u ask me as getrag 220 is more then enuf for M50B25 unless u intend stroke to 3.0 in future .....M3 clutch set wil cost u around 2k...

Option2.M50B25 engine with my current manual M42 gearbox.
-Yes ......The simple and cheapest way .......U can use back ur rear axle ir u dun mind the ratio is a bit high......If u change to 325 axle @ 3.15....u need to change the driveshaft and whole subframe ...and modified ur longshaft as well cos it will a bit long ......

Option3.S50M30(M3) engine with Manual M3 3 litre gearbox.
-The best upgrade but wil cost a lot ....

For Option1: do i have to replace my current propeller drive shaft and
-Yes ....u must

For Option2: i have read that this set up i can still use back my orginal gearbox, ecu, drive shaft and?? Correct me if i am wrong.
-All can use back except ECU (if u mean engine ECU)...FYI manual box dun hv any ECU


For Option3: I know quite diffcult to find but still possible but can be very costly.
-Yes ......But i know got one complate USA M3(3.0) laying around ...PM me if u interested .........

i already have lobang to secure the S50 and rear differential and i need advices whether which set up will be the most effective in terms of cost and power output as i understand changing into a M3 engine is not as simple as putting it in.If Option 2 is affordable and not so complicated with increase in power i will ditch the m3 gearbox and rear differential idea and concentrate on looking for a B25 then.Many help appreciated.

Thanks for reading

 

[ALBundy]

Hi ALBundy, thks for sharing.btw where is the rear subframe u mention? Isit the piece where u mount the differential together? Are the subframe and drive shaft diffcult to find in our local chop shops?

The subframe is not difficult to find and neither is it expensive. Its just that you need replace the subframe and driveshafts in order to fit in the bigger rear axle. This subframe will also fit the M3 rear differential.

Cheers.

 

[mybmmer318]

The subframe is not difficult to find and neither is it expensive. Its just that you need replace the subframe and driveshafts in order to fit in the bigger rear axle. This subframe will also fit the M3 rear differential.

Cheers.

Someone on ebay is selling the complete assembly of the subframe, differential, drive shafts, knuckles and even rear rotors and calipers from a M3 for 800USD excluding shipping.But he mention that this will fit most 4 bolt mounted differential.Does the 1992/3 318is comes with 4 bolt or 6 bolt mounted differential as the seller mention that for 6 bolt differential u need different drive shaft or is he talking about the long shaft then? The whole assmble + shipping will roughly set u back ard 1-1.1k USD so wondering isit worth getting it or from our local chop shops?