giovani58 0 Report post Posted January 24, 2008 I have a 1988 e30 320i i want to replace the engine with a 325 from a 1990 model. Do i need to chance the gearbox and diff? Do i need to change the wiring, computer etc? Quote Share this post Link to post Share on other sites
antony 0 Report post Posted January 24, 2008 (edited) Gearbox no. Diff maybe. Will depend on what ratio diff you have, but with the 325 engine it will more than likely make it rev happy, good around town, but not so good on the open road. Some people like it. But I would recommend you change it. You won't need to change wiring, but will need to swap computers (ecu's). O, and welcome. Edited January 24, 2008 by antony Quote Share this post Link to post Share on other sites
tire 10 Report post Posted January 24, 2008 I'm interested as to why you are going for such a marginal upgrade? Surely to make it worth your while taking the engine out and faffing round for hours you would go for something like an M50B25? Just curious.. Quote Share this post Link to post Share on other sites
antony 0 Report post Posted January 24, 2008 Time and Money. Quote Share this post Link to post Share on other sites
will 169 Report post Posted January 24, 2008 (edited) I'm interested as to why you are going for such a marginal upgrade? Surely to make it worth your while taking the engine out and faffing round for hours you would go for something like an M50B25? Just curious.. 2.5 M20 motor is significantly stronger (Power/torque wise) than 2.0 M20. Also it is a job that can be done in a few hours with NO mods. M50B25 involves a lot of mods to make it fit and will probably take weeks to get it all fabricated/installed and will cost significantly more than an M20 2.5 transplant. The 2.5 will bolt up to the 2.0 gearbox, diff might be a bit short depending on your taste, 2.5 generally has a 3.64 ratio, and you will need the 2.5 computer box. Will EDIT>>> forgot that the exhaust manifold is normally different between the 2.0/2.5. Most 2.0 have a 3stud manifold where the downpipe bolts on and the 2.5 has a 4stud connection. You can swap the manifolds but the 2.0 generally has a smaller internal diameter so I would recommend using the 2.5 one and changing the downpipe on your exhaust. Edited January 24, 2008 by will Quote Share this post Link to post Share on other sites
Mike 1 Report post Posted January 24, 2008 2.5 M20 motor is significantly stronger (Power/torque wise) than 2.0 M20. Also it is a job that can be done in a few hours with NO mods. M50B25 involves a lot of mods to make it fit and will probably take weeks to get it all fabricated/installed and will cost significantly more than an M20 2.5 transplant. The 2.5 will bolt up to the 2.0 gearbox, diff might be a bit short depending on your taste, 2.5 generally has a 3.64 ratio, and you will need the 2.5 computer box. Will couldn't have said it better. 320's got nothing on a 325, 2.5 is a really worthwhile upgrade, much better than stuffing round with chips, exhausts etc on a 320i Quote Share this post Link to post Share on other sites
tire 10 Report post Posted January 24, 2008 2.5 M20 motor is significantly stronger (Power/torque wise) than 2.0 M20. Also it is a job that can be done in a few hours with NO mods. M50B25 involves a lot of mods to make it fit and will probably take weeks to get it all fabricated/installed and will cost significantly more than an M20 2.5 transplant. The 2.5 will bolt up to the 2.0 gearbox, diff might be a bit short depending on your taste, 2.5 generally has a 3.64 ratio, and you will need the 2.5 computer box. Will EDIT>>> forgot that the exhaust manifold is normally different between the 2.0/2.5. Most 2.0 have a 3stud manifold where the downpipe bolts on and the 2.5 has a 4stud connection. You can swap the manifolds but the 2.0 generally has a smaller internal diameter so I would recommend using the 2.5 one and changing the downpipe on your exhaust. Understood. Thanks Quote Share this post Link to post Share on other sites
giovani58 0 Report post Posted January 24, 2008 Understood. Thanks I bought a 1990 325i in damaged condition has a good running engine my 320i engine needs fixing but would cost to much. so this is my best option. Quote Share this post Link to post Share on other sites
giovani58 0 Report post Posted January 24, 2008 I don't know where the computer on the 320i is. On the 325 we have it is on the left rear mudguard. Where will i find it on the 320i? Quote Share this post Link to post Share on other sites
will 169 Report post Posted January 24, 2008 I don't know where the computer on the 320i is. On the 325 we have it is on the left rear mudguard. Where will i find it on the 320i? I don't think what you have found is the ECU for the engine, it is always above the pedal cluster in the E30 (RHS). Follow the engine management loom where it goes through the firewall on the driver's side (next to the battery) and you will find it up under the dash above the pedals. You may have to remove the cover under the steering to get to it. Will Quote Share this post Link to post Share on other sites
ED1RTY 2 Report post Posted January 24, 2008 ^ What Will said, the one in the boot will be ASC OR ABS Quote Share this post Link to post Share on other sites
*Glenn* 855 Report post Posted January 24, 2008 I don't know where the computer on the 320i is. On the 325 we have it is on the left rear mudguard. The computer in the boot is for transmission. The one in the glovebox is ABS if it has ABS and as Will said the engine computer is under the dash on the drivers side. Quote Share this post Link to post Share on other sites
ED1RTY 2 Report post Posted January 24, 2008 Ahhh so we figured it out Glenn? When we were looking at it when I was in the shop we seemed to think that the boot one was for ABS Quote Share this post Link to post Share on other sites
*Glenn* 855 Report post Posted January 24, 2008 Ahhh so we figured it out Glenn? When we were looking at it when I was in the shop we seemed to think that the boot one was for ABS Part numbers=ETK=solution Quote Share this post Link to post Share on other sites
will 169 Report post Posted January 24, 2008 ^ What Will said, the one in the boot will be ASC OR ABS ASC in an E30?? Been smoking the wrong brand of socks again Chris?? Quote Share this post Link to post Share on other sites
giovani58 0 Report post Posted January 25, 2008 Thanks every one for the help. will keep you posted on the progress. Quote Share this post Link to post Share on other sites
giovani58 0 Report post Posted January 29, 2008 the 320i has a diff ratio of 3.59/1 the 325i has a diff ratio of 3.73 I was looking through the service record for the 325i it was bought new by the Soviet Embassy in Wellington in february of 1990. Quote Share this post Link to post Share on other sites
