Transmission - Auto to Manual

Post Wed Oct 08, 2008 1:13 pm

I'm planning to do an engine swap at some point to change my 320i Auto into a 325i. I would like to get the car converted to manual soon and was wondering if a 325i gearbox could be used to convert my car to a manual rather than a 320i gearbox? Or, if the engines can use each others gearbox could i use a 320i gearbox for the transmission conversion and then put the head of the 325i (+everything else) onto that and do it that way? I know that if the gearboxes are compatible they would have different gear ratios, and if this could be done what would the differences be? would the 320i gearbox have shorter gear ratios and allow for quicker acceleration? Sorry probably going too far here so any info would be appreciated! Cheers.

p.s. or is worth putting up with a 320i auto for next 9ish months and then doing the whole thing outright?

Post Wed Oct 08, 2008 9:40 pm

The 320 manual box will work on the 2.5 motor. i used a 320 box for 1 year after changing my 320 to 325 the 320 have the better ratios of the two, as the ratios are very close to the sportbox/ close ratio box that bmw had on some 325 models. in the 320 box the first gear is longer than 2,5 2nd bit longer 3rd a bit longer, 4th and 5th same ratios. the drop on rpm between gear changes is smaller allowing you to stay in the power band all the way to 4th gear after a gear change. its only the prop shaft that is longer on the 320 box as the box is shorter than a 325 one . if you keep the auto box youl only really enjoy the car after you convert it to manual
here is a link to a how to do the auto to manual conversion
http://www.e30clubsa.co.za/forum/index.php?showtopic=50

Post Thu Oct 09, 2008 1:08 pm

Thanks hennie, good info! i may just get a 320i box then and convert my car to manual for the time being. Then next year convert it.

Otherwise, i found a 325i with a working engine that could be used to completely fix my car up (+Engine) but as its a 325i sport (tech2) i may sell my car as a nice working vehicle in good nick and fix up this 325i thats had a knock on the front corner (would also need the engine completely reconditioning, but i would of done that anyway to make it a nice car to drive as its done 118k and in Jersey thats a very large amount in comparison to englands motorway milage). The dudes asking a fair bit tho for it, was 1200 but got him down to 750 + a banger of a fiesta but still its a little high. Otherwise it'll be an engine conversion for the 320i!

Cheers for the help tho, much appriecated!