Samm 0 Report post Posted October 29, 2014 I have a 1998 e36 sedan which I got a manual conversion on - any tips on how to increase performance? its gone a bit slower from when it was automatic - I think because it still has a automatic diff? Quote Share this post Link to post Share on other sites
Ahmedsinc 414 Report post Posted October 29, 2014 Replace the engine with an M52B28. The M52B25 was a crappy midpoint between the B20 & B28. Most auto 323i used a 3.64 final drive, if you still have the auto diff it should be quicker off the line than an auto given the 5 speed Getrags (and I believe the ZF too, though correct me if I'm wrong there) use a 1:1 5th. Did you do the manual swap or was it done by the previous owner? If you bought the car with the conversion already done they might have used a 3.15 or even 3.07 / 2.93 diff. Have a look at the tag on the diff cover, will have the ratio stamped on it. There are plenty of online calculators that will show you the real world differences between diff ratios (engine rpm vs. speed), all you need to know is your 5th gear ratio and tyre size, it does all the thinking for you Quote Share this post Link to post Share on other sites
thorburn 121 Report post Posted October 29, 2014 How much do you want to spend? Has it has a full service, scan and check over recently Quote Share this post Link to post Share on other sites
No name user 379 Report post Posted October 30, 2014 check Realoem for the ratio based on your chassis number for the manual/auto diff ratio Quote Share this post Link to post Share on other sites
