E30 Zone

I've got a 90 spec 318i with an m40 in it, accelerating through lower gears is slow and sluggish. After a bit of snooping about, I've heard its possible to put a single mass flywheel and a clutch from a 325 on my car which will help it accelerate through the lower gears(add some umph). Any ideas on this guys? Is it possible? anything else I could do? cheers!

Use a lightened m20 flywheel, iirc you will also have to use the starter.

Another option would be going for a lower ratio diff.

You've got a single mass flywheel to start with, but the M20 ones are more commonly available in a lightened form. However, while this will help the engine rev up better, it's not going to make a huge difference to an asthmatic 4-pot.

If you want acceleration, it might be better to change your diff, which will get you off the line quicker at the expense of your cruising fuel economy.

My 1991 M40 318i pulls off very well and flies through all the gears in no time.

Is the engine revving up to 5,500 RPM easily? If not then you probably have a worn camshaft and changing the diff or flywheel will not help much!