Hey guys, great mag — it’s always a good read! I’ve got a question for you about my '85 BMW 323i (E30 shape). At the moment it’s got the 2.3-litre, straight six engine, which is reliable and goes alright. However, an opportunity has arisen for me to purchase a 325i (2.5-litre) engine from an '87 E30 BMW. How much power would I gain from this conversion or is it worth going with something else? If I go for the BMW engine, will the 2.5 fit easily into my engine bay and can I keep my manual gearbox, clutch and diff? Any information will be appreciated.

Cheers, Matt Oliver

Yes it will fit and it is worth doing as you’ll definitely pickup a bit more power and torque. You can keep your setup as is, but I would replace the clutch with a H/D so it’s ready for more mods. I’m building a similar setup at the moment for my 5 Series and building the motor to take a large hair dryer. You could go to something else like a 2JZ, but you’re up for a lot more time and money. Extracting 400hp out of the M20 2.5 engine isn’t hard to do, but like me, I’m sure when the bug bites, you’ll want to go for a little more than that!

SM

This article is from Performance Car Issue #113. Check it our here.