E30 Zone

could someone tell me if you can fit for example a 320i back box on to a 325i system , i know there's a 2 part and a 3 part system .
The reason i ask is when I've had a look in the gsf cat the price difference is quite alot

I believe you might be able to fit them together although I wouldn't recommend it. Although the pipes under the car look very similar in size they are actually a slightly different diameter.

I've got a 320 system on my 325i Touring from the manifold back. It works ok but my fuel consumption has gone up - don't know if that's coincidence or if it's cause the smaller exhaust creates a bit more back pressure.

Easiest way to tell with back boxes between 320 and 325 is the tailpipe diameter. On original BMW exhausts 320 have 45mm diameter tail pipes and 325s slightly larger at 60mm. If I were you I would go for the proper 325i system, you can bet the BMW engineers designed the system to work best this way.

I think you will find the 325 system is a twin system from front to rear and the 320 is a single system. On this theory you will end up with one pipe on your 325 centre section not having anywhere to go infront of the 320 back box.

I fitted a complete 325 Scorpion system inc. manifold to my 320i with no problems at all.

I disagree, 6 cylinder engines including 320 and 325 have twin system as far as I've seen - pretty sure!

If you want people to hear you coming Scorpion is great and it's got a nice burble at low revs, otherwise stick with something slightly more standard to be a bit more discrete

I agree with dannosail ,
320's do have twin system from 1987 as far as i know. Earlier 320's had a single system. Also pipe dia is slightly bigger on 325, although i couldnt tell you the actual dia. Im sure sure someone on here will know though.

lee

IIRC, the 325i system does fit on the 320i. So I'm lead to believe

dannosil - my early 320i had a single system when I purchased it. I think you might be right with the later ones having twin systems half or maybe the full way.

The Scorpion exhaust is loud when you rev it. At cruising speeds it is not too bad, although I can definately appreciate some might not like it because it does make the car louder than standard.