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E30 318i M42B18 Exhaust Question

Posted: Sat Aug 02, 2025 4:47 pm
by Scottlaw
Afternoon Zoners

Long time lurker here.

I bought a pretty nice E30 318i 3 years ago and have spent some time making it my own. I am a OEM+ kind of guy. Don’t know how to add pictures here, anyhow.

I recently swapped a m42b18 from a z3 into the car and it’s going well, it’s got a lightened fly wheel from JB racing. I have the original 318i exhaust fabricated on for now but intend to replace it.

My question is, how much different, if at all, was the IS exhaust compared to the I?

Secondly, will I see any performance gain by going aftermarket and am I restricted flow with my current set up?

Lastly, do you guys have recommendations for a back box type set up? I’ve seen the super sprint options and it’s expensive.

Best

Scott
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Re: E30 318i M42B18 Exhaust Question

Posted: Sun Aug 03, 2025 12:21 pm
by martauto
Can`t help with the exhaust but have a look at this for the pictures mate .:)
Mart.

viewtopic.php?f=114&t=277018

Re: E30 318i M42B18 Exhaust Question

Posted: Sun Aug 03, 2025 1:13 pm
by Scottlaw
Ah yes, sorted now, thankyou

Re: E30 318i M42B18 Exhaust Question

Posted: Mon Aug 04, 2025 12:35 am
by Speedtouch
Car looks great, though I would perhaps improve the air filter, maybe by going with the standard airbox but with a K&N panel filter.

Is the whole of that house actually painted like that?!