m30 exhaust.

[gooner1]

Have been supplied with some exhaust flange drawings for the m30
conversion( thanks again Gareth) but getting really confused as to which
route to go.Will be using at least some of the E34 downpipes so do i try M3
straight through from there, have read that its doable but not easy, E30 235I two or three peice, or mate up with m30 sections. Really after the easiest and most straightforward route tbh. Have done a few searches but would like to hear from owners of this conversion please.
Will be going into a 93 318 touring btw. Thanks all

[gareth]

easy peasy!

fit the M30 (ideally with late M30 manifolds)

then get a E30 M3 exhaust system on there.

when you offer up the M30 downpipes, you'll immediately see where they need to be cut back to and the '8' shaped flange welded on.

the '0' shaped flanges i sent on that email are if you want to make up your own manifold... not necessary unless you're fitting a turbo

[charlE30]

The quickest and easiest way of doing it is to use a 325 system, it's not ideal but will mean you can use your car. I'm trying to find a complete 535 system to butcher up and hopefully fit. I want to get mine sounding like a standard 535 with a nice quiet burble if you know what I mean.

If you can weld though anything is possible....

E34 downpipes with slits cut in to close it up.



Section of 325 3 piece downpipes



Slides inside E34 downpipe



Then it fits onto a standard 325 system although it's now a Scorpion 325 system

[e30_singh]

looks good fella!!

[gooner1]

Gareth,not a great pic i know but are these the later shape manifolds, take it if not they will still be ok.

[ed325i]

I would use the 325 system.

[gooner1]

Thanks for info and pics charlE30, think im leaning more to the m3 route. Take it your 325i rad is still coping well.

[charlE30]

Thanks for info and pics charlE30, think im leaning more to the m3 route. Take it your 325i rad is still coping well.

My exhaust was a "balls I've run out of money" system Works well and sounds good although I don't know what power I'm losing, my friends 535i sport still couldn't keep up

What is the internal diameter of the M3 system? I only ask as I did have an old supersprint M3 backbox which fitted perfectly to the 325 standard centre box...

On the radiator front.. yep still going very strong never gets above half crawling in traffic and sits just above 1/4 at speed. It has actually surprised me considering the size difference.

Judging by your piccy of your engine you do have the later type manifold, the earlier one was one piece a bit like the M20 mani..

Have fun with it all mate

[gooner1]

[quote="ed325i"]I would use the 325 system.[/quote
What makes you say that Ed?

[ed325i]

As said above the m3 system is the same size as the 325 one and is going to flow better than a 535 system.

[gooner1]

Aahh got you, thought you meant use the e30 325 one as oposed to the m3.

[ed325i]

They say on e30.de to use a performance exhaust (conservatively) to be made of 2 x 50 mm pipes.
What I was trying to say is if the 325 system is the same size as the m3 one I would use the 325 one.
The 325 one is going to flow better than the 535 anyway.
someone on here used a e36 328 back box. I think it was toby.

[beefy]

dont mean to hijackim

Im going to be coming accros this problem very soon ive got the manifold on the engine and ive got the down pipes. I was going to knock a system up from stainless steel components would this be as good or better or expensive opinions?

Sorry again

[alan335i]

i used a e36 m3 evo back box,welded the two brackets off the e30 box on, fabracated two straight through pipes to join it up to the m30 downpipes,fits well,sounds nice just needed to modify the shape the tail pipes came out.

[gareth]

the M3 system IS larger bore than a 325i one. the two M3 systems i've measured were both 46mm bore at the manifold (downpipe) to system flange. i've not got records of the 325i one but iirc, it's nearer 42mm. so, the M3 one is 20% larger area (assuming 42mm is right?)

the 46mm bore is also the same as the E32 and E34 3.5 M30 systems and downpipes i've measured.

charlE30, did your M3 backbox have the wierd extra hanger between the tailpipes? (the M3 has a different hanger arrangement at the back)

[gooner1]

Must admit i did wonder why, if the E30 bore was the same as the E30 M3, BMW bothered to make the E3O M3 one..

[ed325i]

The 323/320 down pipes I have are 43mm dont know if the 325 ones are bigger.

[gooner1]

Well just bought a E30 M3 exhaust off ebay, so no going back now.