Need a new exhaust.

[Jos]

My current backbox has more holes in it than a Microsoft Inoperating sytem and the MOT man won't be happy about it. So I need either a new backbox or a new system but here is the catch... I don't want to have to change the sodding thing when I put the M30 in, so what are the recommendations?

Current thoughts are a Powerflow (although apparently they rust which stainless isn't supposed to do if it's any good). What about the Mongoose system? would it have enough flow to cope with the displacement increase? And would the 325 touring one fit the 318 M40 I am thinking the downpipe/front section will be different..

Would like it to be fairly offensively loud, backbox only would be fine by me

Thoughts? Particularly from Andy335 and Toby!

Forgot to mention ideally I would like 4 tailpipes 2 sets of twins..

[Andy335Touring]

If you are handy with a welder could you patch the box up for now until you know what you are going to use with the M30 ? It's a bodge but its a cheep temp' fix to get you through the MOT ?

Are M40 exhausts single bore ?

As for two pairs of tail pipes i think some one said you have chop out your spare wheel well so you have some where to put the pipes ?

Toby uses a home made exhaust with a single E36 328 back box, sounds nice but will be too quiet if you want a loud exhaust. I'm using an E30 M3 Scorpion exhaust which is to loud for me but i want a quiet exhaust to go with the street sleeper image i want of my car.

I wonder if a 325 system with just the back box would give you the noise you want with the M30 ? Or may be a 325 sports/aftermarket back box ?

[Jos]

Thanks Andy, the current one isn't that bad, could probably patch or reskin the backbox to get it through then worry about it afterwards. Is the e30 M3 a straight fit to the M30? Yes the M40 is single bore. (I think)

Still probably looking at Powerflow, don't really care if they rust, lifetime warranty and a new exhaust for free every year is fine by me

Had a look at the underside of the car, the problem seems to be either the very edge of the wheel well (don't want to get too close to it as I want to go LPG) or the battery tray. If the tray was cut out then there would be enough room to get the tailpipes in. Also need to watch the fuel filler as it's on that side of the car..best thing is probably a centre box with long tailpipes following round the spare wheel.




Possibly too much effort trying to do that, although it would be very cool..

[Andy335Touring]

Cool picy mate

The M3 exhaust mounts are a little differant to normal E30's but it's not much bother to hang them.

On my car the e34 M30 down pipes were chopped to length and then an M3 exhaust flange was welded on to the end of the pipes, this means i can still separate manifolds/down pipes/exhaust as normal. You are probobly going to have to cut the down pipes to match up to virtually any exhaust as if i remember correctly the E34 down pipes are quite long and include the first smallish silencer.

I got the M3 flange from the US but if you know some one that works with thick metal(12-15mm) they should be able to knock you one up fairly cheaply ?

http://vacmotors.phpwebhosting.com/cgi- ... tem_id=334

These are made in two sizes so check which one you need.

[jmc330i]

What I.D. are the pipes on the E30 M3 exhaust Andy? Ive been offered one for my conversion but Im not sure if its standard or not.

The 325i exhausts are the same no matter if its a Sport or touring etc. I think the I.D. is around 45mm with the E34 535i being 50mm and the E36 328i is 48mm.
I would guess that the smaller the pipe diameter, the less noise, although my 325i was overly loud after I ripped half the baffles out

[Andy335Touring]

Hi mate, the Scorpion M3 exhaust is 50 mm I.D. if i remember correctly, i think i read some where that the standard M3 exhaust is a bit smaller some thing like 45 or 47 mm ?

Whats the I.D. of the donor M3 exhaust ?

The Alpina B10 six branch i had has an I.D. of 52 mm so i'm not to far off on the bore size on mine hope fully ?

Have you got much more to finish off your conversion like the water pump ?

[jmc330i]

Hi mate, the Scorpion M3 exhaust is 50 mm I.D. if i remember correctly, i think i read some where that the standard M3 exhaust is a bit smaller some thing like 45 or 47 mm ?

Might be the same size as the 325i exhaust then. I measured my old one and that was 45mm, so the E30 M3 one is probably to small for mine if its standard.

The E36 M3 down pipes I have (I dont have the exhaust) are 57mm I.D. so they are pretty big. I might just stick with the pipes that I have.

Its been raining too much here to do anything with mine really. I got the alternator off earlier today, but then had to stop due to rain. Hopefully this weekend will be dry and I can get the rest of the oil filter housing off and then get to the water pump.

Oh the fun of it