backbox exhaust for M235i 2014MY

355 Views 9 Replies 3 Participants Last post by George123, 5 d ago

George123

Discussion Starter · 9 d ago

Hi there, new to the forum, just bought a very nice M235i but the previous owner has removed the backbox for a straight through pipe......and it sounds horrendous! Drones on the motorway and wakes everyone up on start up (I guess made worse because there's no warm up value?).

New-ish to BMWs so looking for advice on where to find a decent 2nd hand OEM backbox with valve , anywhere I should look apart from on ebay, or maybe someone has one for sale? Nothing on the classifieds but will post on wanted also .

Many thanks.

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Simon Site Manager

· #2 · 9 d ago

Hello and welcome, George. Try posting here:-

Wanted

A place for members to source items from the community. Please read the forum rules before posting.

www.babybmw.net

I'm sure some people will have changed their back box and have an OEM sitting in their garage.

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George123

Discussion Starter · #3 · 9 d ago

Simon Site Manager said:
Hello and welcome, George. Try posting here:-

Wanted

A place for members to source items from the community. Please read the forum rules before posting.

www.babybmw.net

I'm sure some people will have changed their back box and have an OEM sitting in their garage.

thanks mate, will do

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140ifan

· #4 · 8 d ago

George123 said:
thanks mate, will do

Hi bud.

I actually have a modified backbox for sale, basically sounds like a m performance backbox, if the rest of the exhaust is stock or only the midpipe has changed it really isent loud just a bit deeper.

I had to take it off as i have a sports cat AND mid pipe delete.

Have a look at modified backboxes a lot of people have it done, i can send pics if interested.

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George123

Discussion Starter · #5 · 7 d ago

140ifan said:
Hi bud.

I actually have a modified backbox for sale, basically sounds like a m performance backbox, if the rest of the exhaust is stock or only the midpipe has changed it really isent loud just a bit deeper.

I had to take it off as i have a sports cat AND mid pipe delete.

Have a look at modified backboxes a lot of people have it done, i can send pics if interested.

thanks for the offer mate but I'm keen to get a standard backbox so I know what I'm getting . The valve that you see on the standard boxes, is that just to keep it quiet on start up ? after warm up it stays open?

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140ifan

· #6 · 7 d ago

George123 said:
thanks for the offer mate but I'm keen to get a standard backbox so I know what I'm getting . The valve that you see on the standard boxes, is that just to keep it quiet on start up ? after warm up it stays open?

No worries bud.

Nah its quite a complex piece of equipment, opens at certain throttle loads and rpm depending on the mode. I dont think it does anything to the volume tbh its very subtle.

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Simon Site Manager

· #7 · 7 d ago

I thought the valve was closed on start up to heat the Cat quicker, then opened and stayed open during your journey?

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140ifan

· #8 · 6 d ago

Simon Site Manager said:
I thought the valve was closed on start up to heat the Cat quicker, then opened and stayed open during your journey?

It does that yes but during driving it opens and closes, there is a table somewhere on this forum showing when it opens and closes.

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Simon Site Manager

· #9 · 6 d ago

140ifan said:
It does that yes but during driving it opens and closes, there is a table somewhere on this forum showing when it opens and closes.

You live and learn. Academic for me as I have the MPE.

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George123

Discussion Starter · #10 · 5 d ago

I’ve bought a second nhand back box off eBay … standard not MPE. However , just noticed the ad said for an M135i not M235i ! OEM part number for both is 7602290 so i guess it’ll fit my M235 ? Looks identical also. Thanks.

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