B58 Downpipe change Guide

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Williams327
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B58 Downpipe change Guide

Post by Williams327 » Wed Jul 18, 2018 9:11 pm

Just a quick guide for anyone thinking of replacing the downpipe on a bmw m140i m240i b58. Note i was removing my cobra 200 cell sports cat and refitting the stock downpipe.


First off get the Car jacked up in the air front and back ideally.Now underneath the car drivers side is best for access undo the two 13mm nuts holding the Cat back exhaust to the downpipe.

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Moving to the back of the car the two exhaust hangers are held on by 13mm nuts these need removing, note the exhaust will lower slightly as its no longer supported. Now lever with your hands on both exhaust tips the cat back away from the downpipe by pulling and twisting away from the front of the car. This will seperate the two.

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Open the bonnet, firstly remove the engine cover pulling up around the edges. Now the airbox needs to be removed, unplug the maf sensor and using a 6mm socket undo the jubiliee connecting the airbox to the hose. Seperate the two. The airbox itself is on rubber bungs to remove simpley pull upwards may take a little force.

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Now you have access to the cat, unplug both lambda sensors in the engine this way its easier to remove them when the cat is off the car.

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Using a 13mm socket undo the Vband which holds the Cat to the turbo.

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Now on a stock downpipe there are two 13mm nuts which hold the cat to the chassis these need removing

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Its now free and you can remove by lowering it down and out underneath the car. Now you can remove both lambda sensors using a 22mm spanner

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Fitting your new Decat/Sports Cat is the reverse procedure. Overall fairly easy job for anyone half competent with a set of spanners


:D :D
Last edited by Williams327 on Sat Jul 21, 2018 8:56 pm, edited 1 time in total.
M140i 3 door Auto

Mods - JB4, LSD, underbody brace, Carbon MPE, PCW silencer, Decat, AFE intake, auto id mirrors>diffuser, kerscher splitter, carbon spoiler, Mp skirts>blades>grills, OZ ultraleggeras, H&R -25mm, M4 pads, braided lines

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MrPocketRocket
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B58 Downpipe change Guide

Post by MrPocketRocket » Wed Jul 18, 2018 9:24 pm

Excellent work mate! Thanks for sharing. Definitely helps especially with images as a reference point.

Admins - Can this please be added as a Sticky

Cheers!


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Last edited by MrPocketRocket on Wed Jul 18, 2018 9:24 pm, edited 1 time in total.
BMW M140i - 5 Door - Coral Red Leather - Mineral Grey - M Performance Exhaust (Carbon Tips) - M Performance Side Decals - M Performance Grills - Front Silencer Delete - Carbon Front Splitter/Side Skirts/Side Mirrors/Rear Diffuser/Rear Spoiler

Williams327
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Re: B58 Downpipe change Guide

Post by Williams327 » Wed Jul 18, 2018 9:42 pm

MrPocketRocket wrote:
Wed Jul 18, 2018 9:24 pm
Excellent work mate! Thanks for sharing. Definitely helps especially with images as a reference point.

Admins - Can this please be added as a Stickey

Cheers!


Sent from my iPhone using Tapatalk
No worries hopefully inspires a few more driveway mechanics :lol:
M140i 3 door Auto

Mods - JB4, LSD, underbody brace, Carbon MPE, PCW silencer, Decat, AFE intake, auto id mirrors>diffuser, kerscher splitter, carbon spoiler, Mp skirts>blades>grills, OZ ultraleggeras, H&R -25mm, M4 pads, braided lines

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MrArthur
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Re: B58 Downpipe change Guide

Post by MrArthur » Wed Jul 18, 2018 11:51 pm

This guide is just great! Thank you very mutch!

Now make it a sticky!
Alpine White BMW M140i 5-door, MPE with carbon tips and front oval muffler delete, PiperCross filter, BlueSpark, Dragy GPS, ZF 8-speed, adaptive, HK, and mutch mutch more, witout moonroof

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and79
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Re: B58 Downpipe change Guide

Post by and79 » Thu Jul 19, 2018 6:17 am

Good work!

BigWill
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Re: B58 Downpipe change Guide

Post by BigWill » Thu Jul 19, 2018 8:48 am

Great write up!
MY18 EB M140i Aus Spec LCI-2 Auto
Alcantara interior, M Performance Steering Wheel

EdButcher
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Re: B58 Downpipe change Guide

Post by EdButcher » Fri Jul 20, 2018 9:01 am

How do people get around MOT time with a decat?
M135i Pre LCI - Estoril Blue F20 - MPE - H&R 25mm - M2 style Black Grill - darklines

Williams327
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Re: B58 Downpipe change Guide

Post by Williams327 » Fri Jul 20, 2018 11:35 am

EdButcher wrote:
Fri Jul 20, 2018 9:01 am
How do people get around MOT time with a decat?
Me personally I’d refit the stock cat takes about an hour start to finish.

Many just palm the mot guys hands with gold :lol:
M140i 3 door Auto

Mods - JB4, LSD, underbody brace, Carbon MPE, PCW silencer, Decat, AFE intake, auto id mirrors>diffuser, kerscher splitter, carbon spoiler, Mp skirts>blades>grills, OZ ultraleggeras, H&R -25mm, M4 pads, braided lines

EdButcher
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Re: B58 Downpipe change Guide

Post by EdButcher » Fri Jul 20, 2018 4:18 pm

Williams327 wrote:
Fri Jul 20, 2018 11:35 am
EdButcher wrote:
Fri Jul 20, 2018 9:01 am
How do people get around MOT time with a decat?
Me personally I’d refit the stock cat takes about an hour start to finish.

Many just palm the mot guys hands with gold :lol:
I see! Haha I may just get my MPE modified for the sound I want rather than faffing with it then ... I know my luck. No MOT tester would touch it haha
M135i Pre LCI - Estoril Blue F20 - MPE - H&R 25mm - M2 style Black Grill - darklines

Mr Kirk
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Re: B58 Downpipe change Guide

Post by Mr Kirk » Sat Jul 21, 2018 1:00 pm

Removing your sports cat you say?

Williams327
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Re: B58 Downpipe change Guide

Post by Williams327 » Sat Jul 21, 2018 8:55 pm

Mr Kirk wrote:
Sat Jul 21, 2018 1:00 pm
Removing your sports cat you say?
Sold it, got a decat on the way ready for a ecu map and hopefully meth
M140i 3 door Auto

Mods - JB4, LSD, underbody brace, Carbon MPE, PCW silencer, Decat, AFE intake, auto id mirrors>diffuser, kerscher splitter, carbon spoiler, Mp skirts>blades>grills, OZ ultraleggeras, H&R -25mm, M4 pads, braided lines

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