Downpipe Replacement Tips

zipphreak · 10-11-2016, 04:45 PM

I'm inviting anyone here who has replaced their downpipe with catted or catless variant to share tech tips that made it easier to replace this sucker.

First you have about 25x 8mm bolts to get the undercarriage guard off.
-A 3/8 air ratchet or electric drill with socket adapter helps here.

Then you have about 10x 15mm hex bolts to get off the metal engine shield. There is one in the back right corner (if you looking under the car from the front, it's on the drivers side). You need to use a regular 3/8 ratchet and socket here, because of another panel sandwiched here.

-A 3/8 air ratchet or electric drill with socket adapter helps here.

Finally you have the two v-band clamps.. The lower one is a piece of cake, but the top one is a challenge to say the very least.
-The clamps will be "stuck" at first. A flat head and a rubber mallet should free up the clamp.
-To get at the bolt from the inside it's very hard to even see, because of an engine mount. If you remove the front right wheel, you will be able to get some access with various size extensions, 6-8". It helps to have a small wobble extension on the socket side to get the right angle..

http://www.harborfreight.com/9-pc-wo...set-67971.html

I also noticed you can use a flexible extension to get the right angle.

https://www.amazon.com/Neiko-00239A-...ible+extension

Just curious have others found easier ways at this?

bryan_G01 · 10-11-2016, 05:02 PM

pay someone else to do it

zipphreak · 10-11-2016, 05:20 PM

Haha today's BMW owners are lazy. If you don't work on your car you are not a real man!
I won't pay people top-dollar to do a half-ass job. You get mixed results in the service industry unfortunately.

But seriously this post is to help those other's that attempt it themselves.

boostaddict305 · 10-12-2016, 06:55 AM

I did it on a lift and removed the mount that's in the way it was a piece of came once that mount was out

JoyRin · 10-12-2016, 07:36 AM

I may not know the easiest way, but i do have some tips.
First, it may be a good idea to loosen the exhaust bracket attached to the midpipe...2 torx bolts (cant remember the size)...to give you a little extra play to work with b/c dps are usually not an absolute perfect fit so you may need to fiddle with it to make fit. As far as the clamps, only the bottom one for me was "stuck" after loosening the bolt. The top one loosened right up for me. As far as reaching the bolt for the top clamp, i dont remember exactly what i did but i do remember unbolting something ( a bracket maybe?) to reach the top clamp bolt with my ratchet. I think i remember using wrench as well as the ratchet to undo the top clamp but i could be wrong. See if you can unbolt something to gain access to the bolt for the top clamp. I gained access to the top clamp with the car on ramps so its definitely possible without removing a wheel.

I also remember when installing the new dp that i had trouble getting both sides of the downpipe to "seal." I figured it out by tightening the top clamp first. Then with my hand i squeezed the dp bracket and mount together which closed the gap on the bottom and then tightened the bottom clamp. Otherwise by tightening up the top clamp first, you'll get a little gap between the bottom dp and mid pipe, but the bottom clamp will still be able to be tightened even with the gap thus causing an exhaust leak.

Getting the downpipe to seal was the hardest part for me.

Sorry for the amaturish tip guide. I did it a few months ago and i cant really remember the step by step process thru memory. Im the type of person that i dont remember shit until its in front of me which it then all comes back to me. I didnt have any instructions so i basically learned as i went thru trial and error. Took me 4 hours by myself on ramps. If i did it again, knowing what i know now, should only take me less than 2 hrs to do.

EuroDude · 10-12-2016, 03:48 PM

JoyRin, did you have the back end of the car in the air or just the front?

JoyRin · 10-12-2016, 05:50 PM

Just the front with the rear wheels chocked. I have just the standard harbor freight ramps. Didnt give me enough clearance to be comfortable so i put some a couple pieces of plywood under it to give me a little extra room.

zipphreak · 10-12-2016, 07:05 PM

There is an engine mount in the way of the upper strap/bolt. is that what your referring to? When you removed this, i believe it was couple torx/e-torx? Did you support the engine at all ?

JoyRin · 10-12-2016, 09:00 PM

Man, i cant actually remember what type of mount it was. I honestly have to look at it to tell you. Me = anti-photogenitic memory. I do know that it is not a load bearing mount. You can bolt and unbolt without any trouble at all. I do know that the actual load bearing engine mount is right below the downpipe. Looking from inside the engine bay, shine your flashlight right where the downpipe is and you can see the engine mount with a black rubber center. That you definitely do not remove. If you could take a picture from under the car looking straight up to the upper clamp, im sure i can tell you which part to remove to gain access to the upper clamp bolt. Sorry for being a schmoe.

10-11-2016, 04:45 PM	#1
zipphreak Captain 454 Rep 986 Posts Drives: m235xi Join Date: Sep 2014 Location: b00ty iTrader: (2)	Downpipe Replacement Tips I'm inviting anyone here who has replaced their downpipe with catted or catless variant to share tech tips that made it easier to replace this sucker. First you have about 25x 8mm bolts to get the undercarriage guard off. -A 3/8 air ratchet or electric drill with socket adapter helps here. Then you have about 10x 15mm hex bolts to get off the metal engine shield. There is one in the back right corner (if you looking under the car from the front, it's on the drivers side). You need to use a regular 3/8 ratchet and socket here, because of another panel sandwiched here. -A 3/8 air ratchet or electric drill with socket adapter helps here. Finally you have the two v-band clamps.. The lower one is a piece of cake, but the top one is a challenge to say the very least. -The clamps will be "stuck" at first. A flat head and a rubber mallet should free up the clamp. -To get at the bolt from the inside it's very hard to even see, because of an engine mount. If you remove the front right wheel, you will be able to get some access with various size extensions, 6-8". It helps to have a small wobble extension on the socket side to get the right angle.. http://www.harborfreight.com/9-pc-wo...set-67971.html I also noticed you can use a flexible extension to get the right angle. https://www.amazon.com/Neiko-00239A-...ible+extension Just curious have others found easier ways at this?
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10-11-2016, 05:02 PM	#2
bryan_G01 Lieutenant Colonel 1165 Rep 1,931 Posts Drives: like i stole it... Join Date: Jun 2012 Location: NY iTrader: (0)	pay someone else to do it __________________ www.nybmwcca.org Current Cars: 1995 M3 Coupe Manual Alpine White 1997 M3 Sedan Auto Cosmo Black Metallic 2018 x3 m40 Auto Grey Metallic
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10-11-2016, 05:20 PM	#3
zipphreak Captain 454 Rep 986 Posts Drives: m235xi Join Date: Sep 2014 Location: b00ty iTrader: (2)	Haha today's BMW owners are lazy. If you don't work on your car you are not a real man! I won't pay people top-dollar to do a half-ass job. You get mixed results in the service industry unfortunately. But seriously this post is to help those other's that attempt it themselves.
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10-12-2016, 06:55 AM	#4
boostaddict305 First Lieutenant 58 Rep 358 Posts Drives: M2 Join Date: Apr 2013 Location: RI iTrader: (0)	I did it on a lift and removed the mount that's in the way it was a piece of came once that mount was out
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10-12-2016, 07:36 AM	#5
JoyRin Private 23 Rep 66 Posts Drives: 2015 EB M235i manual Join Date: Sep 2015 Location: South Jersey iTrader: (0)	I may not know the easiest way, but i do have some tips. First, it may be a good idea to loosen the exhaust bracket attached to the midpipe...2 torx bolts (cant remember the size)...to give you a little extra play to work with b/c dps are usually not an absolute perfect fit so you may need to fiddle with it to make fit. As far as the clamps, only the bottom one for me was "stuck" after loosening the bolt. The top one loosened right up for me. As far as reaching the bolt for the top clamp, i dont remember exactly what i did but i do remember unbolting something ( a bracket maybe?) to reach the top clamp bolt with my ratchet. I think i remember using wrench as well as the ratchet to undo the top clamp but i could be wrong. See if you can unbolt something to gain access to the bolt for the top clamp. I gained access to the top clamp with the car on ramps so its definitely possible without removing a wheel. I also remember when installing the new dp that i had trouble getting both sides of the downpipe to "seal." I figured it out by tightening the top clamp first. Then with my hand i squeezed the dp bracket and mount together which closed the gap on the bottom and then tightened the bottom clamp. Otherwise by tightening up the top clamp first, you'll get a little gap between the bottom dp and mid pipe, but the bottom clamp will still be able to be tightened even with the gap thus causing an exhaust leak. Getting the downpipe to seal was the hardest part for me. Sorry for the amaturish tip guide. I did it a few months ago and i cant really remember the step by step process thru memory. Im the type of person that i dont remember shit until its in front of me which it then all comes back to me. I didnt have any instructions so i basically learned as i went thru trial and error. Took me 4 hours by myself on ramps. If i did it again, knowing what i know now, should only take me less than 2 hrs to do.
	Appreciate 0 Quote

10-12-2016, 03:48 PM	#6
EuroDude Second Lieutenant 67 Rep 201 Posts Drives: 2017 GT350 Join Date: May 2016 Location: Florida iTrader: (2) Garage List 2017 Ford GT350 [0.00]	JoyRin, did you have the back end of the car in the air or just the front?
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10-12-2016, 05:50 PM	#7
JoyRin Private 23 Rep 66 Posts Drives: 2015 EB M235i manual Join Date: Sep 2015 Location: South Jersey iTrader: (0)	Just the front with the rear wheels chocked. I have just the standard harbor freight ramps. Didnt give me enough clearance to be comfortable so i put some a couple pieces of plywood under it to give me a little extra room.
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10-12-2016, 07:05 PM	#8
zipphreak Captain 454 Rep 986 Posts Drives: m235xi Join Date: Sep 2014 Location: b00ty iTrader: (2)	There is an engine mount in the way of the upper strap/bolt. is that what your referring to? When you removed this, i believe it was couple torx/e-torx? Did you support the engine at all ?
	Appreciate 0 Quote

10-12-2016, 09:00 PM	#9
JoyRin Private 23 Rep 66 Posts Drives: 2015 EB M235i manual Join Date: Sep 2015 Location: South Jersey iTrader: (0)	Man, i cant actually remember what type of mount it was. I honestly have to look at it to tell you. Me = anti-photogenitic memory. I do know that it is not a load bearing mount. You can bolt and unbolt without any trouble at all. I do know that the actual load bearing engine mount is right below the downpipe. Looking from inside the engine bay, shine your flashlight right where the downpipe is and you can see the engine mount with a black rubber center. That you definitely do not remove. If you could take a picture from under the car looking straight up to the upper clamp, im sure i can tell you which part to remove to gain access to the upper clamp bolt. Sorry for being a schmoe.
	Appreciate 0 Quote