[Who's on first]

Originally Posted by David1

Don't worry about torqueing the o2 sensors. They just need to be snug. I have installed hundreds over 25 years, never torqued them and never had one come loose. On this car, don't even bother with the O2 sensors until you have the downpipe out. The hardest thin about the O2 wires is getting the one clip back on the block like how it was.

They just need german torque.

[cecaa850]

Originally Posted by Who's on first

They just need german torque.

Tighten till it breaks and back up a quarter turn is usually perfect.

[Who's on first]

Originally Posted by cecaa850

Tighten till it breaks and back up a quarter turn is usually perfect.

German torque = goodntight. (Say it with an accent).

[David1]

If let out a big fart while torqueing, its to tight.

[Who?]

Originally Posted by McGary911

I installed the sensors on the Fabspeed DP before installing it. Very easy to get to then with a regular wrench. Then once installed, you just have to fish up the 2 wires. After installing the DP that's refreshingly easy.

I'd expect that's what most would do, but could be wrong.

Here is my mistake, I took the sensors out with the stock downpipe, but instead of reinstalling the sensors outside of the car, I plugged it in to th engine then installed it under the car

If I get an error, I’ll just have to go under and do it again

[Xchange43]

Originally Posted by Fabspeed Motorsport

You don't "have to" but it is a good preventative measure.

So i m about to install my dp, do i need to teplace all vbands or just the one with the ring ?

Thanks

[Nezil]

Originally Posted by Xchange43

So i m about to install my dp, do i need to teplace all vbands or just the one with the ring ?

Thanks

You don't have to replace anything... except the bolts that hold on the stiffening plate because they're designed to stretch and only be used once.

BMW recommends that you replace all the V-band clamps and the turbo to DP gasket. I didn't replace anything the first two times I changed my DP, and did the most recent time. I didn't notice any difference and I had no leaks re-using the clamps and gaskets, but it's your call.

[Xchange43]

Originally Posted by Nezil

You don't have to replace anything... except the bolts that hold on the stiffening plate because they're designed to stretch and only be used once.

BMW recommends that you replace all the V-band clamps and the turbo to DP gasket. I didn't replace anything the first two times I changed my DP, and did the most recent time. I didn't notice any difference and I had no leaks re-using the clamps and gaskets, but it's your call.

I bought all the v clamp brand new this morning but not tue screws.

[Xchange43]

Originally Posted by Nezil

You don't have to replace anything... except the bolts that hold on the stiffening plate because they're designed to stretch and only be used once.

BMW recommends that you replace all the V-band clamps and the turbo to DP gasket. I didn't replace anything the first two times I changed my DP, and did the most recent time. I didn't notice any difference and I had no leaks re-using the clamps and gaskets, but it's your call.

So i have a stupid issue ... i m under my car atm like live and the dp is all unscrewed except the o2 sensors and it dosent move.

I removed the vclamp from the exhaust and unscrewed the turbo.. but it still stuck there.. any idea?

[Drop the hammer]

Pry the clamps loose. It’s squished onto the flange on both ends. Once they pop free you can spin them easily. Too on for me was real tightly stuck. I used a long flat blade to work it free one side at a time. Some guys knock on it with a hammer. I keep a bolt loosely connected on the support bracket so it doesn’t fall into my head. If I recall correctly on the m2 there’s two supports on the stock pipe as well, one is a bit hidden.

[Drop the hammer]

Looks like your bottom clamp is released off flange, top one looks like it is still seated. I see the bolt hole from the brace. Is the other one off? I think it’s just a nut as the bolt part is welded onto the second brace on downpipe.

[Xchange43]

Originally Posted by Drop the hammer

Pry the clamps loose. It’s squished onto the flange on both ends. Once they pop free you can spin them easily. Too on for me was real tightly stuck. I used a long flat blade to work it free one side at a time. Some guys knock on it with a hammer. I keep a bolt loosely connected on the support bracket so it doesn’t fall into my head. If I recall correctly on the m2 there’s two supports on the stock pipe as well, one is a bit hidden.

Thanks, so somehow i was able to free the top clamp a bit but still the dp dosent come down :/ i dont know really what to do

[cecaa850]

The seal may be holding you up. Muscle it up and down a bit and see if it pops loose.

[Xchange43]

Originally Posted by cecaa850

The seal may be holding you up. Muscle it up and down a bit and see if it pops loose.

Got it free but now i need to unplug the co2 sensors is there a specific way?

I m been 3hrs on it lol

[Xchange43]

Finally finished.. damn its hard!

However i m not yet fully happy with the sound on a catless dp with the stock exhaust.

I feel like i lost some sound and i got more drone style noise.

And at mid rpm i get a strange drone from the back . As if the exhaust vibrates..

[Nezil]

Originally Posted by Xchange43

I bought all the v clamp brand new this morning but not tue screws.

How did you torque the stiffening plate screws?

They're supposed to be tightened to a specific torque, and then further tightened by 90 degrees. If you re-use the bolts, you can damage the threads in the front sub-frame, because the old bolts will be stretched and therefore not the correct thread pitch any more, and you'll be effectively over torquing them because they're a already stretched.

I re-used mine the first time and wish I hadn't. I doubt it's dangerous, but it's worse than reusing the exhaust clamps for sure.

[Xchange43]

Originally Posted by Nezil

How did you torque the stiffening plate screws?

They're supposed to be tightened to a specific torque, and then further tightened by 90 degrees. If you re-use the bolts, you can damage the threads in the front sub-frame, because the old bolts will be stretched and therefore not the correct thread pitch any more, and you'll be effectively over torquing them because they're a already stretched.

I re-used mine the first time and wish I hadn't. I doubt it's dangerous, but it's worse than reusing the exhaust clamps for sure.

Which plate are you refering to?

The one bolted to the dp on the left?

If so, the dp came with 2 regular screw with a stop nut. I only reused the two tuat we are supposed to loosen up

[UltraMagneticAL]

Originally Posted by Xchange43

Got it free but now i need to unplug the co2 sensors is there a specific way?

I m been 3hrs on it lol

the o2 sensors should be unplugged from the electrical clips under the engine cover before dropping the DP. when the DP is out, you then use an o2 sensor socket to remove them from the DP. move the sensors to the new DP, install the DP, then plug in the sensors. way easier this way.

edit: also the low/mid-range rattle may be the wastegate vibrating. it's more audible now without the cat dampening the sound

[Nezil]

Originally Posted by Xchange43

Which plate are you refering to?

The one bolted to the dp on the left?

If so, the dp came with 2 regular screw with a stop nut. I only reused the two tuat we are supposed to loosen up

The massive Aluminium plate under the front of the car covering everything up that you presumably removed to access the downpipe.

It has 8 torque to yield bolts holding it onto the front sub-frame, and a number of 8mm self tapping screws holding other plastic shields to it.

[Xchange43]

Originally Posted by UltraMagneticAL

the o2 sensors should be unplugged from the electrical clips under the engine cover before dropping the DP. when the DP is out, you then use an o2 sensor socket to remove them from the DP. move the sensors to the new DP, install the DP, then plug in the sensors. way easier this way.

Thanks for sharing, it took me 6,5 hrs the other day. I did exactly what you descibed.

Note my car is 2mth old and 1200km

I had to use an hammer to unscre the o2 sensors.. they were stuck. No way i could unscrew them hanging in that tight space.

Overall you guys are lucky to do that job in 30mins .. if everything would go well, i could do in 2-3 hrs but no way 30mins

[Xchange43]

Originally Posted by Nezil

The massive Aluminium plate under the front of the car covering everything up that you presumably removed to access the downpipe.

It has 8 torque to yield bolts holding it onto the front sub-frame, and a number of 8mm self tapping screws holding other plastic shields to it.

Oh wow no i havent replaced them i was not expecting that

[Drop the hammer]

Originally Posted by Xchange43

Thanks for sharing, it took me 6,5 hrs the other day. I did exactly what you descibed.

Note my car is 2mth old and 1200km

I had to use an hammer to unscre the o2 sensors.. they were stuck. No way i could unscrew them hanging in that tight space.

Overall you guys are lucky to do that job in 30mins .. if everything would go well, i could do in 2-3 hrs but no way 30mins

Unscrew the O2 sensors at the workbench, not on the car! I’ve done my downpipe 4 times now. Takes me longer to get the car up on jack stands than the removal and replacement. I use an impact to spin the fasteners off, and then to snug everything up prior to torquing the fasteners. I do not replace those bolts. I did however buy a new bottom clamp and gasket as it stays attached to the downpipe and makes swapping way faster. I also pre stretch the clamp so I don’t have to monkey with it to get it over the lip.