[Billy_BMW]

Hi guys,

I’ve seen a few threads where people have said that removal of the OPF’s will lead to limp mode. Can we get confirmation that this is 100% true?

The reason I ask is that both Remus and Superprint have made midpipes for the M2C that delete the OPF’s. Surely they would mention the risk of limp mode if the OPF’s were removed?

I could tolerate a soft CEL every thousand miles as the N55 cars just triggered a light that could be reset via OBD tool and DashCommand or similar app. However, limp mode is actually quite dangerous and unexpected.

Please could anyone clarify?

[MR.]

Originally Posted by Billy_BMW

Hi guys,

I’ve seen a few threads where people have said that removal of the OPF’s will lead to limp mode. Can we get confirmation that this is 100% true?

The reason I ask is that both Remus and Superprint have made midpipes for the M2C that delete the OPF’s. Surely they would mention the risk of limp mode if the OPF’s were removed?

I could tolerate a soft CEL every thousand miles as the N55 cars just triggered a light that could be reset via OBD tool and DashCommand or similar app. However, limp mode is actually quite dangerous and unexpected.

Please could anyone clarify?

100% true... We did it a few times on my car I wrote a big long post about it. You will find it here:

https://f87.bimmerpost.com/forums/sh...&postcount=126

Remus and Supersprint maybe don't know that it happens or haven't tested it properly. God knows why they don't mention it on the site, but I can ensure you if you install those cat-back exhausts, remove the OPFs and don't install an ECU software file that disables the OPF pressure sensors you will get a limp mode over 5K rpm.

It happens 100% for every car built after mid-August, a small number of cars built before run an old ECU software, but that software might well be updated as soon as you go in for a service at your dealer.

MR

[Billy_BMW]

Thanks Marc. That’s disappointing to hear! I was really keen on deleting the midpipe and combining with Remus/Eisenmann. However, I’d rather not risk limp mode.

Will the Akrapovic link pipe that you’ve got fitted which deletes the OPF’s need the Delete-R to prevent a CEL/limp mode?

[MR.]

Originally Posted by Billy_BMW

Thanks Marc. That's disappointing to hear! I was really keen on deleting the midpipe and combining with Remus/Eisenmann. However, I'd rather not risk limp mode.

Will the Akrapovic link pipe that you've got fitted which deletes the OPF's need the Delete-R to prevent a CEL/limp mode?

Yes, it does... Any OPF removal requires this and the Akrapovic exhaust has no OPFs in the linkpipe. If you don't want to tune your car then there is no solution right now for the removal of the OPFs.

In the future there might be displays or control units that allow you to apply "delete-r" on the OPF pressure sensors similarly to currently with the sensors when you install catless downpipes, but those systems or settings in existing displays (e.g. Awron) or other products don't exist yet.

MR

[Twinsturbo]

I would like a linkpipe that starts after the opf:s, that and a eisenmann race backbox!

[Billy_BMW]

More information on OPF’s here:
https://www.newtis.info/tisv2/a/en/f...tem/1VnbnDH7q9

Seems from some M140/240 forums, limp mode is a hit and miss - some cars have it and some don’t.

If it happens every couple of thousand miles then it’s not the end of the world if you switch the car off and restart.

CEL seems to be triggered by the pressure measurement on the second sensor after the primary cat.

Some people have had mixed results with valved exhaust backboxes, i.e Remus etc.

Either way, I’ll want to find a way to remove them for extra sound. Let’s hope an ECU fix comes out to code the pressure check off. 😉

[MR.]

Originally Posted by Billy_BMW

More information on OPF’s here:
https://www.newtis.info/tisv2/a/en/f...tem/1VnbnDH7q9

Seems from some M140/240 forums, limp mode is a hit and miss - some cars have it and some don’t.

If it happens every couple of thousand miles then it’s not the end of the world if you switch the car off and restart.

CEL seems to be triggered by the pressure measurement on the second sensor after the primary cat.

Some people have had mixed results with valved exhaust backboxes, i.e Remus etc.

Either way, I’ll want to find a way to remove them for extra sound. Let’s hope an ECU fix comes out to code the pressure check off. 😉

We need a feature in Bimmercode or in the Awron display to disengage the sensor, called Delete OPF or something.

That will come for sure, but for now it is only a ECU tune!

MR

[VIERsr]

Are we sure that it's enough just disengage the sensor? Or maybe an ECU modification is required to disable the input of rigenerations, like in the diesel engines?

[ICantDrive4Sht]

Originally Posted by Billy_BMW

More information on OPF’s here:
https://www.newtis.info/tisv2/a/en/f...tem/1VnbnDH7q9

Seems from some M140/240 forums, limp mode is a hit and miss - some cars have it and some don’t.

If it happens every couple of thousand miles then it’s not the end of the world if you switch the car off and restart.

CEL seems to be triggered by the pressure measurement on the second sensor after the primary cat.

Some people have had mixed results with valved exhaust backboxes, i.e Remus etc.

Either way, I’ll want to find a way to remove them for extra sound. Let’s hope an ECU fix comes out to code the pressure check off. ��

The way i see it, it definetly would be the end of the world when car goes to limp mode while overtaking someone.

[Billy_BMW]

I’m hoping the PTF team can add some functionality with BM3 to disable the check. From reading around, another EU M2C owner says they only got the limp mode after 1000km which isn’t the worst. Yes, if it comes unexpectedly then it’s bad, but if it goes away after switching off and restarting car then for me it’d be worth it to run a decent straight midpipe with sound.

[MR.]

Originally Posted by Billy_BMW

I’m hoping the PTF team can add some functionality with BM3 to disable the check. From reading around, another EU M2C owner says they only got the limp mode after 1000km which isn’t the worst. Yes, if it comes unexpectedly then it’s bad, but if it goes away after switching off and restarting car then for me it’d be worth it to run a decent straight midpipe with sound.

I would not drive around with knowing it happens, but knowing when... Be aware it could also be different depending on the type of linkpipe you mount!

MR

[Billy_BMW]

Just wondering whether BM3 CEL suppression would work to stop limp mode from happening? Maybe a question for them.

As for the risk of limp mode, it can happen to stock cars with faulty oxygen sensors or even gearbox issues. It’s a risk in any event.

[JackDW]

Can anyone tell me whether the Burger Motorsports JB4 for the M2C would be able to be able to delete the CEL in relation to the OPF’s. I know it has the feature to read and delete codes. I’m thinking of getting the full Eisenmann system for mine but afraid to pull the trigger if it’s going to cause me lots of issues with limp mode.

[vale007]

hi, i‘ve a supersprint set for sale, full exhaust excl. downpipes.

just write me in there is a need!

my idea is to run downpipes with us exhaust, if someone offers an exhaust let me know!

br,
vale

[MR.]

Originally Posted by JackDW

Can anyone tell me whether the Burger Motorsports JB4 for the M2C would be able to be able to delete the CEL in relation to the OPF’s. I know it has the feature to read and delete codes. I’m thinking of getting the full Eisenmann system for mine but afraid to pull the trigger if it’s going to cause me lots of issues with limp mode.

Ask the guys who make the JB4 if they have OPF delete, if they don't then opt for a custom tune at your local tuner or go bootmod3. Those guys have the OPF delete in their software.

MR

[JackDW]

Thanks for your help. I was thinking BM3 but wasn’t sure if they offered OPF delete so thank you for clearing that up!

[doughboy]

There's a lot of OPF delete exhaust around now, but I've not seen ONE supplier mentioning codes / limp mode or mapping needed.

Not good really. Have they even done proper testing?

[MR.]

Originally Posted by doughboy

There's a lot of OPF delete exhaust around now, but I've not seen ONE supplier mentioning codes / limp mode or mapping needed.

Not good really. Have they even done proper testing?

Akrapovic is mentioning it 100%!!! It is all over the order portal and on the main website. Not sure what the others have done.

Some of them, I am not going to drop names, are often characterized as plumbers for a reason. Testing is often done by the customer and they develop exhausts like installing new piping in your bathroom.

MR

[doughboy]

Hi all,

Does anyone have any more details about OPF removal issues?

We really need to know the actual fault codes generated rather than just "CEL" or "LIMP". Once you know the codes you can see what the actual detection issue is, without that we're guessing.

If it is a LIMP code then a regular CEL clear feature on JB4/BM3 etc probably won't deal with it. A limp code would usually be something where the drivetrain it at risk, so power is reduced. I can't see how OPF could be that serious, more like BMW engineers trying to make it more difficult to mess with the exhaust!

I'm considering Decat DPs (which are cheap) then add non EU midpipes with secondary CATs (to pass UK emissions test). This depends on price of secondary CATs as spare parts..

[MR.]

Originally Posted by doughboy

Hi all,

Does anyone have any more details about OPF removal issues?

We really need to know the actual fault codes generated rather than just "CEL" or "LIMP". Once you know the codes you can see what the actual detection issue is, without that we're guessing.

If it is a LIMP code then a regular CEL clear feature on JB4/BM3 etc probably won't deal with it. A limp code would usually be something where the drivetrain it at risk, so power is reduced. I can't see how OPF could be that serious, more like BMW engineers trying to make it more difficult to mess with the exhaust!

I'm considering Decat DPs (which are cheap) then add non EU midpipes with secondary CATs (to pass UK emissions test). This depends on price of secondary CATs as spare parts..

The issue is a back pressure failure on the two sensors located at the end of the down pipe. I have seen the fault codes, but I don't know by heart what they said. Just disengage those sensors are done.

I hopefully have some news soon that will put an end to all this shit with OPFs. Removal will then be a piece of cake everyone. More on it soon.

MR

[doughboy]

I might do some testing this weekend and remove the bleed pipes from the pressure sensors which will simulate OPF removal, then I can use ISTA to diagnose in detail.

They are quite easy to reach turbo side of the engine.

[MR.]

Originally Posted by doughboy

I might do some testing this weekend and remove the bleed pipes from the pressure sensors which will simulate OPF removal, then I can use ISTA to diagnose in detail.

They are quite easy to reach turbo side of the engine.

You can also try to reach the pressure difference sensor box and disconnect it. It is a small black box on top of one of the downpipes.

MR