[Danj94]

Evening all,

I have a late 2019 440i fitted with the dreaded OPF filter and I have a couple of questions for those who also have one or have knowledge on the subject.

I understand tampering with this OPF is illegal and also deletion make the car un-roadworthy by UK law and could result in void insurance so removal of this filter is not an option.

1. Where is the OPF located, ive read conflicting information some saying its located on the downpipe with the catalytic converter, others say its located seperately on the mid pipe

2. Any of you out there with stage 2, 2+ 3 etc tuned OPF cars and if so have you kept the OPF and what products did you use ?

I am asking these questions because I will be tuning my car, its easy enough to go stage 1 no hardware needed but i'm interested in stage 2 or stage 2+ but this requires some exhaust mods.

Any info would be much appreciated cheers.

[TurboWeasel]

OPFs/DPFs are nearly always right next to the turbo discharge. Canisters further down the pipework are usually downstream secondary cats.

You could do what most people do and gut a used OPF and pre-cat pipe, and just keep the factory one for MOTs.

Spot checks are more or less non-existent in the UK. The rozzers can only be arsed to attend 1 in every 100 burglaries/home invasions, so will have zero interest in road side exhaust sniffs.

[SimonBMW1]

Lots of people remove opf now, can be coded out. Unsure if it makes your insurance invalid.
Pcw exhaust mods guts it out from the top. No one will ever know

[Danj94]

Originally Posted by SimonBMW1

Lots of people remove opf now, can be coded out. Unsure if it makes your insurance invalid.
Pcw exhaust mods guts it out from the top. No one will ever know

Interesting, just had a look at his website and nothing of the OPF filter gutting, might give him a ring and see what the score is as if there is no evidence id be very interested in that.

[TurboWeasel]

Technically you can tell an OPF/DPF has been gutted as it makes a different sound when tapped with a small hammer. Hollow and empty sounding, unsurprisingly. Whether MOT testers do that though, I doubt it.

[SimonBMW1]

Originally Posted by Danj94

Interesting, just had a look at his website and nothing of the OPF filter gutting, might give him a ring and see what the score is as if there is no evidence id be very interested in that.

The OPF is in the resonator or near it on 40i engines, He modifies the exhaust to make OPF cars louder or something. Seen lots on his insta page.
He also modifies the backboxes and resonators to make them louder.

Other kits exist to remove and code out etc.

[jamborees]

I’ve got an OPF 2018 340i, fitted a 200 cell Wagner cat and swapped the centre section of the exhaust with one from a M140i pre OPF car. Kept my OPF centre section just in case. Just went through an MOT no issues at all. Stock OPF is in the position of the first resonator on Pre-PPF cars.

Tuned with TU pump, and running Stage 2+ MHD. Completely transformed!

[Danj94]

Originally Posted by jamborees

I’ve got an OPF 2018 340i, fitted a 200 cell Wagner cat and swapped the centre section of the exhaust with one from a M140i pre OPF car. Kept my OPF centre section just in case. Just went through an MOT no issues at all. Stock OPF is in the position of the first resonator on Pre-PPF cars.

Tuned with TU pump, and running Stage 2+ MHD. Completely transformed!

Interesting to read this,

So you fitted a wagner 200 cell downpipe and changed the mid pipe to a non OPF one, so you're essentially running sports cat and no OPF filter? So your new midpipe just has 2 resonators rather then a res and an OPF.

Any issued with check engine lights or have you masked this with MHD?

[jamborees]

Yes so I used a Wagner 200 cell but I chose to fit the B58 gen 2 version which has the OPF tube, just in case in the future I need to put the OPF back. The difference with this one is the connection from the downpipe to the centre section on Gen 1 is a slip on, Gen 2 used a V band. Dimensions are very similar and connection at the turbo end is the same.

I had the fabricators cut the Wagner at the end and weld universal V band clamps on the centre section and then join them that way. The centre section, I removed the first resonator, and left the secondary with stock back box. Sounds great with the valve open but it’s subtle still.

Tuning wise just MHD selecting OPF delete and that’s it. I’m Stage 2+ with TU pump and it all works perfectly.

[Danj94]

Originally Posted by jamborees

Yes so I used a Wagner 200 cell but I chose to fit the B58 gen 2 version which has the OPF tube, just in case in the future I need to put the OPF back. The difference with this one is the connection from the downpipe to the centre section on Gen 1 is a slip on, Gen 2 used a V band. Dimensions are very similar and connection at the turbo end is the same.

I had the fabricators cut the Wagner at the end and weld universal V band clamps on the centre section and then join them that way. The centre section, I removed the first resonator, and left the secondary with stock back box. Sounds great with the valve open but it’s subtle still.

Tuning wise just MHD selecting OPF delete and that’s it. I’m Stage 2+ with TU pump and it all works perfectly.

Thanks for the info, that does sound exactly what im looking for, just to be clear the OPF is in the mid pipe on the OPF cars, rather then 2 resonators we have a 1 res and 1 OPF. I think the M3 etc has the OPF in the downpipe with the cat?

I am going to take a look at the wagner downpipes now. Wouldnt happen to have a link to the one you bought would you?

Dan

[jamborees]

No worries Dan. This is the one I used - https://www.wagner-tuning.uk/500001037.html

The OPF is in the mid pipe, first box after the joiner. On the OPF exhaust this section uses a squarer pipe profile, pre OPF it’s a rounder profile therefore easier to remove well and replace with a straight pipe if you want to do a res delete.

[Danj94]

Originally Posted by jamborees

No worries Dan. This is the one I used - https://www.wagner-tuning.uk/500001037.html

The OPF is in the mid pipe, first box after the joiner. On the OPF exhaust this section uses a squarer pipe profile, pre OPF it’s a rounder profile therefore easier to remove well and replace with a straight pipe if you want to do a res delete.

Thanks, this pretty much answers all my questions, if I do decide to go stage 2 thats the downpipe I will go with, I was so confused because all the tuning parts websites display downpipes for B58's but it says on them not compatible with OPF models, I see that one in the link is listed under the Toyota B58 and has a number of BMW models in the description.


I am not sure I will have the OPF replaced I just wanted to make sure if I replace the downpipe the hardware (existing mid pipe & new catted downpipe) would be compatible and it appears it would be.

[Danj94]

Just posting this after the great information which Jamborees has posted as it may help others who have similar questions, there does seem to be a lack of info out there for EU cars with this engine in my experience.

I found this really good website that gives great explanation for the OPF B58 cars with options for mods.

https://www.psr-parts.com/en-gb/blog...e-tuning-guide

[jamborees]

That’s a great guide! I wish I’d seen that when I was looking in to it. Really good resource

[jamborees]

I cut just after the flexi and then welded the joiners for a v-band clamp to the downpipe and centre section to link.