M340i tuning - Downpipe discussion

[DJS1994]

Hi Guys,

Looking for anyone who has experience in tuning the B58 platform particularly around downpipe choice for stage 2.

So I own a 2020 M340i G20. I have had is 7 months or so and I bought a 2020 because the ECU date means it wont require unlocking to tune. I have checked and it is unlocked.

I want a bit more sound from the car but I'm reluctant to spend thousands on exhaust parts which only give sound improvement so I am looking at replacing the downpipe with a 200 cell sports cat when looking at choices there is a wide range of brands and the price range is equally wide but I don't know what the difference is and what warrants the premium price of Wagner/Active Autowerke for example over VRSF and CTS Turbo choices. So I am asking here, does anyone know the difference between these downpipes?

I accept that I may get a check engine light with the 200 cell cat, I will declare the mods on my insurance etc. I may or may not tune the car to stage 1/2 but for now the idea is just around noise enhancements and the downpipe seems a good choice as it will get the car stage 2 ready if I want it.

Downpipe choices below, please chime in with what you know.

https://www.mlperformance.co.uk/products/wagner-bm...

https://www.mlperformance.co.uk/products/cts-turbo... - Wagner £900

https://www.ospreyperformance.co.uk/product-page/b... - Osprey - £450

https://performancem.co.uk/choose-your-car/toyota/... - scorpian £520

https://www.mlperformance.co.uk/products/active-au... - Active Autowerke £1500

[scz4]

I can comment on my experience with the B58, but in the Supra.

Had Wagner downpipe with sports cats and Milltek OPF delete with MHD Stage 2, along with ModStock silencer mod. Very loud and to be honest gave a hollow sound, raspy, no real tone or depth to it.

Ended up putting it back on OEM map, but still Wagner sports cats and it sounds very nice indeed, about right volume wise but much deeper.

Can't comment on the warning light with just the sports cats, as MHD may still have been masking it, but it instantly came on with the OPF delete.

Edited by scz4 on Tuesday 20th January 13:55

[DJS1994]

scz4 said:

I can comment on my experience with the B58, but in the Supra.

Had Wagner downpipe with sports cats and Milltek OPF delete with MHD Stage 2, along with ModStock silencer mod. Very loud and to be honest gave a hollow sound, raspy, no real tone or depth to it.

Ended up putting it back on OEM map, but still Wagner sports cats and it sounds very nice indeed, about right volume wise but much deeper.

Can't comment on the warning light with just the sports cats, as MHD may still have been masking it, but it instantly came on with the OPF delete.

Edited by scz4 on Tuesday 20th January 13:55

Thanks for commenting, did you have your Supra MOT'd with these mods? How did it go emissions wise?

Thanks,

[scz4]

DJS1994 said:

Thanks for commenting, did you have your Supra MOT'd with these mods? How did it go emissions wise?

Thanks,

Yes with the downpipe and OPF delete once and it passed ok. However, one of the reasons (other than sound) for removing it was despite declaring the exhaust mods to the insurance, I was always conscious the OPF is technically illegal, whereas high flow cats are ok and if the worst happened they would wriggle out of it.

[VeeTenM]

I would avoid buying anything from mlperformance
Items never in stock or take weeks/months to arrive. I ordered a bunch of service bits and they couldn't even get those to me, after 9 emails of BS from them. Look at the Google reviews by recent.....

[mooseracer]

VeeTenM said:

I would avoid buying anything from mlperformance
Items never in stock or take weeks/months to arrive. I ordered a bunch of service bits and they couldn't even get those to me, after 9 emails of BS from them. Look at the Google reviews by recent.....

Yes, well known for this - there are plenty of other places to get bits from.


I had a Wagner on my 140, nice bit of kit.

[DJS1994]

Whats the justification for the difference in price between the Osprey and the Wagner though?! Wagner is almost double the price.

[G30001]

I had carless with GPF still on and std back box on an A90, wasn't the best sound so would have gone for a sports cat if I did a B58 again.

I now have Active Autowerke sports CAT's on my S55 M3 with a std exhaust and it is a little louder but certainly much deeper. No EML light and sails through the MOT. I spent the money so I don't have to mess about each year, when you add up the labour and wasted time to get the exhaust sorted each year for the MOT it soon pays for itself.

[Mirinjawbro]

I had an f series m240i. Double ress delete and downpipe. Super loud. Probably too loud. Really loved the sound and many comments

I then changed to an m340i. I had ( so I was told ) 2 x opf bypass / delete and downpipe . It sounded half as good and half as loud