[elprincep]

I have changed the exhaust on my M240i to Milltek, including the downpipe. I used LEIB Engineering sensors to avoid error codes.
Now I love the sound, and I feel like the car pulls a bit more.
However, I’ve read in some places that installing a downpipe without remapping can be harmful to the car's engine. Is that true? Should I remap it no matter what? I’d prefer not to do it to avoid issues with the warranty.

On the other hand, I’ve always used 95-octane fuel, as that’s what the car recommends. But I’m not sure if with the downpipe I should switch to 98-octane, or if it doesn’t really matter...
Thanks!!

[IanH]

98 Ron = 93 octane in the us version, it's what most people run if available here.

Read a bit about this and many people say you can run a downpipe on an oem tune. A downpipe enables you to run more boost so some kind of tune/piggyback would be complimentary if you want to have more power.

[elprincep]

Originally Posted by IanH

98 Ron = 93 octane in the us version, it's what most people run if available here.

Read a bit about this and many people say you can run a downpipe on an oem tune. A downpipe enables you to run more boost so some kind of tune/piggyback would be complimentary if you want to have more power.

Yep, I know, if the downpipe does not harm my car, I will wait some months until I remap the car to avoid warranty issues and until the car can be remapped without sending the ECU to Finland to do the bench unlock.

[7ssainf]

Never had an issue running a downpipe without a tune.

[elprincep]

Originally Posted by 7ssainf

Never had an issue running a downpipe without a tune.

are u using sensors too? which brand?

[7ssainf]

Originally Posted by elprincep

are u using sensors too? which brand?

Yes, VRSF catless

You will get CEL every 30mile/50km which you can clear with bimmerlink or similar app.