[Seer501]

Looking for feedback…anyone have experience with 2021 M440i Xdrive using JB+?? I have catted AA downpipe and have found very little, if any info regarding performance of JB+ on 2021 M440i. Any input would be greatly appreciated!!

[mike@x-ph.com]

What kind of info are you looking for?

its a very simple concept, easy install, adds 3-4 PSI of boost. Each PSI makes 10-15whp

[Seer501]

Originally Posted by mike@x-ph.com

What kind of info are you looking for?

its a very simple concept, easy install, adds 3-4 PSI of boost. Each PSI makes 10-15whp

Thanks for the response, Mike. I’ve read a lot of your posts, good stuff. I understand tunes (piggyback vs true). Just looking to add a few psi. I’ve read with skepticism where some have said JB+ didn’t work with mild hybrid and actually lost HP, along with “jerky” shifting. Have access to 93 so octane not an issue. Any issues with CEL or any other issues? Thx

[Seer501]

Originally Posted by mike@x-ph.com

What kind of info are you looking for?

its a very simple concept, easy install, adds 3-4 PSI of boost. Each PSI makes 10-15whp

Are there any know issues with CEL? If not, I will place the order with you. Please advise. Thx

[totalone]

Originally Posted by Seer501

Thanks for the response, Mike. I’ve read a lot of your posts, good stuff. I understand tunes (piggyback vs true). Just looking to add a few psi. I’ve read with skepticism where some have said JB+ didn’t work with mild hybrid and actually lost HP, along with “jerky” shifting. Have access to 93 so octane not an issue. Any issues with CEL or any other issues? Thx

Actually 93 will be an issue for you since these B58s run higher boost on stock.

So you want better fuel

You probably want JB4 and come here to discuss more
https://www.supramkv.com/threads/sup...view-v1.20544/
It takes some time to dial in AA pipes, or you can just run map4. Map4 pushing 20 PSI but with AA your car will request between 18 to 20, so gains are minimal. If you want more gains you need to run custom map, couple guys dialed in custom map2 with 21PSI peak.

[Seer501]

Still under factory warranty and purchased extended warranty. I understand JB+ can void warranty, just like JB4, however, not looking to push the turbo with JB4 until warranty expires. Very little info anywhere on the forums or internet with JB+ on M440i.

[mike@x-ph.com]

Originally Posted by Seer501

Are there any know issues with CEL? If not, I will place the order with you. Please advise. Thx

no issues with the JB+

if you want to be conservative, set it at +2 PSI