[jkafetz]

Hello all!

I recently purchased a 2014 118i with 80.000km and yesterday I took it to the tuning shop for a remap.

The dyno results were pretty weird/bad. Drops of power, nonlinear curves and the turbo pressure was all over the place. The power curve became a little bit smoother with every consecutive run, but it became apparent that there is something wrong with the car. We also made sure it runs stock ECU software.

He showed me a dyno chart from a stock 118i he recently tuned and I was brokenhearted lol.

I didn't have the chance to take to a mechanic yet but at the shop they said that it might be a clogged air filter or carbon buildup in the engine or a faulty catalytic converter (there was a weird smell after the first run). They also told me to replace the N75 valve just to be sure because its inexpensive.

Has anyone ran into similar issues? What was the root of the problem in your case? I know it's difficult to diagnose such things, but any insight or suggestion is certainly welcome!

I have attached 2 charts. Blue is the first dyno run and red (the top line in the second chart) is the last dyno run we did.

[IJO]

Definitely something not right.
My 2014 116i is great after a MHD remap.

However I did replace the maf and wide band 02 sensors, changed the airfilter and replaced the rear silencer (in case the original was clogged with soot as the car had done 85k miles).

A new N75 valve is probably a good idea, but also remove and clean the turbo pressure sensor - the one in the lower intercooler pipe.

Finally, the turbo bypass valve should be checked. I removed mine from it's housing to make sure it was free to move.