[Omaar]

Hello everyone,
Long time lurker new owner on the forums.

I am the proud owner of a 2015 428xi and have just finished installing on what appears to be most of our sadly limited mod list including: catless dp and the gfb dv+.

I live in Turkey where the tuning options are limited as is the quality of the gasoline ( 91 octane )

After going to the local tuner ( obd tuning ) and installing his tune I have noticed that the car goes great from idle to 5.5k rpm but after that the engine seems to be running out of breath.

It is more prominent when at higher speeds like 70 mph+. It was not a " limp mode " as the car repeated the same performance over and over. So I told my tuner to revert it back to stock ( pulls fine on the stock tune ) without the cat less dp warning message.

My tuner told me it might be because of the octane rating of the gasoline we have here but I was thinking it might be IAT related and the eec was dialing back the power.

What is everyone’s take on this? Tune too aggressive? IAT too high? Plugs need to be colder range?

I have a brand new snow performance water injection lying around that I am thinking of installing if it will help.

Last but not least: does running with not cat affect performance in any negative way?

[Martin.328]

take a log and see what is going on.

[Omaar]

Turns out it is my fault. I had to see other dynos and even read a few posts regarding why people want an upgraded turbo for these cars.

The top end is weak compared to low and mid. I am planning on installing a water injection system pre turbo as it helps out with compressor map to help improve it’s efficiency.

The good part is even on the stock tune the cat less dp and dv+ made a noticeable improvement on eco-pro/comfort and even sport modes.

[bmwchue]

Originally Posted by Omaar

Turns out it is my fault. I had to see other dynos and even read a few posts regarding why people want an upgraded turbo for these cars.

The top end is weak compared to low and mid. I am planning on installing a water injection system pre turbo as it helps out with compressor map to help improve it’s efficiency.

The good part is even on the stock tune the cat less dp and dv+ made a noticeable improvement on eco-pro/comfort and even sport modes.

your best bet is stage 2 turbo with water meth injection, upgrade fuel pump and a tune