BMW M140i - JB4 and decat downpipe

BMW M140i - JB4 and decat downpipe

This is the first BMW M140i which comes with the new B58 engine we have tuned on our dyno. We had seen a lot of dyno graphs in the past which showed a huge range of figures with a lot of owners speculating what their car would actually produce.

The owner of this car brought us a BCS decat downpipe to install at the same time as a JB4. Whilst we waited for the downpipe to cool down we installed the JB4 which was extremely simple. With both parts installed, we strapped the car to the dyno with the JB4 disabled and got a "stock" run. Standard, this car produced 364 bhp, almost 30 bhp more than BMW claim the car actually has (340 ps, 335 bhp).

We tested map 1 and map 2 due to the car using premium fuel. With map 2 we managed to get almost 440 bhp, but that was past the limit of the fuelling system. Map 1 provided us with a brilliant power level, whilst the car was running perfectly safe. With some additional fuelling modifications, this car has fantastic potential!

Power gained: 47 bhp

Torque gained: 124 nm

BMW M140i rolling road dyno graph

Older Post Newer Post