Zare

Does JB4 has option to control valves, If it does is there a difference between jb4 and renntech mod ?
On their website in the description this option is not listed but I saw on other forums that they are discussing that JB4 can do this.

JB4 is $150 more but if it does the same thing as ASR/Renntech mod then it is better to go with JB4.

MaverickC43

Pretty sure the JB4 does not have valve control
@BMS
@Payam@BMS

JMPCNB

I have a JB4, the Renntech ASR module, and stage 1 ECU/TCU tune. JB4 is a piggyback tuner that is installed between your engine map sensors and your ECU to manipulate performance. The Renntech ASR module plugs into the exhaust flap module in the trunk and acts as an intermediary controller for the exhaust valves. Both are completely different and JB4 cannot control the exhaust flap module. I dont see this functionality mentioned on the BMS product website either.

Zare

Thank you for your explanation.
I saw in some topic they were discussing about bmw jb4 and opening exhaust valves.
Maybe i misunderstood them.

JMPCNB

No problem. BMWs have a larger platform for modding so maybe the JB4 does do that with their vehicles, but not ours. I do recommend the ASR module as it increases the sound dramatically at lower rpms. There is a little bit of drone when cruising on the highway but it's not bad at all.