I have tried to log the boost via OBD2 Bluetooth adapter along with the Android program "Torque", I could only see 22.5PSI peak boost up till end of 4th gear in both S/M mode with ESP sport. I am just wondering have anyone of you guys tried to measure boost, I am still far from the 26PSI advertised from Mercedes.

 

Mercedes advertises 26.1 psi but I want to bid that the 26.1psi are for a fraction of a second on the initial full boost spike. You are probably reading correctly on the mid 22's psi. I can see the turbo boosting higher initially then slightly coming down. 22.5 psi is still a very healthy reading. My .2c

 

NO ONE has seen the 26 PSI advertised boost. Most are seeing 22-23 max. Is this with your renntech tune too?

 

Yes.. With Renntech tune.. 22.9PSI so far.. I contacted Renntech Germany. They said even with a tune box, we will not see higher than stock boost numbers.

 

So MB built the engine to handle 26 psi but tuned it conservatively. That means that there's still room for improvement. Tuners will eventually get us a way to turn up boost across the rev range, but frankly I'd be satisfied with the current available tune for daily driving purposes.