Boost ? low vs high rpm

[skippydoo]

My 08 is now approaching 70k and I'm noticing a change in my boost. I used to get just a tick less than 40psi at lower rpm. High rpm (over 3000 rpm) was never over 35. Now I feel less power and my boost at low rpm is never over 32psi. High rpm is aprox 28psi. So I have two questions is the boost difference normal (low vs high rpm)? I took it back to my dealer and they said all checks out fine no codes so is the boost pressures normal? My 6.4 is a day one smoker! Also my regens have gone from 400 to aprox 250 miles.

[OMCUSNR]

Originally Posted by skippydoo

My 08 is now approaching 70k and I'm noticing a change in my boost. I used to get just a tick less than 40psi at lower rpm. High rpm (over 3000 rpm) was never over 35. Now I feel less power and my boost at low rpm is never over 32psi. High rpm is aprox 28psi. So I have two questions is the boost difference normal (low vs high rpm)? I took it back to my dealer and they said all checks out fine no codes so is the boost pressures normal? My 6.4 is a day one smoker! Also my regens have gone from 400 to aprox 250 miles.

You're approaching half life of the DPF. If its a smoker, and / or you've used a bit of LSD frequently, you may be having problems there. Maybe some backpressure issues.

OMC