ISX 2350 485

[mmssvv]

(02-04-2017 )gearhead Wrote:  Only because you are at 32 psi and the ratio changes the higher the boost levels. I have seen 1 to 1 on cm871 until about 16psi or so. You can check your ratio by monitoring your gauge exhaust backpressure against you boost pressure gauge. Gauge means that barometric pressure is not added to the value. If you use insite to monitor it you have to subtract about 15 from value to get gauge number. You can tell because it reads the same as your barometric pressure sensor with the key on and truck not running.

This is true.Then at 32psi boost ,I have close to 50psi exhaust,just checked my data.This mean the ratio is about 1:1.56 which sounds right for my turbo.
Thanks!