Turbo RPM?

[Wheelz]

Out of morbid curiosity, I have to ask..

What is the turbo rpm PID useful for? If its just wanting it to be right I understand totally, I just can't figure out a reason to monitor it at all

[beav]

Out of morbid curiosity, I have to ask..

What is the turbo rpm PID useful for? If its just wanting it to be right I understand totally, I just can't figure out a reason to monitor it at all

Really, I just ran across the value while browsing the data tab.

Howeer, there is a compressor map developed from each turbo manufacturer and sometimes other firms that show the ratings, performance areas, and limits of the turbo. Turbo speed is one of those metrics that if outside of the choke line (asdefined on the map) you risk overspeed.

In my specific case, I knew that 2 million RPM could not be a correct reading from my turbo. If that was the case, it would be more likely to have seen the compressor wheel launch straight though my hood and land somewhere in Kansas! It appears to be either a bug in the EFILive software or there is some issue in my ECU, etc.

[DoghouseDiesel]

Without knowing what you have done to the motor and what you are actually running for tuning anything we say is a guess. I mean, full open on the nozzle on stock injectors shouldn't be producing those boost levels, unless you're running crazy high injection pressures.

[beav]

Without knowing what you have done to the motor and what you are actually running for tuning anything we say is a guess. I mean, full open on the nozzle on stock injectors shouldn't be producing those boost levels, unless you're running crazy high injection pressures.

It is a newly rebuilt 6.7 bored .020 over. Milled head approx .001. ARP studs, MLS gasket, shimmed r rail plug, stock but new vgt and stock sticks. Deleted with 4" exhaust and AFE CAI.

While I do have a mild tune in it now but it was reaching higher than normal boost and ebp pressure. Even though the 2 million turbo rpms is just an incorrect reading or bug in the software, I believe my issue has to do with the turbo actuator. For some reason it is fluctuating. During this period is when it reaches the high boost and ebp but at no time at all does the fuel pressure get above 25 kPSI.

[KhakiCummins]

I think I know why the boost and EBP are so high now. For some reason the turbo commanded and actual position readings are fluctuating during movement. When at idle the turbo position is at the expected 74% and as RPMs increase it starts to fluctuate until it goes to max RPM (close to 3,000) then immediately drops down to 0-5%. At higher RPMs it is no wonder that Boost hits 46 PSI and EBP hits 62 PSI...not good.

Any idea what would cause fluctuation in the turbo? My tables have been smoothed out pretty well so I do not think the tune is doing it, but I could be wrong. And it is too consistent when it fluctuates to be a short, but again I could be wrong there too. I would think that it would fluctuate at other times if it was a short.

Are these Boost and EBP readings from a mechanical gauge or from the EFI PIDS?

[beav]

Are these Boost and EBP readings from a mechanical gauge or from the EFI PIDS?

EFI PIDs, CTS, and my Ford OEM "dummy" gauges all agree. The Ford Gauge may be slightly lower as well as the EFI MAP PID is a bit lower as well - all still entirely too high.

Wish I still had another turbo to try out - even though this one is new. Used to have 3 sitting on my bench but got rid of them.

[KhakiCummins]

I don't know about the CTS or the Ford Dummy gauges but the EFI PIDS are absolute pressures so depending on just where you live, that 46 PSI boost is really only about 32 PSI and the 62 PSI EBP is really only about 48 PSI.

[beav]

I don't know about the CTS or the Ford Dummy gauges but the EFI PIDS are absolute pressures so depending on just where you live, that 46 PSI boost is really only about 32 PSI and the 62 PSI EBP is really only about 48 PSI.

Well that is where mechanical gauges come in handy for sure. We are closer to sea level so if what u mean by "absolute" then I would subtract approx 14 PSI from the numbers that I am seeing. Only concern I have with that is the the map pid is about 10 psi lower than the boost pid. I'll need to double check that though...

[beav]

Just confirmed...MAP PID is ~9 PSI below the BOOST PID - 37 PSI and 46 PSI, respectively.

[KhakiCummins]

I use the Ambient Air Pressure (CM.AAP) PID to get my atmospheric reading.