7 Bar LB7 boost sensor questions

Good morning,

I have an LB7 with an S475/Stock turbo setup that I am trying to get instrumented to start tuning the valley turbo wastegate, turning up fuel and adjusting timing. I am data logging with a CTS3. Currently I am reading interstage boost, final boost, drive pressure, pre turbo EGT, oil temp, as well as all other relevant PIDs the E54 ECM has to offer.

In place of the factor MAP boost sensor I am using a Lowdoller 7 bar MAP sensor. I rescaled the sensor with EFILive. The scaling was the validated with a second boost sensor from an Edge EAS module. Despite changing the sensor scaling the ECM will still only report up to 22 psig. Where my Edge sensor will continue on up to 30 psig. I thought that maybe the max boost tables may have been limiting the ability to report boost pressure over 22 PSIG as it maxes out at 37 PSIA. However, I am unable to set anything above 37 psia as that is a hard limit in EFILive.

After replacing the factory MAP sensor on an LB7 is there any way to get the E54 ECM to read higher than 22psig/ 37psia?

Thanks in advance!

Here are some snips of the tune file showing the scaling as well as the max boost pressure table. I've also included a sample data log. While not the best/ cleanest data, it shows how boost pressure continues to climb on the boost sensor connected to the CTS3 but the MAP sensor connected to the E54 stops at 22 psig.

*Labels "boost" and "Drive prs" are measuring the same pressure. "Boost" is what is reported by the E54 and "Drive Prs" is what is reported by the Edge CTS3. Both are measuring final boost pressure.

There are multiple PIDS for boost on an LB7. If memory serves the SAE PID which Edge uses maxes out at 37psiA (22psiG). There are at least two boost PIDS in EFILive for the LB7, one is an enhanced PID that will read out further much further than the SAE PID. I'm not sure exactly what the limit is but I suspect it may do what you need.

For what it's worth, we have heavy duty wastegates and wastegates mounts that won't flex when set to 60psi cracking for your LB7. They're not on the website but we use them on our STR series LB7. The factory gate and bracket is not useful at high boost. Also noteworthy, the stock LB7 wastegate puck is notorious for cracking and breaking in half in high performance applications. We use stainless pucks in our chargers for this reason.

815-568-7920 if you need us

Nick

Nick,

Thank you for the reply! I will log the Boost PID in EFILive and see if I get different results. I’ll also check the Edge to see if there is a different PID or advanced PID I can make.

Thanks for the offer Nick, however, I believe I have solved all of those issues with a BD diesel wastegate and an RDS Pro Stock charger. Yes, my wastegate is not set nearly tight enough and that data log I posted I was probably only running 700usec of fuel.

thanks for all the educational videos and your contributions research and education to diesel enthusiasts!

Sounds good, thanks for your appreciation!