OBDII plug and turbo boost

Revspan · April 8, 2019

I have an OBDII plug in module that can monitor lots of engine info, and some car info. It is nice to see IAT on gas engines, spark advance etc. this was the original intention of use, as I wanted to see what was going on with my 6.0 engine. Simply searching for optimized power.

Well, I gave up on the 6.0 and bought a Dmax and plugged the same module in and was surprised to see the boost top out at 8psi. The module could be reporting wrong, but this was the highest boost I saw, even when attached to my 11k boat trailer and WOT. Everything seems to run right, and did some research on line and guess that the boost is supposed to be around 28psi.

Is the correct boost supposed to be 28-30psi? Just looking to see if it is the module, or maybe the boost is lower than I thought it was supposed to be. Just not sure.

Thanks

redwngr · April 9, 2019

How fast were you running?

WOT in lower gears will be in torque limiting, so lower fuel and air to suit.

Yes somewhere around 30 psi is max boost.

Revspan · April 10, 2019

I had it on the interstate for enough time to get the boost up. I would think that it would have maxed out. Wot on an on-ramp with the boat hooked up should be enough to get the most out of it. I bet that the OBDII module is not reporting correctly. Was also surprised that it showed a vacuum for most cruising speeds. Would have thought that there would be boost at highway speeds with a good load.

EJCarter · April 12, 2019

I would guess whatever brand of monitor you are using is not reading the boost correctly. This may sound stupid, but is it now set to diesel if you were using it for a gas motor before? Is the internal firm wear up to date with the latest version?

If your truck was only producing 8 lbs of max boost, you would have very little usable power throughout the entire RPM range...

I have a CTS2 monitor that also receives its data from the OBDII port...boost is one of the PIDs I have selected and I'll see it up to the 30's under heavy acceleration or heavy loads. It has been noted on this and other forums that OBDII data may not be 100% accurate, especially when dealing with EGTs for example. These are more accurate with probes installed and linked to the CTS2 with additional optional equipment from the manufacture. The accuracy through the OBDII will be close enough for normal monitoring should a problem arise and you see numbers, values, percentages, etc...moving in the wrong direction.

But again, I would think it's your monitor as opposed to the data being sent to it...