Quote Originally Posted by gbaumann View Post
Would love any info on what exactly the tuner did. If mileage went up then it sounds like your leaner now. Seems like the S/C manufacturers' tunes are rich to avoid the risk of leaning out. How did your tuner conclude that you're getting boost at 1,600 rpm? I've been told by Magnuson that the bypass won't close unless the intake is at zero BAR which is WOT. Is he/she saying that at WOT boost comes on at 1,600? Great info.

There's a chance (small) that I'll keep my 3.6 on a stand with the S/C and tear it down to the rotating assembly and see how it looks after living half its life under forced induction. Then put it back together with any and all improvements I can and experiment with electromechanical bypass control on the S/C and a custom tune. All toward the end of finding a used 6-speed JK to build as light a truck as I can and have it be capable off road.
I don't have exact details on what the tuner did. He had my Diablo Trinity connected to the OBDII port and simultaneously connected to his laptop that was running Diablo software. We took my jeep for a drive in stop and go traffic and did some WOT in some areas that had no traffic. We put it on the dyno for three pulls to get more data logging while he still had the Diablo Trinity and his laptop connected to my jeep. After the dyno pulls and some tuning adjustments, we took the jeep for another road test to make sure there wasn't any engine knocking or stuttering at idle, WOT, or cruising.

I have an air fuel ratio gauge installed, so I can see the numbers as well as the boost. He did lean out the WOT fuel map by about 6% and fine tuned the other settings because Magnuson's tune was running a little rich. He said the company was being over cautious because their tune had to work on every jeep. It made sense to me because Magnuson has told me that their tune also works without modification with their high altitude pulley that adds another 2 psi boost.

My WOT AFR is about 12 and normal cruising is about 14.6. The AFR is not a steady number, so it varies a bit with each cylinder combustion/exhaust cycle. The tuner determined that I was getting boost at 1600 rpm from the data logging. Using my boost gauge, I can see boost even driving on the interstate if I'm going up an incline or running against a headwind. I've had as much as 5 psi boost in a bad headwind on the highway and I definitely wasn't running WOT.