LSJ high boost tuning

[SalvoBros]

hey guys I'm brand new to Hp tuners although ive really been diving in to learn how to properly tune. i am currently working with obviously my LSJ engine with a p12 computer ive been looking al over the site and cant seem to find anything about being about to surpass the 2 bar restriction that these PCMs have. I'm looking to throw a bunch of boost to this motor and trying to figure out how other people are able to properly tune for boost over 17psi. thnx in advance.

[AP83]

My car pegs the 2.5 bar TMAP at 22.67 psi or so on a MAF only tune and a Mini-AFC. It runs just fine while it does so. Once I get a proper boost gauge/controller later this spring, I intend to crank the boost as high as 25/26psi.

To tune it VE is trickier, and would involve tuning the VE table, then skewing the PE ratio for anything above the limits of the table.

[cobaltssoverbooster]

i ran an oil pressure sensor for boost when we ran 50 psi. just get a 5 volt reference map sensor in a bar range that exceeds your desired target boost and calibrate it accordingly using manufacture specifications. most people steal them from other gm cars so they can just transfer the data from one file to another without having to look up the linear mfg. data.

[AP83]

That's pretty clever. Did you just drill and tap the intake, leave the TMAP in place for the IAT2 readings, then clip the factory wires and move them over to the sender?

[SalvoBros]

both Are really help full thnx guys
i was unaware of a Mini-AFC which makes soo much sense definitely a little confused about the larger MAP sensor though. going with a 3 bar makes sense and recalibrating it, im just unsure about how to do so, in the VE table it doesn't allow you to change the MAP values to a voltage reading which is what i thought you were getting at. would i be comparing voltages from the original sensor to the new one and tuning based on what the original sensor would be outputting or is there a way to recalibrate the table

[cobaltssoverbooster]

That's pretty clever. Did you just drill and tap the intake, leave the TMAP in place for the IAT2 readings, then clip the factory wires and move them over to the sender?

drill and tap original map port to accept new sensor and a fitting to provide clearance, and install open air element gm iat sensor to feed now missing iat signal. you have to re-scale usually to run high boost because of an internal limit in the lsj. (https://www.hptuners.com/forum/showt...ll=1#post68901) This limit is the main reason why there isnt a 3 bar OS upgrade for that ecu.
It became a pain to keep track of fuel past 35 psi so we eventually swapped out to a Big Stuff ECU and that was the last i heard of that car.