hillbastard

I just started fooling with TunerPro on a $EE PCM (94-95LT1), and there is no way to scale the MAP beyond 100 KPA (boost), nor is there a function to rescale the MAP reading itself to make 100 KPA actually be greater than 100 (trick it into measuring boost).

How are the PCM tuners getting around this when tuning a boosted application without resorting to a FMU?

I done several searches on the subject and there seems to be a lack of a way for a home tuner to do this, is this something the professional tuners are keeping a secret or what?

Eurospec2

iTrader: (2)

Get EFI Live or HP Tuners, use one of thier respective custom operating systems and use a 2 or 3 bar map

2xLS1

iTrader: (25)

They must really be custom to be able to use them on 94-95 OBD1.

To the original poster, since there are no 2 or 3 bar custom operating systems for those OBD1 PCMs, most just control the spark in boost with the 100 kpa row. The PE fuel can still be controlled because it is rpm based, not MAP based. You can replace the 1 bar map with a 2 bar map and then double all the MAP based tables in the calibrarion. Example , a 50 kpa row becomes 100 kpa and a 100 kpa row becomes 200 kpa, but you must do it all in your head because there is nothing that will relabel the tables for you and you loose 1/2 of the resolution in the MAP based tables.

hillbastard

Thanks for the info, so after you add a 2 bar MAP does the MAP itself report half of the actual value, or does the program need to be rescaled to the new MAP to get the 50 KPA to in reality be 100 KPA (is the MAP just a plug in and then you alter all tables that use KPA to reflect the reality of 50=100 etc.)?

I would guess if this is the case then a 3 bar MAP would make 33.3 KPA= 100, 66.6=200 and 16.615=50 KPA and so on.

2xLS1

iTrader: (25)

Map sensors output 0-5V whether 1, 2, or 3 bar. Their calibration determine if the 0-5V range is 0-100 kpa, 0-200 kpa or 0-300 kpa. 2 and 3 bar map sensors are available for Gen3 motors that directly replace the stock 1 bar sensors. I'm not familiar with what is available for LT1s.

hillbastard

Thanks, thats what I needed to know, sounds like it's directly propotional, and if not it sould be close enough to change the MAP and then start tuning based on the new understood value, whatever differences there are can be compensated for in the table values.

2002_Z28_Six_Speed

iTrader: (19)

Exactly! The computer is being lied to and you just keep it in mind what data you are really working with.

Of course any table that is affected by the map sensor you would also have to keep those in mind, too.