Hey guys,

I built my own turbo setup earlier in the year consisting of the following.

Stock block 4.0 (for now).
GT3582 .63AR (chinese turbo)
Air to water intercooler
SRT4 2.25 bar map
Originally Siemens Deka 60lb injectors, now Bosch 36lb injectors (Barra injectors for other Aussies)
GFB 44mm wastegate plumbed back
3 inch turbo back exhaust


So I'm reasonably mechanical having started working on and building cars 30 years ago and whilst I understand tuning as a concept I've never bothered doing it myself and always paid professionals mostly with good results.... Until this car.

Here in Australia asking someone to tune your jeep is like asking someone to tune your space shuttle, lots of no thank you's, some laughs over the phone and many many unreturned messages and phone calls. Eventually I find a tuner with seemingly good reputation who says 'yes I'll do it send it down'.


He has the car for several days but can't get the fuelling right, it's incredibly rich at idle and everywhere else actually. Eventually he calls me and says hey cars ready come and get it BUT the map sensors died (genuine mopar, 3 days old) so you can't drive it. Like a complete moron I pay the bill, drive down with spare GM 2 bar map sensor, wire it and fire it up only to see its so rich it's spitting raw fuel out the exushst, stumbling and missing until combustion temps come up to where it can ignite fuel but burns so rich it hurts your eyes. He tries to blame the 2bar map but it's apparent it's more than that - to shorten the story I buy another new genuine 2.25 bar map and fit it and no change.

Further to this its so rich it filled the sump with fuel and melted the cats driving it home.... There's other damage he caused too but I think you gey the idea.

The car runs at 10 to 1 Afr at nearly every single throttle and load position including Idle and it's even a richer than 10 to 1 in many conditions but my gauge won't read any richer

So after this I buy a copy of HP tuners which our Postal Service immediately loses only to be told it's the last one in the country and for the last 4 months the car has sat at home.

Last week I finally find an MVPI2 and actually receive it. I pull the tune and immediately realise I have no idea what I'm doing, it's nothing like more common manufacturers tuning parameters and not even like JTEC which I was expecting.

Now if you're still awake what I'm hoping is for some plain English advise on changing parameters to go from the 60lb Siemens injectors to 36lb Bosch on STOCK tune. Basically I want the car to start and run and then I'll probably spend another $1600 and hope the next guy doesn't rip me off again.

There is no injector flow rate option, all I have is pulse width vs fuel mass, voltage offset (I have this information only), and Min PW.

Can anyone explain to me in simple terms on a stock tune if I was to go from the factory 28lb injectors to 36lb injectors how I calculate the difference and how I enter it into what seems to be incredibly complex injection parameters on the NGC3 in these TJs

Apologies for the incredibly lengthy post, I'm just hoping to provide as much relevant information as possible.