305 to 350 Swap 96 K1500

[Schurkey]

So if you replace poppets with electric injectors, you have to change the computer tune?

 

[L31MaxExpress]

So if you replace poppets with electric injectors, you have to change the computer tune?

For them to work the way they should it would be advisable. The flow rate is different as are the injector dead times and voltage compensations. I correct the data on every one I tune that has the upgrade spider. Data was easy to grab out of the newer 4.3L engines or 5.7L Mexican trucks that ran the newer style upgrade injectors from the factory. GM has data for those injectors in a returnless system as well at a constant 58 psi.

 

[Jimbo2312]

Hey L31, the shop I was planning to use for my computer is called Black Bear Performance here in Idaho. Do you think they can modify the computer the single cat system, or would they just delete them? I wish I had more specs to give them, the invoice I got for this motor was trash. Thanks in advance man

 

[Jimbo2312]

Update, I called them, if you want to do this it has to be registered as an off road vehicle only. I wonder how detrimental this check engine code would be, thankfully I live in a county without emissions..

 

[Caman96]

For them to work the way they should it would be advisable. The flow rate is different as are the injector dead times and voltage compensations. I correct the data on every one I tune that has the upgrade spider. Data was easy to grab out of the newer 4.3L engines or 5.7L Mexican trucks that ran the newer style upgrade injectors from the factory. GM has data for those injectors in a returnless system as well at a constant 58 psi.

Now you got me wondering about this. Just read the TSB and they make no mention of adjusting pcm tune for MPFI upgrade, can’t imagine dealership ever doing that either. Not doubting you though, as you pointed out, the 5.7L Mexican trucks had updated data. I would think most haven’t done this. How much of a disadvantage in not updating? TIA

 

[L31MaxExpress]

Now you got me wondering about this. Just read the TSB and they make no mention of adjusting pcm tune for MPFI upgrade, can’t imagine dealership ever doing that either. Not doubting you though, as you pointed out, the 5.7L Mexican trucks had updated data. I would think most haven’t done this. How much of a disadvantage in not updating? TIA

Fuel trims are off because the fueling is off and the engine does not run as smoothly or start as easily as it could.

GM also offers a plastic body MAF that is not completely correct for our trucks either with the stock tuning.

 

[Orpedcrow]

Fuel trims are off because the fueling is off and the engine does not run as smoothly or start as easily as it could.

GM also offers a plastic body MAF that is not completely correct for our trucks either with the stock tuning.

Do you think that has to do with the Mexican heads being a little different? Or emissions/government regulations?