Jeep tuning master thread
Hello I am Tom an experienced Tuner and Jeep enthusiest !
I have been messing with my HP TUNER MVPI 2 PRO and want to start a thread on how to tune 4.0 engines.
#1 before starting tuning a radical change - switch to 93 octane for safety against pinging - final tune switch back to 87 if desired for $ saving and datalog more and adjust for 87
#2 what you put into the base map is not what will happen ! other parameter move and scale the base map so go slow ! - it may say 17 degrees timing but have x1.5 somewhere you have to datalog and watch it !
My finding with MVPI 2 =
- We can now adjust transmission protocols by adjust the shifting triggers from the PCM so that overdrive downshifts to 3 sooner for those hills and highway driving (previously you needed almost WOT)
- We can adjust the torque converter lockup parameters and make life more enjoyable on the highway
- My stock tune was pretty messy im sure yours was too, the best thing to do is smooth the ignition curve out and ad more from idle to WOT through 3500 RPM's = still testing
- when changing any table be aware ignition and fuel timing have multipliers and we cant just change the EGR off base map
My tuning experience comes mainly from Carburators and to tune my jeep I started that way and turned my PCM into an emulator to act like a carburator which gave me a great basemap to tune in for my Large upgraded camshaft, low vacuum added so much fuel so it needed to lean out considerably, next i datalogged with wideband and adjusted from there then smoothed out the 3D map with my mouse, datalog - repeat I have much more work to do
(caution multipliers make this tricky and cant trust base map must datalog !)
0 to 2000 rpm 14.7 to 1 2 to 4000 rpm 13.5 to 1 4000 to 5400 11.5 to 1 and set shift point to 5400 rpm because big camshaft. - soon to be 14.7 to1 then 13.5 to 1 then 13 to 1 i am dialing it in slowly as im playing with timing at 34 degrees max now (reduced to 30 to be safe) - tune timing fatt then lean out and watch plugs and pinging sounds. (wish i had a standalone knock sensor $$$ to tell me when to stop adding timing )
after my tune is done at 25 degree F Ill wait for summer time then datalog and adjust intake air multiplier to match - no other way to test only guess.