My first tune file created for the LLY
- Thread starter raceghost
- Start date
This is exactly what you should NEVER do with an allison, and it changes HUNDREDS of tables you can't see. NEVER touch the speedo settings in the tcm. I've said before they should remove those tables imo. If you're going to make changes, make them in just the tables. Myself I see very little reason to alter them for a tire change.
took another look at your tune, your PW seems ok for the areas that will be making the power. tuning has advanced much since the 20/20 tune was done, and like others have mentioned, maybe tone down the bottom left of the table to something closer to stock. those 4680us pulse' won't do you any good
Quick question, when updating the PCM for larger tires, do you utilize the speedo calculator, and more importantly since there are 4 tabs within that calculator, do you adjust the shift points in the PCM? Any clarification on this would be great.
Thanks in advance,
Thanks in advance,
Bumping the pulse up in those low mpa / high mm3 areas won't hurt anything, it's just not necessary.
While the McRat tune will run fine, it doesn't have to be a starting point. It's purpose was to familiarize new EFI live users with the functions of the software and table interaction. When EFI added support for the Dmax, current users weren't familiar with diesel tuning, and the diesel crowd wasn't familiar with custom tuning.
For your speedo, just look up the revs/per mile on your tires, then do the backwards math to calculate the speedo pulses.
Jesse is right on the money with his post. The McRat tow tune is still a great tow tune for LLYs, and it served a great purpose to give people confidence to dig into EFILive themselves and start tuning. It really was a special time all those years ago when everyone was learning and sharing together. It's nice to see someone with the desire and guts to dig into it themself. I've always believed that the best tuner for your truck is you. Who better to know what you like? The nice thing about diesels is they aren't nearly as sensitive to bad tuning as a gas engine, and they will generally let you know when they aren't happy without causing any damage unless you get completely stupid with stuff. Take small steps and use all your senses to pay attention to what your truck is doing when you drive it after a new tune. Keep up the effort, and there are plenty here who are willing to help as long as you are willing to put in the work.
Leave the shift points alone. Even the stock tables are incorrect from where it actually shifts. Correct your speedo for bigger tires(do not go taller than a 34.5" tall tire or else you'll trip the abs), and call it good. The tcm shifts at the same driveshaft speed regardless of tire size. Gas tuning(except 8.1l/allison) requires you to update the shift points because of how the tables are written in relation to the speedo output, but the allison os different. Some people bump the shift points up some and alter the lockup points for taller tires to help get some of acceleration back by bringing it up in the power band more, but for most this isn't needed.
Ok, good to know, and thank you.
Thank you, and most definitely, we share the same enthusiasm.
Please educate and enlighten me? Would love to take a look.
Thank you, and good to know. Will do another revision for I have stumbled across some tunes on some other threads and forums, and doing a bunch of comparisons and discussion will help me understand what is going on. I have always been good at re-engineering things, but question weather I understand what is goin on. So some more questions to come.
Today, I am playing around with 52 Gallon Super tank and scaling. I am going to the shop tonight to empty it for it is almost empty, and then going to go to the pump to play the couple gallon game until I get the voltages and capacity all worked out. It is an actual supertank, I found it in a Diesel shop a year ago still in the box, never opened. Installed it at that time, but have never adjusted PCM to read right, so thats on the docket today. Ill make a post with proper scaling so its on here for others when I am done.
So question to ALL, is there anywhere that explains the tables and lets me know if they are limiting tables, compensation tables, tables to play with, tables not to play with? Just looking for something to give me a general Idea of what I am looking at in reference to should or should not play with in respects to all areas of the ROM and maps. Over on my Turbo gassers forum, in the last 18 years we have done that for the general community with explanation of what the tables do in relation and respects... Made it real easy for new comers to dig in and get there feet wet...
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The timing calculator is a basic excel spreadsheet I made to take pulse width and fuel pressure tables to calculate injection timing based on what percentage of fuel you want injected before top dead center. It is a tool that makes it easy to quickly build a timing table for the areas of the map where the engine is operating under power (20mm+ fuel quantity and 1400+ RPM). It does this by looking at the rail pressure at a given fuel quantity and RPM and then referencing that fuel pressure and fuel quantity on the pulse width table to find out the pulse width for that particular fuel quantity and RPM. Once it has the pulse width and RPM, it calculates how many degrees of crankshaft rotation there will be for that main injection cycle. When I first wrote it, it was a straight % across the whole table, but I eventually built in some dynamic tables that allow different percentages across the map (you could do 75% at low load low RPM operation and 45% at high load high RPM operation). You can play around with it some, but a good starting point is 50% which will inject approximately 50% of the fuel before top dead center and 50% after.