Hey all,
I've been lurking for quite a while, and been trying to just read and learn. Jim and Steve, you guys have been a plethora of help.
I purchased and studied the course from HP acadamy, which seemed redundant to what I was reading here (so consensus is nice) But I will admit that I feel like I just am not getting it, and this tuning thing has been a lot of frustration for the last 9-months.
Usually, the story is I'm just starting to get some tweaks going, Then I end up changing something huge like Bigger injectors or tires, and I'm back to the drawing-board.
Those physical mods dropped my fuel mileage from 17.xx to 13.xx (not surprised) and now I'm wanting to get this engine to run more efficiently to see if I can get much of that back.
Yes, I know that you "Don't buy these trucks for the mileage" and "if you want economy, don't put mods on" but I feel like it had room for improvement before those 2 swaps, and I just wasn't uncovering the secrets this thing needed.
So, I'm hoping to get help on some basic questions, and consolidate knowledge that seems to be impossible to find sifting through the pages of the Cummins diesel forum.
One such question:
When/where/how much duration should I be cutting to compensate for these bigger injectors??
Details:
They're BBi Stage-1s, (roughly 30% overs or +90s) and The smoke is really NOT that bad on the stock tune, and I've even removed the post events before trying to use them to spool the turbo faster.
Speed limit is 70-80mph, and I now cruise 60-70. Which is turning 1500-1800RPMs. Boost was at 4-5psi @65 on flat ground, but after I advanced the Main timing 3* and boost actually climbed to 8-12 at the same speed (weird, I thought)
I THINK that my throttle position was 20-30% (guessing, as I cannot find my log files ATM)
5000ft elevation, and below freezing about 1/2 of the year.
SO, I know that cutting duration will also advance timing: (so to ask again, and ask about a very specific part of the tune) where/how much can I cut duration? Can I do it across the board? across the throttle range? Would it taper off as demand/pressure tapers off??
How to I get this pig to squeal??
Many thanks in advance,