Basics on how to build a tune (im stumped)

[Advanced Diesel Power]

Hi guys and girls i am new to the EFI V2 world and would like a little push is the right direction. I am looking to built my own DSP5 tunes for my LBZ and my friends LMM. I have a built trans and his is stock. What tables should i be worried about looking at and what ones should i leave clear alone? Any help would be GREATLY APPRECIATED! So far i have learned how to activate the turbo in a tow tune, turn the EGR off and a few tips on making an ECO tune.

[StinkyDog]

How much do you know about diesel timing?


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[Advanced Diesel Power]

i know a little bit about it but i do not understand it 100% yet. i know more timing and gain you power and too much is not good i just do not know where that wall should be.

[StinkyDog]

Unlike a gas engine, diesel timing is commonly referred to a %BTDC. What this means is, the amount of the injection cycle in mS that is before TDC. A 50/50 timing would be 50% BTDC and 50% ATDC. There are some calculators out there for figuring % timing based on RPM or you can do the formula yourself.

A diesel will not warn you like a gas engine will when you have gone too far. The diesel rattle MAY get somewhat louder, but not always.

I started by messing with the pulse width (PW) table. The truck will mostly run in the "B" table for the LBZ. To start with, try adding 10% the numbers above the idle range. DO NOT MESS WITH THE IDLE! YOU WILL REGRET IT! At least until you become more comfortable with it.

For serious tuning I think a pyrometer is essential equipment. Although EGT is not the end all beat all, you certainly don't want to melt your turbo with excessive heat!

Send me a PM and I will share some of my personal tunes I made for my LBZ. I also have a calculator for figuring % that I made.

[Advanced Diesel Power]

PM'd

thanks again!

[Snipesy]

There's more to a Pyro than just temps. The best probe would monitor cyllinder pressure but that's a bit hard to setup. You can think of extra boost as a sort of blanket for those higher temps. If you're running without egr. You'll want lower boost in general (wastes energy), but lowering boost also increase egts. Air is your heat sink, and it'll be your primary tool for tweaking egts, especially when towing. Although if you keep it mostly stock you won't really have a problem there.

[Advanced Diesel Power]

i have an egt and boost gauge in you truck, what should a guy be doing with timing? where should the limits be on a stock tranny/ motor?

[Snipesy]

Timings kind of a gotchya because a little something called pilot injection, and it's chaos. The '50-50' tune is kind of a convenient hack. I will tell you that the best tunes would have ranges fron 30% to 80% to -50% (yes after tdc).

Unfortunately there's no really good way to calculate what the 'best' timing is. Not even the OEMs really know, they just kind of guess and tweak to the specifications. Additionally there can be things like temperature effect on timing, so when your hot all is well, but when cold weather hits, timing gets boosted to dangerous levels and your snapping piston rods.


Having said that I have never actaully seen a case where lowering timing actaully gave more mpgs.

Can't really help you more than that, never touched the LMM. The people who have brute forced decent timing out obviously aren't going to tell you what they are.

[StinkyDog]

Tried to send you a PM, but it wouldn't let me. I accepted you as a friend, try again and see what happens.

[Advanced Diesel Power]

i changed my settings' it should work now.

[StinkyDog]

OK. I'll try again tomorrow.

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[Troy Gards]

Hi StinkyDog

I am from Australia & if you haven't heard yet there is a lot of Duramax engine conversions being done over here.
I am a diesel mechanic but never got into learning about tuning until now. I have done a conversion on my bro's car & I want to learn how to tune.
In the goodness of your heart, would there be any chance that I could learn from your tunes also.
If you decline on my request I can understand. If you don't ask you will never know the answer.

Cheers Troy Gardner

[Tommy ashley]

Hey Man U think u could help on lmm and teaching the main essentials and some helpful tips, personal email tommyashley27@gmail.come

[Tommy ashley]

U elaborate a like on the numbers is that fuel pulse or pilot,, or timing, I got fuel, assumed Tim

[Tommy ashley]

Can someone tell me about the 30-50% to -50% thing,, if more timing is more power why would u want less timing and are u adding 30-50% to ur timing tables or is it to the pilot timing,, can u please explain

[StinkyDog]

I tried to send you an e-mail, but I don't think that you got it.
when you hear something referred to as a 50/50 timing, or 50% if you will, it's referring to the amount of PW that is before top dead center.
Obviously this depends on the rotational speed of the engine.
When you're setting degrees of timing, that refers to the beginning of the fuel pulse event. I have not found the pilot to make any difference with regard to ignition timing. logic says that it does, but I think it is such a small amount that it really doesn't make a difference. It also tends to make a much smoother ignition event, hence less noise.
It is true that more advanced timing will give you more power, to a point. However, that power comes at a cost in terms of internal cylinder pressure.
There's always an aspect of negative torque in a diesel engine. It's just the nature of the beast.
Answer your question about reducing timing.... Place that you want to do this is high pulse width and low RPM.
If you make a spreadsheet, and put your formulas in there to figure percent BTDC on your pulse with, you can see what Chevy does. it'll give you a pretty good idea of where to start.

Shoot me an email and I'll send you what I have for timing calculators that I developed. mwagg737@gmail.com

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[Madspeed]

You also get to a point where your pulse width is so wide that you get more than desired BTDC and mor than desired ATDC and there is a point where you need to stat thinking about larger injectors to make the needed squirt in the window that works. Like closer to stock. And as far as the comment that the manufactures dont even know what timing is, Couldnt be father from the truth. Your talking about multi BILLION dollar company's with more engineering power than nasa. amd the Dmax was a colaboration with Isuzu who DEFIANTLY knows a shit ton about tuning a diesel.

[StinkyDog]

You also get to a point where your pulse width is so wide that you get more than desired BTDC and mor than desired ATDC and there is a point where you need to stat thinking about larger injectors to make the needed squirt in the window that works. Like closer to stock. And as far as the comment that the manufactures dont even know what timing is, Couldnt be father from the truth. Your talking about multi BILLION dollar company's with more engineering power than nasa. amd the Dmax was a colaboration with Isuzu who DEFIANTLY knows a shit ton about tuning a diesel.Well said!

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