EFI tuning - Where are all the good resources?

J

JasonCzerak

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Aug 10, 2006
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So, with the future looking bright for us CR guys with EFILive right around the corner... Can we post links to information that is useful to understand basic through advanced tuning? Links to EFI theroy (gas or diesel)? Links and formulas to figure out how much timing, duration, pressure is too much.


Sure there's google, but humans in the know can weed though the crap better :)
 
You can spend all day doing formulas based on engine speed, injector spray angle, etc. to try and figure out the limits. In the end a lot of time is needed on the street and dyno to figure out what works best for you engine/combo. It took a while before everyone had a good handle on the dmax stuff and there is still a lot of different opinions on what is "safe". The cummins software will have a learning curve and it will be interesting to see what all we will have access to. I have three trucks that we are going to start experimenting on as soon as I can get a hold of the software.
 
Jason you know the EFIlive drill already. It's basically a SDLC:

Change one thing. (dev)
Did it work? (debug)
No, change it back. (fix)
Yes, change it more. (dev)

Change the next one thing...
 
joefarmer said:
Jason you know the EFIlive drill already. It's basically a SDLC:

Change one thing. (dev)
Did it work? (debug)
No, change it back. (fix)
Yes, change it more. (dev)

Change the next one thing...
Click to expand...

yes, but a bad change is more expensive and out of my pocket :) However, I do have a DR vehicle.... :)

I'm not the only one in this boat. I wish to start with a good tune and tweak. but a much much better understanding of limits and theory would be awesome to make educated guesses.

like fuel temp. what do you change knowing your fuel temp is 90 degrees vs 60. :) That's some of the ideas I'm looking for.
 
Well I guess you could check out the D-Max sites, it would help with a basic understanding. I for one don't want to see the Dodge boys go through the carnage that we did in the begining.
 
JasonCzerak said:
yes, but a bad change is more expensive and out of my pocket :) However, I do have a DR vehicle.... :)

I'm not the only one in this boat. I wish to start with a good tune and tweak. but a much much better understanding of limits and theory would be awesome to make educated guesses.

like fuel temp. what do you change knowing your fuel temp is 90 degrees vs 60. :) That's some of the ideas I'm looking for.
Click to expand...
Yes, it can be expensive. However, the smaller steps you make, the smaller the wallet dents become. I would guess with a little intuition you could make a decent tune in an afternoon and spend a month tweaking it.

Really, you'll spend most of your time turning off the stupid correction tables that always end up limiting your horsepower tunes. At least thats what it seems like on teh dmax version.
 
Glen knows a thousand times more than I do but the efi university $ is pretty steep. I think you would be money ahead to just buy the program and mess with it without being stupid - but that's from a guy with driveability experience...

Second, I remember a GM guy telling me they had something like 10,000 man hours into the tune on the ramjet 502, but thats OE level perfection, from scratch (no base tune) complete with EPA hurdles... Just to give an idea of what can be involved.

I say just get the setup and fool around with it. EFI university when I looked into it was something like 3-4x the cost of buying the equipment to tune. Learn by doing - just keep a sharp eye on all the vitals. "They always run the best right before they blow up."
 
bluthndr said:
"They always run the best right before they blow up."
Click to expand...

Yep. I can attest to that factLOL

I'm with Jason though, it would be great to know something like "do not go above xx degrees of timing" or "above xx rail" but I suppose we'll know those limits roughly after someone goes there and doesn't come back.

Think I'm going to log the Smarty and roughly keep in those paramaters until I get a feel for it
 
The EFILive Scan Tool and Tune Tool documents will provide users with documentation on how the software works, it's not a HOW TO TUNE guide.

My suggestion, in addition to what's been mentioned above would be to download our software (refer to Bob's link), then jump on a Diesel forum that has a tune library (Diesel Place or Duramax Diesel) and download a Duramax stock file and a modified file of the same OS and take a look around. Look at the files, the changes, the comments. Also read some of the tuning software threads on those boards while you are there.

Drawing comparisons to the Duramax and transposing learnings will only go so far in giving you a tuning insight - the ECM's are VERY different. You need to remember that tuning software for the general Cummins population has never been publicly available; so in many cases YOU are about to start creating that tuning knowledge. It's going to be the discussions that YOU and your fellow enthusiasts have on boards like these, and the sharing of your tunes seeking feedback is what is going to drive your learning and the learning of others.

Cheers
Cindy
 
For as little as I know, it seems the primary thing missing from the equation to safely and quickly tune these engines is a good measurement of in-cylinder pressure.

With in-cylinder pressure (Kistler, etc), a crank shaft encoder (BEI, etc), and some software/DAQ capabilities, all the guess work goes away. Drivven (for one) has done a great job at this, and offers combustion analysis packages that provide an incredible amount of data.

Simply having crank angle resolved cylinder pressure allows you to tune according to peak pressure, pressure rise rate, SOI, 10% 50% 90% burn time, heat release, etc, etc.

Obviously, cost is the limiting factor for most people. However, this one thing really puts everything on the same playing field. As you know, the ambiguous question of "how much timing can I run" is completely dependant upon compression ratio, injector size, injection pressure, swirl, rpm, temperature, fuel properties, and about any other variable that you can think of. With in-cylinder pressure, it's no longer about the ambiguous golden "timing" you can run, but about peak pressure and PRR...and as long as you're within some boundary, you can choose your own power/longevity ratio.

--Eric
 
The timing question is actually quite simple. Increase timing tell piston cracks and then back it off a bit
 
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