More Timing Questions

[2006Cummins]

Just wondering what kind of luck you guys are having with the new timing maps produced by the timing calculator. I have played with it a little, but have been more focused on other parts of the tune lately. The maps that the timing calculator produce seem to be quite different from what I have used, and what I have seen other people using. It seems like there is far less timing in the low mid-range, and quite a bit more at the top-end. I don't know how I feel about running the 33* (actual) that it recommends.

Also, table D6273 is a boost adjust multiplier table. Is the psi in psia? If it is, it looks like it would only be used at high altitude?

Mike

[AdamRRT]

Just wondering what kind of luck you guys are having with the new timing maps produced by the timing calculator. I have played with it a little, but have been more focused on other parts of the tune lately. The maps that the timing calculator produce seem to be quite different from what I have used, and what I have seen other people using. It seems like there is far less timing in the low mid-range, and quite a bit more at the top-end. I don't know how I feel about running the 33* (actual) that it recommends.

I'm having no problems. Remember, you have parts of the maps that aren't used. Plus some people change timing based off the stock timing, so they're not really going for best performance or efficiency. They're basing it off an emissions-friendly timing.
What % are you requesting that is resulting in a 33% ACTUAL timing? You DID remove 20* from your timing before pasting your table into the spreadsheet, right?

[2006Cummins]

I didn't change the 50% that was requested. I also didn't add my timing table to the spreadsheet. I just pasted my pressure and duration tables. According to the spreadsheet, 3100ms and 170kpa = 32.55* at 3500rpm.

Mike

[JoshH]

The low timing in the low end is why there is a minimum timing option, and the high timing at the top end is why you can adjust the percentage at every spot along the way. You fine tune it for what you find works best for you. At 3500 RPM, it takes about 65 degrees of crankshaft rotation to spray the injector for 3100 microseconds. Just remember, if you start the event 2.5 degrees sooner, it will continue to spray 2.5 degrees later (in other words, if you start at 30 degrees BTDC, the injector will not stop until 35 degrees ATDC).

[2006Cummins]

So, that brings up the question - what is the useful maximum degrees of crank rotation that fuel can be injected without creating extreme cylinder pressure, or wasting fuel and creating excessive egt's? Something like 29* BTDC and 45*ATDC?

Mike

[CIDRAUGHN]

Subscribing to this. I am also curious as to how this works. C7001 is limiting how far the injector can stay open past TDC. Ive upped mine to 22.5 across the board, but have any of you benefited from going higher? Im running around 23* of timing at 3200 RPM, and its works very well.

[AdamRRT]

That's good info that the guys who have fine tuned on the dyno can answer. I haven't made time yet to go play on the dyno because I feel I have a lot I want to learn before I waste my buddy's dyno time. I wanna hit the dyno to FINISH my tune instead of to start it, basically. So I'm in to hear some on this as well. Thanks guys.

[DoghouseDiesel]

You don't FINISH tuning on a dyno, that IS where you tune.

There is NO OTHER place that you can get safe, repeatable, verifiable and recordable results.

Motors get tuned on the dyno, chassis' and suspensions get tuned on the track.

Seat of the pants tuning yields one thing.....frustrating results.

You can believe what you like, but a few hours on the dyno is worth it's weight in gold if you're trying to tune.

Even if you're not trying to tune for max power and are just trying to tune out smoke. Set the dyno to steady state RPM's so it will adjust the load and maintain a consistant engine RPM and you roll into the throttle and see where it's producing smoke.

Dyno time is never wasted time unless you just don't know what you're doing. Then you're just guessing and that's wasted time.

[2007 5.9]

You don't FINISH tuning on a dyno, that IS where you tune.

There is NO OTHER place that you can get safe, repeatable, verifiable and recordable results.

Motors get tuned on the dyno, chassis' and suspensions get tuned on the track.

Seat of the pants tuning yields one thing.....frustrating results.

You can believe what you like, but a few hours on the dyno is worth it's weight in gold if you're trying to tune.

Even if you're not trying to tune for max power and are just trying to tune out smoke. Set the dyno to steady state RPM's so it will adjust the load and maintain a consistant engine RPM and you roll into the throttle and see where it's producing smoke.

Dyno time is never wasted time unless you just don't know what you're doing. Then you're just guessing and that's wasted time.

Well put Rich...dyno time is critical.

[DoghouseDiesel]

Everybody thinks the dyno is just for seeing how much HP and TQ you make.

That is just one small function of it and if that's all it gets used for, you miss out on the value of it.

Most guys are only concerned with the peak power and that's such an over-emphasized number.

The guys that really get the most out of it are the ones that look to maintain the peak power the longest and get it there the quickest. This is why you you not only compare the runs in RPM, but you also compare the runs in time.

If one pull makes 600 hp and takes 6.8 secs total and 4 seconds to peak and another run makes 580 hp, but takes 5.8 seconds and 3 seconds to peak, which one is really the more powerful tune?

Like I said, if you think you're going to FINISH tuning on the dyno, you're a long way away from being dialed in.