Max Rpm

[jneal]

I have heard that the LBZ/LMM ecms can control fueling accurately north of 5k due to its processing abilties. The LB7 and LLY delphi ecms can fuel that high but can not accurately control fueling. They do not have the ability to process the data quickly enough.

 

[Fingers]

The problem with the LLY and LB7 processors is the driver that controls the injections and timing events. The accuracy is degraded after about 4600. Can you go higher? Yes. But the error factor starts to become significant. At what point parts start flying is an interesting question.

The timer on the LBZ is like 10 time faster/more accurate. But then there is the regen/duty factor capability of the injection pulse feed.

 

[Dan@PPE]

Spinning that high on a "free rev", "light load", or a shift flare is one thing. Making power and actually controlling everything at that RPM is another. I would say PPE is pretty close on what they say. I have seen a log of a stock LB7 hitting well over 5000 RPM in neutral at the end of a pull. Big deal. It was popping like crazy and sounded awful.

I have no idea how much power it was making when I did but it was not popping or banging. It was very smooth. But I can not say it would be that way everytime. I dont disagree with PPE. Just because I have spun more does not mean the my fuel system is accurate enough to do it eveytime. I really think injectors help this as they tax the FICM less. But I still have doubts as to if I am really getting the timing and fueling that my logs shows at that RPM. I cant prove that I am or that I am not. What is known is that the processor is really working for a living at those speeds. Again I will say that reducing the injector duty cycle seems to really help.

I can remember when I was told over 3 years ago that spining over 4000rpm would be very hard on the engine and cuase failures. The truth was my engine looked fine after a year and half of 4K+ beatings. I have broke more stuff just letting the truck sit idling than I have running 4K+. With the setup I have know luanches happen around 4600 to 4800 and down track is any where between 3800 to 4200.

But as Fingers would say. "but what do I know?"

The problem with the LLY and LB7 processors is the driver that controls the injections and timing events. The accuracy is degraded after about 4600. Can you go higher? Yes. But the error factor starts to become significant. At what point parts start flying is an interesting question.

The timer on the LBZ is like 10 time faster/more accurate. But then there is the regen/duty factor capability of the injection pulse feed.

Listen to these guys, they are all correct in one way or another.....

I'm not sure who you spoke to when you called, but if you spoke with me then you might of miss understood me or I did not properly understand your question.

A stock Duramax (stock injectors) will only be good till about 4600-4800 rpm with the fat pulse width of our larger Hot +2 E.T. tunes. If you were to install larger injectors you could spin more rpm and need with less pulse width and make more power at the same time. It really come down to injector duty cycle and accuracy of injection...

Dan

 

[dracing70]

sounds good i just wanted some more opinions cause seein is believin and we have a truck that has been bein built for the last two seasons and should be comin out here and rarin its face in ne ohio and pa any week now and it turns 5300 without a blink and asks for more and just sounds herendous. definately scary . it will surely be a crowd pleaser this thing is wicked and has alot of time and money in it. and it will be a head turner

 

[Dan@PPE]

non stock injectors correct?

 

[dracing70]

yes definately

 

[03maxpower]

sounds good i just wanted some more opinions cause seein is believin and we have a truck that has been bein built for the last two seasons and should be comin out here and rarin its face in ne ohio and pa any week now and it turns 5300 without a blink and asks for more and just sounds herendous. definately scary . it will surely be a crowd pleaser this thing is wicked and has alot of time and money in it. and it will be a head turner

i would like to know when you are at some of these pulls i would like to see it!!

 

[dracing70]

it might show its face at burton , oh on thirteenth but i am not positive due to a recent accident in the family but it is possible

 

[03maxpower]

it might show its face at burton , oh on thirteenth but i am not positive due to a recent accident in the family but it is possible

sorry to hear that im sure ill see it somewhere:hug:

 

[Fingers]

As some of you might know I do a lot of chamber pressure testing. I frequently match my readings from my monitor to the tune to see what's what.

Well today, I was playing around in the 3000 to 3500 RPM range and noticed something rather interesting and relevant to this thread. The timing errors at the engine ranged form 2* to 3.5* and varied both plus and minus of the intended mark. The majority of the errors in this RPM range were within a degree. But some pushed 3.5*s too soon.

Wonder what the errors will be in the 3500-4000 range when I get there? Things that make you go hmmmm...

 

[TrentNell]

dang 3.5 deg seems like alot of error for that low of rpm , i would have never guessed seeing that . keep up the good work fingers i always enjoy reading up on what you are testing

 

[McRat]

With the PPE twins on the truck, peak HP and boost occurred at ~4500rpm, but because of a programming error on my part, the engine rev'd to 5250rpm under load while I was racing it in Arizona. It went through the traps in 4th gear, but the water pump came apart, which in turn overheated the engine.

 

[juddski88]

As some of you might know I do a lot of chamber pressure testing. I frequently match my readings from my monitor to the tune to see what's what.

Well today, I was playing around in the 3000 to 3500 RPM range and noticed something rather interesting and relevant to this thread. The timing errors at the engine ranged form 2* to 3.5* and varied both plus and minus of the intended mark. The majority of the errors in this RPM range were within a degree. But some pushed 3.5*s too soon.

Wonder what the errors will be in the 3500-4000 range when I get there? Things that make you go hmmmm...

Can you define "Timing Errors" for me please?
I have never heard that term.

 

[McRat]

Timing error is the difference between the programmed value and when the injector actually opens relative to the crankshaft position. With gassers it used to be called "spark scatter". Play in the gears, computer lag, injector driver lag, etc, all have a window of tolerance. 3 deg probably isn't a lot, but 0 would be better.

 

[juddski88]

so it has a ton of variables still right? nozzle size, PW, fuel temp, rail pressure, actual voltage to the injector, etc.

 

[WolfLMM]

so it has a ton of variables still right? nozzle size, PW, fuel temp, rail pressure, actual voltage to the injector, etc.

Right. With bigger nozzle's 3.5 degrees can kill parts much faster than stock nozzle.

 

[Fingers]

To be a little clearer, what I am looking at is the actual injection command pulse and comparing that with the tables.

You can see the injection event too on the pressure graph and the then the actual ignition. Though the injection event is harder to see at higher RPMs. Probably because the "event" is less significant time-wise compared to the stroke speed. But what I am comparing is the electrical pulse to the injector.

 

[Fingers]

Timing error is the difference between the programmed value and when the injector actually opens relative to the crankshaft position. With gassers it used to be called "spark scatter". Play in the gears, computer lag, injector driver lag, etc, all have a window of tolerance. 3 deg probably isn't a lot, but 0 would be better.

I was a little surprised to see that much at those RPM.

But what do I know.....

 

[WolfLMM]

To be a little clearer, what I am looking at is the actual injection command pulse and comparing that with the tables.

You can see the injection event too on the pressure graph and the then the actual ignition. Though the injection event is harder to see at higher RPMs. Probably because the "event" is less significant time-wise compared to the stroke speed. But what I am comparing is the electrical pulse to the injector.

The crank shaft pos sensor can be cocked a little messing with readings big time, also. Correct?

 

[juddski88]

how would numbers like that (3* error) be magnified with the stroked engines? with the higher torque, given a constant degrees of error, would it be more likely to hurt parts?