A must read

[bruce]

You guys really really really really have to read thru ALL the files at the DS Collection site.

The info is OVERWELMING

Figure on spending hours just slowly pouring over the info..
Especially in Scope Mode.
You can really see what some cars ARE doing, and NOT doing.

Amazing stuff.
Like Yogi says, It's amazing what you see when you look.

 

[LinearX]

Bear with me here if you don't mind. Having never used DS before, I downloaded the program and some of the files to look over. In particular I downloaded cat2-1 that Striker asked you about in another thread. When reading the injector pulse width in scope mode (or in dial mode), there are 2 lines there. What is the significancce of the top line vs. the bottom line? Is one commanded, and the other actual? If so, which is which? It was interesting to see how closely the injector pulse width at 26 or so corresponded with about 2.3° of knock retard.

If I'm off on this, please fill me in. Thanks.

 

[bruce]

Originally posted by LinearX
Bear with me here if you don't mind. Having never used DS before, I downloaded the program and some of the files to look over. In particular I downloaded cat2-1 that Striker asked you about in another thread. When reading the injector pulse width in scope mode (or in dial mode), there are 2 lines there. What is the significancce of the top line vs. the bottom line? Is one commanded, and the other actual? If so, which is which? It was interesting to see how closely the injector pulse width at 26 or so corresponded with about 2.3° of knock retard.

If I'm off on this, please fill me in. Thanks.

One line is Pulse width, and the other avilable time for injector opening.

It can be hard to see, but when they cross you have over 100% DC and the injector is static. In text mode you can easily read the calculated Duty Cycle.

Once you get to being able to play and replay things looking for certain events it gets easy. DS is such a powerful tool that it takes a while to grasp.

 

[LinearX]

One line is Pulse width, and the other avilable time for injector opening.

Is that to say the the bottom line is injector pulse width and the top time is the available injector opening time? Just want to clarify so I'm understanding correctly.

I don't recall seeing the calculated duty cycle in text mode, but I only messed with that part for just a few moments. I was playing with scope mode quite a bit. Is the calculated duty cycle plainly visible? Looking at some of these files at lunch tomorrow will make the time go by more quickly.

 

[LinearX]

One more dumb question....

Ok, let me ask one more dumb question. I found the calculated injectory duty cycle on the text screen while playing back one of the buffers. In looking at Cat2-1.dat the calculated DC goes to 125.9%, but there is no corresponding knock that I would assume would be present given that the injector is well past static at that point. Am I missing something as to why there isn't a huge amount of knock present for when the injectors are giong past static? For what it's worth, that at 5000 RPM around 100mph or so. I'm assuming that since the timing is down to around 19° that is what is keeping it from knocking. Perhaps I'm wrong here.

 

[BM Computer Src]

The injectors can be over 100% DC and you can have no knock. The reason you will get knock when it goes over 100%, is from a lean condition because the injectors cannot supply the fuel requirement.

So in the instance you describe, they went over 100% and had no knock, because it was not overly lean.

I do not recommend doing that, anytime you get anywhere near 100%, it's time to get larger injectors.