tkae a look at the new MLV beta.. does scatter graphing.

 

Please excuse my ignorance, but other than looking pretty, what use is that?

I'm not saying there isn't I just want to know what I could do with it.

 

Found this link for injector dead times http://injector-rehab.com/shop/lag.html

 

Is that MLV software free?

FWIW AEMLog (free) has been doing scatter plots for years and years.
It can also run equations on your variables, and plot them. Such as to do software dyno runs.

 

nope gotta register it.

 

AEMLog can import data in a text format.

 

Still free despite the nag screen.

 

Can't get the scattergraphs without registering though.

 

Try AEMLog. Download here
http://forum.aempower.com/forum/inde...c,17194.0.html

 

double click the log, no nag screen

 

Yellow RX-8 injectors @ 13.2 volts. I ramped the dead time down from 2 ms to ~1.2 ms before the engine died. There are two distinct slopes:



I had been running with a dead time of 1.0 ms but was leaning out as the intake temperature went up. I retuned for 1.45 ms based on the 2 vs 4 squirts method. Too early to say how that works. I'm not clear on how to square that with a 0.8 ms intercept here.

 

I'd stick with 0.8ms for those.

 

Like I said, 1.0 ms was not enough dead time -- it went lean as the IAT went up.

 

I'm going to use the published data for mine. No need for me to introduce error into this by evaluating a graph. The RC750 stops being linear when you get to 12V, but I've never seen 12V in any of my logs. I'm usually at 13.6V

 

Can someone explain how to interpret that graph for me?

I have RX8 injectors too, 1.45ms seems rather high for a relatively modern injector deadtime though?

 

Supposedly the y-intercept is the deadtime, but I see a huge difference between the published deadtime and the experimental values achieved by users. I'm using the published data and it works fine. I had to retune fuel though.

deadtime for RC750 high impedance

10V 1.36ms
11V 1.12ms
12v .92ms
13v .76ms
14v .63ms
15v .50ms

Nice and linear from 13v-15v. My question is how can a big *** injector have a shorter deadtime than a smaller injector? Seems like smaller would be faster.

deadtimes: http://injector-rehab.com/shop/lag.html

 

I'm not sure how to interpret it. Nor am I confident that 1.45 ms is the right dead time -- it does seem too long. The two measurement methods disagree considerably here. (1.45 is from the 2 vs 4 squirts method.) Barring any brilliant insights the flow may actually have to be measured when driven with the MS. But I am planning on going full sequential this summer, which will change the drive electronics, so I don't want to go to the effort of measuring flow until I have the final setup.

 

here's the thing, all the deadtime code does is add that value to the end of your calculated pulsewitdh. if the code calculated 1.7ms and you have a deadtime of .8ms, it will fuel 2.5ms total.

Just pick a number and go with it. Tune the voltage correction curve to mirror that of the published rates and be done with it.

 

Yeah, but you only have a finite amount of time to get the next pulse into the cylinder on time. If you list a deadtime that is too long, then it may not start squirting until past the point you desire. The shorter the deadtime the better until you exceed the mechanical limit.

 

with 750cc injectors you wont have that problem. it takes like 16ms of fuel at 7000RPM to reach 90% DC.