End of Injection timing VS-VY

[The1]

I made a excel sheet years ago to help show the injection timeline, now ive tried to workout how the code works and how we can match up cam specs with valve timing and EOI settings, have a look at the spreadsheet and see what you think.

[The1]

Anyone tried it or have thoughts? Or need more info?

[VX L67 Getrag]

I haven't downloaded the new spreadsheet yet but when I tested it years ago I didn't notice a major difference but didn't test too much either as I didn't notice that much change.... sorry I should have tested more.

[immortality]

I haven't got a machine here with MS Office on it Can't be arsed paying the subscription fee.

[The1]

Fair enough. Openoffice or similar should open it.

Here's the timeline that were working with that ive worked out.

[IVO]----[Injection Starts -5.87°]-------[EOIT 227.99°]--------[3X Ref ]-----[Boundary Scalar 9.84°]-------[IVC @ 57°ABDC]

Stock Cam intake duration is 243.7 Degrees
EOIT Table value 227.99 + Boundary scalar value 9.84 = 237.83 - 243.7 = -5.87 Injection starts after valve opens, calculated after first 3x loop, the boundary scalar tells the ecu when the valve closes after the 3x pulse, then the table value is calculated back from when the 3x pulse will happen to calculate start of injection.

Hope that makes sense.

So the spreadsheet you can update your new cams intake duration and valve close values to get new values to enter.

There's also calcs in there if you want it show the proper values in tunerpro for your cam.

[immortality]

Yeah, I need to get an alternative.

Talking with some of the LS crowd there is power to be made or lost getting your injection timing right or wrong.

[The1]

defiantly is, i have no measured value from a dyno, but with my cam that has overlap on my L67 it's running so much better and smoother with the settings right, it would have been injecting to early and fueling going in the intake and out exhaust

[VK_3800]

As an anecdotal/generic data point this is one of the reasons I went to the Link, for sequential injection with more control over the timing. I did find that it improved the surge at low rpm cruise (242/252 @ 0.050 cam). Just went by trial and error, the best result seemed to be when the fuel required was the lowest to achieve the same AFR (makes sense as less is wasted), the difference in VE is fairly noticeable. Ended up delaying injection by around 80 (cam) degrees up to 1500rpm.

[AngelMarc]

then the table value is calculated back from when the 3x pulse will happen to calculate start of injection.

Hope that makes sense.

Curious how the code compares to my code. I measure time for one tooth cycle (15 degrees, would be 120 in your case) then multiply that (by 48, or 6 in your case) for the full 720 degree cycle time prediction. Subtract calculated fuel pulse to get the delay before injector starts.
I'm sure OEMs do way more real time unit conversion, where as I left everything in microseconds Use a spread sheet to put the right time numbers in for degrees; time per degree varies with RPM.

[The1]

From my understanding it measures an entire 120deg crank rotation every 3x pulse so it can keep track and account for rpm changes. It keeps track of which of the 120deg cycles it's in then it also has 0-255 count tracking within each slot. It then works backwards to find the start injection point in the next 120deg slot. It takes off desired fuel pulse calculated from maf airflow etc, then battery voltage offset and if applicable, low pulse table to help with keeping the injectors linear, then it knows where to open injector for the next cylinder.