Quote:
Originally Posted by mosier
dcb:
What method did you use to calculate your microseconds per gallon?
For a DOHC Saturn, with 21lb/hr injectors I get
Code:
21.00 lbs/hr
6.25 lbs/gal gas (~72 deg F gas)
3.36 gal/hr
17.86 minutes/gal
1,071.43 seconds/gal
1,071,428,571.43 microseconds/gal per injector
267,857,142.86 microseconds/gal with 4 injectors?
Fuel temperature will have a big impact on the calculation, I wonder how scanguage or oem systems handle this (ignore it?).
I just put in my order, and hope to get it running on my nonobdii SL1 pretty soon..

I tried your byhand formula versus the Excel Spreadsheet calculator posted on the Ecomodder.com Wiki, as applied to my 1991 Jeep Cherokee Laredo 4.0L InlineSix engine, and found two different numbers as a result, with a variation of 7,894,737 between the 197,368,421 as done by hand, versus 189,473,684 as calculated by the Excel Spreadsheet calculator.
My advice, in this case, would be to try each of both numbers, first the low, then the high, then adjust incrementally by around 510% of the difference (193,421,053, in my vehicle's case) until you find the actual "SweetSpot" for accurate fuel consumption numbers. I have found my MPG numbers are
POSSIBLY off by as much as 1015% or
MORE when just using the Excel Spreadsheet calculator's number, otherwise. Hope this helps, even if only a little...
Edit: Just tested out my theory, based on the two calculations and found that also dropping
BELOW the lower calculated MicrosecondsperGallon by the calculated difference between both numbers
MAY also have a positive effect on accuracy of the MicrosecondsperGallon equation. More testing
AND recalibration of the MPGuino will be necessary in order to confirm this, of course.