I have just hooked up my scan gauge and it works great. I have the guage set for ingnition timing (ING). What I can't find is a reference to tell me what the numbers mean. I am getting readings fron 5 to 17. Can anyone tell me what they mean or where I can go find out. The manual tells what it will tell me but does not reference they nymbers. Thanks, Bill
The numbers for ING on the SG are indicating degrees of advance. For example, 5-17 degrees before top dead center. When the car is in warm-up mode(S1) the numbers are actually negative numbers which mean the spark is occurring after tdc. I think it does this to send a little raw fuel to the catalytic converter to help it warm up faster?
Assuming you're driving a Prius you are shooting for IGN 13 (extremely hard to maintain for me) or 14 or 15. As it rises it uses more fuel I believe. There is an excellent Scangauge thread/sub-forum on cleanmpg.com that gets so technical I can't understand all of it fully, but I remember seeing a chart over there about it. Check it out.
I think the thread you were talking about was the SHM(super highway mode) thread? If so, you are looking for IGN 14 while maintaining the TPS(throttle position sensor) of 17-19 with 18 being ideal.
See? That's what I mean about not understanding it all. Thanks for setting it straight. So I have to display both IGN and TPS to get it right. Now I definitely need a second SG. Will there be a SG discussion at Hybridfest '08? (I also need to learn to calibrate it - the SG and MFD are different on miles driven. The MFD reads about 4.4% more miles than the SG shows, but I don't know which one is the correct one yet.)
Slightly off topic but, I'm not sure if your odometer is the same as mine since you have the touring package but, on a 200+ mile highway trip last summer, I did 4 separate 50 mile checks of my odometer against the mile markers and found that the MFD was under-reporting miles by 1.6%. I checked several of my routes with Google Earth and found that I needed to set the Scanguage at +3% to match the Google distance. Just last week, I borrowed my son's Garmin Street Pilot and found that the 3% setting on the SG was as close as I could get to dead-on until the SG can be adjusted by 10th's of a % for speed. The Garmin also confirmed that the MFD was off by the amount I had determined from my highway trip.
Over on CleanMPG.com there is the best explanation of how to use the ING reading to increase gas mileage: http://www.cleanmpg.com/forums/showthread.php?t=6179
I'm not an expert on the Scan Gauge, however after speaking with the designers of it, I was told that the MPG in the scan gauge is not derived from the car directly, it is computed with live data from the car. Linear Logic's formula to compute MPG could possibly be different than how the MFD computes it, however if the SG is setup correctly, it is very close. Your never going to get 100% perfect numbers however the information we get from both the MFD and the SG are pretty darn good enough for what we all are using them for. I have had my SG for just over 24hrs and I have to say, that this is one of the greatest products I have seen for a car, well since Car Phones! I'm certain that anyone who learns it and uses it, will pay for it in fuel savings in a short period of time. I just learned today that simply letting off the gas in the Prius charges the car very slightly, however applying slight brake pressure, causes massive amps to go back into the Hybrid Battery and the harder you push, the more amps goes in there. If you haven't added the X-Gauge to your SG. Do it now! It gives you a lot more info.
Just an FYI: As your tire tread wears down, the circumference of your wheels change, causing your mileage to be off every so slightly. This may be the cause of what you are talking about. For all intensive purposes, the figures are fine, however we don't live in a perfect world. Also if you change your tire size or rim size, you will also throw off those figures.