Interesting. I was under the impression that the UG was much easier to configure, with the SG requiring you to press each button dozens of times to find the data you want...I sure get annoyed pressing the button a million times only to go right past the data I want and have to start over again.
I cant do the UG without instructions. It has areas of the display represented by letters. ABCDEF for the first page. you scroll through a very long list, and set the letter next to the item you want there on the list. Page 2 is GHIJKL, and so on. I fumbled with it for a while to get page one the way I want it. Gave up on the subsequent pages, I don't use them. It has more features, and a more complex menu, and a larger display. I use it for a speedo/tach because when I tilt my steering wheel I cant see my analog gauges very well...
About the SG and UG.... I assume they both plug into the OBD II connector. The OBD II connector has a battery + wire in it that I assume they are using to power the devices. Do they haye an on/off switch? Or do they stay powered up all the time? Or does it also have a wire run to the ignition circuit? I assume they use fuel injector pulse width and the wheel speed sensor to calculate mileage. If they do, do you have to tell it what kind of car it is on so it knows the injector flow rate? And last question, are they very accurate? Thanks guys.
The SG (and I assume the UG) detects when the car is on and off. I believe there is an ignition wire output in the OBDII connector. When the car is off, the SG sleeps like a stereo. Drain while asleep is probably similar to the stereo while off.
I'm still not sure exactly where they get the data for the fuel economy calculation, but it most likely is MAF + O2 + VSS (or, in cars without MAF, MAP + RPM + O2 + VSS). You have to tell it engine displacement, engine type (gas, diesel, hybrid), and fuel tank size (so it knows how many gallons left before empty). Fuel injector pulse width isn't part of standard OBDII data (AFAIK) and the SG can't display it, unfortunately.
When you fill, you reset the SG by telling it how much you pumped. At that time it calculates an error percentage and until you fill again it adjusts by that percentage. Accuracy is good enough to help train your driving habits, but not good enough to scientifically say a technique or modification is definitely good/bad.
Thanks. That was my other thougt if it didnt know injector flow rate, that you would have to tell it gallons and it would have to learn. What happens if you engine-off coast, or just go key on, engine off, does it power up? It may use rpm to turn on. Ya I can see that would make it less accurate. I sounds like it would help its calculations if you didnt combite City/Highway on the same tank. It also sounds like you would want one per vehicle, or will it accept different vehicles and save the old one? I have 3 obd II vehicles and would like to have one for each, or use it on each. If I get a used one on e-bay with no manual, can I find a printable one on the internet? Also, Im looking something for my 95 Saturns OBD I. Would the MPGuino be the way to go or is there something else. I cant find a MPGuino anywhere.
I can't remember if it powers up just for turning on the ignition. For EOC, set the SG to "hybrid", otherwise it will shut off and not count your miles while the engine is off.
I don't know about the UG, but the SG can only be set for one vehicle at a time. It's not a pain to change those settings, only takes 30 seconds, but the way it operates is conducive to using it for a whole tank at a time...your tank average would be meaningless if you carried it from one car to the next every day.
Complete documentation for the SG is right on Linear Logic's website. However, a used SG probably still costs more than a new UG (and the UG's manual is probably up on the web too). Lately I'm enamored with bluetooth OBDII dongles that you use with software on your laptop/tablet/phone, those are $15-30 and more versatile. I haven't used one so I can't compare actual usage.
Pre-OBDII vehicles are tough. I don't remember seeing any particularly successful device except modifying and rigging up a fuel gadget from another vehicle. The only other thing that's practical is to accept that you won't get that kind of data and settle for mere fuel injector duty cycle information, which can be useful. All you have to do for that is tap a fuel injector wire and run it to a duty cycle meter. Harbor Freight sells a digital multimeter with a dwell function that suffices for that job (and it's a great meter otherwise, too).
Thanks! Ill check out the OBD II dongles too. the dwell/ duty cycle is a good idea too, and I have some extra DMM's laying around. I think I would perfer a MPGuino, I cant find any on e-bay or Amazon, but Im going to look around online too.
No one has mentioned using an OBDII Bluetooth dongle and the Torque Pro app on an Android device. That combo will do what SG and UG do, at lower cost.
I own both UG and SG, and concur the UG is a better buy for most people. The exception is Priua owners, for whom the SG offers a plethora of unique gauges.
An unmentioned advantage of the SG is its data logging capabilities. I've cabled my UG and SG together, used the UG to monitor engine load, and used the SG to data log actual fuel consumption every 0.4 sec during engine pulses. The SG allows me to compare, say, fuel consumed during a 10 second 70% pulse to fuel consumed during 8 second 83% and 6 second 90% pulses.
I have mine set to reset every time the car is cut off for 3 minutes or more. I actually really like that feature on my car as it tells me how I am doing for a run and I can compare day to day and what works and what doesn't.
there again, I am assuming.
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