I have a scan gauge on my 97 OBW. Car is getting inspected in a few days, so i did what i could do. i bought a puerolator air filter. i looked at the old one, i kicked myself for buying a ne one, as the old one looked ok.

ive only put 3000 miles on the car in the last year because of my back. Well i put the new airfilter on the car and i gained 2mpg. Shocked me as i didnt think the old one was that bad.

normally i say when figuring gas milage do it on three tanks of gas, except when your reading directly off the ecu. i find it easier to compare things in real time since there is a percent of load feature, which can keep you consistant and see how changes affect mileage.

 

 

nipper

Cool nipper that's a pretty sweet mpg gain! What kind/brand of air filter did you have in there before? I've done a few experiments with things like acetone, propane, xylene, etc., but didn't see any real difference, but maybe air filter is the ticket!

Cool nipper that's a pretty sweet mpg gain! What kind/brand of air filter did you have in there before? I've done a few experiments with things like acetone, propane, xylene, etc., but didn't see any real difference, but maybe air filter is the ticket!

 

same brand i always use purolater.

 

nipper

[...]normally i say when figuring gas milage do it on three tanks of gas, except when your reading directly off the ecu. i find it easier to compare things in real time since there is a percent of load feature, which can keep you consistant and see how changes affect mileage.

Nipper, I'm curious:

Over what period does the scan gauge average the mileage? (It may be real-time, but as you know, nothing is instantaneous, and for gas mileage you probably don't always want it to be.) Have you run a few tanks and compared the calculated mpg with what the scan gauge indicates?

Nipper, I'm curious:

Over what period does the scan gauge average the mileage? (It may be real-time, but as you know, nothing is instantaneous, and for gas mileage you probably don't always want it to be.) Have you run a few tanks and compared the calculated mpg with what the scan gauge indicates?

 

you can set the time scan. It has instantanous and per tank, as well as previous trip. The handy thing is the % load on the engine. That allows you to keep at a set load and see the changes. Actually if you want to save gas you want instantanous, as ive already went from 19 to 22 before the air cleaner with just the scan gauge and bt keeping the % load under 30%. The scan gauge is dead on the money. All the scan gauge is doing is what the trip computer would do, just reading the info off the ecu.

 

nipper

How does the scan gauge and/or ecu actually measure fuel flow?

It doesn't have to measure fuel flow; it can calculate fuel consumption based on all the parameters available to it from the ECU such as intake air temp (IAT), engine coolant temp (ECT), mass air flow (MAF), manifold absolute pressure (MAP), throttle position, engine RPM, and so on. You set the engine size and cylinders and stuff in the configuration. It does a pretty good job; when I fill up the scangauge is usually within .1 or so gallons.