How to properly test modifications (AKA: don't believe every MPG claim you read)

[Nerys]

I know and I did not mean to come off like that.

under normal conditions I would think it would be pretty hard to get 13mpg. I mean you would have to drive a whole tank of gas at WOT and up a hill etc..

it hit me afterwards that he said first 17 miles which he can not possibly know "NORMALLY" then I realized he was using an FE read out (scangauge) so he was getting instant readings or real time readings and feedback etc..

instant as in he knows before he adds more gas about what his FE is which also explains how he can know he got 13mpg his first 17miles.

Once all of that "clicked" in my head it made sense :-) I am not always the greatest at expressing thought to words :-)

I apologize for any mis communication errors on my part :-)

[SentraSE-R]

Don't beat yourself up. If you learned something and I taught something, we both end up winners.

[Nerys]

too late - hehehe - ouch that hurt :-)

nah just wanted to clear it up. I can come off very "strong" sometimes so I wanted to clear it up :-)

[JeepNmpg2]

Originally Posted by Nerys

wow - even with bad parts clogged egr etc... I never got under 42mpg in my metro. My van never saw less than 13mpg even towing a 7000 pound trailer on Ethanol with the AC on!!

I just did not think it was possible under normal conditions to have such a massive swing in FE in a vehicle short of massive issues with the car.

I was just shocked is all :-)

well actually I don't think you CAN get 13mpg in that car. maybe 13mpg INSTANT reading maybe but average even over a few miles I don't think you can get 13mpg without REALLY hammering it or something.

I totally understand you man, but I had a pretty bad experience with my 2006 Kia Sedona (4700lb curb weight, EPA 25 HWY). It's pretty regular at getting anywhere from 22-26 mpg on the HWY at 70mph (my wife likes AC in the summer). But.... I made a trip from eastern Texas to western Washington and my average MPG was 14.6 with a midsized Uhaul trailer with a total weight of 2100 on one axle. Long story, 3000lbs of people and stuff + aero-deficiant trailer + running a day behind and going 75mph+ (went 85 for a solid day)= 13.2 as my lowest fillup and 18.8 as my highest actual tank mpg(mountains VS plains).

[hondo434]

On your ambient temperature effect on milage point. I have a Nissan Altima and it has a air intake temperature sensor which when the temperature is low the ecu will add fuel to help engine run. This is in addition to the normal choke like action when starting the car. When I am driving as the car warms up I can actully watch the speed increase as the the rpm decrease.

[Nerys]

wow man !!! 3000 pounds AC and 85mph. THATS HAMMERING IT :-) hehe not bad considering :-)

[SentraSE-R]

I just drove my wife's Elantra 400 miles to my mom's, averaging 40.8 mpg. Not bad, considering it's Winter, & half my drive was in the dark with lights on. I tanked up near my mom's this morning & drove down to San Diego to my son's. Got 44 mpg through LA. Love the warm weather & light holiday traffic.

[MetroMPG]

Let's try to keep this thread on topic. Thanks!

[RJVLER]

I thought this might be a good place to jump in . I read on another thread as so as I find it I again will post a link. I guy or someone who ever it is ? Claims you cannot acheive over 50 MPG out of a Geo Metro ( What and idiot )

Here are my specs

1990 metro stock
Unknown High Milage
Burnt exaust valve # 3
Very low compresion
Overload car
Burns a quart of oil per tank
Blowby blowing out of everything
I have to carry a spare plug with me so when it fouls

I dont or cant have scangauge so with last consecutive 3 full tank runs

42.5
43.7
43.2

Not bad for a totally shot car - 50 is an easy grab. I am going for 60. Got alot of parts on the way. Just thought you guys would get a chuckle out of it Thanks John

[oldbeaver]

I you had a onboard computer (as I have) you would be surprised.

My car has a VW 1.9 TDI engine and can show fuel yield in real time, factory installed.
I can get up to 70 MPG while at 70km/h (about 45 miles/h) on a flat road, after warming up, of course.

However, when I am driving on the streets of my town, warming up and between traffic boxes, my same car starts yielding 10 mpg ! Not sport accelerating ! Just normal getting there.

It is only after the car increases its speed (not possible in high traffic between traffic boxes) and warms up, that fuel yield improves. A normal short round trip in town, even trying to get most of it, yields me about 30 mpg.

Oldbeaver

Originally Posted by Nerys

A GALLON IN THIRTEEN MILES!! what kind of car uses a gallon in 13 miles warming up but gets WELL over 40mpg normally?

even my 5 liter 5500 pound van does not use a gallon in 13 miles (unless I get 10-11% ethanol :-) hehe