Originally Posted By: Ramblejam
Either you're using imperial, or made a mistake in conversion.
Few things first:
2001 GMC Sierra C3 was equipped with the LQ4 (325hp/370TQ), which albeit rated differently, is the same engine that's under the hood of your friends 2500. This is not the "Cadillac version" of the 6.0L, which is the LQ9 that appeared in later models. For the sake of reference, 1999/2000 LQ4 had iron heads, and later models were rated higher (such as my '04).
225,000km is equivalent to 140,000 miles.
Back to the topic...
Conversion is as follows:
mpg (imperial) = 282.48 ÷ L/100 km
mpg (U.S.) = 235.21 ÷ L/100 km
I have no doubts about your ability to exceed EPA numbers to some degree, but at the reported 20 MPG, we're talking a 43% increase over those figures (11 city/14 highway). Additionally, you've stated that you're able to match EPA highway numbers while towing a trailer that weighs 3,500 pounds empty.
My conversion was based on a fuel conversion app I got from the App Store. I compared it to the trucks digital fuel consumption display and it was always within 1mpg based on fuel burned.
When I filled the truck I filled it to the brim and shook it so all air bubbles were bounced out and the fuel level was almost dripping out.
After 4 months of comparing the digital readout vs the amount dispensed at the pump I quit bothering with the app.
I used 3 different fuel consumption apps just to make sure they were accurate and all 3 gave me identical numbers.
Iirc the cam in my truck is different than a stock 6.0. I got the truck with an intake spacer and cold air intake,not that I put any stock in those mods helping in any appreciable way and it's got a magnaflow exhaust vs the stock piece.
All combined it's possible they help power and or fuel economy however like I said I don't put much stock in that idea.
My driving habits are likely the contributing factor. No jack rabbit starts,easy passing. To be honest I might have floored it 10 times in 2 years.
So if the calculations are off then 3 different apps are also incorrect and the display on the console is also incorrect.
In the city the display averages 12 at best. Highway it's great considering.
My 04 ram quad cab hemi 4x4 in the winter got 20mpg consistently on the highway with 4x4 engaged,if that tells you anything about my driving habits.
Both the C3 and my charger are tuned with a diablosport handheld tuner,running maps from diablosport. The maps a have been tweaked by diablosport. I data logged from the ecu on both vehicles on 3 separate occasions to which they adjusted the fuel and ignition timing maps.
So if there's any errors it's beyond me how. Both the charger and the truck have fuel consumption displays that when compared vs consumption based on full to the brim tanks were within 1 mpg.
So I'm not saying there isn't a chance for error,just that I'm not seeing where.
