Gas Mileage - GM Performance Tuning

Jagey · #1 (**permalink**) 04-28-2006, 03:36 PM

I was reading a thread similar to this on Winnipeg Heights, and was wondering if perhaps my Grand Am's gas mileage really did suck as much as I suspected. What is yours?

Grand Am GT: 320km from when the tank is filled right to the top until the warning light comes on

Videoman · #2 (**permalink**) 04-28-2006, 06:09 PM

Well, I drive from a completely full tank to about 1/8th full and I average about 440kms per tank. Most if not all of that is city driving, but I do know I was able to make it back from Grand forks on just under 1/4 tank.

Jagey · #3 (**permalink**) 04-28-2006, 07:53 PM

Jag = Jealous

GMTuners.net · #4 (**permalink**) 04-28-2006, 11:47 PM

umm, im too lazy to convert to miles in my head. but i can average anywhere from 180miles-260miles in the city per tank of gas depending on how much of a lead foot i have.

Videoman · #5 (**permalink**) 04-28-2006, 11:59 PM

Miles Kilometers
180.00 289.68
190.00 305.77
200.00 321.87
210.00 337.96
220.00 354.05
230.00 370.15
240.00 386.24
250.00 402.34
260.00 418.43

99blackSE · #6 (**permalink**) 04-29-2006, 08:02 PM

Hmm city driving last summer, I got ~300 km on half a tank one time. Highway driving I can get around 200 km per 1/4 tank so I guess I get decent mileage.

Jagey · #7 (**permalink**) 04-29-2006, 08:14 PM

The gas guage on our cars aren't very accurate. I can usually get up to 200-250km on the first half of the tank, and the last half of the tank drops like hell so I can only get about 70-100km on the last half of it.

Videoman · #8 (**permalink**) 04-30-2006, 02:27 AM

It's no that they arent accurate, its that alot of fuel on the top end of the tank cannot be read by the level. The top 10% of the tank is not really considered part of the tank since its the filler neck and the very top end of the tank. U can see on the diagram how the tank is not perfectly even and the half full point in the tank is more like the 40% full of the entire storage system.

I normally can get about 65-70kms before the gauge even goes below the peak full mark. In the manual they say our tank holds 55L. But I have run my car dry and then filled up. I was able to squeeze about 66L in the tank.

Of course with gas prices the way they are, filling the car til it overflows is not a good idea, because of spillage and a few other things. Keeping the car filled at about just under full to over a 1/4 tank can help the fuel economy a bit.

99blackSE · #9 (**permalink**) 04-30-2006, 11:44 AM

I haven't calculated my mileage in a while, although low-mid 30's on the highway was common last year.