3:08vs3:42 and gas milage

[ellik]

this weekend was the first long distance trip that ive took since putting in the 3:42's. I havent corrected the instruments yet, but from 3:08-3:42's my spedometer is off by about 10% (hit one of the digital speed checks) and my odometer is off by exaclty 8% (read 10.8miles in a measured 10 mile stretch)
i expected this but what i did not expect is that on one tank of gas constantly cruising at 75-80 mph i read 458 miles when I used to only be able to get around 350-360. with the 8% error, that means that I picked up about 60 miles on a tank of gas or 4.3 mpg.

[stubborn portugee]

I was told that going from 3.08 to 3.42 would throw your speedometer and odometer off by 13%, so if I'm right you would have gotten about 398 miles out of ur tank. I know I get about 24mpg on the highway doin an ave of 80-85...just remember that out of that 458, around 60 extra miles were racked up.

[speedy-v6-camaro]

If your odometer is off by 8%....so is your speedo. Think about it.

[ellik]

would make sense, but i wanted to actually verify. going through a speed trap isnt precision when everyone around you is hitting thir brakes, so all i could get is around 10, which 8 is around 10 [img]smile.gif[/img]

[Riles]

It's not unheard of to gain gas mileage. I gained i think 3-4 mpg when I switched to 3.73's from 3.23's. I can't remember the exact amount anymore, because i have since gained MORE gas mileage with my supercharger!

[95Batmobile]

He's right, it's off by 10%.
9.942 to be exact [img]tongue.gif[/img]