99 4.2l new exhaust catback duals ideas??
Your 5.4 might get good gas mileage on a trip but if we both filled up (since we're both 1998 SuperCabs), I'd bet my next paycheck you would run out first. You've got bigger injectors and a higher fuel flow, along with more air intake.
According to my ScanGauge:
At idle (850 rpms) my 4.2L sips 0.35 GPH
At idle (850 rpms) a stock 5.4L sips 0.48GPH
Since its near impossible to do an apples to apples test sans the fill up and run em out idea, if you got two identical trucks, with identical gears, at 60 mph the 5.4L would pull more fuel. This is confirmed by the EPA in the CO2 emissions test which they base fuel mileage charts (see above) and window stickers on. You can scream about 20 mpg on a trip all you want. I'm getting 17-19 in a pure city environment. My last tank lasted for 435 miles. That was with four runs to the station, doing well over 80 mph on a cold block. The last time I was on a trip with no trailer I saw (at since then my personal best) of 22.32 mpg in which I had filled up after 512 miles. That's my last word.
According to my ScanGauge:
At idle (850 rpms) my 4.2L sips 0.35 GPH
At idle (850 rpms) a stock 5.4L sips 0.48GPH
Since its near impossible to do an apples to apples test sans the fill up and run em out idea, if you got two identical trucks, with identical gears, at 60 mph the 5.4L would pull more fuel. This is confirmed by the EPA in the CO2 emissions test which they base fuel mileage charts (see above) and window stickers on. You can scream about 20 mpg on a trip all you want. I'm getting 17-19 in a pure city environment. My last tank lasted for 435 miles. That was with four runs to the station, doing well over 80 mph on a cold block. The last time I was on a trip with no trailer I saw (at since then my personal best) of 22.32 mpg in which I had filled up after 512 miles. That's my last word.
Last edited by Raptor05121; Aug 19, 2011 at 11:45 PM.
Under the hood. From week to week. I do not need anything special to figure mileage like you do. Just an occasional pencil and paper. There's no need to contemplate physics when it's right in front you. That would be simple math to you, I guess lol.
The 98 4.2 we owned didn't touch the 5four as far as economy. Plus it wouldn't preform when needed. We got rid of it.
The 98 4.2 we owned didn't touch the 5four as far as economy. Plus it wouldn't preform when needed. We got rid of it.
i put a light performance cam in it, and its tuned, the fuel economy is amazing, and the get up and go is just stupid for being a v6 its got a 355 LS in the back as well, its just got stupid power for a v6 i love it! mines a 01 4.2 tho in my 98