fuel efficiency question

[VehiGAZ]

Talk about timing - pick up the Feb issue of Car and Driver magazine for an editorial on how driving habits & style affect mileage. The context of the editorial is about hybrid vs. non-hybrid versions of the same model, but that doesn't matter.

PS - warmer weather makes for better mileage, as most of us must have noticed. I don't know whether it is the higher temperature of the air or the lower density the vehicle has to push through, but this rule has been constant on every car I have ever driven.

[mbeach]

My mileage plunges dramatically in the sub-zero temperature range.
It is a combination of three things:
1. Denser air (at -30, the air is super dense!), the truck needs more fuel to maintain the proper fuel/air ratio.
2. Thick fluids in the diffs and transmission/transfer case. I have heaters on everything but the diffs, and I know that they thicken up when cold. This drags on the gears and creates friction.
3. Idling. This is the big one. I let our trucks run for 5 to 10 minutes before even moving them out of the driveway. This translates into 0 mpg.

As it stands, I am refilling every 230-240 miles. I really haven't math'd out the mileage, because I don't want to know.
It'll go back up in the spring.

[SPAZZ]

my VX new untill like 10 or 12,000 miles got 400 miles per tank then 300...then 200...that was like 10 miles per gallon highway and less city.

Then I modded the crap out of it and now it gets about 13MPG. I agree...I shoulda bought the biggest V8 Turbo Diesel Truck I coulda bought for the same price of the VX and got better mileage.
Replaced everything from Fuel filters, MAF, O2 sensors, Pcv, cleaned EGR, manifold gaskets, ECU, coils, etc..you name it.... even installed 4.56 axle gears. I have never got the original mileage back only inproved the down fall with mods.

The VX has been my worst financial investment, but my best hobby/mental investment

[VehiGAZ]

Don't forget about the confounding effects of local and seasonal differences in fuel formulations - that will introduce a significant variability in what mileage different drivers will get. Not to mention changes in formulations gas over time (for example, they used to put MTBE in our gas here in CT, then they switched to ethanol. I don't know which would give me better fuel economy, but I'm SURE the two additives give me different mileage).

Bottom line - don't get hung up on differences between your observed mileage and the mileage someone else says they get, because there are too many variables you can't account for to make it a useful comparison.

[WormGod]

Ya, I think I am finding out MANY things these past few weeks around. I started going to a newly opened Sunoco since my Exxon closed its doors, and I am getting MUCH less mileage now. Last week I got 185 miles on a single full tank. This week is looking much the same. That is down DRAMATICALLY. I figure that this SUnoco is buying some crappy, wholesale fuel that is probably 80% water and not only am I getting worse mileage with it, but I am also rusting my engine from inside out, heh. Starting next fill up, I am gonna try another station and see what I get.

The blowjob of it all, it's just the VX that creates the fuel economy situation. It's also the penny pinching gas stations that want to rob you.

[Velvis]

Flatlander with fresh gas right out of the Gulf -- 380+ miles per tank. '01 VX K&N, synth lubes, and cool stuff from Tone.

[Joe_Black]

Woohoo! Drove the 120+K mile '99 IronMan to Miami and back today and got 431 miles out of the first tank! Filled up at 60/95 in Vero and topped with 20.8 gallons. When the odometer started getting close to 400 I started thinking "please break 400 so I can post!". LOL!

Oh, the first leg to Pompano was even towing a small utility trailer.

[VehiGAZ]

431 km???

I just can't believe you got that kind of mileage, and with a trailer, too.

[WormGod]

You know what would be REALLY useful.... an average MPG of each owner here with access to their mods list. We should compile some sort of variable table to see if we can determine "which mods hurt fuel economy more" and which "aid fuel economy".

Sound useful? Anyone have the means of doing this?

I just hit 1/4 of a tank when I reached work this morning and I have only gone 148 miles. !@#$%!!!!!!!!!! Not sure what's up, cause she is running smoother than ever.

[Joe_Black]

431 km???

I just can't believe you got that kind of mileage, and with a trailer, too.

Well, it's not typical. Usually this one gets 350+ consistently, so I was really watching the odometer and fuel gauge on the trip back. Cool weather, tail-winds, whatever... it was a real treat.

This IronMan has always intrigued me as to how much better it performs than any other 3.5L I've had. I got it off eBay with 99,500 miles on it and it's peppier and consistently gets better mileage than my bought-new '01 VX or the '01 2WD Trooper we just sold. The only non-stock driveline goodies are a K&N drop-in filter and all Mobil-1 lubricants througout. This is just one of those vehicles where the planets and stars were all in alignment during assembly.

[blacksambo]

I guess the only way to sort out all this variation is to get several of these VX's on a dyno and test under identical circumstances? Does anybody have a dyno they want to donate for this test?