What Octane?

[89Vette]

Of course, 300 miles from a tank is possible. 22gal x 15mpg = 330miles -- if you ran it bone dry. With your typical 2 gals left, you're sitting right at 300 miles. For me, that's mostly city driving as I get right at 15mpg city.

On the opposite end, 19mpg would net 418 miles from a tank. If you jumped in, got on the hwy, and ran from a higher elevation to a lower elevation -- hwy only -- I bet it could be done. You'd probably have to stick with 60mph or just barely above that.

A strong tail wind could give you the same result.

I've seen a couple post 400 miles in a tank (in earlier years) but you have to remember 100% gasoline provides better results than that cheap-azz E10 they're ramming down our throats. (Plus, in the earlier days of the forum, the units had lower miles and were in better shape [on the average])

Because of the way the VX tank reads, it's hard to believe people run it empty enough to hit 400 miles anymore. Same goes true for 300 in the city. But, it's certainly possible.

If you're not getting close, pump your tires up to 35psi and make sure everything is tuned up (including clean injectors). You can get it.

(Caviat: high elevations)

[Cobrajet]

I just came back from a trip from Northern Virginia to Nashville where I kept very good records of mileage because of this thread. I drove a total of 1321 miles (mileage corrected based on GPS), using 69.2 gallons, getting an average 19.1 MPG. I would say this was 95% highways miles, and probably 70% at 75mph. (I generally ran at 5-over posted speed.) First tank (ALL highway) I got 379 miles on 19.8 gals, with the low light on the last 4~5 miles. Tank two (a few local and stop-and-go miles) I got 381 miles on 20.1 gals, again with the low fuel light on for the last few miles. The next tank was all highway, and I played it safe filling after only 353 miles, 19.1 gals. The last fill was only a partial fill after 183.7 miles, 10.2 gals.

I generally do not get over 300 miles on a tank because I no longer make long commutes, but lots of short trips over the course of weeks between refills, which is the worst case scenario. It was nice to see that my VX is still capable of getting 19+ mpg on the highway. I have a few more trips planned for this year, so I won't need to rent a car to save money!

And to keep on topic - ALL regular unleaded! My VX has never seen premium, and never will!

[89Vette]

I just came back from a trip from Northern Virginia to Nashville where I kept very good records of mileage because of this thread. I drove a total of 1321 miles (mileage corrected based on GPS), using 69.2 gallons, getting an average 19.1 MPG. I would say this was 95% highways miles, and probably 70% at 75mph. (I generally ran at 5-over posted speed.) First tank (ALL highway) I got 379 miles on 19.8 gals, with the low light on the last 4~5 miles. Tank two (a few local and stop-and-go miles) I got 381 miles on 20.1 gals, again with the low fuel light on for the last few miles. The next tank was all highway, and I played it safe filling after only 353 miles, 19.1 gals. The last fill was only a partial fill after 183.7 miles, 10.2 gals.

I generally do not get over 300 miles on a tank because I no longer make long commutes, but lots of short trips over the course of weeks between refills, which is the worst case scenario. It was nice to see that my VX is still capable of getting 19+ mpg on the highway. I have a few more trips planned for this year, so I won't need to rent a car to save money!

And to keep on topic - ALL regular unleaded! My VX has never seen premium, and never will!

Very nice and thought out! I love the detail provided -- and comparison between city/hwy! Glad to hear you can get 19mpg!

Nice job, Gregg!
Gregg <LOL>

<cheers!>

[antdag22]

Just drove from FL to NJ. 22mpg all the way. 99 black, mobil one 10w30 and filter, 35psi factory 16s, 93 octane. Checked 3 times.

[VXobsession]

I used 87 when I first got my VX but tried 93 once and never went back. Much more power and idles super smoother. Oh, and my highest mileage was about 320. It's my daily driver but I occasionally drive an Intrepid about once every couple of weeks...it'd be nice if I could remember to use 87 in my CAR instead of involuntarily hitting 93 out of habit from driving the VX so much.

[44ficus44]

I just get whatever mexico sells.... kinda stuck with one down here. the other one is just full of lead.... must say.. my VX prob hates it

[SinJin]

My best MPG is 17.2.

That's nearly all freeway driving @ 65mph+.

I run 87 Octane.
No mods on the VX.
My engine has 145K on it now.
I use 5w 30 Royal Purple oil and it's changed within every 5K miles max. As often as 3K.
I ran Michelin summer tires (Latitude Sport IIRC) @ 35psi during my MPG checks.
Air Filter was new during the MPG checks.
No tune-ups in the past 50K.

*EDIT : Also, I only drive using the Power Drive selector.

[RedBlur]

I was just wondering what type of gas mileage people were getting during my road trip yesterday. I ended up at 19.3 MPG using Shell 87 gasoline, although I was probably closer to the 20MPG range before I sped up from 70 to 75MPH. That was about 90% highway miles. I'm lifted and have oversized tires, so that isn't helping my mileage any. I'm also throwing an EGR code, but I tend to ignore most EGR codes I get unless the engine doesn't seem to be performing well.

I thought that was pretty good considering that my VX was sitting for the better part of 3 years, although I did help it out a bit with a fresh oil change and injector cleaner. Definitely better than the ~8 MPG I got for the first few miles I had it on the road... I probably needed to get through the old gas.

I bought a gauge a while back that hooks up to the OBDII port to monitor MPG as well as other vitals. I need to calibrate it because the gas consumption numbers aren't super accurate (seems to be about 5-7% low), but it is nice to use as a comparison and to monitor driving habits. Maybe I'll throw some 89 or 93 in it on my way back and see how it compares.

[vp277]

There are more efficient newer vehicles out there, I think what counts with the VX is fun per gallon and the fact that you're driving a unique vehicle. Lousy mpg is a small price to pay...

[Leon R]

I am staying at consistent 14mpg (about 80% highway commute). But my coolant temps are almost always around 160*. So am pretty sure that my thermostat is stuck partially open. Only if it wasn't such a PITA to replace it .

[vp277]

Running cold is bad for the fuel economy and bad for the engine, change that thermostat. Test a replacement in a pot of boiling water to make sure that it opens correctly. Also, according to some posts here the "Power drive" option improves the mpg a little.

[magellan]

Some interesting replies here - i guess most of you all run the 3.5 where as here in Australia we run the 3.2, and going on 300mi = 482.80km i get an average with hwy driving of 520km in winter and 500km in summer - AC doesn't make that much difference really. I use Caltex Vortex Premium 98 and do notice a difference if i run 95 or 91. 20 inch rims help to i believe.

[EVO]

I ran E85 half tank twice (E85 is equivelant to 105oct) and there is a noticeable difference!! E85 did trigger the check engine light after the second tank though! Horrible gas mileage running it, I got around 12mpg. But it ran better with it in the tank! Have gone back to 87oct. and the check engine light has gone away. I think I'll make it a bi-monthly treat!!

[VXCanada]

I typically get 330 miles per tank 530 km as per the GPS log (summer time). Using around 75-77 liters on a fill up typically (19.8-20.3 US Gallons). I'm on 31.5" tires (285/60r18 Geolander AT-S).

This translates to about 14.5 L/100km or 16.22 MPG (US). It's around 75% hwy, 25% city normal driving with "occasional" heavy footed acceleration.

I use 89 Gas.

T.

[Hades]

I get crap mileage, making me think its running in limp mode or something. Like 10 mpg around town and 17 highway. Granted the 10 mpg is usually trips less than 5 miles, but does suck having to refill every 150 miles. 87 only, fuel gets boated in up here and is almost always over 4 bucks a gallon unless you go to costco or the company that barges it in.