Improving mileage in the V-Cross

[mdbomb]

I purchased my 2000 V-Cross with approximately 60k miles and no modifications. I am wondering why I am getting between 13 and 17 mpg and I am not even driving hard.

Does anyone have any thoughts on why my mileage is so bad and/or any suggestions on how to improve it.

Much appreciated!

[mdwyer]

That might be pretty close to normal, I'm afraid. I'm getting about 13 to 16, depending on driving patterns on mine at about 83k.

Aside from the usual stuff (avoid jackrabbit starts, try to drive 'evenly', check the air in your tires, etc), the only VX-specific thing I can think of is to turn off the POWER button except when you need (want!) it.

[etlsport]

thats not necessarily true, depending on driving style, some vx drivers actually increase their gas mileage with the power button, it allows the vx to run at optimum RPMs for longer, running more efficiently, as long as you arent running to 5500 rpms every time with power mode, i dont think it affects your gas mileage all that much

[PHO2GR4]

I'm only getting 19 MPG on this road trip...all highway miles, with the cruise control set at 65 MPH. I've got a few things working against me, though:

1) I didn't remove my roof racks. That screws up the aerodynamics.

2) I'm pretty heavily loaded, with me and the two dogs and all of our gear.

3) I have larger tires and wheels, and I'm lifted 3", which has to hurt mileage.

4) I'm driving a Vehicross, which is REALLY bad for your mileage.

5) I keep hitting bugs. Millions of bugs.

So far, gas has been the most expensive part of this road trip. I'm almost in Moab, though!

[blacksambo]

Try running your tire air pressure at 39 instead of the factory recomended 29 lbs. Also, try using Lucas brand gas treatment, the silly stuff actually works and does pay for itself. Yeah, get rid of the roof rack, you can actually here the difference.Switch to Mobil 1, this works too, if not already using synthetic oil. We've got two '99's, 90K plus and we routinely get 19 plus mpg with these simple tricks.

[PHO2GR4]

I'm running my Yokohama Geolandars at 37 PSI on really hot pavement. I don't know if I should boost it any higher!

And I don't know why I didn't just remove the racks before the road trip. I guess I figured, "what if I buy something huge during the trip and I need the rack..."

http://www.vehicross.info/gallery/data/500/thumbs/passengers.jpg (http://www.vehicross.info/gallery/data/500/passengers.jpg)

Check out the dead bugs on the rack...

[nfpgasmask]

Yup! That's what I have to look forward to! I was gonna wash the VX one last time before I leave, but its fairly clean right now as is, and I know if I wash it, its only going to be covered with bug juice within the first 3 hours of the trip. So its kinda pointless. I just hope there is a nice car wash with a strong pressure gun in Moab. :rolleyes:

Bart



I'm running my Yokohama Geolandars at 37 PSI on really hot pavement. I don't know if I should boost it any higher!

And I don't know why I didn't just remove the racks before the road trip. I guess I figured, "what if I buy something huge during the trip and I need the rack..."

http://www.vehicross.info/gallery/data/500/thumbs/passengers.jpg (http://www.vehicross.info/gallery/data/500/passengers.jpg)

Check out the dead bugs on the rack...

[WormGod]

My advice.... keep it parked. Don't mean to sound like a smart-arse, but it isnt likley that you can improve gas mileage any better than 1mpg over stock.

[Ascinder]

I'm only getting 19 MPG on this road trip...all highway miles, with the cruise control set at 65 MPH. I've got a few things working against me, though:

Try 12MPG, I think I'm going to start trying whatever you're doing, because whatever is "working against you seems a whole lot better than what's working for me :p

[JHarris1385]

13.2 here. Been that way for a while. Gotta change that damn Fuel Pressure Regulator sometime soon.

[Jolly Roger VX'er]

I just filled my tank today and computed the mileage.....18.4 gallons divided into 313 miles = 17.01 miles/gallon. That is mixed-driving on rural back roads and a few highway miles with some city driving thrown in.

[WILLY]

Here is an idea! put a smaller engine in it.lol :jump: :luck:

[PHO2GR4]

Try 12MPG, I think I'm going to start trying whatever you're doing, because whatever is "working against you seems a whole lot better than what's working for me :p

Ascinder, I only get around 13 - 14 MPG normally. Seattle city driving sucks, with the traffic and the lousy drivers and the idiotic traffic signal timing.

I thought I'd be getting slightly better mileage on this road trip, though. 19 MPG sort of bites, considering how tame I've been keeping things. I mean, really...65 MPH? Even on the 75 MPH stretches of highway? I'm in no hurry...I'm really enjoying the sights...but I usually drive 85 in a 65 zone when I'm in my 350Z!!!

BTW, the Z Roadster gets around 25 MPG on the highway, and 17 MPG city. But it drinks PREMIUM FUEL.

[JAFO]

I have heard a gasoline Internal Combustion Engine (ICE) is only about 20% effecient in it's ability to convert the fuel into forward motion. This is not including the loss of energy in the drivetrain, just the engine itself. A diesel engine is 30% to 35% effecient. The rest of the energy is lost as heat.

In comparison an electric motor is over 90% effecient in it's usage of it's fuel, being electricity.

Regarding the drivetrain loss of energy I found this article on TireRack interesting. Although there is room for improvement in the drive train, the biggest room for improvement is in how the ICE converts fuel to forward motion.


Rolling Resistance:
"In the United States, vehicle manufacturers are required to maintain an average fuel economy for the "fleet" of new vehicles they sell each year. Currently, the government Corporate Average Fuel Economy (CAFE) mandate is 27.5 miles per gallon (mpg) for cars and 20.7 mpg for light trucks (includes minivans, vans, and most pickup trucks and Sport Utility Vehicles). However because it's an "average" fuel economy, in order to sell large cars or trucks (that use more fuel), the vehicle manufacturer must also sell small cars and trucks (that are fuel efficient). The vehicle manufacturer can be fined if their annual vehicle "fleet" uses too much fuel, and can earn "credits" towards future years if their fleet's average fuel economy is better than the government mandated level.

A tire's rolling resistance does affect fuel economy. For that matter, CAFE is so important to most vehicle manufacturers that they demand their suppliers develop low rolling resistance tires to be used as Original Equipment on their new vehicles. In order to meet these demands, these tires are often designed with a priority on reducing weight and rolling resistance and are molded with slightly thinner sidewalls, shallower tread depths and use low rolling resistance constructions and tread compounds.

However, in order to understand CAFE tests and the roll that tires play, it is important to recognize that CAFE tests are conducted in a laboratory and not on the highway. Many aspects that affect fuel economy in the real world are reduced to "constants" incorporated into the formulas specified.

A vehicle's fuel economy is the direct result of its total resistance to movement. This includes overcoming inertia (Newton's Law), driveline friction, road grades, tire rolling resistance and air drag. In order to offer the same level of performance, heavy vehicles require more power (and more fuel) than light vehicles. All-wheel and four-wheel drive vehicles require more power than two-wheel drive vehicles; and boxy vehicles require more power than low drag aerodynamic vehicles.

But how much influence does each of these elements have and when are their influences felt? The relative percent of influence that these factors represent during stop-and-go city driving are very different then during steady, state highway driving.

During stop-and-go city driving, it's estimated that overcoming inertia is responsible for about 35% of the vehicle's resistance. Driveline friction is about 45%; air drag is about 5% and tire rolling resistance is about 15%.

Overcoming inertia no longer plays an appreciable role in the vehicle's resistance during steady speed highway driving. For those conditions it is estimated that driveline friction is about 15%; air drag is about 60% and tire rolling resistance represent about 25%.

Now, lets explore a scenario where a High Performance replacement radial tire has a whopping 20% increase in rolling resistance over a low rolling resistance Original Equipment standard passenger radial. To calculate the potential change in mpg resulting from using the High Performance tires in place of the Original Equipment tires, we would multiply the tire's percentage of influence in the vehicle's overall resistance (15% in the city and 25% on the highway) times the High Performance tires' 20% increase in rolling resistance.

If the vehicle equipped with standard Original Equipment low rolling resistance passenger tires normally provided 25 mpg in the city and 30 mpg on the highway, installing tires with 20% greater rolling resistance would only drop fuel mileage by a calculated 3% (to 24.25 mpg) in the city, and a calculated 5% (to 28.5 mpg) on the highway. While this is a measurable difference, it probably isn't much more of an influence on real world fuel economy than being stuck in rush hour traffic a couple of times a week or being stopped at every red light instead of continuing through a string of green lights.

Additionally, the easiest way to reduce rolling resistance to enhance fuel economy is to make certain that the tires are properly inflated. A vehicle that requires its tires to be inflated to 35 psi (based on the vehicle's tire placard) will have an increase in rolling resistance of approximately 12.5% if the tires are allowed to become underinflated to just 28 psi. Therefore, maintaining the vehicle manufacturer's pressure recommended for light load and heavy load conditions may almost be as important as the tires being used."
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=29



Internal Combustion Engine (ICE) on Wikipedia. The five and six stroke engines are interesting.
http://en.wikipedia.org/wiki/Internal_combustion_engine

[PHO2GR4]

Hey JAFO! You still driving that Ebony? I hope you have decided to keep it. I'd still like for someone to set up an Oregon VX Meet-up so I can take another road trip! There are quite a few Oregon VXers, right?

http://www.vehicross.info/gallery/data/500/thumbs/oregontrail.jpg (http://www.vehicross.info/gallery/data/500/oregontrail.jpg)

[Cobrajet]

This may very well be my solutions to fuel mileage issue...
http://home.comcast.net/~gregg.north/yellow_mini_1.jpg
29 city/36 highway. 172 turbocharged horses, and only 2660 pounds. 15 second quarter mile, 0-60 in 6.7 seconds.

My VX has served me well for the last 100K miles and she deserves a rest. I'll still keep her, in the garage, with the Mini, my Cobra and my CBR600F4.

(Sat in the Mini today -- FORGET IT!! -- I'll keep my gas guzzling COMFORTABLE VX!)

[TexVeX]

My Bf says we got 26 miles per gallon on the highway driving my VX, home from Dallas. Is that possible?

[etlsport]

i would very very seriously doubt it, how did he calculate that? run the gas tank til empty, fill it up and divide the miles by 22 gallon tank? the fuel gauge in the vx is notoriously inaccurate, the only true way to check your fuel economy is to fill your tank completely (dont put extra in after the pump stops on its own) reset your trip odometer, drive around, next time you fill up, fill it up until thet pump stops on its own, dont put any more in, look on the pump to see how many gallons you put in, divide the number of miles on your trip odometer by the number of gallons u put in (140 miles divided by 11.6gallons = 12.06 mpg) sorry if this is just telling you what you already know, i just like to explain things fully

i thought i was getting like 22mpg for awhile.. turns out the scangauge i was using to calculate it was set wrong.. i was actually around 16mpg

[driver3]

Remember... When calculating your trip odometer you have to adjust for the tire size if you've changed it...

For instance.. I just filled up today... 20.8 gallons... I had 315 on the trip

Because of my tires, 315 is really 346.5
I get that from the fact that when I'm going 60 on my speedo, I'm actually at 66... so 66*315/60 = 346.5

346.5/20.8 = 16.65 mpg for this tank

not 15.14 which some may have thought

SO maybe 13 mpg is really someone getting 15 or 16 with 33 inch tires... ?

You can use the infamous miata tire size calc to figure out your speedo difference from stock tires to your new tires...

btw.. who's getting 23? are you running 13 inch wheels and tiny tires? :p

[TexVeX]

We didn't do the usual test because we wanted to see how many gallons it took to drive home from Dallas, about an hour away. We topped off the tank drove home, topped it off again and calculated from how much we added which was 2 gallons to drive 52 miles. But I was wondering if you can get an accurate reading in such a short distance.

At the time we had bald tires, same size that originally came on the vehicle. We didn't get new tires till the second day we had it.

[jemorga]

I filled mine yesterday and had 16.9 mpg. Thats a little better than normal. It usually runs 16 to 16.5. That is a combination of city and highway driving about 50/50. The tires are about 1/2 inch taller than stock. I am going to be going back to stock rims and tires this weekend. Biju gave me a killer deal on the tires he had. So maybe in the next week or so I will be able to tell if there is any difference with such a small difference in tire size. At one point just after I bought my VX the mileage was down to 12.5. I took it to the dealer for the 45,000 service and they did the EGR/PVC service but also cleaned the fuel injection. The mileage jumped almost 2mpg. When they switched our fuel here to the summer blends (less ethanol) it jumped almost another 2 mpg. I got rid of a Honda Accord with 22mpg for this, but I love it. :rolleyes: