Got around to installing my Volo Performance FS1 fuel saving chip. I have seen a couple other LRForumers have installed this little device and had positive results so I thought I'd give it a try and run my own little "experiment" to see the real life application and compare the numbers. To set the stage here are some of the "experiment" controls.

Vehicle : 2002 Disco II with 114K (Engine/Drive train 100% Stock)
Oil : 5W-30 Full Synthetic Oil w/ K&N 3001 Filter
Fuel : Shell 92 Octane
Daily Mileage : ~100 miles (mostly highway)
Additives : Lucas Upper Cylinder Lubricant (~8 oz. per full tank)

I don't have Scanguage and I will only be measuring miles/tank so this will NOT be exact by any means. For the previous 5 full tanks I have hit 320-330 miles/tank before the gas light comes on (the gas light will be my end marker). I drive approx 100 miles round trip to and from work M-F, so it won't take long to get some results. I'll top off today after work, and to quote Ron Burgundy : "Let the games begin! HIYO!"

 

Quit running your tank down to the warning light or you will be buying a new fuel pump soon, cause that causes your pump to over heat.

 

im with mike. don't let your fuel get that low. make it easier on your truck and fill it at 1/4 tank. then use the mileage vs the gallons it takes to fill up to figure out your avg mpg.

 

Mike and Ed,

Thanks a lot for the input, I've seen this mentioned before just didn't know that it would overheat the fuel pump. Sounds like I need to change my fill up habits and I'll adjust my "experiment" accordingly

What is the actual capacity of a DII gas tank? The manual says over 25 gallons, but when I fill up I have never gotten more than 23 gallons filling up RIGHT when the light comes on (@ approx 1/8 tank). 3 gallons seems plenty safe to me, but I'd trust your experience over the manual 99.89% of the time.

 

25 gal is from dry, so run it out of gas and you will get 25+ gal in.

I fill up once a week, I drive a average of 150 miles a week and that takes me down to 3/4 of a tank.
Filling up once a week helps the wallet, instead of spending $100 to fill a empty tank I spend $30.
Add to that if there were a major event I will have at least 3/4 of a tank of fuel to get my family to safety.
Add the 10 gals of treated fuel in the garage and I can get to safety and then some.

The excess fuel that is pumped to the engine is returned to the gas tank and it is sprayed over the fuel pump.
The fuel pump supplies way more fuel than the engine needs, thats why there is a fuel pressure regulator.
The fuel pump supplies ~60 PSI and the engine only needs 35 psi, full throttle and top speed obviously you need more.
The fuel pump runs at only one speed and provides only "X" amount of pressure, no more and only less when there is a problem.
Also the pump is submerged in the fuel.
Both os these keep the pump cool.
Continually running it down to empty and the pump will keep overheating and eventually burn its self out.

 

Thanks for the detailed info, always good to know "why." So 3 Gal=Empty....damn Redcoats.

If 3 gallons left is an unsafe level, why have the light come on at all if it's already too late and you're already killing your fuel pump...and if that's the case, why not make it red? (rhetorical question/thinking out loud/venting).

I need a commuter car that gets 30mpg on 87 octane grocery store gas...

 

They dont care about your fuel pump, they just dont want you running out of fuel.
Its not bad to run it empty once and awhile, just not all the time.

And contrary to popular belief, the fuel pump ALWAYS sucks from the bottom of the tank.

 

yolo,

Try this for accurate measurements. As DiscoMike has said, don't go to the light and that is not very accurate anyway. I have been using gas milage as an idicator of "engine/drivetrain/tire health" for years. I check gas at least unofficially every tank. By the way, I get 17 to 17.25 on my 2003 Disco II at 70 to 75 mph on the highway routinely. I did all of DISCOMIKE's 60K service when I got the truck. I imagine I could get 18+ or so if I slowed down to 60 but my time is worth something. I don't worry to much about in town since there are too many variables to control to interpret of the results. I am an nginer (spelling does not count) and an nuclear engineer to boot so excuse my **** desire for accuracy and procedures but it comes with the territory.

For as accurate as possible (probably more accurate than scangauge II without formal calibration of all the inputs)
1. Fill up with the particular gas you use at the same station filling up to the cutoff - do not top off. If you want to be as accurate as possible, use the same pump each time so the auto cutoff of the pump is the same each time.

2. Either do this for highway driving or drive the same route you are using as your comparison. If you do anything different or hit some unusual traffic (heavy or very light), or if you mix in some highway traffic and you normally don't you will skew the results probably beyond the benefit that the chip could ever provide. Do you accurately know what you got on the highway? That is your best bet because it is easier to reproduce. Even if you do it on the highway it makes a difference in if you are going from Beaufort SC to Jacksonville Fl or if you are going from Beaufort SC to Ashville NC (flat versus up hill on the long haul) If you can't do it on the highway you will probably need several tanks to tell if there is a difference since that will average out the anomolies in the one trip.

3. When you are down in the tank (well before the light - say to 1/4 tank or so) go to the same station if you can and use the same pump if you can. Go to the cutoff - do not top off. If you are on the highway and can't go the to same station just go to the cutoff. There will be some variation in the cutoff point but that should be minimal.

4. Now divide the miles driven on that tank by the gallons used. (I do this every time I drive on long trips) Do this for several tanks with similar driving conditions to get your "normal gas milage" and you can and should use different numbers for "highway milage." Except on long trips very few people ever actually get an accurate highway milage figure and in reality most people mix in some highway miles on a normal drive for a week so they really don't get an accurate "city driving" number so that is why I call it "Normal gas milage"

Good luck and let us know the results. I am more interested in the highway milage as I do not off road my truck but to be honest I am very skeptical at the claims of these manufacturers.

Thanks

Dan

 

Thanks for the input!

I completely understand the desire for accuracy as I spent (far too) many hours in the bio-stats and chemistry labs through college doing and RE-doing experiments to make them accurate as possible...unfortunately, I am not willing to put forth that sort of effort to make this a very official "experiment." Before installing the Volo I measured range, my numbers were around 310-330 and I was putting 20-22 gallons in at each fill up from empty, sometimes with the gas light coming on, sometimes not....roughly averaging out to 15.24 mpg.

As I noted in the original post, I am doing my best to keep everything controlled as possible (i.e., filling up at the same Shell, using the same pump, using the same amount of Lucas, driving the same route, same driving habits). The amount of afternoon rush hour traffic is the biggest unknown in my route so accurately predicting "highway" mileage or "city" mileage will be nearly impossible with the amount of work I'm willing to put into this. I just wanted my overall range per tank, because that is what matters to me.

I am not expecting a miracle, nor am I expecting my Disco to turn into a Prius, I just wanted to see if there was any effect since I do so much driving and gas isn't all that cheap. I wanted an accurate measurement based on MY drive so that anyone interested (not many, it seems) in squeezing a few extra miles out of their tank could see some actual on road results in a Disco, rather than listening to the company's claims, whatever they may be.

I'm not understanding why "going to the light" is not accurate?. Overall total tank range seems like the the MOST important thing, because in the end, that is all that matters right? More miles per tank means more MPG.

More than anything, I wanted to see if it worked in MY particular situation since I spend SO much time on the road, and if I can get an extra 20-30-40 extra miles out of my tank, I consider that a win and worth the $60.

Tank #1 with Volo = 375 Miles (gas light kicked on as I was pulling into the station)......*DISCLAIMER - Changed my oil right after fill up, so that may have skewed the numbers a bit. MPG - 17.05 mpg

 

yolo,

By your own numbers going to the light is not very accurate. If you go to the light (which is based soley on gas content detect) then you should put in exactly the same amount of gas, no matter how many miles driven since, say the light comes on with 1.5 gallons left in the tank, then it will take the tank capacity minus the 1.5 gallons (a fixed number if the light is accurate) to fill it up. If it takes 20 to 22 gallons by your numbers then there is an automatic 10% error induced, which translates to about 1.5 mpg in error.

Its really not hard. Always fill up to the auto-shutoff on the pump. Every time you put in gas just keep the receipt and note on the back the kind of driving (highway, city, mixed, bad traffic etc) and record the miles driven for that fillup and throw it in the glove box. Then at some time later just add up all the miles, add up all the gas, and divide the miles by the gas. The more miles and tank fulls the more the "anomolies" are smoothed out and don't factor in as much. If you have a few that are really odd, like a major accident that held you up or stop and go construction, etc you can even throw those out so as not to skew what you normally see.

I really find it hard to believe that a chip can improve the milage by more than 10% so if you already have a 10% error then any improvement may be burried in the grass. Its not really hard and its not sophisticated. I explained the details for the most accurate methods without some sophisticated cal lab type equipment, use whatever is convenient but the go to the light is probably not very accurate. Another reason is that if the light comes on and you drive 15 miles to the Shell station after it comes on, there is another 10% error that you have not accounted for.

Smokey73