bates's Forum Comments
Showing comments 1-30 of 116 by bates.
richardharo, Fuelly is designed to calculate your fuel consumption and mileage based upon fill ups, not partials. It sounds as though you are expecting Fuelly to calculate your mileage based upon partial fill ups which is mathmatically impossible. Fill your tank and reset your trip meter or log your odometer reading. Then drive until your next fuel stop, fill the tank again and record your trip meter or odometer reading. The number of miles driven between fill ups divided by the quantity of fuel added is your mileage for that tank. Reset your trip meter and continue to drive, refuel fully, log your miles driven, and repeat. This will yield your fuel economy in a meaningfull manner. Partial fill ups don't work because there is no way of telling how much fuel was consumed between partial fill ups since the tank didn't start out full and end full thus giving a fixed quantity of fuel consumed.
posted by bates November 22 at 5:31 AM
I've done both time and mileage and found very little difference in the calculation, it was more for my personal edification and tracking oil changes than tracking mileage data. (I subscribe to the oil changes at 100 engine hours or thereabouts theory of maintenance schedules. The old rule of 3,000 miles was based upon the assumption that the average speed of the vehicle was 30 mph, hence 3,000 miles equaled 100 engine hours, similarly when the manufacturers started accepting 5,000 mile oil change intervals for "highway driving" conditions that was based upon 50 mph average speed but the same 100 engine hours.) So for me it was a proof of theory that with my current commute that around 4,000 miles was a good target for oil changes, and since I was already tracking the data I played with it to see if it was working out percentage wise to my driving city vs. highway and it was pretty close there too, again further validating my theory.
In your case I'd do what is easiest to figure or estimate for you. For me I know how many miles my commute is and I know how many of those miles are on city streets and how many are on freeways so I use that as my base breakdown and then adjust it to account for extra trips be those around town running errands or on the freeway taking excursions. The bigger factor is going to be that you're consisitent in what ever method you choose to use, don't use method 1 for one fill up, method 2 for another, and method 3 for yet another fill up, that might work out to bad data since it lacks consistency, just figure out one that works well for you and stick to it.
posted by bates November 8 at 5:17 AM
I don't have a smart phone, I've kept my fuel up records for years on note book paper and put the data in when I get to work on my computer. Just remember to write everything down. Fuelly even allows you to add multiple fuel ups one right after the other so I add my wife's car's fuel ups when I remember to collect her credit card receipts out of her center console, sometimes it is a month or more after the car has been fueled before I get the data added.
posted by bates November 1 at 5:27 AM
I completed your survey, but must admit to being a little confused, I'm not sure if it was a translation issue or what but nothing on Fuelly is even remotely physical save the key strokes and mouse movement so I was unsure as to how to answer the 3 or 4 questions about how fuelly affected my physical fitness. Or were you asking about my overall physical fitness? Anyway, I hope I could help you and that you get some usefull data for your assignment. Good luck.
posted by bates October 29 at 5:45 AM
@SactoMailMan, one other thing that I forgot to mention, fill up in Arizona, not California if possible. Arizona doesn't have So Cal's AQMD mandates and therefore you can get pure gasoline, not the gasohol crap we get here, that will give you a significant increase in mileage due to the higher btu's in gasoline compared to methonol. For my cars I get 10-20 percent increase in mileage by using Arizona gas not to mention that you won't be paying all the CA gas taxes, so you pay less and get more mileage, a true win / win situation.
posted by bates October 15 at 5:11 AM
@SactoMailman, I've driven the Amboy road to Vegas once about 18 years ago, picked up a buddy who was stationed at 29 Palms and drove him to Vegas for a bachelor party, that is some lonely road with many miles between service stations or civilazation for that matter. If you're a fan of the desert, it is an intersting drive and the Amboy Crater is pretty impressive.
You could also take Arizona 60 off of I10 and cut up that way, but check to make sure that it hits the I40, I'm not positive it does.
posted by bates October 8 at 5:29 AM
Penske rentals along with several other companies like Ryder and Uhaul are designed for average American Drivers to be able to rent one and drive it themselves. They are all equipped with an automatic transmission since few drivers licensed in the US in the last 20 years can drive a manual transmission and most of us who have been licensed for more than 20 years haven't driven a stick in years. Most if not all are equipped with gasoline (petrol) engines because diesel is not as prevelant and the idea is to make them user friendly, not require drivers to go to truck stops and the like to refuel, another factor is that very few drivers have diesels here on this side of the pond so many renters would just drive straight to the nearest gas station and pump the same thing into the truck that they put in the personal cars, gasoline in a diesel isn't a good mix.
@SactoMailMan, I would suggest heading up to I 40 from Moreno Valley via the 215 to the 15 to the 40 East rather than taking the 10 to Phoenix if you're concerened about speeds. The 10 in that corridor tends to have very fast moving traffic and the speed limit once you cross the Colorado River into Arizona goes up to 75 or 80 mph if my memory serves. Also, you would be well served to fuel earlier rather than later when the opportunity affords itself. That truck may have a hard time fitting under the roof line at some gas stations and you don't want to be sweatting it on fumes only to pull up to a service station only to realize that you're clearance height won't allow you access to the pumps. I've been there done that in the past with a full sized Chevy Van and a "car topper" aluminum boat on roof racks, not fun.
posted by bates September 24 at 6:06 AM
Yes, aerodynamics play a part in fuel consumption and seemingly minor modifications can have meaningful impacts. This is increasingly true as speed goes up. Aerodynamic drag increases with the square of speed so a car going 100 kph will have significantly more mileage impact than the same car going 40 kph around town.
If I've done my math correctly you're seeing something on the order of a 17% decrease in mileage at highway speeds so that seems pretty high for the kind of aerodynamic impact that a tow bar should have. I used your 31.4 mpg, doubled that to come up with 100 kms, multipled 3.8 by 2 (liters per gallon) and came up with 7.6 and divided 1.3 by 7.6 to come up with 17%, I realize that this is your overall average mpg, not highway but it is something better than a wild a$$ guess. I'd try putting the tow bar in the trunk for a few highway tanks and see if that makes a difference. Is that an option for you or is your tow bar permenantly mounted?
posted by bates September 20 at 5:14 AM
RebelHybrid, thank you for your response, this is exactly what I was looking for, real world ownership and driver's feed back. Better yet, a direct comparison to the TDI.
A good friend just replaced his 10 year old Prius with a 2013 Prius and has been impressed with the increased mileage and accessories now offered on basically the same vehicle and at a lower total price. I definately still need to do some test drives and a lot more research. Hopefully with the arrival of the 2014's there will be some serious deals offered that will help make my choices more clear.
posted by bates September 6 at 5:21 AM
Thank you to Matt and Paul for all you've done to create and maintain this site over the years, I truly appreciate all your hard work.
Welcome Andy, you've got some big shoes to fill but with Matt's endorsement, I'm sure you're up to the job.
posted by bates August 27 at 6:39 AM
Thank you for your thoughtful responses, I appreciate them.
Miata492, all things being equal and my personal admittedly biased preference having the final word, I'd be in a TDI Passat. My rational side however has looked at my current commute, 25 miles each way 7 on the freeway, 3 on a highway (without traffic lights or stop signs, 50 mph speed limit) the rest on surface streets, and deduced that the diesel probably isn't the best fit for me, not to mention the higher capital investment of the Passat TDI over the Jetta Hybrid, let alone the Prius C which is going to be basically 2/3 the cost of the Passat. Also, I live in Southern California, so I'm not nearly as affected by the extreme tempertures as some other parts of the state, country, and world are.
BDC, thank you for the information on the Li vs. Nimh batteries, I haven't done enough research yet to have uncovered that. I agree with your assessment on the proven Nimh technology. As you know I've never been a big fan of the Prius, but it is looking like the best new car option for me at this point. So I'll accept that it won't fit all of my family in it comfortably but 90% of the time it is just me driving anyway so if the kids are a little cramped for the occasional trip then so be it. I just need to go down to the dealership and measure one to make sure that my surfboards will fit inside. I don't want to put roof racks on and reduce the fuel economy that I'm looking at that makes the Prius C such an attractive option for me, if you know what I mean.
Draigflag, I'm a long time proponent of diesels, I owned a 1980 VW diesel Dasher wagon back in the mid to late 1980's. 50 mpg no matter how I drove it, used it to travel to Baja California in Mexico lots of times for surf trips to very remote beaches. My first career I deck handed, drove, and maintained boats for 15 years. Almost all of the yachts and sport fishers that I worked on were diesels and I have literally thousands of hours spent sitting on screaming diesel marine engines. That being said, I live in California, our Air Quality Management Districts, Environmental Protection Agency, Local, State, and Federal Government Officials and Agencies are highly corrupt and pay more attention and give creedence to the positions supported by their campaign and financial supporters than to any real science. Generally speaking and my personal preference a diesel would be first choice, but alas, my current situation and driving shows that the Hybrid is a better fit, use of capital, and will provide significantly better fuel economy for me at this time.
posted by bates August 22 at 7:17 AM
You only have 2 fuel ups on your new truck so far, the site doesn't display any vehicle with less than 3 fuel ups. Fill it up again, post your data and it should start to show up.
Congratulations on your new truck.
posted by bates August 16 at 5:58 AM
The best you can do is hope for a reasonable average, remember that as your tires wear they decrease in diameter, hence they will indicate more mileage for the same distance as they wear down since it now will take more revoloutions of the tire to go the same distance. For some knobby truck tires this can be significant, my son's GMC Jimmy's mud and snow tires have probably 3/4 of an inch of tread on the tires that can wear before they get to the wear indicators, that would work out to 1.5 inches in diameter difference from full tread to nearly bald, over miles that will make a statisticlly relevant change in mileage. It still is true for even high performance tires with relatively small changes between full tread height to worn out but again you're still dealing with averages. If you want to track the difference add in your multiplier and adjust your trip or odometer number accordingly, assuming that you know the proper and correct adjustment figure. Don't forget that if you're using odometer tracking here on fuelly, that you'll need to remember what adjusted number you used last time and start from there for the next fuel up, which will become quite complex very quickly.
posted by bates May 28 at 6:18 AM
Are you considering gas from out of state in your comparisons? Last weekend the wife and I took a trip across state lines, I'm well aware of the extra taxes on gasoline in CA, especially in the southern California AQMD so I always make a point of filling up when I'm in Arizona or Nevada. Gas was nearly a dollar a gallon cheaper in AZ due to relaxed AQMD additive requirements and taxes.
posted by bates May 23 at 6:58 AM
There are a few things here that I think you're missing. First, as another poster pointed out, the switch back and forth from Ethanol blends in states and areas that allow it would definately skew your results, here in California the switch to and from "summer blend" makes a difference in our mileage even with all gas being mandated to be at least 10% ethanol for years now. Second, and a driver for me is the "cleaner" gasolines that don't clog fuel filters in my vehicles. This isn't as big a deal now as it was 10 + years ago, but I still tend to shy away from a couple of major brands after having to change fuel filters that were clogged after several tanks of "dirty" gasoline back in the 1980's. I also stay away from one brand that Chevrolet attribuited to clogging fuel injector poppets on my 1998 Chevy S-10 Blazer and all GM vehicles equipped with a 4.3 liter V-6 and V-8 engine applications. According to the Chevrolet service bulletin there was an additive in southern California gasolines that was required to meet AQMD requirements that was gumming up the poppets and causing them to stick, GM did a recall and warned against future use of So Cal Chevron gasoline. Finally, most independent gas stations and even some major brands will buy fuel from other refineries if there is a supply interruption. I've seen brand x trucks at brand y stations before and a family member who drove gas trucks years ago has told me that a fair portion of the time even though he drove for Shell, his orders would have him fill his truck at another refinery to make his deliveries.
posted by bates May 23 at 6:51 AM
You don't have to empty your tank to get a full fuel up, only ensure that the tank preceeding it and the current tank are topped off at the filling station. That is a full tank, regardless of how low the tank was prior to the current fill up.
With in tank electric fuel pumps letting your fuel level get too low can cause problems, fuel pumps in the tank rely to some extent on fuel in the tank for cooling, when the pump is exposed it won't cool as well due to air / fuel vapors being much less efficient at cooling the parts than liquid fuel is. Also, the lower the fuel level increases the percentage of dirt, grime, and impurities in your fuel which can lead to both fuel pump wear and clogged fuel filters, especially when you get really low and the fuel starts to stir up the sludge as is sloshes over the bottom of the tank that is uncovered during hard accelerations, braking, and sharp turns, now you're picking up stuff that can lead to a near instantaneous fuel pump failure or filter clog that will leave you dead on the road.
Just my $0.02, but I try to never let my tank get down to the fuel light coming on with 2 gallons left in the tank.
posted by bates May 3 at 6:49 AM
I drove boats for a living for about 15 years, the manufacturer's recommended oil change inverval was 100 engine hours for most diesel engines in private yachts. Some with large oil tanks went signifcantly longer but again it was normally a function of the engine's internal oil capacity multiplied by the external oil tank's number of additional crank case capacities times 100 hours. For example, one boat had a 5 US gallon crank case capacity and a 20 gallon external oil tank, it's change interval was 500 hours.
Aircraft ICE engines are also based upon engine hours, most are between 100 and 200 hours of cruise power, but high performance turbo charged engines can be as low as 50 hours between oil changes.
For what it is worth, the 3,000 mile oil change used by most auto manufacturers up until about 20 years ago was based upon an estimated average speed of 30 mph for 100 engine hours. Then later when there was the 3,000 around town interval and 5,000 mile freeway interval it was still based upon 100 hours at 50 mph average freeway speeds. Yes, some engines are good to go with much higher mileage between changes, especially considering the better additives and some synthetics having drastically improved qualities from traditional oils, but thank you very much, I'll still change my oil around the 100 engine hour mark for my cars, it is frankly cheap engine insurance and once in a while I find a problem early that prevents me from having to pay for a full rebuild when I can replace a small sub assembly or part.
If you choose to go with more than 7,500 mile intervals I strongly suggest that you regularly use a Spectrometric Oil Analysis Program to monitor your oil and engine for wear and issues. I have no idea about the cost in Europe but in the US there are several available that charge around $35 to $50 per test to check your oil for engine wear, oil breakdown, dilution (from fuel getting past the rings), and other issues. I tend to run a SOAP test on my cars after 100,000 miles or so every year or two even though I change my oil at the 100 hour mark, again, it is cheap insurance IMHO over costly repairs.
posted by bates April 29 at 6:20 AM
>That link I posted, that car only used gas for 1.15 miles out of 10,053.27 miles.
I was a beta tester of the Chevy Equinox Hydrogen Fuel Cell Project and we were given the opportunity to drive the Volt and see much of GM's R&D prior to the vehicle's release. I distinctly remember that the Volt would run its' Internal Combustion Engine from time to time even if it wasn't required to recharge the batteries to cycle the gasoline through the system. That number appears to be impossible unless the system archetecture has been drastically changed. With a fuel tank that holds 9.3 gallons it would take over 150,000 miles between fill ups even with a 20,000 mile reserve range. The gas would be bad by then even if the vehicle was driven 24/7/365 at highway speeds it would take more than 4 months without stopping to put on that kind of mileage let alone allowing for recharging times between trips. Also, for the record the Volt is an electric vehicle with an onboard battery recharging system, not a hybrid since the ICE does not have any direct connection to the drive wheels, it is only a generator and can not propel the vehicle other than by charging the batteries that power the electrical motor.
> Other you dont, but have to replace the battery every few years at a cost of $18,000!
I believe that the Toyota Prius replacement battery cost is around $2,500 USD and the cost list for the Chevy Volt replacment battery is around $3,000 USD.
posted by bates March 22 at 8:03 AM
>... Are the inactive accounts being removed after a certain period of time? ...
>>I doubt it ... why would that be a good thing?
I don't know about the rest of the US let alone the world, but the fuel formulations in California have changed significantly in the last few years leading to lower mileage for my vehicles. There might be a case to if not remove, then at least display inactive accounts into an archive sub folder so that the mileage figures from several years ago don't artificially inflate the averages for current fuel ups.
That being said, I know and understand that the moderators are very sensitive about the prospect of members and contributors trying to make their fuel economy and mileage figures a contest so this might not be appealing to PB and Mathowie. Not to mention that once an individual vehicle is opened that it is obvious if there hasn't been a fuel up added by the charts and graphs on the vehicle page.
posted by bates March 22 at 7:42 AM
MMUK, thank you for that update, I was under the impression that it was a scientific research paper, not a student's work.
BDC, the experience of your friend the Toyota Engineer is exactly my point, because of a situation that affects less than 1% of the vehicles on the road there is now a smog mandated piece of equipment on every vehicle, and in Cali if that solenoid heater is inoperative for me in the LA Basin, I would fail my next smog check living, working and driving in an area that gets down to freezing a handfull of times each year and NEVER gets any where near zero degrees, let alone below zero.
Again, peace brother, thank you again for your responses.
posted by bates March 5 at 6:52 AM
I also would suggest the octane booster if your owner's manual requires the 91 octane. As BDC points out your onboard computer should have a knock sensor that will retard your ignition timing, alter your fuel mapping, possibly change your valve settings if your engine application has that option any one of which will affect your engines performance but should protect it from potential damage from using a lower than specified octane rating. A bottle of Octane booster from your local auto parts store shouldn't be too costly, pick one up, add the amount recommended for the amount of 87 octane that was added at that fuel up and top it off with 91 to mix the booster into the tank and you should be fine.
posted by bates March 5 at 6:42 AM
BDC, points taken and you are correct, I definately am not a fan of much of the Hybrid technology and manufacturing processes.
The point I was making with the Heavy Duty Truck was a real world, personal experience that I prefaced by dating as 25 years ago, this was the late 1980's and a 1986 Chevy Heavy Duty 1 ton full sized van came equipped with a smog pump and catalytic converter along with a carburetor and was listed as smog exempt, not subject to smog checks either by tail pipe emissions or visual inspection for the life of the vehicle. The CARB changed the rules mid stream about 10 years ago and now that vehicle is subject to all the same emissions regulations including tail pipe and visual inspections while it lacks the other systems that would make it more effiencent and less polluting.
No, I was not aware that the battery was a mere 90 pounds in a Prius, is that for all generations or the current models? There was a study a few years back and admittedly I can't recall the source but at the time I believed it was reliable, that evaluated the environmental impact of a Toyota Prius and a Chevrolet Tahoe that showed the Tahoe polluted less over the vehicle life cycle, if I recall correctly it was 100,000 miles when the impact of the production of the batteries was considered. The author went into quite a bit of detail about the battery manufacturing process, discussing that the minerals were mined in Canada, shipped to China where they were smelted and impurities were removed, shipped to Europe for battery assembly and then to Japan for installation into the vehicle before the vehicle was shipped back to the US for sale.
It was not my intention to cruicfy Toyota or the Prius, as I reread my post I can see where it came off that way, I appologize to you BDC, the moderators, and the members at large of Fuelly. I'm sorry and didn't mean to rail against any brand or model. My issue is with the EPA and CA regulations which are far from a level playing field, but rather designed and manipulated to profit and benefit a few political allies at a cost that is borne by the consumers and the environment.
Thank you for your well thought out and researched response, again, I'm sorry that you were offended and upset by my previous post, please accept my appology.
posted by bates February 27 at 6:41 AM
blackfive, " I filled it with summer fuel I had in cans, it did not make any noticeable difference to the mpg" did you have stabil or some other fuel stability additive in the cans with your gas? For me the ethanol gas lasts about 2-3 months before I notice performance loss even in my garden equipment like my lawn mower, edger, and weed wacker that are hard to start with ethanol gas that is more than a season old if I don't add Stabil to it when I buy it. I used to buy gas 2 gallons at a time for my garden equipment and it would last me about a year, but now I buy it in 1 gallon increments and still have trouble when I get near the end of the can.
posted by bates February 27 at 6:17 AM
I haven't seen hyper mileing associated with the auto start stop function which is what you appear to be talking about here. The short answer from a mechnical standpoint is that it would not be recommended as a matter of course for things like the red light in your example for a car that isn't equipped with an auto start stop function like that in say a hybrid like the Toyota Prius. Cars that are designed for auto start and stop have heavier duty starters and larger battery cranking capacity batteries.
In a nutshell, yes if you regularly start and stop your engine at red lights you'll be buying more starters, it really shouldn't hurt a normal battery as long as you're not doing it at every light but a few times a day over the course of several miles. Starters are expensive and labor costs if you're paying a mechanic to install it can be high, especially on modern transverse engines installed on front wheel drive vehicles. I would suggest doing this only in situations like a rail road crossing where you can see a large freight train that is slow moving and you're sure that you'll be stopped for several minutes, for 20-30 seconds at a red light you're just increasing your vehicle's lifetime service and repair costs IMHO.
posted by bates February 27 at 6:12 AM
The thing that you're missing is that American regulations are much less about the actual tail pipe emissions than they are about political agendas and favors. In California 2 stroke motorcycles were outlawed for "high emissions" for new registrations about 25 years ago inspite of the fact that my Vespa Scooter averaged 80 plus miles per gallon when my full sized Chevrolet Heavy Duty 1 ton Van that I used for hauling tools to worksites got less than 10 mpg, but was exempt from smog rules and checks because it was a Heavy Duty Truck. This had much more to do with bribes, er I mean campaign contributions and the smog check lobby than it did with actual emissions.
The laws vary from state to state, but currently in California a new car is exempt from smog checks for 3 years, then they must be checked prior to registration renewal every 2 years with a system check, a tail pipe emission sniffer, a visual inspection that requires OEM parts on all emission control systems like the catalytic converter, smog pump, pcv valve, O2 sensors, etc. which the manufacturers then charge 2-3 times or more than the going rate because if you buy an identical aftermarket part you'll fail the visual inspection even if the function and tail pipe checks are perfect. It is a racket done more for political gains than for emissions controls but in our crooked system that is what we're left with.
A similar situation occured about 10 years ago with the Hybrid market. In CA the Toyota Prius was allowed to perform their "Highway" cycle at a greatly reduced speed to get the MPG figures that they claimed on the stickers. This was done with the full cooperation and knowledge of the EPA in the previous generation of the test cycles. Toyota was gaming the figures and the EPA not only didn't put a stop to it, they actually facilitated the scam to sell Hybrids to the public. The batteries can't even be manufactured in this hemisphere because the process is so polluting, that is why they are shipped off to China for the battery manufacturing, in stead of waiting for the battery manufacturing process to clean itself up before allowing the sale of Hybrid vehicles. Apparently China has their own atmosphere so it doesn't pollute the rest of the world, I just never got that memo.
As for the VW TDI's along with their technology shares with Audi, Porsche, etc. they are still much more efficient than the vast majority of the gasoline engines available on this side of the pond, unfortunately most of the US auto consumers are turned off by the thought of diesels and they still struggle to gain traction.
A couple of years ago the Department of Transportation was trying to add a tax to highly fuel efficient vehicles based upon their average miles driven so that they could reclaim the "Lost" fuel taxes that drivers of highly fuel efficient vehicles weren't paying them. That is the polar opposite of the supposed goal of the DOT and EPA in pushing for HEV's. But again it all came down to money and bribes, HEV's are great as long as they pay the same share of the road and fuel taxes as gross polluters, the atmosphere be damned.
posted by bates February 22 at 6:27 AM
>...as I cannot go below 65mph on our California freeways...
I always have trouble understanding statements like this. Presumably the road rules are different. On our motorways we have everything from HGVs limited to 50mph, and sports cars going illegally at 100mph+. They mix fine without issues (as long as people correctly obey lane discipline of course).
MMUK, the road rules here in Cali are probably not that different from yours, the big difference here is that the speed limits are seen as minimums by 97% of California drivers when there isn't heavy traffic. I personally believe that it is presumed to be a speed average for all hours spent on the freeway system by many drivers, for every hour that I spend it 5-25 mph rush hour traffic I "NEED" to go 80 for 3 hours to make up for it. Remember that the average Southern California Commute is roughly an hour each way so most drivers average 10 hours a week in stop and go traffic, many spend several times that many hours. When I work at LAX depending on my shift I have as many as 5 hours a day of average commute added to my regular work day. I personally don't subscribe to the above theory of average speeds but regularly observe other drivers who will blow you off the road with their air push if you're driving even in the far right lane, at less than 65 mph.
It was interesting back about 5 or 6 years ago when the fuel prices went through the roof, all of a sudden my preferred 55 mph freeway speed was not only accepted, but actually embraced by a large percentage of the commuters due to the pain at the pump phenomena, unfortunately, that only lasted a couple of months before the fuel prices fell again and it was back to the 80 mph flow of traffic.
posted by bates January 15 at 6:28 AM
This is interesting, I know that in boating the newer Ultra Low Sulfur Diesel fuel has created problems from lack of lubricisity (sp?)for the fuel system and related components. The older generation diesels didn't have this issue. Using some 2 stroke oil might mitigate those problems. I'd be careful though and check with the engine manufacturer to ensure that you're not creating more problems than you're solving by adding different oils to your fuel system. Also, as MMUK points out, if you choose to go forward with this ensure that you're not using synthetic 2 stroke oil. I used to ride 2 stroke motorcycles and scooters and used a synthetic 2 stoke oil for a while in one of my Vespa's only to discover that it weeped through the fuel lines and made a huge mess that was a major pain to clean up and cost me a set of fuel lines to stop the leaks. It was great lubricant, but made my fuel lines leak and dribbled out of the exhaust in an oily goo rather than combusting.
posted by bates December 14, 2012 at 6:38 AM
What about making a duplicate vehichle for your Durango, call it say Durango Tow, and add the towing fuel ups to that "vehicle" and your regular fuel ups to the original? That way you can track them seperately but still within the site's current parameters. As an added bonus someone searching for vehicle stats could easily discern between the towing fuel ups and the standard ones.
posted by bates December 14, 2012 at 6:22 AM
Stbal, you mentioned in your follow up post that the rental was driven out of state and again this could very possibly explain the increased mileage with a change in ethanol content for the Colorado, Wyoming, and South Dakota areas.
posted by bates November 20, 2012 at 7:15 AM
stbal, I have had similar experiences to BDC with slight improvement as the engine breaks in and the rings seat and loosen up but as he states gaining 5-7 mpg from a 32 mpg baseline isn't likely as that would be roughly a 20 % improvement and frankly from a mechanical standpoint your engine would be seized at this point if it was that much too tight.
One other thing to check is the gas and ethanol blend that you might be using. I'm guessing that the Greater Washington DC area has significant AQMD regulations and requirements. You might try a tank or two from an outlying area in the hopes that there is less or even no ethanol in that gasoline blend. I know that my car gets 15-20% loss in mileage now that Southern California has gone to a mandatory 10% ethanol blend year around. I used to just suffer that using the "Summer Blend" until about 6 years ago when the AQMD out here changed the rules and outlawed MTBE and forced the E10 gasohol on us. When I drive out of state to Arizona and Nevada several times a year I get significantly better mileage, often 20% or so better by shopping for gasoline with little or no ethanol in it, especially in Arizona where it is realitively easy to find. That is in the same car, with as you said, the same "nut behind the wheel" etc. It might be worth a try to see what happens.
posted by bates November 20, 2012 at 7:12 AM