bates's Forum Comments
Showing comments 1-30 of 101 by bates.
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
In the old days the speedo and odo were driven off of a gear on the drive line that spun a cable which read on the dashboard display. Is this no longer the case? I imagine now that with the amount of computer equipment onboard that it could be done electronically.
Again in the 1980's switching my speedo was simply a matter of putting the car on a dyno type machine which was calibrated and removing and replacing the gears until the speedo read the same as the dyno. I wasn't aware of any difference in the odometer, but that may have just been ignorance on my part if it was designed to be spot on while the speedo was reading high.
posted by bates November 1, 2012 at 8:41 AM
Brown12, I'm not sure what the current policy is but as recently as 10 years ago speedometers in the US were intentionally calibrated at the factory to read low. The theory is (was?) that when you're driving down the highway at a posted speed limit most drivers will add 5-10 mph and feel safe from a speeding ticket so by making the speedometer read high by 3-5 mph at highway speeds the drivers are actually driving at the speed limit or just a couple of mph over but think they're speeding. It was intended to make our highways safer. More recently with the mass usage of GPS and now GPS enabled smart phones this may no longer be the case, but I can tell you that my 2000 Acura and my wife's 2005 Mazda both have speedo errors that show on the high side compared to the GPS.
Back in the 80's I used to as a matter of course get my speedo's calibrated for all my cars and street motorcycles. It cost about $20 and took about 15 minutes at the local shop. In my experience, my domestic vehicles had the greatest error stock, then European cars and the Japanese were the closest.
So that we're clear here, most odometers are driven off the speedometers so speedo error translates directly into odometer error.
That being said, changing tire and wheel size and even tread wear differences in stock tires and wheels can also have an effect as well as slight side to side movements.
posted by bates October 29, 2012 at 6:54 AM
That's interesting, in Southern California I get less mileage from the summer blend than the winter blend, but I think that has to do with the increased oxygenator content for smog rules here. Back east you probably have fuel gelling issues due to the colder tempertures so there may be antifreeze type additives in the winter to prevent fuel ice and other issues that we don't have in less severe winters.
Before the switch to 10% mandatory ethanol in Southern California Gasoline, I could tell to the fill up when we switched from winter blend to summer blend by the drop in mileage that was around 10-20% on the same commute, same conditions, etc. No one has ever been able to explain to me how we get better air quality from burning significantly more fuel for the same miles traveled, but then again, I'm not an ethanol producer whose bought off our crooked politiicans and AQMD folks, so maybe that's what I'm missing.
posted by bates October 29, 2012 at 6:44 AM
The mileage difference between a V-6 and a V-8 for the same chassis, drag, weight, etc. should be almost the same. The difference you'll run into is that the V-8 will require slightly more maintenance costs but will likely have a greater life expectancy due to the engine being run at highway speeds using a lower percentage of the engines available horsepower which effectively means that the engine doesn't have to work as hard and therefore has a longer life expectancy.
All bets are off if you're considering the EcoBoost engine, from what I've seen that engine is significantly more fuel efficient than other powerplant options.
posted by bates August 15, 2012 at 12:46 PM
Monkeyrench, thank you for that, exactly the type of information I'm looking for, especially the real world mileage numbers for a non-Eco Cruze.
BDC, I'm not a fan of hybrid technology for a number of reasons, but let's just say that the production of the hybrid components off sets the environmental advantages of the reduced fuel economy, they are expensive to work on, and the initial capital cost is high enough that it is almost impossible to recoupe it in mileage benefits in my case and use cycle.
DieselDub, if it wasn't for my 3 kids I'd definately go with the Sportwagen, it is a better fit for my lifestyle and activites, but it is significantly more narrow than the Passat for the rear seat and my kids won't fit.
Draigflag, the US EPA and particularly the California AQMD are far from interested in reducing emmissions, they are more concerned with Political Correctness and benefit for certain manufacturers. Why did the first generation Prius's get the HOV lane stickers when the VW diesels, Minicooper, and several other vehicles with better real world mileage numbers not? Plain and simple, there were bribes involved, the CAFE standards were manipulated to give advantage to some while punishing others. Why isn't the Chevy Volt now eligible for the HOV Sticker without the "Fuel Efficiency" option in spite of being an electric vehicle with an onboard gasoline generator? The same reasons. Don't try to inject logic or reason into US Governmental regulations, never the two shall meet. Yes, you're absolutely correct, that commercial vehicles have yet another standard. They've outlawed 2 stroke motorcycles with 100 plus mpg ratings but allow exotics from Europe that can't get 8 mpg for the same reasons. Apparently the motorcycle lobby isn't as strong as that of the rich and powerful who want to drive around in Phalyic Symbols to make up for their own inadequcies.
Cinderbarrel, agreed but remember that the Audi and some of the BMW's are using the VW TDI for regulation compliance reasons. Mercedes Benz has been in the Diesel market for decades, but they've greatly scaled back their diesel offerings due to increasingly more complex emmissions standards. The only market that seems to continue is the heavy duty trucks, and even there the big 3 seem to only offer a diesel option on the 1 ton and heavier trucks in their model lines. I've been looking for a tow vehicle for a boat and need a heavy duty truck to tow it with but can't come anywhere near affording an F-450 or 550, not to mention that I can't use it for much of anything else other than towing which makes them very unappealing.
posted by bates July 17, 2012 at 7:55 AM
Also, as a previous poster noted, ethanol has a high octane rating, making it appealing to manufacturers and retailers for use in Premium grade gasoline since it is a cheap octane booster in the sense that it is already used as an oxygenator and approved as an additive by the AQMD, after the outlawing of MTBE this is an important factor, so it is a no brainer octane rating booster. The downside to this is that ethanol lacks the BTU or energy content of gasoline so drivers suffer a mileage loss by using gasohol, regardless of octane rating, and the alcohol is a great attractant for water and therefore increases the rate of corrosion in fuel system components as well as the degradation of many different fuel lines as the rubber in non ethanol compliant lines is disolved by the polar solvent qualities of the alcohol.
posted by bates July 17, 2012 at 7:22 AM
I don't know about Ohio but you should be able to go to Ohio's AQMD, Energy Department, or EPA site and figure out what your state's requirements are. In most if not all states the ethanol content is supposed to be clearly posted on the pump. CA isn't totally compliant with this since the state's requirement is for all pumps to be dispensing E10 gasohol and sometimes the only mention is that the gas is blended with ethanol or when it is approved to be higher than 10% ethanol ie E15, E85, etc. due to those contents violating some manufacturer's warranties, especially those of motorcycles and boat engines.
posted by bates July 17, 2012 at 6:59 AM
This probably depends on what state and even Air Quality Management District you're in. In California all gas has ethanol in it, but a friend of mine lives in Montana and there isn't any ethanol gas in the whole state because of some transportation and tank issues experienced there. When I travel to other states I actively seek out filling stations that sell pure gasoline as I get significantly better mileage on pure gasoline than I do on the ethanol blended fuels.
laplantebd, if there is a 10% mandate for regular and mid grade then your Premium is going to have ethanol as well since your mid grade is a blend of Premium and regular, mixed in the pump. If the regular is 10% and the Premium was 100% gasoline then the blend would be around 5% ethanol depending on the Octane Rating of the Premium, mid grade, and low test.
posted by bates July 13, 2012 at 8:13 AM
Thank you all for your input, I appreciate your time and consideration.
MMUK, I do need the extra sheet metal, I have 3 kids and they are all big and getting bigger. Truth be told, the Jetti SportWagon would probably be the best fit for my personal lifestyle, surfing, biking, etc. that all need the greater interior space of a wagon but the rear seat just isn't wide enough to get the family into.
Draigflag, unfortunately, our EPA on this side of the pond and Air Quality Management Districts aren't interested in true fuel economy, only in their bribes, err, I mean political contribution funds, and favors to corporate supporters. If they were honest and fair, the TDI's, Chevy Volt (with or without the low emmissions package), Chevy Cruze ECO, MiniCooper, and many others would be eligible for the High Occupancy Vehicle Lane Stickers, but alas, those eligibility figures are based more upon bribes and favors than fuel economy. So I'm limited to what is available on my side of the pond, also again I need more space than the tiny microcars afford.
BDC, thanks for the link, I'll check it out.
Toycop, I currently get my tranny flushed and refilled every 15K miles at about $150 a pop so that doesn't seem unreasonable to me, thanks for the real world figures on the TDI dsg, that is all that I've been able to find so far.
HolySdrJR, is your Cruze Eco an automatic or stick shift? I'm guessing from the hard shifts that it is an auto since you could feather the clutch on a stick to soften the jolts. I do like the fit and finish of the VW, but like you the price point and mileage of the Cruze appeals to me. How many miles do you have on your Cruze? Was there a break in before your mileage numbers came up to the 50+ MPG range? My current commute is about 35/65 highway to city driving so I don't expect to be able to do much better than 40 mpg but that would be a great improvement over my current 27ish in my Acura Integra.
posted by bates July 9, 2012 at 7:17 AM
The biggest advantage to drafting is seen by being very close to the rear bumper of the vehicle that you're following. As most posters above have already shown, this is incredibly dangerous. If you are within about 4 vehicle lengths you will achieve some fairly significant advantage so staying 3 of your car lengths back will benefit you, but if the truck brakes suddenly you'll be lucky to have enough time to duck in order to avoid the rear bumper as it comes through your windshield.
Another danger to following big rigs closely is your inability to see the road ahead of you, for sighting off ramps, traffic issues, road construction, etc. The danger versus return on this just isn't worth it IMHO.
posted by bates July 9, 2012 at 7:01 AM
If you're experiencing spongy brakes on a traditional hydraulic braking system (not one that has electronic controls actuating hydraulic pistons)there is almost certainly air in the system. A power brake bleed should cure your problem at a relatively low price point. This is especially true if as I understand your post you're experiencing "unpredictable" response from the brakes, when an air bubble in the system settles in the caliper or piston it will react differently than it will when it is in the wheel line or master cylinder. BTW a brake bleed from a reputable brake shop shouldn't set you back too much money and has the added benefit of completely flushing your brake fluid for just a few buck more, IMHO well worth the money before you start swapping out expensive rotors, pads, and lines. That being said, braided brake lines are a nice upgrade and you've already ponied up for the rotors and pads and slapping them on will require a brake bleed anyhow so it might not be a significant cost for your case at this point.
posted by bates June 29, 2012 at 6:53 AM
I bought and had installed on my wife's Mazda MPV Minivan a set of LRR Goodyear Tires about 6 months ago. Truth be known, I haven't seen any difference in mileage or fuel economy over the previous set of tires. My thought on replacing them the next time they're worn out is that while it probably can't hurt to use LRR tires, if they're the same or close on price I'll get them again, if they're much more, I'll go with the traditional rolling resistance tires and take my chances.
posted by bates May 29, 2012 at 7:03 AM
I did this for a while by using a simple stop watch that I paid $5 for at a local sporting goods store. Basically, when I started the car I also started the stop watch, when I turned off the car I stopped the watch. I was using it to track engine hours for maintenance and to validate my current presumption that my driving style works out to about 4,000 miles per 100 engine hours. I use 100 engine hours as my basic oil change interval since it is much more indicitave than mileage on your odometer to the life of the oil. If you're looking for long term data that isn't a very good option, for me I just used it about5 tanks to validate my theory of average mph per engine hour. It is a simple, low cost, low technology way to give you a pretty close idea on your driving habits assuming your commute or driving style doesn't change significantly from week to week.
posted by bates April 30, 2012 at 7:33 AM
The theory of break in mileage versus regular mileage comes from high performance engines with high compression ratios and exceedingly tight ring tolerances that come from the factory. I've noticed it in turbocharged diesel engines on boats, it takes most engines with tight compression rings at least 25-100 hours to seat the rings into the cylinders. During that break in period there is an elevated friction loss due to the rings grinding (seating) against the cylinder walls as they wear into each other.
I would guess that this phenomena is able to be documented in engines like a TDI and probably the Chevy Cruze Eco turbo but harder to see in engines built with looser tolerances like a Kia Soul, Honda Civic, etc.
That being said, it is usually on the order of less than 10% mileage change from break in to long term operations consumption under similar conditions. On a yacht for example where the new engines consumed 15 gallons per hour per side at a given cruise rpm (speed varies on a boat due to currents, winds, and other conditions that vary from one day to the next so we use gph not mpg)may decrease to something on the order of 13.5-14 gph. It isn't like your new TDI is going to jump from 30 mpg to 50, but if you're banging around 36 an increase to 40 is probably reasonable everything else being equal.
Just my $0.02 from years of driving boats and building engines for cars, boats, airplanes, and motorcycles.
posted by bates April 11, 2012 at 6:27 AM
For my values I blend the time and distance that I drive in town versus on the highway. Basically I use a weighted average for the time/mileage value between fill ups. Basically if I'm on a road trip where all my miles are freeway I use 100% highway, if I only drive around town I use 100% city. My commute is about 15 miles on city streets and 9 miles on freeways but the time breakdown is more than 70/30 because of the higher freeway speeds.
posted by bates March 20, 2012 at 7:03 AM