Era of Supercharged medium sized motorcycles coming!

[jas67]

Unintended consequences of poor regulatory conditions.

Case in point, Ford's Powerstroke turbo diesel engines.

The 7.3L power stroke, circa 1997-2003 was capable of returning 18-19 MPG in a 7,500 lb F250.

Then along comes tougher EPA regulations on emissions of NOx (oxides of nitrogen, NO, NO2, etc).   The easy solution was EGR, which reduces these emissions by lowering combustion chamber temps.    Of course, lower combustion chamber temps also cuts efficiency.    The resulting 6.0L power stroke (2003-2007) made more power than the 7.3L (by using higher boost), but, returned about 15% lower fuel economy, and had additional complexity in the form of the EGR system, and its accompanying EGR cooler.

The lower combustion temps, in addition to lowering efficiency, also caused production of my particulate emissions (soot).   Well, gotta fix that now.     So, for the 2008 model year, the EPA required diesels to be fitted with a DPF (Diesel Particulate Filter), which requires a "regen" cycle to clean it, which essentially burns extra fuel to get the DPF real hot, thus burning the trapped particles to a (supposedly) less harmful gas.

The result is the 6.4L Powerstroke of 2008-2010 gets about 15% less fuel economy than the 6.0L of 2003-2007, bringing it down to the same as the V10 petrol powered engine, but, much more expensive and complicated.

For the 2011 model year, NOx emissions standards got tighter again.    So, now, most diesel vehicles (including large commercial trucks) are fitted with DEF injection (Diesel Emissions Fluid, urea).    This did allow the amount of EGR to be reduced, in turn reducing DPF regen cycles.     The results of those changes brought the fuel economy of the 2011 6.7L power stroke back to that of the 1998 7.3L.   How's that for progress.

Also, consider if you will the false savings in emissions of these various targeted  standards that, not only cause more fuel to be burned, but, also INCREASE emissions of green house gasses CO2 and CO ("carbon emissions").   The EPA measures these in "parts per million", which is a percentage of total exhaust gasses, so, in the EPA's eyes these numbers didn't get worse, but, any way you measure it, more fuel burned = more carbon emissions, and also more costs, not only in terms of fuel cost for the end user, but, the total environmental cost of extraction, refining, and distrobution of said fuel.

Another thing to consider is the considerable complexity these emissions systems have added to vehicles, which translates directly into higher costs, both at time of purchase, but, also maintenance and repair.    The same can be said of turbo petrol vehicles.   

Another example of this is the VW TDI.    The 2006 Golf TDI was good for 50 MPG highway.    It didn't have a DPF.   The 2009-2014 Golf TDI has a DPF, and is only rated for 42 MPG highway.

[Kev m]

For the most part, the only ones that "know" what their vehicles are getting for fuel economy are relying on what the on-board computer is telling them.    In my experience, those on-board computers typically lie by about 10% optimistic.      I've had 3 BMW's, a MINI, and two VW's with on-board computers.    All but one read about 10% high, and that one was one of the BMWs (2005 330ci).

Using actually tank-to-tank records for MPG, the only vehicles that I've been able to get EPA MPG numbers on a regular basis have been the two VW TDI's that we have now.     The 3 normally aspirated BMWs and supercharged MINI all had to be babied to get EPA numbers.

But, if I relied on the computer, then, I'd thinking I was meeting or exceeding EPA numbers.

I'm gonna throw a theory out that the computers are likely more accurate than your calculations.

Why?

1. Talk to someone from the bureau of weights and measures (we've had a member chime in before) has pumps may easily be slightly out of calibration.
2. What's the chance that the auto fill stops at the same point every time?

Vs

An ECM so precise in measuring fuel delivery that it holds the air/fuel ratio in a very narrow band.

I'm thinking YOU are more fallible.

My experience with personal owned 2 Jeeps, 2 Subarus, 1 VW, 1 Mini, 1 Nissan (not to mention years of press fleet vehicles) is the mileage read outs were always close, often < +/- 1 mpg.

I find it hard to believe there's a pattern of straight optimistic readings. That smells of personal tin foil beanie bias bra.

:-*

[Kev m]

Case in point, Ford's Powerstroke turbo diesel engines.

The 7.3L power stroke, circa 1997-2003 was capable of returning 18-19 MPG in a 7,500 lb F250.

Then along comes tougher EPA regulations on emissions of NOx (oxides of nitrogen, NO, NO2, etc).   The easy solution was EGR, which reduces these emissions by lowering combustion chamber temps.    Of course, lower combustion chamber temps also cuts efficiency.    The resulting 6.0L power stroke (2003-2007) made more power than the 7.3L (by using higher boost), but, returned about 15% lower fuel economy, and had additional complexity in the form of the EGR system, and its accompanying EGR cooler.

The lower combustion temps, in addition to lowering efficiency, also caused production of my particulate emissions (soot).   Well, gotta fix that now.     So, for the 2008 model year, the EPA required diesels to be fitted with a DPF (Diesel Particulate Filter), which requires a "regen" cycle to clean it, which essentially burns extra fuel to get the DPF real hot, thus burning the trapped particles to a (supposedly) less harmful gas.

The result is the 6.4L Powerstroke of 2008-2010 gets about 15% less fuel economy than the 6.0L of 2003-2007, bringing it down to the same as the V10 petrol powered engine, but, much more expensive and complicated.

For the 2011 model year, NOx emissions standards got tighter again.    So, now, most diesel vehicles (including large commercial trucks) are fitted with DEF injection (Diesel Emissions Fluid, urea).    This did allow the amount of EGR to be reduced, in turn reducing DPF regen cycles.     The results of those changes brought the fuel economy of the 2011 6.7L power stroke back to that of the 1998 7.3L.   How's that for progress.

Also, consider if you will the false savings in emissions of these various targeted  standards that, not only cause more fuel to be burned, but, also INCREASE emissions of green house gasses CO2 and CO ("carbon emissions").   The EPA measures these in "parts per million", which is a percentage of total exhaust gasses, so, in the EPA's eyes these numbers didn't get worse, but, any way you measure it, more fuel burned = more carbon emissions, and also more costs, not only in terms of fuel cost for the end user, but, the total environmental cost of extraction, refining, and distrobution of said fuel.

Another thing to consider is the considerable complexity these emissions systems have added to vehicles, which translates directly into higher costs, both at time of purchase, but, also maintenance and repair.    The same can be said of turbo petrol vehicles.   

Another example of this is the VW TDI.    The 2006 Golf TDI was good for 50 MPG highway.    It didn't have a DPF.   The 2009-2014 Golf TDI has a DPF, and is only rated for 42 MPG highway.

Preach it brudda!!! 8)

[Aaron D.]

Careful what you wish for in VW diesels, the '06 indeed had better fuel economy, due to better injection pressure, but it will eat its camshaft and lifters. They didn't change the design for emissions, not completely.

[bad Chad]

The Breva I ride always shows my milage about 2-3 mpg lower than what I get when I do it the old fashion way.   My Mazda 3 which has no trip com, gets 25-27 around town constantly.  Just slightly better than EPA numbers.

[jas67]

I'm gonna throw a theory out that the computers are likely more accurate than your calculations.

Why?

1. Talk to someone from the bureau of weights and measures (we've had a member chime in before) has pumps may easily be slightly out of calibration.
2. What's the chance that the auto fill stops at the same point every time?

Vs

An ECM so precise in measuring fuel delivery that it holds the air/fuel ratio in a very narrow band.

I'm thinking YOU are more fallible.

My experience with personal owned 2 Jeeps, 2 Subarus, 1 VW, 1 Mini, 1 Nissan (not to mention years of press fleet vehicles) is the mileage read outs were always close, often < +/- 1 mpg.

I find it hard to believe there's a pattern of straight optimistic readings. That smells of personal tin foil beanie bias bra.

:-*

I'm using longer-term calculations over several tank fulls to help eliminate the errors of getting the same top off every time.
Any error in attaining a precise top-off would cancel out over many tankfuls.

Yes, the ECM *can* calculate fuel used exactly, the same as speedometers *can* calculate exact speed, but, are often 3-5% optimistic.
Add to that countless forum posts to the same (Ford Powerstroke forum being one of them).

[jas67]

The Breva I ride always shows my milage about 2-3 mpg lower than what I get when I do it the old fashion way.

Funny, the MPG readout on my Breva 1100 is usually about 2-3 MPG HIGHER than wha tI get calculating it the old fashion way (again, like with my cars, tracking and averaging many tankfuls).

[oldbike54]

Serious question . Is EPA mileage testing done with straight gasoline as opposed to ethanol blends ?

  Dusty

[Triple Jim]

I'm gonna throw a theory out that the computers are likely more accurate than your calculations.

Maybe in some or many cases, but not in my own experience.  We keep log books of all the gasoline that goes in each car and the miles they go.  Our 2004 Taurus' average MPG readout consistently shows 20% lower than my log book calculations, which when averaged over the same tankfuls, pretty well removes the problem of exactly where the pump shuts off.

In case anyone wonders why we bother keeping logs, I find it helps me know if a car needs attention, particularly if it's one that I don't drive very often.

[charlie b]

I want one of these :)

[Kev m]

I'm using longer-term calculations over several tank fulls to help eliminate the errors of getting the same top off every time.
Any error in attaining a precise top-off would cancel out over many tankfuls.

Yes, the ECM *can* calculate fuel used exactly, the same as speedometers *can* calculate exact speed, but, are often 3-5% optimistic.
Add to that countless forum posts to the same (Ford Powerstroke forum being one of them).

Nah, several tankfulls just allows you to potentially increase the inaccuracy no? Especially if you're a creature of habit and use the same station/pump multiple times.

And forums are probably filled with tons of guys making bad calculations or with agendas or...


PS, I equally doubt all assumption that speedos are optimistic. Many late-model vehicles have GPS tied in and you can tell right away. Plus optimistic speedos would normally be coupled with optimistic Odo's which would open the manufacturer to warranty law suits.

[Kev m]

Funny, the MPG readout on my Breva 1100 is usually about 2-3 MPG HIGHER than wha tI get calculating it the old fashion way (again, like with my cars, tracking and averaging many tankfuls).

And I often got closer numbers with that and bike, but I was way snap anal-retentive about fueling to the lower lip of the filler neck, on the center stand, on level ground or I threw the calculation away.

[Kev m]

Serious question . Is EPA mileage testing done with straight gasoline as opposed to ethanol blends ?

  Dusty

I BELIEVE it is...

[Kev m]

Maybe in some or many cases, but not in my own experience.  We keep log books of all the gasoline that goes in each car and the miles they go.  Our 2004 Taurus' average MPG readout consistently shows 20% lower than my log book calculations, which when averaged over the same tankfuls, pretty well removes the problem of exactly where the pump shuts off.

In case anyone wonders why we bother keeping logs, I find it helps me know if a car needs attention, particularly if it's one that I don't drive very often.

Well, I'd still want to eliminate the variables of the pump, level-ness of the station, accuracy of the odo (throw tire sizes in that), but I'm not going to doubt that some manufacturers, models, or particular examples might be more or less accurate.

Still 20% seems high...

[oldbike54]

I BELIEVE it is...

Well, that could account for some of the variation in EPA and real world mileage figures .

  Dusty

[Kev m]

Well, that could account for some of the variation in EPA and real world mileage figures .

  Dusty

True, though it wouldn't account for CR's comparative variances, nor our own NA model that has been beating epa ratings on E10 for about 3 years/36k miles.

[oldbike54]

True, though it wouldn't account for CR's comparative variances, nor our own NA model that has been beating epa ratings o n E10 for about 3 years/36k miles.

Probably not . I am curious about the effect of blended fuels on pressurized engines .

  Dusty

[jas67]

Nah, several tankfulls just allows you to potentially increase the inaccuracy no? Especially if you're a creature of habit and use the same station/pump multiple times.

WRONG.   You're forgetting which one of us is an engineer.    I log, track, and analyze data as part of my JOB.

By doing this on EVERY tankful, I get total gallons over total miles.
For example, if top off, then drive 10,000 miles on, and top off again, and I put 250 gallons in over those 10,000 miles, my average MPG for the 10,000 miles is 10,000 / 250 = 40 MPG.    It does matter if I topped off every tank during that time at all, so long as I kept track of EVERY fill during that time.

And forums are probably filled with tons of guys making bad calculations or with agendas or...


PS, I equally doubt all assumption that speedos are optimistic. Many late-model vehicles have GPS tied in and you can tell right away. Plus optimistic speedos would normally be coupled with optimistic Odo's which would open the manufacturer to warranty law suits.

Actually, in many cases the speedo is optimistic, but the odo accurate.   This is, supposedly be design, so that if there is a real speedo error, someone doesn't end up getting a ticket and suing.   If the odo is accurate and the speedo optimistic, it HAS to be designed that way, at least with electronic speedos.  In the days of mechanical speedos, the discrepancy could've been do to wear.   

[Kev m]

WRONG.   You're forgetting which one of us is an engineer.    I log, track, and analyze data as part of my JOB.

By doing this on EVERY tankful, I get total gallons over total miles.
For example, if top off, then drive 10,000 miles on, and top off again, and I put 250 gallons in over those 10,000 miles, my average MPG for the 10,000 miles is 10,000 / 250 = 40 MPG.    It does matter if I topped off every tank during that time at all, so long as I kept track of EVERY fill during that time.

Actually, in many cases the speedo is optimistic, but the odo accurate.   This is, supposedly be design, so that if there is a real speedo error, someone doesn't end up getting a ticket and suing.   If the odo is accurate and the speedo optimistic, it HAS to be designed that way, at least with electronic speedos.  In the days of mechanical speedos, the discrepancy could've been do to wear.   

Well, it seems that YOU as an engineer seem to doubt the work of OTHER engineers who came up with the mpg monitoring programs so I'm in good company. :-*

The problem with your objection is your calculations ASSUME the accuracy of inputs not proven to be so.

For instance you're ASSUMING the number on the pump is never wrong.

Why is it that only the speedo and mpg calculators are suspect but not the pump and odo?

[oldbike54]

Kev , I'm guessing that if Jay has logged and averaged mileage for 10,000 miles the figure he is coming up with is damned accurate . Unless he only buys fuel at the very same pump every time , the other variations will average out over that data period . Of course , I enjoy a good squabble twixt brothers , so carry on  ;D

  Dusty

[Kev m]

Kev , I'm guessing that if Jay has logged and averaged mileage for 10,000 miles the figure he is coming up with is damned accurate . Unless he only buys fuel at the very same pump every time , the other variations will average out over that data period . Of course , I enjoy a good squabble twixt brothers , so carry on  ;D

  Dusty

Perhaps, but it makes a lot of assumptions, odo accuracy alone can swing it one way or the other no?

Why is my theory the least plausible when all it really is boils down to the thought that WE as humans are the least accurate. That it's just as likely the factors we are using to log and calculate mpg are at least as flawed as the ECM based calculations from which we are seeing deviations!

For example, he runs winter tires on most (all) of his cars. Are they the exact diameter of the OEM tires? How about the summer tires?

Until his last two vehicles he tended to buy used with at least 50k on the odo, while I tend to sell by that point. How does that effect the fuel system or drive line with regards to accuracy of not only fuel metered, but miles traveled?

[oldbike54]

Perhaps, but it makes a lot of assumptions, odo accuracy alone can swing it one way or the other no?

Why is my theory the least plausible when all it really is boils down to the thought that WE as humans are the least accurate. That it's just as likely the factors we are using to log and calculate mpg are at least as flawed as the ECM based calculations from which we are seeing deviations!

So... if Jay starts charting all of his trips , and measures his odometer readings against GPS mileage figures , and only makes right turns on the second Tuesday of each month while driving with his windows half way up , then will you believe his numbers ? Huh , huh  ;D

  Dusty

[Kev m]

So... if Jay starts charting all of his trips , and measures his odometer readings against GPS mileage figures , and only makes right turns on the second Tuesday of each month while driving with his windows half way up , then will you believe his numbers ? Huh , huh  ;D

  Dusty

I might believe YOU then... ::)

[jas67]

Well, it seems that YOU as an engineer seem to doubt the work of OTHER engineers who came up with the mpg monitoring programs so I'm in good company. :-*

The problem with your objection is your calculations ASSUME the accuracy of inputs not proven to be so.

For instance you're ASSUMING the number on the pump is never wrong.

Why is it that only the speedo and mpg calculators are suspect but not the pump and odo?

I don't so much doubt the work of OTHER engineers, but, suspect the motives of the corporations themselves ($$$).

[Rough Edge racing]

Serious question . Is EPA mileage testing done with straight gasoline as opposed to ethanol blends ?

  Dusty

 From the EPA website...maybe we can argue if the EPA is lying.. ;D

   

EPA's test fuel for light-duty gasoline-fueled vehicles does not currently contain ethanol or other oxygenates. However, EPA does account for the impact of low-level ethanol blends in our fuel economy estimates. Ethanol has a lower energy density than gasoline—about 1/3 less energy per gallon. That means a car operating on E10 (10 percent ethanol and 90 percent gasoline) would require about 3 percent more fuel to travel one mile than a car operating on gasoline and thus have about 3 percent lower fuel economy. EPA adjusts the fuel economy label estimates downward by about 10 percent to account for a variety of factors that are not currently accounted for during laboratory fuel economy testing, such as tire under-inflation, wind, hills, and road conditions. It also includes a 1.5 percent downward adjustment to account for the average national ethanol content.

[Kev m]

I don't so much doubt the work of OTHER engineers, but, suspect the motives of the corporations themselves ($$$).

Which brings us back to my tin foil beanie comment.... ;)


In related news I finally checked on the new Eco Boost Ford motors and it does look like they can at least run on regular and not premium. That's a plus.

[jas67]

.... Until his last two vehicles he tended to buy used with at least 50k on the odo, while I tend to sell by that point. How does that effect the fuel system or drive line with regards to accuracy of not only fuel metered, but miles traveled?

I would guess that the onboard computer uses injector "on" duration to calculate how much fuel is used.   I would think that as the injectors age, that the orifice could wear and become larger, thus letting through more fuel than the computer thinks is getting let through.

Since all EFI (4+ wheeled) vehicles have an O2 sensor for closed loop control, this is OK from a mixture standpoint, as the ECU will compensate.    BUT, it's fuel usage calculation would then be low.

I'd be willing to bet that small variation (tolerance) in actual orifice sizes, as well as open and close times are at least as big, if not bigger than errors in fuel metering at fuel dispensing pumps.

Which brings us back to my tin foil beanie comment.... ;)

Do YOU trust greedy corporations and/or the gov't?

[Kev m]

I do think that could be a factor.

And it's not about trusting corporations so much as trusting the market place would figure it out.

[Rough Edge racing]

Which brings us back to my tin foil beanie comment.... ;)


In related news I finally checked on the new Eco Boost Ford motors and it does look like they can at least run on regular and not premium. That's a plus.

 The question of F150 Eco boost engine real live fuel mileage got me interested so I looked on several forums dedicated to these trucks....Form what I saw the average fuel mileage most reported by owners was 14-20 MPG. About the same as  larger N/A engines with similar performance.
 No matter what,it takes a certain amount of fuel for a given power rating.

[charlie b]

First off, measuring exact mileage cannot be done on the open road in a manner that allows comparison between vehicles.  Too many other variables that cannot be repeated.  Even driving them on the same road at the same time doesn't work due to other cars on the road disrupting air flow differently.  So, one person, measuring mpg in an accurate manner is not comparable to what I would get in the same car.  If you want to discuss in pure engineering terms I can, but, I guarantee that none of you have measured enough of the variables to make a meaningful comparison.

What you have done, in some cases, is measured how much you have paid for fuel, a close number for how much fuel you have pumped into your tank, and a close (some of the time) measure of mileage driven.  So, FOR THE CONDITIONS UNDER WHICH YOU DROVE, you have a close approximation of the mileage you got in that vehicle.  It does not mean that anyone else will match those numbers, and , they might not even be within 20% of your numbers.

As to turbo effects on gas mileage it is an arguement against driving styles.  If you take two cars, in identical conditions and drving speeds, the turbo should get better mileage.  BUT, people who own turbos don't drive them at the same speeds as their NA counterparts.  So, they will typically get less mileage.

Superchargers, unless some 'tricks' are employed, like disengaging the supercharger at less than full throttle, will typically not see a much increase.  Yes there will be a little, since combustion efficiency will be a little bit better, but, since the engine is still directly compressing the air charge, then there is not a savings on work thatyou get with a turbo.