Fuel economy

[Petervs]

While driving along on my way to POG2, I started thinking about a way to impress my good friend Brian ( owner of an 8V92) with the fuel economy of my Series 60. We both have a ProDriver installed, and it shows the average fuel economy obtained since the last reset.

My curiosity was really, how high could the fuel economy go in a completely best case situation? It seems to me that this would be just driving along at a steady speed, no wind, no hills, always in the highest gear of the transmission. Well, of course a higher number would be obtained if going down hill with a tailwind, but that would not be realistic.

I live in Washington State, and it seems that no matter where we go, the road has hills. In regular driving, with traffic, various accelerations and decellerations, over the course of a tank of diesel, I usually average right around 7.5 MPG. That is my 45 foot Marathon, loaded with everything we use, and towing a VW Golf at 2500 pounds.

So, I filled up the tank in Winnemucca, NV, reset the Pro Driver, hopped on I-80 and set the cruise control on 55 mph, and let the traffic roll past ( the speed limit was 75!). I did this for 80 miles and watched the fuel economy average creep up until it got to 9.32 mph! There were a few hills, but not much wind. It was a real world situation. I am amazed that the economy is this high considering we have a house going over the road.

I took a picture of the display at 9.25 mph and emailed it to Brian with a link to one of those magnetic fuel conditioner websites, and told him how good it was working.....he did not bite.

Anyway, I think that gives a kind of upper limit on the efficiency of operating the coach. On the way home, I did it some more at different speeds to see how the faster you go burns more diesel.

95 miles at 62 mph in Oregon yielded 8.71 mpg, no headwind.

65 miles on I-84 with a 7 mph headwind in Northern Utah at 65 ,mph yielded 7.45 mpg. There was one big pass.

92 miles at 66 mph near Boise yielded 7.6 mpg, 5 mph headwind


136 miles at 71 mph on I-85 in southern Idaho yielded 7.13 mpg. 8 mph headwind.


Conclusion:

At $3.00 a gallon, you can minimize operating cost by driving 55 mph, and you will pay 33 cents a mile, or if you hustle at 71 mph, you will pay 42 cents a mile. A 1000 mile trip would cost $90 more at the higher speed.

My idea was just to put this all in perspective. Your thoughts and comments are always welcome.

[Jon Wehrenberg]

At the risk of waking up JDUB, Peter has spoken volumes.

As an owner you can choose to save time or money, but not both. Fast is clearly going to allow you to save valuable time, while going a little slower saves not only fuel, but is safer.

When Fast Roger and I headed west for the rally we cruised at about 70. I lost mileage because we were heading into the prevailing winds, I was towing the equivalent of a tank in the form of a Hummer, and we were going from a few feet above seal level to the higher western elevations.

Going home we set our cruise control on 62 and as Peter pointed out our mileage climbed. What hurt us on the return was we encountered severe winds, mostly on the nose that made the coach shudder, and were strong enough to flex the top of the entry door outward enough so Di could see it flex.

I will not try to preach or advocate anybody drive slow. That is a personal choice, but I am certain we would have hit two cars in the rear on the return if we were driving at 70. Both put us in conditions beyond our control. The first was a lady in a Focus that suddenly and without warning spiked her brakes when we were hit suddenly with gusty winds and a torrential downpour. I was lucky the adjacent lane opened up so I could avoid her. The second was a small pickup merging that failed to notice the end of the merge lane was occupied with a stalled truck, and he opted to jump immediately in front of us, instead of slowing until we passed. He was all of a sudden in front of us going very slow and we used heavy braking. At 70 I would have run over him.

[Jerry Winchester]

Nice analysis and perspective. Jon will take exception to my comments, but Roger won't :D And I had already typed this response before Jon posted his, so I didn't change it or wake up ;)

So then the 1000 mile trip at 55 would be +/- 4 hours longer, which depending on what you have going on isn't much especially if you are driving in an area devoid of traffic.

Since Roger belongs to the "I don't know where I'm going, but I hate to be late" crowd, I have also reconciled myself to the "drive the speed limit" view and pay the extra bucks. I kinda view the bus like I do the airplane; I didn't buy it to save money on fuel, I bought it to go fast. Or in the case of the bus, as fast as the appropriate limits allow.

Lastly, there was a large debate in Texas over the raising of the speed limit in West Texas to 80 mph. In the end, the safety issue wasn’t the speed, it was the differential in speed meaning if everyone was driving along about the same speed, there were less issues (insert accident here) than when someone was driving 70 and someone driving 55. Now I know this was not the point of your post, but it was going to get around to this eventually, so I just added it for the sake of bothering the Luby's crowd.

Blast away.

And welcome Pete. I enjoyed meeting you at POG II and look forward to your posts. I think this is a good forum for your technical skills.

[Jon Wehrenberg]

Jerry, Despite the Geritol bottle dents in Fast Roger's coach front end I have to make a few points.

I was in the lead. I often had to slow down so Roger could catch up. He couldn't have gotting the prune pit and Geritol bottle dents if I was following.

I agree with the speed differential issue, and anyone who drives through Ohio knows exactly how scary it is. Our two near misses on the return were not related to a posted differential or related to our choice to drive home slower. Both instances were small vehicle drivers who were completely unaware of the fact that the speed differential they created put us in a very difficult situation, and had our speed been greater the outcome may not have been as it was.

We have driven hard and fast, but now at this point being gainfully unemployed we adopt the attitude that we are already "on vacation" when we get in the bus, and the destination is just a point along the way. Hurrying down the road just robs us of time in the coach.

[Chris and Debbie Yates]

Here is a comparison of fuel consumption with and without a trailer.
JW and I have similar coaches, both 40' with 8v92s.
We both fueled up in OKC on the way to POG11, after 543 miles we fueled again in ALB. Jerry needed 91 gallons, mine took 115. I was drafting Mango Andretti all the way so I guess it could have been worse. This got me to thinking - if running in a convoy, if you are not leading causes you to use more fuel because you are constantly modulating the throttle:confused: How did you California boys do in your six coach train?

AP

[Jerry Winchester]

I also ran my generator from about 11:30pm to 8am. When I downloaded my DDEC info, it says my coach gets 6.5 mpg but driving with AP and MM, it got 6, so that must be the difference.

We were also running 71 mph more or less.

[Petervs]

There is a place in the Pro Driver Set up where you can enter a correction factor to get the fuel economy to come out right. The DDEC brain has lots of sensors, like engine rpm, road speed, fuel flow from tank to engine and from engine back to tank. The computer has to be told things like the axle ratio and the tire diameter, and if everything is exactly right, then you get the correct read out on the Pro Driver.

You have to have the Pro-Link or Nexiq Download reader Jerry showed us in order to reprogram all the variables, but the Pro Driver has one place where you can enter a correction factor to force the result to come out right.

Remember, the Pro Driver was designed for truck drivers working for a large fleet, and they did not want to give the driver much control, only the fleet manager is supposed to have access to some factors. But they figured the Pro Driver would not be accepted by drivers at all if they could not make it read right. Hence, the correction factor in the Setup page.

If you compare your reading to the actual mileage on several fillups, then you can enter a correction factor, and after 1-3 tries you will have an accurate number. No reason to have incorrect data displayed all the time.

In my case, my correction factor is 1.00, and the result happens to correllate within 0.1 mpg or so every time, unless I use the generator a huge amount which rarely happens.

Detroit Diesel has a web page for the Pro Driver, also people on the phone who are very helpful. If you don't have a user manual for it you can get one from the website.

http://www.detroitdiesel.com/products/Electronics/index.asp

[merle&louise]

Peter:

Thanks for the information from your experiment. I have always wanted to do a test like that, but never took the time. The results are about what I thought they would be.

I used to drive 70 - 75 most of the time if the roads were good (in Louisiana we have to drive 20 - 25 mph). A few years ago, I had a blowout on the driver's side front tire at 65 mph on I-25. Luckily, no damage occured; I was able to pull over and stop. 5 or 10 mph can make a big difference in reaction time. Now I drive 65 mph and I feel much safer.

On the way home, we passed thru El Paso to visit a friend. On I-10 (6 lanes) a woman passed me doing about 70. I was driving about 55 because we had just pulled onto the interstate. When she was about 500 yards in front of me her driver's side rear tire blew out! I hit my brakes, she fish taled right, then left, then spun around and did a 360! She managed to stay in the left lane and not hit the concrete barrier. When she stopped and got out of the car she was visiably shaken up. If I had been driving 70 we would have both sustained some damage.

Jon is right; slow down, be safe, and enjoy these beautiful machines that we are fortunate enough to own.

[Jon Wehrenberg]

I nominate Peter for the Pro Driver seminar in April.

This is the kind of stuff we need to learn.

[ken&ellen]

Although that is a Harley term referring to center of gravity and slower cruising speeds I apply it to our Liberty. I do not have Pro Driver or any type of computer style fuel monitor, but I do have a pencil as well as a calculator. My 8V92 averages 6 mpg and drops to 5 - 5.5 towing. I like Jon set the cruise control on 62 mph for fuel economy as well as for safety. We are on the road most weekends as well as all vacations racking up the highway miles. I would rather get to our destination in one piece vs set a land speed record.:cool: Ken & Ellen

[Just Plain Jeff]

My feeling about fuel economy is that a safe driver is using the proper amount of fuel. And further, that safety is more important than chipping pennies.

I drive a bus about 20K a year, perhaps more. Using the old-fashioned 5 alert system of managing a bus in traffic seems to work.

Here's how it goes:

You have 5 things to be concerned about: The people ahead, the people behind, those on either side and yourself. If you keep a zone of safety in all those 5 areas, you will avoid problems.

That being said, my take is the primary concern is that buses do not stop as well as other critters on the roads, and also we don't corner like the semis do (time delay valves and the like). Furthermore, every bus seems to brake differently than another.

The XLV with disc brakes stops faster than previous year coaches; being mindful that with air brakes, you put your foot on the brake and stay with it.

We've all seen coaches slamming it down the hammer lane, probably because they can; and lots of complaints from other rvs about that, "Yeah, I've seen those Prevosts going by me at 80 mph."

Latest trip was an H3-45 with a big trailer who had to be in the 80-85 mph. Willing to bet his/her stopping distance was a whole lot more than my portly 68 mph, which was the flow of traffic in the center lane on flat level surface on I-95 for the big boys.

The idea is that one should probably be more concerned with what is going on outside the windshield than inside, but I watch the turbo boost. Using the motorcycle mentality of the 3-second rule, "Three seconds ahead, 3 seconds nearby," I try to watch the boost. If I am consistently at say, 20 pounds, that's not going to be good mileage as the engine is creating more power/using more fuel.

With the advantage of height over 4-wheelers, we can see down the road a bit farther. If you see a slow down in traffic ahead, it's a public service to hit the 4-way flashers to warn at least the commercial drivers that there's trouble up ahead. Those behind you will usually put theirs on as well and avoid an, "Oh-oh," situation. Maintaining a longer than usual interval ahead is a really good idea.

For those who may be newer to driving a 25-ton vehicle down the road: When you see a Weigh Station that's open, time to get to the middle lane if you are in the right lane, as there will likely be slow moving truck traffic coming out into traffic.

Generally speaking, I figure if, in moderate to heavy traffic, if you can keep in the center lane with the flow of bg-guy traffic with the 5 alert system, you'll get to where you need to go, safely; with the fuel mileage that follows safe driving.

Lastly, don't worry about the drivers of charter buses whipping down the road. Driving your coach is not supposed to be a competitive sport. Bob-OO sells stuff for the Kart people, now that's competitive. Our deal is enjoying the ride, taking in this beautiful country in comfort and safety.

There are probably a bunch of things wrong with this approach, but for an old geezer it seems to work.

[lewpopp]

This is real scarey. To dp something that Jon does. I always have driven the bus at 62-63 for saftey and economy. Anything less than that and I get saluted the same way I saluted the old people 10 years ago.

I change the air filter every year and am amazed how the mileage increases easily a few tenths. I normally don't drive in too many dusty areas but a lot of air is sucked thru that system.

I thought I was getting the air filters wholesale until I saw the retail on the bill along side of the price I was getting. I paid around $55 for the filter on my 8v92. Anyone else getting a better price?

Lew

PS. Note that I am on the computer in the AM. Bride is playing golf with Annika and Michelle. Shhhhhhhh !

[dreadnought]

yall are hurting my feelings with these big mileage claims.
I only have one 700 mile trip from Florida to home with my new ride, but with the cruise set on 79 & towing nothing we averaged 4.7 mpg:eek: Oh well, maybe my wife is right.. "this is not your Peterbilt dahling, slow down."

[win42]

Jon: The lady in the Focus and the guy in the small truck would have been far behind you when the incidents took place had you been driving 70 prior to meeting them. However at 70 you would have probably hit the deer that crossed way ahead of you while you were at a slower pace. What the Hay.
Slower is calmer, safer and easier on the right seat passenger. Ken is correct 8V92 = 6 not towing 5 towing.
Harry

[Orren Zook]

Lew,

I paid $42.29 last month for mine (PA2333 Baldwin).... is that the one you're running?

[Jon Wehrenberg]

I think Orren is paying the right price. As near as I can determine some suppliers offer trade price to anybody (such as Truck Pro), but some charge full retail (such as Fleetpride) unless you fill out the Baldwin credit application and then they set you up to pay the cheaper prices. It pays to shop.

In my experience air filters have a fairly long life based on the restriction gauge that I installed in line between the filter and turbo on both my coaches. Not replacing the filter prematurely is probably the most cost effective way to conserve Lewbucks.

I got my gauges from Prevost, and the kit comes complete with the gauge (which is a spring loaded indicator), hose and fittings to screw into the air intake tube.

[Jon Wehrenberg]

Harry,

Only Jeff in his new postal service job has the ability to forecast where all the idiot drivers will be at any point in time via his satellite spy network, but assuming we were moving at Dreadnaught speeds it is probable we would encounter a different set of speed control devices disguised as cars.

Maybe it is an age thing, but I drive the bus at way different speeds than I do my Corvette. There are just too many folks out there trying to get run over by a bus so I just hope for the best and expect the worst and drive slow to enjoy the ride.

[dalej]

Jon, when I picked up our coach yesterday the DDSM (detroit diesel service manager) said he would replace the KN filter with a paper filter. Do you think that is good advice? Or does anyone else have thoughts? Is the PA2333 filter work on all years of buses?

[Jon Wehrenberg]

I think that is the number for the 8V92, and the number for a S60 is different.

I have no way of evaluating different filters, so I can't determine if the advice to change filters is sound. I do know with the gauge, the paper elements such as the number you posted have almost no restriction when new and after about 20,000 miles I end up changing them, not because the gauge is approaching the red zone, but out of guilt.

I'm heading out to the garage in an hour or so and I will photo the gauge and get the part number so whoever doesn't have one will know what I am discussing.

[truk4u]

You guys crack me up! You go out and buy the most expensive rolling toy/house known to man and then worry about how your going to squeeze a 1/2 mile per gallon.:D You should be more worried about that 18 wheeler thats closing on you and half asleep that has to make a quick move before hitting your toad in the ass.:eek: I do 65 - 68, 7.4 mpg and go with the flow.
Of course opinions are like, well you know, everyone has one!;)

http://www.car-accidents.com/2005-Car-pics/8-11-05.jpg

[Jon Wehrenberg]

Dale,

Here is the gauge I have monitoring my air filter condition.



Prevost lists three different part numbers for the item described as an air restriction gauge or air restriction indicator. They are 530121, 530161, and 530193. I suspect a parts house will have the same gauge. On my first coach the gauge did not have the rubber hose, but screwed directly into a threaded fitting in the intake pipe.

[MangoMike]

Well, since post bling, obviously the pix was taken w/ available lighting.

I'm blindid' by the light :)

MM

[dreadnought]

is that a run in the paint I see behind the restriction guage? on Jon's bus? shock!:eek:

[Joe Cannarozzi]

Isint a dash guage available? Hmmmmm, something Liberty actually doesnt have?

[Jon Wehrenberg]

It's a run in the paint. What can I say? The bling contest is over, I am licking my wounds, and I have stopped polishing my slack adjusters and worrying about runs in the paint.

[Petervs]

OK, so I am a new member, and what right do I have to comment about the comments anyway. But I just have to .

I started this thread with some technical details about fuel economy so we could all have a few facts to bat around. It did not take very long for the discussion to degenerate into sniping about paint runs on the air filter housing. Now really guys!!!

Actually, my original post was not trying to make any kind of suggestion about how fast we should drive or why, but it was meant to provide data so we would know what the performance of our rigs was at various speeds, and how that performance changes with speed. Anyone can draw their own conclusions and drive accordingly.

I do need to speak out and refute a post by LEWPOPP, he said: "
I change the air filter every year and am amazed how the mileage increases easily a few tenths. I normally don't drive in too many dusty areas but a lot of air is sucked thru that system." I do not think this statement is correct and here is why.

The diesel we burn becomes energy expended in various ways, such as
1. Overcoming tire friction with the road.
2. Heat out the radiator and radiated from the warm engine parts.
3. Heat out the exhaust.
4. Overcoming friction of all the moving parts on the coach.
5. Power to the wheels overcoming air resistance.
6. Noise.
7. Power used to accelerate.
8. Power used to gain height as in climbing a grade.
9. Some small amount of diesel might not be burned at all and just goes out the tailpipe.
10. Overcoming the forces created by the air entering the intake until it exhausts. This is where a dirty air filter would cause problems. But a look at the ways diesel energy is used above and you will see overcoming the resistance of the air filter is a trivial part of the total. And only if the engine were running at wide open throttle. Any less than that and the resistance of the filter is but a microscopically trivial part compared to the rest of the air flow path. A dirty filter would prevent the engine from developing full rated power, but it would not really increase the fuel consumed because the amount of fuel injected is controlled by the DDEC to match the amount of air sucked into the cylinder. The engine will not run "rich" just because the filter is restricting air flow a little bit.

If you think the air filter does reduce the milage, then the best answer would be to remove it completely, especially if you were not in dusty conditions!

I think the mileage data I generated really does show that you can affect your tank to tank fuel mileage by a few tenths of a MPG very easily, and that is by varying your cruising speed a little bit. Of course my numbers reflect best case, fairly steady state cruising down the interstate. If you are in traffic, driving in town, driving in hilly areas, or any conditions that require more frequent speeding up and slowing down then your overall mileage will go down.

I hope my explnation makes sense, anyone is encouraged to let me know politely if they think I am full of beans from all the mexican food at POG 2. I think this forum will only be useful if we all try to keep the details as correct as possible.

And please, no one try to convince me I will get better mileage if I fill my tires with nitrogen either.

Regards to all

Peter vS
1994 Marathon XLV

[MangoMike]

Peter,

Sometimes these posts wander around a bit, get joked up and smacked down, but in the end invariably, like cream rising to the top, good information does surface. Like yours did.

The non-informational comments keep readers coming back. Like watching a train wreck or me leaving a Jimmy Buffett concert.

Thanks for participating.

Mike

[truk4u]

Peter,
I like to coat the front of my bus with a light film of Mango's french fry oil and pick up a couple tenths per gallon.:D

[MangoMike]

...and there you go.

[rfoster]

Pic taken from the windshield crossing Texas on I-10 running fast enough not to get run over, 7.92 mpg

325
But hey I decided to get home by Sunday nite!

[BrianE]

Okay. Here's the scoop on Peter. As a dear friend and acknowledging that he would give his buddies the shirt off his back:
1. Peter is a very smart mechanical engineer, entrepreneur and retiree.
2. For you aviators, he is an A&P, I.A. and one hell of a pilot besides.
3. He approaches all problems from an engineering standpoint including social, political and religeous issues.
4. He is almost always right.
5. His wife and kids (his boys engineers also) are smarter than he is.
6. He makes Jon look like a piker when is comes to being annal, however out of respect should be referred to as A-2.
7. He deserves to be kidded, and should always (like JDub and others) be addressed as "whippersnapper".:rolleyes:

BrianE
94Liberty XL

[Coloradobus]

Hey Roger,

We travelled 415 miles home from Santa Fe while towing the Airstream van at a speed of 65, and got 7.5 mpg. Gross combined weight between coach adn van (51,560 lbs and the van 8,560 lbs) 60,120 lbs, we thought was good mileage.

[Orren Zook]

There are a couple of different types of air filter restriction guages, most are similar to the photo shown in this thread. Wet or rainy operating conditions will cause this type of guage to show excessive restriction and when the filter element dries out sufficiently the guage will then read less restriction when reset. No sense changing an expensive element prematurely. A more accurate reading may be obtained by using a dash mounted vacuum guage and replacing your element when 27 inches of vacuum is reached - you can watch the air filter restriction under actual driving conditions this way rather than reading the Farr type guage when the motor is shut off.
On the K&N topic, I used one for a while until one day while washing it to re-oil the element I realized that the rubber gasket on the inlet side had compressed substantially.... air cleaners that don't seal properly can't do the job they're designed to do, so I went back to using paper elements.

[Joe Cannarozzi]

Petervs, Very informative post. Probably reminds some of my tire pressure post, HOWEVER we run a MECHANICAL 8V92TA and it gets about 51/2 at ANY speed and although we havent changed the element yet I can tell you my mechanical 3406B Cat in our Pete will go further on a tank of fuel with a clean filter.

This post was not to help most of the members as I know most are computer controled powerplants but to stand by Lew, my newest best friend:eek:

[Jon Wehrenberg]

Peter,

We will never try to convince you nitrogen improves mileage because we already know the real answer is helium. By lightening the coach via the use of helium filled tires the energy required to go up hills is reduced, and therefore fuel consumption is reduced.

As a contender for the anal award (and probable winner) I expect you will soon realize that with few exceptions you are dealing with folks who believe LEDs will reduce fuel consumption due to the reduced electrical load on the alternator. It is lonely here in anal land

Whatever you do, try not to expect POG members who have the attention span of a gnat to stick to a topic, or understand anything more complex than simple addition or subtraction. Remember, these folks are still struggling with the concept of emptying the holding tank.

Just so there is no doubt as to the mentality of those who frequent this site, (and who are aiming 50,000 pound buses down a highway), an award is given to folks who drive into rocks, and an award is given to folks who think lights and shiny surfaces are more important than having a bus that actually runs. It is lonely here in anal land.

BTW, how much did you pay Brian to write that puff piece? Did you annual his plane for free? Do the annual on my P210 and I will write nicer words than Brian ever could.

[Just Plain Jeff]

While there has been a decades-long struggle to reduce unsprung weight in vehicles for the benefit of handling, weight distribution and stopping distance, the advent of the Bilstein gas-shock was considered to be a real breakthrough.

Recent research has clearly demonstrated that there are wide variety of possibilities in reducing unsprung weight, but the implementation of theoretical strategies has been difficult from an engineering point of view.

It would appear that further R & D will be necessary to enhance tread-to-pavement compatibility.

[MangoMike]

Probably the most fuel effecient Prevo on the road.

328

[win42]

Since this topic is leaning toward one upmanship, I can't keep my secret to solving my fuel costs problem away any longer. Since purchasing two oil company stocks 3-4 years ago Chevron is up 91% and Exxon Mobile is up 77%.
After a long trip such as POG2 I add up my fuel costs, go to the computer and check these two stocks and get a warm fuzzy feeling. So please help this 8V92 owner with his fuel costs by purchasing your fuel at the above companies. I always seem to find some way to piss off the Liberals a little more. Oh Well !!
Harry

[Joe Cannarozzi]

Win42 -:confused: There must be something very important to you to explain your current State of residence.

[win42]

Joe: I was just stating one instance of being lucky. It can all go away tomorrow. No I'm not in the habit of blowing smoke. Like you I worked hard all my life to get a little ahead and am not ashamed of it. Try to look at the humorous side of that single situation. I despise the high fuel prices as much as anyone.
Harry

[Joe Cannarozzi]

I was refering to that left coast.

[win42]

Joe: Coast, what coast? I live up in the hills with the rest of the red necks. I have to drive three hours west to see salt water. You better get that muffler fixed, the fumes are getting to you. Hope to see you at the next POG rally. Remember too much work can kill ya. "You gotta chill out baby" Now thats left coast talk.
Best to you.
Harry

[lewpopp]

Now, now boys, calm down

As for JPJ's post of the suspended coach. Was that one of your Air Mail inventions?

[Petervs]

Hello All,

Well, first off, as for Joe Cannarozzi saying he has a mechanical injected 8V92 and always gets 5 1/2 mpg, well, that is just absurd. Drive up a grade real fast and your milage will surely be lower than when you drive back down. If you are saying you always average 5.5, well, that just means your driving habits are consistent.

And if your air filter is clean and new or old and dirty, the difference in mileage can only be an infiniteessimal amount in any case, even if you are mechanically injected. The injectors still meter fuel in based on the amount of air going into the cylinders, same as an old mechanical carburetor or mechanical fuel injection on a car, or fuel injection on an airplane engine; all of which has been around since the 1950's. Your foot pedal controls an air valve, which allows the fuel metering system to correlate the fuel injected to match. If the filter is dirty, it takes a little more work to get the air through it, but that is such a tiny amount of energy compared to moving a bus along the road it really makes no differnece in mileage. But like I said before, it could affect the maximum horsepower the engine can make if it was really dirty. I hope this makes sense.

Now, secondly, as for BrianE's post about me, to answer Jon Wehrenberg's question, yes, as a matter of fact I do annual Brian's plane for free. And I think his little explanation about me was way less puffy that he promised. Since you fly a P210, you must already be puffed up to a pretty high pressure, better not let any go in my direction.

Now, it seems only fair that I illuminate you all a little about Brian.

1. Brian is a very smart machinist, airline pilot and retiree. Airline pilots always think they are in complete charge of everything and like wearing hats with scrambled eggs on them.
2. For you aviators, he is an A&P, and one hell of a pilot besides, but since he has to buy his own gas now, he never flies anything fast.
3. He approaches all problems from some strange standpoint I have never understood; including social, political and religeous issues.
4. He almost always thinks he is right.
5. His wife is smarter than he is.
6. He has a special talent when it comes to spreading black water tank contents everywhere but the sewer pipe, and he has special shoulder high rubber gloves to wear when that operation is in progress.
7. He often invites us over for dinner, but we never accept since he insists on serving the food on his hangar or bus garage floor sans plates. Now, there is nothing wrong with that since the floor is always spotless, but gee, we have to draw the line somewhere!

I hope this helps you understand a little better.

Peter vS
1994 Marathon XLV

[MangoMike]

All I can say is that it's refreshing to have some new blood spread (smeared) around POG. Some new guys to watch harass each other. The old Jon vs Mango vs JW vs Fast Roger was running out of material - kinda like jumpin' the shark.

Go at it boys.

Mango M

[rfoster]

Mango: In the resturant bizness, isn't that term "new meat", or does that term come from WWWF? At any rate, I am glad to see Jon is got some competition coming for the 07 "Anal Award".

We may have to branch out into "Bus and Non Bus" Categories.:D

[Jon Wehrenberg]

Competition Hell!!!!!!!

I'm going to chase Peter down and personally force him to take it. He already deserves it.

Also, I am going to stay on the good side of Brian and Peter because I may have some help from them in dealing with guys who fly forked tail doctor killers.

It is clear there are also more Kevin type tales, and the Mango Bent Metal award may have to be supplemented with some other award, such as the famous "s**t creek" paddle.

[Joe Cannarozzi]

Petervs, welcome to the club! Absurd, I like that caricterization, Ive deffinatly been called worse. We are going to Tenn. for thanksgiving and inbetween Chi. and Indy I-65 it is flat as can be with a cross wind that will affect you the same going both north or south and at 150 miles its long enough for a fuel test. We will go down at 62 and come back at 72 and post the results. All our milage posts are estimates, Mabye you are correct, we might save some, but I suspect it wont be much.:)

[Petervs]

Hi Joe,

Hey, I did not call YOU absurd, I just labeled your comment absurd.....

I do look forward to seeing the results of your mileage test. Just be sure the wind is really from the side. If it is a quartering headwind or tailwind that would make some difference. A calm day is best, or at least, note the conditions by standing outside to really check to see how much wind there is and from which direction.

Also, traffic has to allow you to cruise steadily along, preferable with the cruise control on for most of the distance. With my tests, I left the fuel station, accelerated once to the speed I chose, and let the cruise control do the rest.

Let us know what you learn,

Peter vS
94 Marathon XLV

[Jon Wehrenberg]

Peter,

Question: I think your post about factors affecting mileage was relative to a DDEC (later generation) coach. Would that be correct? If I am not mistaken pre DDEC and DDEC I coaches deliver fuel based solely on throttle position, and thus the driver and the air cleaner condition may have a greater impact on mileage.

I think later generation DDEC models delivered fuel based on turbo boost in response to a CA "snap accelerator" emissions requirement to eliminate sooting on rapid accelerator application.

A-1

[Petervs]

Hi Jon,
I am not an expert on pre DDEC or DDEC 1 systems, but I can not imagine that the fuel supply is controlled directly by the throttle position. The engine would flood out if you opened the throttle too quickly, the metering control has to sense the air pressure in the cylinder or going into the cylinder and respond to that.

Perhaps someone else will have a definative answer.

Peter VS

[Jon Wehrenberg]

Peter,

On mechanical engines (pre DDEC) the throttle position determined how much fuel the injectors supplied. A wide open throttle at low boost (low RPM) resulted in unburned or incompletely burned fuel (black smoke).

On DDEC I the same condition could temporarily be created. The computer was not as sophisticated as on later versions, and until the turbo spooled up you could roll out the black smoke with excessive throttle.

Our later versions will only allow fuel quantities that can be almost completely burned.

[Just Plain Jeff]

All the above ignores the PBF factor, which can be deliterious as to fuel economy.

[Jon Wehrenberg]

JPJ, Don't you have some mail to sort?

[Gary & Peggy Stevens]

I know I saw a post just yesterday about the difference between the ULSD and our older diesel fuels, but can't find it.

So I am posting this website on this post site, HOPE you don't mind.:confused:


http://www.clean-diesel.org/

Gary S

[lewpopp]

Doesn't the "potentiometer" come in there somewhere?

[JIM CHALOUPKA]

lewpopp;Doesn't the "potentiometer" come in there somewhere?

Lew, The elaboration of your query.

Automotive jargon: Throttle position switch. = Electronics jargon: potentiometer.

Personally I think you new that! ;)

:) JIM

[Jerry Winchester]

In the older mechanically governed 8V92's there was actually a piston that pushed oil out of a tube with a small hole it it that acted as a buffer between mashing your foot in the throttle and the fuel system going to full fuel. If you wanted to improve your pull from the stop sign, just drill the hole bigger, but be ready to face the fact that the sun was going to be blocked out by the black smoke.

The Cummins PT fuel system used an aneroid valve that sensed turbo boost pressure and adjusted the fuel flow accordingly. Mack "Maxidyne" engines had a similar feature on their high pressure injection pump.

I think this is all for naught in the new engines as the sensors and computers keep this all in check with electrons and or 1's and 0's.