Ok, I have about 10 trips on my 1984 Eagle 10 now. The conversion is at the starting point and light weight. No surplus water (7 gal camper potty) and two coolers for food. Does have a camper stove and reg sink draining into a 5 gal bucket. Like I said, light. The runs have been from Indianapolis to Nashville and back. Running speed 75-80 mph and 18-19 on the tach (looks like 22 @ full petal). 8 of the trips I filled until I saw non-foaming fuel in the filler. I show that I am getting around 13 mpg, 12 when the bays are 1/2 full of heavy stuff. It is a 6V92 blower and turbo, 5 spd manual. The tires are 11R24.5 running 90 PSI. I do not know the injectors or timing at this point.
When I first started figuring gas mileage, I was sure this was wrong. Now I have made this run enough that I keep getting the same mileage and I'm sure it's right. I think I need a tune-up or something, because it takes longer to start than most posts I read say it should. On a damp or cold day it takes 6 to 8 10sec presses on the button to get going and 2 if I use either. I get a bit of smoke during this time, but it clears up as soon as the motor starts running. If I restart it after a short trip I get no smoke and it fires up on the 1st press.
I would like to take it in for a tune-up, but not sure if my mileage will take a hit (can that happen?). Also is anyone else getting this mileage? I thought these got around 6-10 mpg. I had planned to get a tune-up and switch trans to an auto to make it easier for others to help with driving, but if that gets me half the mileage I'll just do all the driving myself. Also not sure how heavy I want to go on the conversion if that will kill the mileage too. Any thoughts? Let me know. Thanks, Jon
P.S. I don't believe in "Bus Miracles" so if this is not normal for this setup, are we looking at worn rings and bearing causing low running resistance? Blocked injectors reducing my power and starving the engine for fuel? Heat looks ok and the power feels good. All other gauges look good too. Just some thoughts.
Jon, that mileage seems very high to me. Most Eagles get less than 10 MPG when lightly loaded - most well below. Of course, road conditions (think hills), start and stop, speed, and wind can have a huge affect. If your are really driving 75-80MPH, your mileage seems even more unrealistic to me.
Something sounds a bit "off" with your MPH and RPM. The two typical rear end ratios in an Eagle are 3.36 and 3.73. With the 3.73 you should be at about 70-72 MPH at 2100. With the 3.36 you should be at 79-80 at 2100.
I would check the odometer against the mile marker signs to make sure that it is giving you a reasonable value. Check it over at least 10 miles to minimize the error. Checking MPH against a GPS does not necessarily guarantee that the odometer is correct (I have seen odometers off by a fair amount and the speedometer pretty close).
If you verify that the odometer is close and you check the fuel over several fill-ups, then you have a great running bus and you should probably not mess with it. Good power, minimal smoke, quick starting, and reasonable oil usage are all signs of a good engine - not one that needs any work.
A tune-up is basically "running the rack". The folks who know how to do that correctly are getting small in number. No need to run the rack unless you have some symptom and it does not sound like you do.
Jim
Leave it alone Jon all of Freedoms Eagles got good millage they were set 315 hp, 2300 rpm with 3:73 rear gears and a 5th over transmission good setup for fuel mileage
good luck
Ck your block heater. Might be bad. Been cold in Indy My 8v92 still starting rite up in E'ville w/o plugged in. Bob by the way 5 mpg here------ 6 at 65 mph.towing 36100 plus 3400 for towed
Clifford, I was not aware of a 5 speed manual transmission that had OD that were used in Eagles. Interesting.
Jim
Freedom never did the standard Eagle stuff Jim even the Cummins engines in his model 15's and his 35ft model 20's with the Cummins
good luck
So to "slightly" highjack this thread, what is the best tuning for a detroit and best rpm to get the best economy? Is the turbo adding any mileage? My understanding of "sweet spot" is the rpm that allows the fuel charge to be fully consumed at the point the exhaust valves open. Too fast and your blowing it out the exhaust, too slow and its not doing enough work, either side of sweet is less efficient.
I remember this old Buick Stationwagon I had when I was 19. 455 V8, it had a hard time getting much over 4 MPG. Its amazing to see a Bus get over 5, 10 seems outragous, 13 is just about enough to make ya do back flips
Artvonne, there definitely is a sweet spot. If I hang around 55 I actually get less mpg and produce more heat than say at 62 to 65. I believe because the engine is turning much lower rpm and not pulling enough air through the blowers to keep it cool, and maybe just below the torque curve of the engine?? If I run @ 75 all bets are off. Heat again begins to climb, and mileage goes out the window. (well, more out the window then normal).
Paul -
IIRC, the "sweet spot" for the 8V71s is 1700 - 1800 rpm running on the flat, w/ or w/o a turbo. Roughly 1900 pulling a grade w/ no black smoke out the exhaust. Black smoke = time to downshift. 6V92s seem to like 1800, 8V92s are happy at 1600 -1700.
Turbo's biggest benefit is maintaining sea-level HP as you climb RockyTop. Also allows you to go further on a grade before having to downshift, so theoretically fuel mileage should be slightly better, but usually isn't because of the "Home Improvement Syndrome."
FWIW & HTH. . .
;)
@ Paul: Since I also have an 8v71 I have a couple questions:
1. Is that "sweet spot" different from 1 motor to the next?
2. " " different from MCI or Eagle?
3. Since my bus doesn't have a tach, where is the best place to attach a tachometer?
Quote from: uemjg on December 22, 2011, 10:03:25 AM
@ Paul: Since I also have an 8v71 I have a couple questions:
1. Is that "sweet spot" different from 1 motor to the next?
2. " " different from MCI or Eagle?
3. Since my bus doesn't have a tach, where is the best place to attach a tachometer?
My understanding of the "sweet spot" regarding diesels, relates to the speed of the flame front after ignition, and the full consumption of the fuel charge. While bore would have some effect, the main factor is the stroke, or, the distance the piston travels from top to bottom. Matching the piston speed to the flame front speed, so that the entire air/fuel mixture is consumed just before the exhaust valves open will put the greatest amount of energy to work. Running the engine too fast opens the exhaust valves too early, allowing high pressure gases to escape and is a loss of energy, as is turning so slow the charge is consumed long before the piston reaches full extension/valve opening.
Other factors are the burn rate of the fuel itself (Cetane), as well as injection timing. I once had a book on tuning the old 6.9 Navistar engine that gave different injection timing figures for fuels with different Cetane ratings, but that was back when you could find Cetane ratings of pump fuel. Back then they timed diesels for power and economy, now they time them for emissions, often making them so inefficient they offer no real gain over a gas engine. I guess if one wanted to dig deep enough you could find the burn rate of the fuel and calculate the time it would take to cover the stroke distance and calculate rpm off that figure. But im lazy and just figured I would ask.
When Hub Van Doorne invented the continuously variable snowmobile transmission (Variomatic), in 1958, the dream was always to connect it to a constant speed diesel where it would achieve its greatest efficiency. Its just never really quite worked out.
Getting back to the original question. If your bus is hard to start after it has sat for a day or two it could be that your fuel system has a leak and you are getting air in the system. This will cause it to take a while of turning the engine over in order to reprime the system. The next time you want to crank it and you feel it has been long enough that it will not start immediately watch the exhaust pipe while you crank it. If it is white smoking the whole time it should be getting fuel. If it either is not white smoking or smokes just a little for a few seconds and then stops you probably have air in the system.
This bus he is asking about is my old eagle. I never got anywhere near that kind of milleage. The best I got was 10 mpg at around 65 mph not sure why it would increase in milleage by running it faster/harder then I did. As for the starting. I was always told that if a diesel starts right up its wore out. This bus has pertty low milleage compared to most and always started as it should IMO. Granted it wasnt very cold when I had it.
I am sure that the engine is fine and I wouldnt worry about a tune up on it yet. just my opinion
If you want your money back I would be more then happy to buy it back ;D
Thank you all....for awhile I believed! HB of CJ (old coot) :) :) :)
Ya just gotta laugh sometimes ;D ;D ;D
I would be ecstatic with even 10 MPG at 65 MPH! Generally I have been right around or just above 8 MPG with no trailer at 65 MPH.
My MPG does seem to have been trending down in the last year or two. I believe we got around 7 MPG on our last trip out west. We have upgraded to a larger trailer and seem to keep adding more and more weight. The difference between 7 and 8 MPG is 71 gallons on a 4,000 mile trip. $300 won't bankrupt me, but fuel is far and away the #1 expense for my bus trips.
I'm right now looking at buying a used commercial party/event tent, but I wonder if I really want to add 200 or 300 pounds to my trailer and bus.
brian are you runnin 12 or 11 60 series?
Most 60 series are in the 6 to 8 mpg range I have heard of few doing a little better but it is only hear say every bus I have ever checked with a ProLink with series 60 are around 6 in the 45 ft tour buses some even 5 the difference is they run the speed limit and not out for bragging rights on what great fuel mileage they get like the bus nuts. lol
The 500 hp ISM in the 45ft S&S jobs are 5 and 6 mpg at highway speed limits no free lunches with a modern 4 stroke engine when it comes to fuel the old 8v92 tuned right will do the same or better
good luck
Just fishing: 10 would be a dream 7 great 5 no better than what I have now. Hoping for 7 with the 10speed and 60 series. Will run speed limit. Like I said just fishing proof will come soon enough. it will be tested .. Bob
I have an 11.1 Series 60. I'm not looking for bragging rights. I drive 65 MPH to save money and be a bit safer. I might drive faster if someone else was paying the fuel bill.
What is the best way to find MPG anyway? Is there a good way to read fuel used? Can't go by when the pump shuts off as a full point, as it could take another 40 gal after stopping. I would top it off and wait a bit, then hit it again until I see it just sitting at the back of the fill neck. I feel after 10 trips I should be within 2-3 MPG of true MPG (let me know if my thinking is off) Oh, and I didn't really start this to be a bragging / best bus mileage ever / pissing rights / post. I noticed different numbers than most stated and wanted to know what could be the cause. Also it should be know that there is a chance this bus is pulling air with fuel as seen in some of DemoDriver's posts when he owned this bus. (Plus the red switch mystery trans he also went into detail on) So I guess I'll just shut up and enjoy the mileage I do get as I have another trip coming up soon.
Bob, not sure about stopping by on my way down to Nashville in January, but would make a trip to Evansville in the bus just to check out your buses and how they are setup (rope LED's and all).
Thanks all for the input on this and if it gives you a laugh, then glad to have brightened your day. Jon
Quote from: robertglines1 on December 26, 2011, 07:50:17 PM
Just fishing: 10 would be a dream 7 great 5 no better than what I have now. Hoping for 7 with the 10speed and 60 series. Will run speed limit. Like I said just fishing proof will come soon enough. it will be tested .. Bob
Just remember that RPM has as large, if not larger effect on fuel economy as does speed. If your RPM is so far under or over the sweet spot to blow engine efficiency down, driving faster where the engine is at optimal RPM may actually pull off better fuel mileage. Everything is a trade off/compromise.
And we should all remember, what you could get for economy driving a particular vehicle has no real bearing on what another could get. Its not all about speed, a lot has to to do with how you work the throttle. Smooth and steady on the pedal gets the highest fuel economy. Constant power adjustments and constant changes in speed will totally blow any chance of good economy.
Quote from: Bus Busted on December 26, 2011, 11:26:10 PMWhat is the best way to find MPG anyway? Is there a good way to read fuel used? (snip)
I did a lot of work testing vehicles back when I was a useful productive citizen. Our rule was try to fill to exactly the same point (much easier with a car with smaller tanks and the possibility of filling to the car filler neck), try to run three tanks in similar conditions (road speed, hwy vs intown, load), and average those three. An average of three is pretty accurate; if you change something (or if something changes like a leaky injector) you'll see it in the three tank average. You'll also note that individual tanks can vary pretty widely.
After it's calibrated, modern electronic measuring is pretty accurate, but that's a luxury most of us don't have.
But the real answer is that it can be very difficult to get an accurate MPG on just one or two tanks.
My tank is just a long rectangle with a cap on either end. There is no filler tube. I can see the level of the fuel and I can fill to the same level every time. I keep filling after the auto shutoff. I also have a Silverleaf that reports exactly how much fuel the engine used.
On any one trip we might have four or five drivers. It doesn't seem to really change MPG any as we all use cruise control. Often the cruise set point is the same between drivers as the engine doesn't get shut off between drivers very often.
Jon: Come by anytime Won't be Fla bound til Feb. Mci8 tin tent few miles away. Hvac guy and a bus nut. Mileage is a gift in this hobby. Just a necessary evil we can all dream about getting better. Very possible your getting 10 would be great. It's all in the science and driver. Looks like original set up was rite on. happy bussin Bob
I record every gallon of fuel added to my coaches along with the location, price, and total cost.
My records go back to 1990. As a result I can come pretty close to calculating my mileage except for usage of the Webasto and the Generator. I have a reasonably accurate estimate of generator fuel usage based on 160 continuous hours and only 2 miles of driving between fill ups.
Anyway I averaged 5.6 MPG based on annual mileage calculations on my 8V92 powered coach, and I am 7.5 on my current Series 60 coach. My ProDriver agrees with my annual averages adjusted a little to compensate for Webasto and generator use. Basing an mileage calculation on a single fill up gives me such a wide spread from one to the next I lack confidence in individual calcualtions.
I have found the greatest impact on mileage is speed (or headwinds), hills (flat terrain is better), the weight of the toad, whether I run the Over the Road Air, and how much stop and go driving is involved.
Yea ,flat lands will yield better mileage but these 50,0000 lb coaches now days not much you can do about it except pay the price doesn't matter what engine you have running 75mph all day long you are not going to average 8 mpg.
My friends at Arrow say 5 to 6 loaded coming or going they never expect more from the Prevost with the Volvo D13 or series 60 in their Setras or the Cummins in the MCI pre EGR engine they do get a little better mpg
good luck
At the risk of being burned at the stake I am going to report my fuel mileage. I put a 12.7 series 60. Allison 6 speed double overdrive, and 4:11 rear. Running 24.5's. I have put about 2k miles on this setup so far. The first trip out 700 miles the silver leaf showed 10.7 running at 65 on the way to the BCM in TN. On the way back I bumped it to 70 mph and it fell to 10.2 mpg. Last trip to Charleston, SC around 650 miles, and a thousand trips around town working on the (CRUSE CONTROL) LOL 9.3 mpg average with a prolink. I expect if driven conservatively, average will be somewhere between 8-9 mpg.
With my 8-71 Allison 654, and 3:73 I averaged between 5 and 7 mpg. Never got better than 7.5 best I could tell. !0-12 with a 6v92 seems way off, but if it is correct I would shoot the first person that layed a wrench on it!!!
Folks have mentioned all the big knobs - engine rpm, speed, wind, hills, weight, etc.
Overall, I have averaged a bit over 7 MPG (as reported by my SilverLeaf) with the Series 60 and AutoShift (over 60K miles). We live at 7500 feet, so I climb some pretty good hills no matter which way I go. My Aqua-Hot and Generator are off a separate tank, so I could weigh through my record book and verify that number, but I think it is pretty close.
I had not given much thought to weight in the past. Once you get the weight rolling, it becomes a lesser factor - except on the big hills. What really got my attention was driving some two lane roads in IL/IN/OH a few times. I figured driving 55-60 (set CC at 68 on the interstates) on relatively flat roads without huge winds, would really help . Boy was I wrong. All of the accelerating when leaving the small towns really hit the mileage. I was in the 5 MPG range during those legs of the trips. BTW, I am at about 46K with the close to 10K service truck.
A couple of years ago I did a lot of investigation about the affect of speed. I did a bunch of running at 63 MPH and did not notice any difference - indeed, it looked to me like my mileage went down (engine RPM about 1380). When I went back up to my normal 68 MPG (about 1490 RPM) my mileage seemed to improve slightly. The 63 MPH trial was over several hundred miles on Interstate highway roads. The only thing I did notice was that I did not have to pass Swift trucks ;D
So, the bottom line is that each of the factors listed above have impacts that are a function of the bus. Some of the factors (knobs) can be tweaked to try to maximize mileage. That said, there is not a lot we have control over in terms of making magical fuel mileage numbers.
Jim
Eric, we were posting at the same time. I suspect your numbers are pretty close to what I would get in your area with a smaller toad - I would probably be a bit less. I am not sure what kind of hills you have, but my trip home from the Denver area is a 2.5-3K foot climb in about 20 miles (with the downhill stretches, that really is about 5K net). My mileage for that leg of the trip is around 3 MPG. I climb I 70 out of Dillon going east towards Denver and just hate to look at my SilverLeaf. I do those roads a lot, so I feel pretty good at a bit over 7 MPG with my 46K weight.
Yes folks, I know that every state has some pretty good climbs, but you really need to travel in CO to get a feeling for what I am talking about. When I leave KS on I 70, I try not to look at the mileage. It is a very slow climb from about 2.8K in Garden City to about 6.0-6.5K on the plains east of Denver then a gradual drop down to 5.3K, then the huge climb.
Jim
Well I had to do it I called Karl Blades with Newell they are getting ready to head out to Pomana for the Fmca rally with his 625 hp Cummins and 12 speed auto shift ZF transmission in the Newell around 50,000 lbs and towing a 10,000 lb trailer he said they average 4.8 to 5.3 mpg down hill about 7 mpg lol same as when he used the C-15 Cat engines with 650 hp according to the Silver leaf dash guess fuel is not important to Newell buyers
good luck
I can't understand all this trouble figuring fuel milage. On HUGGY a 4104 with a 6v92 with big injectors and big turbo. In the mountains of NC at around 55 mph I get about 12 to 14 mpg. And when I get on the Interstate at 75 to 80 mph i get around 6 to 8 mpg.
It is easy to figure just take the milage going and the milage coming back and add together.
uncle Ned
PS i get invited to all rallys in the south east in the summer. Rumor has it that there no mosquitoes around for weeks after I get there
We are fairly flat here. We are at the base of the Appalachian mountains. @9 miles from here we start up. It is a 4 mile 7% grade, then hill after hill. With more hills it will fall definitely. My hp is set higher also. My coach is in the 40-41k range. With the higher hp it doesn't work as hard or so I've been told.
Eagles historically got better mileage than similar sized MCI's and Prevosts. They were a bit lighter due to the aluminum skin vs stainless and better aerodynamics. As I understand it, Eagle did some wind tunnel tests and slightly tapered the rear ten feet or so of the bus for mileage.
;D
Eric,out here in the west we have 3 or 4 % grades that will last for 40+ miles then the 7% grades start lol,you leave Phoenix heading north 120 miles of uphill grades till Flagstaff
good luck
Ours are more up 4-7% for a few miles, flat, then up again. We have one 6% on I-77 going into VA. that is 6-8 miles I think. That one burns some fuel!!!!
Looks like the Silverleaf is what most use for MPG. I'll be getting one very soon, as a tech guy I feel more info is better. When I bought this bus from DemoDriver he had gutted it most of the way. I have since removed the bathroom and some of his conversion to be reinstalled later in a diff spot. He had removed the rolling AC and I removed the roof AC (need to fix leaks before re-installing) Those bathroom walls weighed a bit lol! So I guess I'm at the rolling tin tent weight. We would run down to TN empty and pick up boxes to bring back to IN. Moving my girlfriend up here and it took 3 trips. Other trips were made empty down / empty back ((no holding water, no toad, no trailer) yet), just some music gear and a cooler. I'll have to run by a truck stop and get the rolling weight soon. Really the only driving I do is back and forth from TN, so the math is easy. Have been driving from 9:00 pm to around 3:00-4:00 am to keep away from heavy traffic so not much speed up or slow down. That is until the hills of KY and TN. Now Dickson, TN is 342.68 miles from my house (685.36 round trip).
I first started tracking MPG after the first 1/2 of the first trip because there is a Pilot station right before I get on the highway. Filled until it didn't go back down and hit the road. Drove to IN and unloaded. Then next weekend headed back down and loaded up. Stopped by the Pilot before heading home. Filled til it stayed at the back of the fill neck. Did this about 10 times with some trips only going as far as Nashville then returning home. Fully loaded with boxes, wood tables, ect, filling all bays and 3/4 of inside showed 11.81 MPG average. Trips running empty (tin tent) 12.67 MPG average.
So if you want to get picky you could say "Hey Jon, figure that 11.81 MPG with 1/2 the trip empty and 1/2 of the trip full" sooo "so if you drive both ways full in the future (150gal fresh water, waste tanks, gen, 1/2 a conversion or more, Propane tanks, ect) you should be looking at 9 to 10 MPG at best for now and 6-8 MPG with conversion done and at full weight" Hmmm. Maybe this helps clear things up a little. Guess I'll see...
Like I said, I'll be getting a Silverleaf very soon to find the fuel cost of my add-ons. Bus travel works very well for me. So does saving money on fuel. I have already learned owning a bus is a series of compromises. I'll use my Silverleaf to decide if I really need 200gal of water, or will the 50gal I need for short trips do for now. Oak table and bed, or camper table and cloth head board. Full size house fridge, or small camper fridge. More tire air for better MPG or less air for longer tire life. All I know is that from the posts I have read here, fuel wise, I am starting with a real good platform to build on!
A Silver Leaf won't work on a MUI engine it has to be a electronic controlled engines for the MUI engines you use a flow meter on the supply and return lines fwiw
Thanks for the heads up. So is there a good data sys out there for MUI?
They have the Floscan system but why waste 1200 to 1500 bucks just keep on trucking you are doing ok with your mileage after all you pay the bill we don't and you know what it costs
You are already using it! ;)
Stick to judge depth of fuel, some way to guess the true mileage (I know my hub meter ain't close to accurate...) and more than anything else - repeatability. You may not be able to get miles per gallons to scientific accuracy, but you should be able to do buckets per furlong repeatably, and that will let you measure change...
;D
Brian (I personally use days per fill-up to measure fuel usage...my bus has been very economical lately, around 400 days per 3/4 fill... ::) )