Rolls Royce Turbo Jet Engine for Blue Birds
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02-19-2006, 05:50
Post: #1
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Rolls Royce Turbo Jet Engine for Blue Birds
Now this ought to get my bus going up the big hills just as fast as
a Corvette !! Just joking, but I wanted to make a point here. Fast and Slow are relative terms. A non-turbo BB is not a Slow bus, it is not underpowered. It drives exactly as it was intended to drive. Horsepower is only half the equation. The other factor in speed performance, just as important as horsepower, is vehicle weight. The reason Blue Bird went to turbos is because they continued to make their buses heavier every year. A non-turbo, non-air ride, non- driveline retarder Bird will run the speed limit any where with the correct gears. That's the truth, so how fast do you want to go? I would not be surprised if a NA 3208 in a '77 will go up hills just as fast as a '85 with it's turbo power. Remember, turbos are not engine friendly. One of the diesels biggest enemys is heat, and Turbos give them an extra heaping dose of it. Turbos wear out any diesel motor faster than if the same motor was naturally aspirated. When the turbo breaks down, notice I said when and not if, you will be sitting on the side of the road looking at a hefty repair bill. There are two sides to every coin. I live in the west and am no strange to big hills. In fact, they are so big out here they call them mountains. I have not, yet, traveled a downgrade lower than third gear in my '78 bus. Keep in mind the huge air tankage in these busses, that is just as important as a drive line retarder in safely navigating down grades. Some folks forget that prior to the eightys there were no such things as turbo chargers, drive line retarders and air-ride suspension. Seems that all the freight in America still got delivered to it's numerous appointed destinations with out problems for over 30 years! How bout that! So what do you want? Speed, what ever that is is a thirty thousand pound truck, or reliabililty? If it's not there it can not break. Yes, you will slow down on the big upgrades, just like trucks always did for many years, but you will climb it without any problems except for the unmentionable shame of being passed by four wheelers. Perhaps another subject, but I think many folks do not realize what great riding busses the leaf-spring 'Bird models really were. Have you ever driven a leaf-spring 'Bird? If not, I am willing to bet that you will be greatly surprised when you do, they have a very nice ride. Again, you will never have an air leak problem, ever, guarenteeed! You can crawl under your bus safely without having to block it up, any time you want to take a qick look around. Even at a rest stop, in seconds. So what are you really looking for? There is no greater teacher than experience. I drove big trucks long before the days of turbo chargers and air-ride suspensions. However, none of them rode anywhere as well as my leaf- spring 'Bird. Still, they were rock solid dependable just like my old bus is. The first time I drove a leaf-spring 'Bird I was totally amazed. For me, it is the choice suspension as far as ease of ownership, dependability and low cost of operation. Oh well, that's enough for now. For those of you still interested in the Rocket Engine Upgrade e- mail me off line for more info. Thanks and have a great day. -James 78FC33SB LasVegas NV |
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02-19-2006, 06:07
Post: #2
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Rolls Royce Turbo Jet Engine for Blue Birds
The main advantage I see in a turbo is maintaining sea-level
horsepower at altitude. Here in Colorado an NA engine looses about 30% of its horsepower going over the passes, strictly as a result of the thin air. A turbo overcomes most of that loss. At lower elevations, the advantage is much less significant in my opinion. Kerry Denver |
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02-19-2006, 06:35
Post: #3
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Rolls Royce Turbo Jet Engine for Blue Birds
Just crunched the numbers. Comparing a 210hp NA with a 250hp T, if
there is a 30% loss on the NA, and none on the T, there is a 70% horsepower advantage with the T at altitude. --- In WanderlodgeForum@yahoogroups.com, "davidkerryedwards" > > The main advantage I see in a turbo is maintaining sea-level > horsepower at altitude. Here in Colorado an NA engine looses about > 30% of its horsepower going over the passes, strictly as a result of > the thin air. A turbo overcomes most of that loss. At lower > elevations, the advantage is much less significant in my opinion. > > Kerry > Denver > |
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02-19-2006, 07:02
Post: #4
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Rolls Royce Turbo Jet Engine for Blue Birds
--- In WanderlodgeForum@yahoogroups.com, "davidkerryedwards"
> > Just crunched the numbers. Comparing a 210hp NA with a 250hp T, if > there is a 30% loss on the NA, and none on the T, there is a 70% > horsepower advantage with the T at altitude. > > > > --- In WanderlodgeForum@yahoogroups.com, "davidkerryedwards" > > > > > The main advantage I see in a turbo is maintaining sea-level > > horsepower at altitude. Here in Colorado an NA engine looses about > > 30% of its horsepower going over the passes, strictly as a result of > > the thin air. A turbo overcomes most of that loss. At lower PS.> > elevations, the advantage is much less significant in my opinion. > > > > Kerry > > Denver Like I said I drove my 3208 from Denver to Seattle and the only time I had any real problems with speed and that would be coming out the Columbia Gorge. I helped Dave Beatty drive his 83 back from Utah and as far as I could tell yes there was a little difference but not 70%. One thing you haft to remember about these coaches that they are big heavy machines and whatever mountain you come up to its still going to become a slow haul if the grade is steep enough. I like the idea of the retarder and kind of wish I had one. But then again this old coach has 148,000 thousand miles on it and its still going strong. Jon By the way does this coach belong to Steve? If it does I bought my coach from him about year ago now. Jon 1978 Wanderlodge Bremerton Washington > > > |
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02-19-2006, 07:15
Post: #5
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Rolls Royce Turbo Jet Engine for Blue Birds
Jon:
Yes, it does. He told me he sold his 78 about a year ago. Kerry Denver > By the way does this coach belong to Steve? If it does I bought my > coach from him about year ago now. > > Jon > 1978 Wanderlodge > Bremerton Washington > > > > > > |
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02-19-2006, 10:18
Post: #6
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Rolls Royce Turbo Jet Engine for Blue Birds
On the way up, it's about power/weight ratio (comparing different
year 'Birds). My '77 FC31 weighed in around 23,000lbs with all tanks full. With several engine upgrades, and 4.63:1 gears, it would run well on the flats at 75mph or better. Slight inclines would slow it down, but doing some simple calculations showed that it added only minutes to each day's drive to slow a few MPH on the climb. Coming down the hills was different. In a diesel rig, you CAN NOT use the brakes to control speed. If you're having to use the brakes to keep your speed down, you need to slow down and downshift. This makes the retarder a huge advantage plus the safety of being able to slow down without using the brakes as the grade changes. This is why Mr. Cummins invented his Jacobs Brake in the (?) '30s? I believe it was a runaway when he was driving into Wolf Creek Pass or something like that, it's been a year since I've heard the story. On a NA engine you lose 3% of your horsepower for every 1,000' above sea-level. At 10,000' altitude, you have likely lost about 63hp, or have around 147hp remaining. Since much of the horsepower is used for frictional losses in the drivetrain, engine accessories, rolling resistance, aerodynamic drag, ... this probably leaves enough power to run around 50mph on the flats and nothing for climbing until you gear down, and down. With our '77 again as an example I was able to climb over 10,000', but with much black smoke which had to be regulated by lifting the throttle so bicycles could see to pass ;~) The turbo burns much cleaner at altitude and maintains most of its rated power up there. Our '77 was 210hp originally, and 23,000lbs. Our '84 was 250hp, and 33,000lbs. The '82-up coaches are heavy and need the turbo. Still, look at the numbers, the '77 was 109.5lbs per horsepower, the '84 is a much lower-performing 132lbs per horsepower. This gave my '77 a performance advantage at low altitudes over the much heavier '80s models even with the Na engine. At 10,000' however, the '77 would have to pull 156.5lbs with each horsepower, so the advantage of the turbo is back. Our '88 FC was more powerful still, with the 300hp and around 33,000lbs, its power/weight ratio is around 110lbs/hp so almost identical to the '77 (at sea level). The overdrive transmission and high-altitude performance of the turbo (and retarder) make it a rocket in comparison though. The calculations are a little more complex than all of this of course, but the basic idea is there and FCs pretty much have the same aero-drag regardless of the year. I don't know if Ernie has retained the hp & climbing calculation from the old forum, if not I can re- submit it. Turbos are good, very good. The low-boost on the 3208 road engines is pretty much not going to hurt a well-maintained engine, not like it does in the 380-435hp marine versions. The engine simply doesn't wear out very often, it is more likely to suffer a cooling system or other failure that damages the engine. Retarders are also very useful, and a safety feature also. I've seen what happens when an FC driver over drives his brakes with no retarder on a grade, it's hard on the coach even when he's lucky (this one was). - Jeff Miller in Holland, MI --- In WanderlodgeForum@yahoogroups.com, "davidkerryedwards" > > Just crunched the numbers. Comparing a 210hp NA with a 250hp T, if > there is a 30% loss on the NA, and none on the T, there is a 70% > horsepower advantage with the T at altitude. > > > > --- In WanderlodgeForum@yahoogroups.com, "davidkerryedwards" > > > > > The main advantage I see in a turbo is maintaining sea-level > > horsepower at altitude. Here in Colorado an NA engine looses about > > 30% of its horsepower going over the passes, strictly as a result of > > the thin air. A turbo overcomes most of that loss. At lower > > elevations, the advantage is much less significant in my opinion. > > > > Kerry > > Denver > > > |
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02-19-2006, 12:15
Post: #7
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Rolls Royce Turbo Jet Engine for Blue Birds
Hello Jeff,
Thanks for the power/weight ratio numbers. They are along the lines I suspected. Your informed posts are always a pleasure to read. Now I know, for sure, why it is better to ride in a bus than on a bicycle :-) Seriously, I don't want to give anyone the impression that drive- line retarders are not useful. They are terrific devices, especially for novice drivers, but they are not mandatory. Of course, proper driving technique is always your best safety percaution. If you go up a hill in 2nd gear, than come down the hill in 2nd gear. Keep an eye on your air, and be prepared to pull over and stop if needed to build more air pressure (I have not, as of yet, had to do this in the 'Bird). Even if you forget to watch the air guages, the low air audio alarm should alert you with plenty of air to get stopped, providing you are not driving at too fast a speed. That's the way I drive the 'Bird, so if you see me coming from behind get the hell out of the way !! ... LOL It would be no fun to have the spring brakes deploy with the bus at speed. No fun at all. If you have never driven a heavy truck before a retarder should make the experience easier and probably safer as well. -James 78FC33SB LasVegas NV --- In WanderlodgeForum@yahoogroups.com, "Jeff Miller" > > On the way up, it's about power/weight ratio (comparing different > year 'Birds). My '77 FC31 weighed in around 23,000lbs with all tanks > full. With several engine upgrades, and 4.63:1 gears, it would run > well on the flats at 75mph or better. Slight inclines would slow it > down, but doing some simple calculations showed that it added only > minutes to each day's drive to slow a few MPH on the climb. > > Coming down the hills was different. In a diesel rig, you CAN NOT use > the brakes to control speed. If you're having to use the brakes to > keep your speed down, you need to slow down and downshift. This makes > the retarder a huge advantage plus the safety of being able to slow > down without using the brakes as the grade changes. This is why Mr. > Cummins invented his Jacobs Brake in the (?) '30s? I believe it was a > runaway when he was driving into Wolf Creek Pass or something like > that, it's been a year since I've heard the story. > > On a NA engine you lose 3% of your horsepower for every 1,000' above > sea-level. At 10,000' altitude, you have likely lost about 63hp, or > have around 147hp remaining. Since much of the horsepower is used for > frictional losses in the drivetrain, engine accessories, rolling > resistance, aerodynamic drag, ... this probably leaves enough power > to run around 50mph on the flats and nothing for climbing until you > gear down, and down. With our '77 again as an example I was able to > climb over 10,000', but with much black smoke which had to be > regulated by lifting the throttle so bicycles could see to pass ;~) > The turbo burns much cleaner at altitude and maintains most of its > rated power up there. > > Our '77 was 210hp originally, and 23,000lbs. Our '84 was 250hp, and > 33,000lbs. The '82-up coaches are heavy and need the turbo. Still, > look at the numbers, the '77 was 109.5lbs per horsepower, the '84 is > a much lower-performing 132lbs per horsepower. This gave my '77 a > performance advantage at low altitudes over the much heavier '80s > models even with the Na engine. At 10,000' however, the '77 would > have to pull 156.5lbs with each horsepower, so the advantage of the > turbo is back. > > Our '88 FC was more powerful still, with the 300hp and around > 33,000lbs, its power/weight ratio is around 110lbs/hp so almost > identical to the '77 (at sea level). The overdrive transmission and > high-altitude performance of the turbo (and retarder) make it a > rocket in comparison though. > > The calculations are a little more complex than all of this of > course, but the basic idea is there and FCs pretty much have the same > aero-drag regardless of the year. I don't know if Ernie has retained > the hp & climbing calculation from the old forum, if not I can re- > submit it. > > Turbos are good, very good. The low-boost on the 3208 road engines is > pretty much not going to hurt a well-maintained engine, not like it > does in the 380-435hp marine versions. The engine simply doesn't wear > out very often, it is more likely to suffer a cooling system or other > failure that damages the engine. Retarders are also very useful, and > a safety feature also. I've seen what happens when an FC driver over > drives his brakes with no retarder on a grade, it's hard on the coach > even when he's lucky (this one was). > > - Jeff Miller > in Holland, MI > > > --- In WanderlodgeForum@yahoogroups.com, "davidkerryedwards" > > > > > Just crunched the numbers. Comparing a 210hp NA with a 250hp T, if > > there is a 30% loss on the NA, and none on the T, there is a 70% > > horsepower advantage with the T at altitude. > > > > > > > > --- In WanderlodgeForum@yahoogroups.com, "davidkerryedwards" > > > > > > > > The main advantage I see in a turbo is maintaining sea-level > > > horsepower at altitude. Here in Colorado an NA engine looses > about > > > 30% of its horsepower going over the passes, strictly as a result > of > > > the thin air. A turbo overcomes most of that loss. At lower > > > elevations, the advantage is much less significant in my opinion. > > > > > > Kerry > > > Denver > > > > > > |
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02-19-2006, 12:59
Post: #8
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Rolls Royce Turbo Jet Engine for Blue Birds
Your comment makes me think again about how many people have hit the
spring brakes while under way. If you ever do, I'm sure you will be greatly surprised. The spring brakes are only on the drive wheels. Under normal operation, the drive wheels do 40% of the braking and the steer wheels 60%. Therefore, the "sudden" braking will be much less than hitting the service brakes hard. I have done it and was impressed about how far it took to stop and how gentle it is. Try it sometime, It won't hurt anything and you will be a better driver for it. George Lowry '06 Alpine Apex - Formerly '95 WBDA 4203 Spearfish, SD Now in Gila Bend, AZ where the air is clear and warm. orbitalsolutions wrote: > >It would be no fun to have the spring brakes deploy with the bus at >speed. No fun at all. If you have never driven a heavy truck before >a retarder should make the experience easier and probably safer as >well. > >-James >78FC33SB >LasVegas NV > > > > > > > > |
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02-19-2006, 14:11
Post: #9
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Rolls Royce Turbo Jet Engine for Blue Birds
Actually George, the drive axle does most of the braking on a heavy
vehicle like the Wanderlodge (including buses and trucks), very unlike passenger cars. The steer axle doesn't have as much tire, as much weight, and therefore smaller air chambers to apply less braking force. The spring brakes will not apply as much force to the brakes as the air pressure will in most cases, designed to avoid lockup. Regardless, I don't recommend using the spring brakes to stop a coach other than in an emergency. - Jeff Miller in Holland, MI --- In WanderlodgeForum@yahoogroups.com, George Lowry wrote: > > > Your comment makes me think again about how many people have hit the > spring brakes while under way. If you ever do, I'm sure you will be > greatly surprised. The spring brakes are only on the drive wheels. > Under normal operation, the drive wheels do 40% of the braking and the > steer wheels 60%. Therefore, the "sudden" braking will be much less than > hitting the service brakes hard. I have done it and was impressed about > how far it took to stop and how gentle it is. Try it sometime, It won't > hurt anything and you will be a better driver for it. > > George Lowry > '06 Alpine Apex - Formerly '95 WBDA 4203 > Spearfish, SD Now in Gila Bend, AZ where the air is clear and warm. |
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