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Yanmar Offers a Turbo Diesel Outboard
wrote:
On Thu, 12 Oct 2017 14:59:28 -0400, "Mr. Luddite" wrote: On 10/12/2017 2:13 PM, Bill wrote: wrote: On Thu, 12 Oct 2017 12:13:08 -0400, wrote: On Thu, 12 Oct 2017 11:17:07 -0400, wrote: Here's a real world example of the diesel vs gas engine trade off. Our old Bertram 33 had a 320 gallon fuel tank which seems like a lot but it had 454 gas engines which burned 35 gallons per hour. Cruising speed barely reached 18 knots on a good day. Doing the math, you come up with a safe fuel range of less than 140 miles, not enough for offshore canyon fishing in the NY area. Converting to diesel engines, the burn rate drops to about 20 gallons per hour, and cruising speed climbs to 23 knots or so, for a fuel range of around 300 miles. That's a big difference in the capability of the boat and has nothing to do with the price of fuel or reliability. That must be one heavy sommich if 2 454s only get you 18 MPH. The guy around the corner has a 36 (Donzi I think) with 2 250s on it that will cruise in the 30s burning a combined 25-30 GPH or so (a whole lot more at WOT tho) === A Bertram 33 is a much different boat than a Donzi: Heavier close to 20,000 lbs; Beamier; Windage from a full flybridge with enclosure; Full cruising interior. It would do 25 kts wide open with half fuel but I was concientious about keeping the RPMs at no more than 3200 or 3300. The whole point of my comparison excercise was to show that increased fuel range with diesel is often the deciding factor as opposed to fuel cost savings. I do understand the diesel thing. My buddy used to captain a bigger Bertie with 2 6-71s in it for a rich guy (46 or 50 sumpin?). Nice boat. Winter at Pier 66 and summer in Annapolis. He gave it all up for IBM and a family. There were IBM guys who said they would have just swapped jobs ;-) My friend has a 39’ Luhrs. Twin Cummins. They are heavier than a gas engine, but I bet not that much more than a 454. Unlike a 6-71. I was curious so I looked it up. A fully dressed 454 with cast iron heads weighs 685 lbs from the factory. A Cummins 5.9L diesel by comparison is 1200 lbs or 515 lbs heavier. Twins would mean a weight difference of over 1,000 lbs. That's quite a bit, even for a 39' boat. Major difference is: The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year) while the diesel Cummins develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. Surprised me the difference in weight. A lot of the short stroke in gas engines is to reduce ring speed. A long stroke and high RPM and the speed of the rings becomes pretty astronomical. Lots of the fuel mileage comes from the BTU’s in a gallon of diesel vs. a gallon of gas. BTU is pretty much equivalent per pound of fuel, but diesel weighs more than gas per gallon. |
Yanmar Offers a Turbo Diesel Outboard
Keyser Soze wrote:
On 10/12/17 4:53 PM, wrote: On Thu, 12 Oct 2017 16:42:10 -0400, wrote: I was curious so I looked it up. A fully dressed 454 with cast iron heads weighs 685 lbs from the factory. A Cummins 5.9L diesel by comparison is 1200 lbs or 515 lbs heavier. Twins would mean a weight difference of over 1,000 lbs. That's quite a bit, even for a 39' boat. Major difference is: The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year) while the diesel Cummins develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. === I believe the extra torque is mostly a result of the higher compression ratio in a diesel. The higher ratio effectively increases the duration of the power stroke compared to a gas engine. I thought it was the result of a combination of factors, including higher compression ratio, more heat content of the fuel, higher turbo boost pressure, and greater heat content of the fuel, and continuous pushing of that fuel into the cylinders. Nice Google search! |
Yanmar Offers a Turbo Diesel Outboard
John H wrote:
On Thu, 12 Oct 2017 16:53:30 -0400, wrote: On Thu, 12 Oct 2017 16:42:10 -0400, wrote: I was curious so I looked it up. A fully dressed 454 with cast iron heads weighs 685 lbs from the factory. A Cummins 5.9L diesel by comparison is 1200 lbs or 515 lbs heavier. Twins would mean a weight difference of over 1,000 lbs. That's quite a bit, even for a 39' boat. Major difference is: The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year) while the diesel Cummins develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. === I believe the extra torque is mostly a result of the higher compression ratio in a diesel. The higher ratio effectively increases the duration of the power stroke compared to a gas engine. --- This email has been checked for viruses by AVG. http://www.avg.com Looks like Krause cut'n'pasted something to show his exceptional knowledge of diesel engines. No doubt. |
Yanmar Offers a Turbo Diesel Outboard
On Thu, 12 Oct 2017 23:58:29 -0000 (UTC), Bill
wrote: wrote: On Thu, 12 Oct 2017 14:59:28 -0400, "Mr. Luddite" wrote: On 10/12/2017 2:13 PM, Bill wrote: wrote: On Thu, 12 Oct 2017 12:13:08 -0400, wrote: On Thu, 12 Oct 2017 11:17:07 -0400, wrote: Here's a real world example of the diesel vs gas engine trade off. Our old Bertram 33 had a 320 gallon fuel tank which seems like a lot but it had 454 gas engines which burned 35 gallons per hour. Cruising speed barely reached 18 knots on a good day. Doing the math, you come up with a safe fuel range of less than 140 miles, not enough for offshore canyon fishing in the NY area. Converting to diesel engines, the burn rate drops to about 20 gallons per hour, and cruising speed climbs to 23 knots or so, for a fuel range of around 300 miles. That's a big difference in the capability of the boat and has nothing to do with the price of fuel or reliability. That must be one heavy sommich if 2 454s only get you 18 MPH. The guy around the corner has a 36 (Donzi I think) with 2 250s on it that will cruise in the 30s burning a combined 25-30 GPH or so (a whole lot more at WOT tho) === A Bertram 33 is a much different boat than a Donzi: Heavier close to 20,000 lbs; Beamier; Windage from a full flybridge with enclosure; Full cruising interior. It would do 25 kts wide open with half fuel but I was concientious about keeping the RPMs at no more than 3200 or 3300. The whole point of my comparison excercise was to show that increased fuel range with diesel is often the deciding factor as opposed to fuel cost savings. I do understand the diesel thing. My buddy used to captain a bigger Bertie with 2 6-71s in it for a rich guy (46 or 50 sumpin?). Nice boat. Winter at Pier 66 and summer in Annapolis. He gave it all up for IBM and a family. There were IBM guys who said they would have just swapped jobs ;-) My friend has a 39’ Luhrs. Twin Cummins. They are heavier than a gas engine, but I bet not that much more than a 454. Unlike a 6-71. I was curious so I looked it up. A fully dressed 454 with cast iron heads weighs 685 lbs from the factory. A Cummins 5.9L diesel by comparison is 1200 lbs or 515 lbs heavier. Twins would mean a weight difference of over 1,000 lbs. That's quite a bit, even for a 39' boat. Major difference is: The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year) while the diesel Cummins develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. Surprised me the difference in weight. A lot of the short stroke in gas engines is to reduce ring speed. A long stroke and high RPM and the speed of the rings becomes pretty astronomical. Lots of the fuel mileage comes from the BTU’s in a gallon of diesel vs. a gallon of gas. BTU is pretty much equivalent per pound of fuel, but diesel weighs more than gas per gallon. I supposed I was to know that after all of the generator talk and the BTUs of Diesel, gasoline and propane. |
Yanmar Offers a Turbo Diesel Outboard
On Thu, 12 Oct 2017 17:47:17 -0400, "Mr. Luddite" wrote:
On 10/12/2017 5:12 PM, wrote: On Thu, 12 Oct 2017 16:22:23 -0400, "Mr. Luddite" wrote: On 10/12/2017 4:03 PM, wrote: On Thu, 12 Oct 2017 13:11:11 -0400, "Mr. Luddite" wrote: On 10/12/2017 1:05 PM, wrote: On Thu, 12 Oct 2017 10:52:37 -0400, "Mr. Luddite" wrote: THere's something about gas engines running for hours at 3,600 to 4,000 RPM that disturbs me, even though I realize they have cams, etc., that are designed for it. Seem to remember the general rule was 1,000 to 1,500 hours before a rebuild. That must have been a "rule" made when engines were still "detroit iron". Once the Japs showed us you can make a better engine, all of them will run many thousands of hours. My Yamamerc 60 had over 3000 on it with no indication it was in need of anything. I got rid of it because of all of the other $200-500 screw on parts that were nearing end of life. I wasn't referring to outboards. Was talking about I/Os that use car or truck engines like the popular GM 350, 454, Ford 460, etc. OK but these days an engine will easily go 5000 hours or more in a car. There are plenty of 200,000 mile Hondas, Toyotas and even Ford trucks around and most got pretty shoddy maintenance in the last half of their lives. Cars usually get junked because things other than the engine go bad. Hell my 71 Jeep 304 had 170k miles on it when I sold it (running) and same with my 69 Corvette. Those were old technology detroit iron running 70 miles a day on the beltway plus my "around town". Both had the **** kicked out of them. Neither were in salt water tho. I suspect it is corrosion that kills I/Os, at least that has been what I saw. I don't think you can compare the wear and tear of say, a GM 350 V8 used in a car with the marine version of the same engine. Unless you are just trolling around all the time, the marine engine is working at or near full load and at relatively high RPM compared to the car version. The car version, cruising down the highway with the torque converter locked up is only turning about 1600 -1800 RPM at 60-65 mph and is only developing maybe 20 or 30 hp to do it. You never rode around with me in my Corvette I suppose. That was before the Maryland cops figured there was money in speeders and there was virtually no speed limit on the beltway after dark. I have made lots of trips at or near WOT(140 mph or so) I also ran it pretty hard all the time. My Chevelle had a 456 rear so 70 MPH was around 4500 RPM The Corvette was a 336 so it was a bit lower at 70. My Honda is turning ~4k on the interstate (75-80). The V-tech kicks in at 5000 RPM and I feel it a lot, just running up and down US41. My boat certainly has an easier time of it. Engine sp Time[h] - 1000 r/m 125 1000 - 2000 822.9 2000 - 3000 101.7 3000 - 4000 175.4 4000 - 5000 51.1 5000 - 6000 0.4 6000 - 7000 0 Engine ho 1276 High RPM for engines designed for them doesn't hurt but "lugging" them sure is. Running a boat is closer to continuously lugging the engine for hours on end if cruising somewhere. That's where the diesels have the big advantage. They are made for it. BTW ... your Honda is turning 4k RPM at 75 to 80? That seems very high. Once the torque converter locks up (assuming your Honda is an auto and has one) cars today usually are running closer to 2K or maybe a little more at that speed. That's my experience anyway. The new Canyon I bought has an eight speed transmission and a lock up TC. At 65 mph I am turning about 1800 RPM. His Honda sounds like my two cylinder Moto Guzzi. It's going almost 75mph at 4000rpm. |
Yanmar Offers a Turbo Diesel Outboard
On Thu, 12 Oct 2017 17:48:36 -0400, "Mr. Luddite" wrote:
On 10/12/2017 5:05 PM, Keyser Soze wrote: On 10/12/17 4:53 PM, wrote: On Thu, 12 Oct 2017 16:42:10 -0400, wrote: I was curious so I looked it up.* A fully dressed 454 with cast iron heads weighs 685 lbs from the factory.* A Cummins* 5.9L diesel by comparison* is 1200 lbs or 515 lbs heavier.* Twins would mean a weight difference of over 1,000 lbs.* That's quite a bit, even for a 39' boat. Major difference is:* The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year)* while the diesel Cummins* develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. === I believe the extra torque is mostly a result of the higher compression ratio in a diesel.* The higher ratio effectively increases the duration of the power stroke compared to a gas engine. I thought it was the result of a combination of factors, including higher compression ratio, more heat content of the fuel, higher turbo boost pressure, and greater heat content of the fuel, and continuous pushing of that fuel into the cylinders. Probably all you mentioned ... oh and also the greater heat content of the fuel in case you forgot. :-) He probably missed that with his cut'n'paste. |
Yanmar Offers a Turbo Diesel Outboard
On Thu, 12 Oct 2017 19:54:25 -0400, Alex wrote:
Keyser Soze wrote: On 10/12/17 12:15 PM, wrote: On 12 Oct 2017 13:51:41 GMT, Keyser Soze wrote: Here's a real world example of the diesel vs gas engine trade off. Our old Bertram 33 had a 320 gallon fuel tank which seems like a lot but it had 454 gas engines which burned 35 gallons per hour. Cruising speed barely reached 18 knots on a good day. Doing the math, you come up with a safe fuel range of less than 140 miles, not enough for offshore canyon fishing in the NY area. Converting to diesel engines, the burn rate drops to about 20 gallons per hour, and cruising speed climbs to 23 knots or so, for a fuel range of around 300 miles. That's a big difference in the capability of the boat and has nothing to do with the price of fuel or reliability. --- This email has been checked for viruses by AVG. http://www.avg.com About $75,000 to $100,000 for removal of gas engines, engineering, plumbing, new pair of 250 to 300 HP diesels. If gasoline is three bucks a gallon, the conversion would cover 25,000 gallons of gasoline. Ouch. ? === The whole point of my comparison excercise was to show that increased fuel range with diesel is often the deciding factor as opposed to fuel cost savings. Oh, I agree with you, and on a 30+ footer, one or two diesels usually are a better choice, especially on a heavier boat Brilliant! Would you expect less from one who has twin Volvo diesels on his trawler (undoubtedly a 30+ footer)! |
Yanmar Offers a Turbo Diesel Outboard
On Thu, 12 Oct 2017 20:22:05 -0400, wrote:
On Thu, 12 Oct 2017 23:58:29 -0000 (UTC), Bill wrote: wrote: On Thu, 12 Oct 2017 14:59:28 -0400, "Mr. Luddite" wrote: On 10/12/2017 2:13 PM, Bill wrote: wrote: On Thu, 12 Oct 2017 12:13:08 -0400, wrote: On Thu, 12 Oct 2017 11:17:07 -0400, wrote: Here's a real world example of the diesel vs gas engine trade off. Our old Bertram 33 had a 320 gallon fuel tank which seems like a lot but it had 454 gas engines which burned 35 gallons per hour. Cruising speed barely reached 18 knots on a good day. Doing the math, you come up with a safe fuel range of less than 140 miles, not enough for offshore canyon fishing in the NY area. Converting to diesel engines, the burn rate drops to about 20 gallons per hour, and cruising speed climbs to 23 knots or so, for a fuel range of around 300 miles. That's a big difference in the capability of the boat and has nothing to do with the price of fuel or reliability. That must be one heavy sommich if 2 454s only get you 18 MPH. The guy around the corner has a 36 (Donzi I think) with 2 250s on it that will cruise in the 30s burning a combined 25-30 GPH or so (a whole lot more at WOT tho) === A Bertram 33 is a much different boat than a Donzi: Heavier close to 20,000 lbs; Beamier; Windage from a full flybridge with enclosure; Full cruising interior. It would do 25 kts wide open with half fuel but I was concientious about keeping the RPMs at no more than 3200 or 3300. The whole point of my comparison excercise was to show that increased fuel range with diesel is often the deciding factor as opposed to fuel cost savings. I do understand the diesel thing. My buddy used to captain a bigger Bertie with 2 6-71s in it for a rich guy (46 or 50 sumpin?). Nice boat. Winter at Pier 66 and summer in Annapolis. He gave it all up for IBM and a family. There were IBM guys who said they would have just swapped jobs ;-) My friend has a 39’ Luhrs. Twin Cummins. They are heavier than a gas engine, but I bet not that much more than a 454. Unlike a 6-71. I was curious so I looked it up. A fully dressed 454 with cast iron heads weighs 685 lbs from the factory. A Cummins 5.9L diesel by comparison is 1200 lbs or 515 lbs heavier. Twins would mean a weight difference of over 1,000 lbs. That's quite a bit, even for a 39' boat. Major difference is: The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year) while the diesel Cummins develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. Surprised me the difference in weight. A lot of the short stroke in gas engines is to reduce ring speed. A long stroke and high RPM and the speed of the rings becomes pretty astronomical. Lots of the fuel mileage comes from the BTU’s in a gallon of diesel vs. a gallon of gas. BTU is pretty much equivalent per pound of fuel, but diesel weighs more than gas per gallon. I supposed I was to know that after all of the generator talk and the BTUs of Diesel, gasoline and propane. Harry did. |
Yanmar Offers a Turbo Diesel Outboard
On 10/13/2017 5:32 AM, John H wrote:
On Thu, 12 Oct 2017 17:48:36 -0400, "Mr. Luddite" wrote: On 10/12/2017 5:05 PM, Keyser Soze wrote: On 10/12/17 4:53 PM, wrote: On Thu, 12 Oct 2017 16:42:10 -0400, wrote: I was curious so I looked it up.Â* A fully dressed 454 with cast iron heads weighs 685 lbs from the factory.Â* A CumminsÂ* 5.9L diesel by comparisonÂ* is 1200 lbs or 515 lbs heavier.Â* Twins would mean a weight difference of over 1,000 lbs.Â* That's quite a bit, even for a 39' boat. Major difference is:Â* The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year)Â* while the diesel CumminsÂ* develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. === I believe the extra torque is mostly a result of the higher compression ratio in a diesel.Â* The higher ratio effectively increases the duration of the power stroke compared to a gas engine. I thought it was the result of a combination of factors, including higher compression ratio, more heat content of the fuel, higher turbo boost pressure, and greater heat content of the fuel, and continuous pushing of that fuel into the cylinders. Probably all you mentioned ... oh and also the greater heat content of the fuel in case you forgot. :-) He probably missed that with his cut'n'paste. yup. |
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