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 > Your search for posts made by 'ShinerBock' found 893 matches.

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RE: Why diesels are most efficient around 1,800 rpm

"When towing, whatever gear keeps engine rpm between 1,800 and 2,000 rpm will give the best fuel mileage and power because that is the rpm window where the Cummins 6.7-liter makes peak torque. I tow at 60 with rpm's about 1,750. Just right! That's with 4.10's. At 70 I am about 2,000. With my last DRW I had 3.42's. I would tow in 5th at same rpm's as above, just right! Exactly right I’ll expect to be getting the 3:31s in my next truck. Whether I’ll have to lock out 9th or tenth will depend on the load I’m pulling but with 1050 lb ft of torque most my loads will be considered light. It not a factor of engine power. I can and have towed my camper many times on my level three tune which puts me at around 470 hp/1,020 lb-ft at the wheels which is about 540 hp/ 1,175 lb-ft at the crank with the standard 15% loss from the drivetrain. These were my dyno numbers with my stock turbo and they are probably 30-50 hp more than that with my current turbo, but I haven't put it on a dyno yet to verify. I still have one more level on my CSP switch that will put me well over 500hp/1,100 at the wheels. So as I have been saying over and over and over..... my truck has more than enough power to tow in 6th and would blow that 1,050 lb-ft PSD out of the water. It just gets better fuel economy in 5th than 6th towing my 13k RV since it puts me at a more efficient rpms (@ 1,800) at the speeds I tow which is backed up by the BCFC map I posted earlier. I feel sorry for you that you refuse to believe that. I will also say that 6th gear in my trans is the same ratio as 10th in the Ford trans. So if I did have a hard time holding 6th with the power that my 3.42 rear geared truck makes, then you would definitely have a hard time holding 10th in a 3.31 geared truck with less power. What kind of fuel economy do you get towing your trailer with the custom tune? If you look at the BSFC map you posted you see that the stock Cummins is similar to most diesel engines in that when you are only requiring a fraction of peak HP you get better fuel economy running low rpm and higher torque. If an engine is capable of 1050 ft lbs of torque at 1800 rpm and only 380 lb ft are required to tow the trailer at 1800 engine rpm and 60 mph, it would be running way off its peak cylinder pressure at that rpm. Better to slow it down. You got any maps or manufacturers data to gob with that? I am at 1775 rpm at 65 mph in 5th not 60 mph. At 60 mph in 5th I am at 1660 rpm and 1270 rpm in 6th. At either speed, I am closer to my most fuel efficient rpm while towing my trailer in 5th gear rather than 6th.
ShinerBock 10/25/20 06:00pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

"When towing, whatever gear keeps engine rpm between 1,800 and 2,000 rpm will give the best fuel mileage and power because that is the rpm window where the Cummins 6.7-liter makes peak torque. I tow at 60 with rpm's about 1,750. Just right! That's with 4.10's. At 70 I am about 2,000. With my last DRW I had 3.42's. I would tow in 5th at same rpm's as above, just right! Exactly right Exactly wrong. The 6.7 cummins only makes it's peak torque at wide open throttle and full boost at that rpm and I'm pretty sure no one drives down the highway at wide open throttel. Fish, I believe you are misunderstanding what is being said here. Generally, engines are more efficient under load around the rpm that they make peak torque. This is actually true for most engines. They are not saying to drive around at WOT. I guess I'm having a hard time wrapping my head around this. Diesel engines make peak power at WOT and full boost, and typically are most fuel efficient at minimum boost. I'm not sure how that can happen at the same ~ rpms. It is not about making peak torque. They are just talking about the rpms at which it makes that peak torque. This is basically what 4x4Ford have been arguing. Towing my 13k 5ver at 65mph would put be at in 6th which is the yellow line below. The red line is about where I am in 5th gear. As you can see, under medium to heavy loads for my gear ratio, I am closer to or actually in the "sweet spot" they were talking about which happens to be around where my engine makes peak torque. https://i.postimg.cc/05YMn9sQ/BSFC.png height=550 width=400
ShinerBock 10/25/20 04:20pm Tow Vehicles
RE: 200,000 Mile Milestone

Congrats!
ShinerBock 10/25/20 02:47pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

"When towing, whatever gear keeps engine rpm between 1,800 and 2,000 rpm will give the best fuel mileage and power because that is the rpm window where the Cummins 6.7-liter makes peak torque. I tow at 60 with rpm's about 1,750. Just right! That's with 4.10's. At 70 I am about 2,000. With my last DRW I had 3.42's. I would tow in 5th at same rpm's as above, just right! Exactly right Exactly wrong. The 6.7 cummins only makes it's peak torque at wide open throttle and full boost at that rpm and I'm pretty sure no one drives down the highway at wide open throttel. Fish, I believe you are misunderstanding what is being said here. Generally, engines are more efficient under load around the rpm that they make peak torque. This is actually true for most engines. They are not saying to drive around at WOT.
ShinerBock 10/25/20 02:45pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

"When towing, whatever gear keeps engine rpm between 1,800 and 2,000 rpm will give the best fuel mileage and power because that is the rpm window where the Cummins 6.7-liter makes peak torque. I tow at 60 with rpm's about 1,750. Just right! That's with 4.10's. At 70 I am about 2,000. With my last DRW I had 3.42's. I would tow in 5th at same rpm's as above, just right! Exactly right I’ll expect to be getting the 3:31s in my next truck. Whether I’ll have to lock out 9th or tenth will depend on the load I’m pulling but with 1050 lb ft of torque most my loads will be considered light. It not a factor of engine power. I can and have towed my camper many times on my level three tune which puts me at around 470 hp/1,020 lb-ft at the wheels which is about 540 hp/ 1,175 lb-ft at the crank with the standard 15% loss from the drivetrain. These were my dyno numbers with my stock turbo and they are probably 30-50 hp more than that with my current turbo, but I haven't put it on a dyno yet to verify. I still have one more level on my CSP switch that will put me well over 500hp/1,100 at the wheels. So as I have been saying over and over and over..... my truck has more than enough power to tow in 6th and would blow that 1,050 lb-ft PSD out of the water. It just gets better fuel economy in 5th than 6th towing my 13k RV since it puts me at a more efficient rpms (@ 1,800) at the speeds I tow which is backed up by the BCFC map I posted earlier. I feel sorry for you that you refuse to believe that. I will also say that 6th gear in my trans is the same ratio as 10th in the Ford trans. So if I did have a hard time holding 6th with the power that my 3.42 rear geared truck makes, then you would definitely have a hard time holding 10th in a 3.31 geared truck with less power.
ShinerBock 10/25/20 02:40pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

Sounds like this guy likes to tow in 5th for many of the same reasons as Shiner but he does indicate he gets slightly better fuel economy in 6th. He might have slightly bigger tires? Seems like splitting hairs to me. I’m certainly going to go for the quieter cab with the lower rpm if I can save a few pennies at the pump. If the transmission needs to be babied to handle towing light why not just buy a Ford? Link Slight? They look like the same size tires as my truck which are 34s. That would put him at 2 inches taller than stock for that truck. But of course it seems like splitting hairs to a Ford fanboy who thinks he knows better than Cat, Cummins, and every other diesel manufacturer engineer just so they can piss on other truck makes. Also, guess what rpm a 4.10 Ram 3500 that is in 6th to get that good mileage when towing? The same rpm I am at in 5th with 3.42s. Who da thunk it..... As for your link, the guy is only towing 15k combined which is within the 5-7k range were I stated that 6th is more economical for me earlier in this thread. I am towing another 6-7k lb toy hauler 5ver with a taller than normal roof. It is not necessarily due to a weak trans, but rather that a tall rear gear combined with a tall OD gear puts more stress on trans clutches than a shorter rear gear ratio would. This goes for any transmission with a tall rear gear combo towing heavy.
ShinerBock 10/23/20 08:48pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

Here's a video of a hot shot driver that did a test pulling a load at 65 mph vs 70 mph. It appears his 6.7 cummins with the aisin tranny doesn't like running at 65 mph with all the gear shifting probably caused his extra fuel consumption. Link I don't see how that guy has over 92k subscribers. He is so annoying to watch. I could only get about a minute into it before I had to turn it off. Although I wonder if he reconfigured his speedo for those oversized tires he has. They look to be at least 1 inch over which would totally mess up his numbers(even hand calculated) if he is doing a mileage run. My Ram and F150 would showed that I got 3-4 mpg less than when I finally got the speedo corrected with my 1 inch oversized tires. He also looks to have some sort of a front end level or lift kit. I can see the white lettering of a Carli suspension torsion bar right under the drivers door which are generally for a 3-6" lift. Not sure why he would be worried about fuel mileage with that kind of setup. All the things he did to the truck is kind of counterintuitive for wanting to attain the best mpg possible. How his truck is configured is irrelevant for his particular test which was to compare the fuel economy at two different speeds and the only variable was the speed he drove and perhaps some road conditions. Now is he was trying to test fuel economy performance to another brand then yes I would agree with you but then again there's no need to perform that test as we know the results and these results I've been predicting early this year. Well, I didn't watch the full video because the guy was annoying and didn't seem all there. So I don't know if he was trying to compare the fuel mileage of this truck to anything else. If he did, it would be stupid of him to do so given the mods on the truck. Also, in reference to you saying that appears the Aisin does not like 65 mph, taller tires also effects the gearing and rpm of the truck from stock as well. His rpm will be lower on oversized tires versus smaller stock tires which also lowers how much power it can make at a given speed. There is also the issue of greater drag due to the lift which eats up power. So this should no way be compared to what the Aisin is capable of in stock form or used as a reference.
ShinerBock 10/22/20 09:28pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

Here's a video of a hot shot driver that did a test pulling a load at 65 mph vs 70 mph. It appears his 6.7 cummins with the aisin tranny doesn't like running at 65 mph with all the gear shifting probably caused his extra fuel consumption. Link I don't see how that guy has over 92k subscribers. He is so annoying to watch. I could only get about a minute into it before I had to turn it off. Although I wonder if he reconfigured his speedo for those oversized tires he has. They look to be at least 1 inch over which would totally mess up his numbers(even hand calculated) if he is doing a mileage run. My Ram and F150 would showed that I got 3-4 mpg less than when I finally got the speedo corrected with my 1 inch oversized tires. He also looks to have some sort of a front end level or lift kit. I can see the white lettering of a Carli suspension torsion bar right under the drivers door which are generally for a 3-6" lift. Not sure why he would be worried about fuel mileage with that kind of setup. All the things he did to the truck is kind of counterintuitive for wanting to attain the best mpg possible.
ShinerBock 10/22/20 08:03pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

I will also say that you will likely please more customers when you tune the trans to put you at too high of a gear at a low rpm with the ability to take out gears as needed than to tune it to put you in too low of gear at high rpm without the ability to force it into the next gear. I have had tunes with both of these extremes on my truck before my trans was tuned on the dyno to how I wanted it(or at least as close as I could get it). While the tune that left me in too low of a gear/high rpm was great for towing, it was horrible to drive in unloaded. The tune that put me at a higher gear/low rpm was better unloaded, but horrible loaded. However, at least I had the ability to take out gears as needed when loaded unlike the other tune.
ShinerBock 10/22/20 02:32pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

Shiner I really don't think we are that different in how we understand things. For one thing I am giving the Ram/Cummins engineers a bit more respect than you do. I believe with today's technology it is not that difficult for an engineer to program a transmission to select the right gear for the load being towed. The truck computer has a lot more information to base things on than you do. Based on what you have posted I would likely lock out 6th gear with your truck if I was towing 13k at 60 mph. If I was towing at 65 mph I would definitely be in 6th unless the terrain, wind or traffic conditions were such that the tranny was shifting back and forth. Between 60 and 65 I really doubt it would make much difference what I did.... According to the BSFC map that you posted the fuel economy would be the same.... Likely about 9.5 mpg. It is not about giving them credit or respect. It is about knowing what they have to work with, how the tuning is done, and what parameters determine shift points. Making shift points for an unloaded vehicle with a known weight is easy. Making shift points for a vehicle towing an unknown amount of weight, unknown grade, unknown drag, and for an unknown speed is not so easy. Then you have the factor that you will not satisfy everyone. Just look at the trans tuning section in the diesel forums. You will have a third of the people who will want to be in the highest gear possible, another third that wants it at higher rpms for power, and another third that want it somewhere in between because they all use their trucks differently. This is why my tuner stopped charging for transmission tuning after three years and just offered one trans tune for everyone. He was constantly getting emails from people wanting to change it for different purposes, and it was hard to please everyone with his trans tuning updates. The only way he will change now is if you go to his shop, put it on the dyno, and be right there with him as he adjust the parameters. This is likely why the makes just offered the select shift, different rear gear options, and in the case of Ram different engine options for power or efficiency because it is easier and more cost effective to offer these options than spend all this money on something that will not please everyone. You are close on my mileage. In 6th it was always below 10 mpg and in 5th it was always above 10 mpg with cruise set to 65 mph.
ShinerBock 10/22/20 01:50pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

I'd be willing to bet the Cummins/Ram engineers have got things set up so that their 400 HP 6.7 Cummins/Aisin will tow light loads, such as a 13k fiver on a level road, at 1500 rpm before downshifting to 5th and towing at 1833 rpm. :S So will my truck, but that does not mean that 6th is the most efficient gear when towing 13k. This is why Ram and all makes have rear gear options so you can pick the best gear on how you will be using your truck. My 3.42 is perfect for those who daily their trucks and want the lowest rpms possible unloaded while having the option of putting it in 5th when towing giving you slightly more torque multiplication and higher rpm as a 4.10 gears truck in 6th. For those who tow more often, the 3.73 or 4.10 is the option to go. The makes don't alter trans shift tunes for every rear gear option. You are suppose to pick the rear gear option that best suits how you will be using the truck and utilize the trans gear selection feature as needed. This is why there are soo many options in the medium/heavy duty world. The customer specs out each truck based o how it will be used. For every truck model. there are generally 1-3 engine options, 4-8 engine power options per engine, 3-10 different trans options with different speeds and ratios, and at least 10 rear gear ratio options. Even in the medium/heavy professional world of hauling/towing, the customer is suppose to spec out the truck based on how it will be used. There is no one size fits all magic truck that the engineers put together. The light duty world has a lot less options and the are mainly tuned for general purposes.
ShinerBock 10/22/20 12:57pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

Funny how even TrailerLife.com even states that around 1,800 is the best rpm for fuel economy. I guess they are wrong too along with the Cummins engineers. Diesel Tech Q&A: Axle-Ratio Selection "When it comes to fuel economy, running empty around town or when driving where speeds are less than 55 mph, you’d see very little difference in fuel mileage between the two axle ratios because the transmission will never get the engine rpm high enough to be a factor. When towing, whatever gear keeps engine rpm between 1,800 and 2,000 rpm will give the best fuel mileage and power because that is the rpm window where the Cummins 6.7-liter makes peak torque. With a little time, you’ll find the engine’s “sweet spot” with the trailer you are towing. The difference in towing mpg between the 3.42 and 3.73 gears at highway cruise speed, under the same conditions, should be less than 1 mpg because of the slightly higher rpm running 3.73s. Vehicle speed actually plays a bigger role in fuel economy than engine rpm. That’s because towing or unladen, mpg drops exponentially at speeds above 60 mph, which is when aerodynamic drag (Cd) really begins rearing its ugly head related to pickups."
ShinerBock 10/22/20 09:41am Tow Vehicles
RE: Regular or premium

Here is a study AAA did several years back that actual has an Escalade with a 6.2L Ecotec in the test. The study tests the impact of regular and premium fuel on engines that require regular and premium. It shows short burst full load dynos and sustained dynos at 2,000 and 4,000 rpm which is where the difference between the two fuels is most noticeable in the real world especially when towing. There is also graphs on the amount of timing is advanced/pulled along with temps of the catalyst along with MAP/MAF sensor readings. One major thing to note is the 7.1% fuel economy increase on the 6.2L with premium fuel under normal load. This was contributed to ability of the 6.2L to stay in 4 cylinder mode more often due to the significant timing advance at this load level creating more power per cylinder. The gen one 3.5L Ecoboost also had a considerable fuel economy bump of 5% with premium fuel. AAA Premium Fuel Research
ShinerBock 10/22/20 07:43am Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

My fuel economy is roughly .5-1 mpg on average.. I would say a 1 mpg savings is significant if you’re actually getting 6 mpg in 5th and 5 mpg in 6th. If on the other hand you’re getting 13.5 in 5th and 14 in 6 th .... it’s still something but I know I find I can get a difference of more than that between two trips leaving the transmission in drive both times. Anyway, what you actually measured for fuel economy in each gear really is relevant to our discussion. At this point, nothing I can say will change a thing. If data from the very manufacturers who makes my diesel engine and from other diesel engine manufacturers will not change your opinions and beliefs, then there is nothing I can tell you that will either. You are going to believe what you want to believe regardless of facts.
ShinerBock 10/21/20 09:35pm Tow Vehicles
RE: Regular or premium

Modern auto engines do not ping - knock detection adjusts timing and fuel to prevent any pre-ignition or detonation. So when you buy an engine that is designed for 91 and you use 87 or less in it will run fine. It is not producing the power you paid for is all. Sometimes the vehicle will use more 87 per mile than 91, especially if you are tow / hauling and actually using max power. Yes and no. While most modern engines can adjust to a certain octane, they can only pull so much timing and alter the cam profile to a certain degree. If the ECU pulls as much timing as it possibly can and the engine still knocks, then it is time to increase the octane. This issue is compounded with single cam pushrod engines versus overhead cam engines that have more flexibility and control of valve overlap along with ignition timing.
ShinerBock 10/21/20 08:01pm Tow Vehicles
RE: Regular or premium

I've actually started running premium in my 13 Eco for the last 2 years now and towing my #7000 TT now compared to the old #5000 TT it makes a world of difference.. I just keep it going when not towing too.. Truck seems to really like it, especially with 93,000 miles on it now. It's getting the best mpg's it's ever gotten not towing. Same route, driving the same way.. I towed my new #7000 TT the first time with 87 in the tank... It was a dog. Thanks to the knock sensor, it ******* the timing so much, it had no power to haul the new beast the way I was used to with the old trailer.. Remember, you just can't dump a half a tank of premium in and expect night and day results. I ran at least a full tank of premium before I towed the new trailer the second time on 92. It was a night and day difference for sure. Well for me anyway.. Your mileage may vary. My owners manual for the Eco says it'll run fine on 87. But, if you tow heavy, they recommend running 92. So, no idea on your 6.2.. But, I would say that if the manual recommends running "premium"... I'd go with it.. :) Good luck! Mitch The 3.5L is a variable fuel engine in that unlike most fixed cam/timing it can adjust timing, valve overlap, and so on to take advantage of different octane ratings. I believe it was Pickuptrucks.com who published that Ford stated that the 3.5L Ecoboost 365hp/420lb-ft on regular fuel went up to 385hp/430lb-ft on premium fuel. So unlike most engines, you are actually seeing/feeling a power increase.
ShinerBock 10/21/20 04:22pm Tow Vehicles
RE: Regular or premium

The problem with comparing the GM Ecotec 6.2L with all those other engines is that the 6.2L has a compression ratio of 11.5:1 while all the others stated are 11.0:1 or lower. Compression ratio is what mainly dictates the need for premium. The higher the compression ratio, the greater the need for premium fuel. Hemi 5.7L- 10.5:1 GM 5.3L- 9.6:1 for non-Ecotec (11.0:1 for 2014+ Ecotec) GM 6.0L- 9.7:1 GM 8.1L- 9.1:1 Ford 7.3L- 10.5:1
ShinerBock 10/21/20 01:44pm Tow Vehicles
RE: Regular or premium

There have been multiple 6.2L owners here stating that theirs would ping horribly with regular unleaded.
ShinerBock 10/21/20 12:10pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

Not to take away from this informative debate, but I have been curious on my 2013 6.7, the RPM in 6th seems low at 1200-1300 unloaded. Just by my ear it sounds as if it needs to be higher so I manually shift it into 5th to be around 1500-1600. Do I have an issue, and need to get something reprogrammed? That is just how the stock 68RFE with 3.42 gears is with stock programming. Nothing wrong with being that low unloaded and the Cummins will easily lug even lower than that. I would not want to be towing 5-7k at that low of rpms though and the stock trans tuning will put you there sometimes. I had an old trans tune on my truck that allowed it to be at 45 mph in 6th(975 rpm) and it still had enough power to slowly accelerate up hills unloaded. Only had it in my truck for about a week and switched to a better tune that kept rpms above 1,400.
ShinerBock 10/21/20 12:08pm Tow Vehicles
RE: Why diesels are most efficient around 1,800 rpm

It makes total sense that the EGTs are going to be higher doing the same work at lower rpm.... so what? Are you saying the EGTs are too hot? What kind of fuel economy are you getting in 5th vs 6th? Maybe this is a result of after market tuning? I like to keep EGT's as cool as I can because it keeps the rest of the engine temps cool as well. In 5th, they are in the 800-900F range and in sixth they are in the 1,000-1,100F range for most of my drive. Not too hot, but the cooler the better for the longevity of parts. Other temps that are lower are trans temps since it is not shifting between 5th and 6th under load. My fuel economy is roughly .5-1 mpg on average. Not much, but considering it also allows me to run at cooler EGT's and lower trans temps, it is a win win. This is after tuning. However, my brothers 2014 Ram was stock until recently and he recorded the same as me. I have provided more than my fair share of data to back up what I am saying. And I am talking about actual data from manufacturers, not data from one trip going off of my truck computer. All have backed up what I am saying that A)my truck is more efficient in 5th between 60-70mph pulling my RV than 6th and B) the automatic transmissions in these truck is not smart enough to put you in the right gear in all conditions hence the reason why the truck makes offer a gear select option. You, on the other hand, have fought me in this and other threads without providing much data to back up what your are saying while asking me for more even though you refuse to believe the data I am providing because it does not back up your beliefs. At this point I would have to say put up or shut up. Provide some actual data like BSFC maps, thermal efficiency numbers at different rpms, and so on or you really don't have a leg to stand on in this debate.
ShinerBock 10/21/20 10:18am Tow Vehicles
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