ShinerBock wrote:
4x4ord wrote:
ShinerBock wrote:
4x4ord wrote:
^^^^I don’t think I’m confused. I’m just asking some questions. If an engine is designed to produce 600 lb ft of torque at 1700 rpm and it is running at 1700 rpm putting out 375 lb ft of torque I think we agree the engine is not lightly loaded. If an engine is designed to produce 1000 lbft of torque and is putting out 375 lbft I would say it is lightly loaded. If an engine is designed for to put out 850 lb ft and is tuned to make 1300 lbft I‘m not sure how to determine how it is loaded? Maybe measure it’s fuel economy? If it’s burning more fuel in 6th than 5th towing 65 mph than it likely indicates it is not lightly loaded.
It is not about the load of the engine at peak, but rather the load at the rpm it is at due to its gearing. There is a difference between using 5% to 75% of an engines output at an rpm you are forced to be at due to gearing, and using a percentage of the peak hp of the engine. I am forced to be at a different rpm in 6th than a 4.10 geared truck with the same trans ratio. If we all drove CVT's then I can see your point, but we don't so you have to look at things differently.
Yes. The current model Cummins makes 343 HP at 1800 rpm ..... At what HP or torque level would you say this engine is lightly loaded while turning 1800 rpm? What about the Powerstroke ... it makes about 360 HP at 1800 rpm. I might say under 50% load but could we agree that usually under 40% load at a given rpm would constitute a light load? That percentage would be significantly lower for many aftermarket tuned engines. Bottom line is we can only guess what gear our truck should be in at any given load and rpm. The engineers who design these trucks could very easily program them to pick the right gear for fuel economy .... If they don't take fuel economy into account when they program the shifting strategy I certainly don't know why they don't but it's not because it is too complicated for them.
Again, take it up with Ram and Ford. Not sure the current Cummins or Powerstroke has to do with my truck getting better fuel mileage in 5th rather than 6th when towing my 13k trailer at 65 mph. Again, take it up with Ram, Ford and the other makes if you think you can tune a transmission better than they can.
What mileage do you get in 5th vs 6th towing your 13 k trailer?
