blofgren wrote:
Cummins12V98 wrote:
But But RAM was the safest of all with ZERO brake applications. Not really anything more important.
Also had had a good time climbing with nice cool temps and guess what the fan NEVER came on.
I totally agree.
And if it wasn't for that silly CP4 fuel pump that is now bolted on to it, it is the truck that will do it reliably for many years to come.
I can certainly see a person buying a Ram for the air suspension or because they prefer the interior of the truck and I can even understand some people liking the idea that they have a Cummins under the hood. It is even possible that the Cummins has a slightly better exhaust brake .... As far as this downhill braking test demonstrating anything I don't think the testers understood the workings of the braking systems well enough to conduct a proper test:
I posted this comment on another thread and although I realize that I could be wrong I feel confident that I have come to a proper understanding of how these braking systems work:
The TFL guys said they had the Ford EB set to auto which is the best setting on the Ford for the downhill test they were doing. However there is more to it than picking a speed to hold the load at and measuring brake applications. For instance, The maximum reverse HP an engine can create occurs at maximum exhaust back pressure and engine redline. So 35 mph was an excellent speed for the Cummins to function at. It put the transmission in a low enough gear to get high torque to the rear axle and had the engine running very close to redline .... At the 4:00 and 6:00 minute marks in the video you can see the EB gauge all of a sudden display 236 reverse HP when the engine reaches redline. I believe the gauge is displaying this value while the computer applies the wheel brakes i order to prevent the engine from over revving. You can see that while the EB gauge displays a value, the speed of the truck slows from 37 mph to 35 and then the wheel brakes are released.
If they had chosen 42 mph as the speed they wanted the truck to hold to the Ram would have had a disadvantage because the truck would have shifted to 3rd gear and the engine would have dropped to about 2400 rpm. At 2400 rpm the engine would have been producing considerably less reverse HP, third gear would have put much less torque to the rear axle and Mr. Truck would have been applying the brakes prior to the engine reaching redline.
I didn't watch the Ford downhill portion again but I suspect they tried to go 35 mph with it as well. The Problem with that is 35 mph puts the Powerstroke in 3rd gear at 2800 rpm and in order to get maximum performance out of the Powerstroke EB they would have run the truck in 3rd gear at about 3400 rpm where it would have been travelling about 42 mph. And better still they could have slowed the Ford to to get it to drop into 2nd gear and ran at 32 mph and 3500 rpm. Had the Ford been running at a higher rpm the computer would have been applying the brakes when the engine rpm reached redline. (I'm not sure what rpm the 2020 Powerstroke needs to reach before the computer applies the brakes .... my '17 redlines at 3600 but I think the 2020 might be even higher)
I think the computer applies the wheel brakes at engine red line, so the Ram computer was performing multiple wheel brake applications where as it was Mr Truck applying the Ford wheel brakes prior to engine red line.
A tester really has to understand the workings of these trucks well to perform tests that demonstrate the full potential of each truck.