Cumins12v98 wrote: When Cummins went from 650 tq to 800 they did not increase hp numbers.
I always found that strange. Mathmatically it doesn't work.
I think that tells why my dyno of 304 is such a low percentage of loss. If you look at the Cummins site for the 6.7 they say max torque 800 @1,600 rpm and max torque is at 3,013 rpm but they don't say what that number is. Interesting
Cumins12v98 wrote: When Cummins went from 650 tq to 800 they did not increase hp numbers.
I always found that strange. Mathmatically it doesn't work.
I think that tells why my dyno of 304 is such a low percentage of loss. If you look at the Cummins site for the 6.7 they say max torque 800 @1,600 rpm and max torque is at 3,013 rpm but they don't say what that number is. Interesting
You mean max horsepower is at 3013 rpm....
Yes, thanks, I will fix.
2011 Ram Laramie Longhorn 3500 Dually Long Bed, Cummins 350/800 HO, Towin Machine
B&W Companion Hitch, Maghytec Trans and Rear Dif Covers, AMZ/OIL Top To Bottom
2007 1/2 Mobile Suites 36 SB3 27,000# Combined
Actually it is not hard for a motor manufacture to tweak the programing per say so their are different torque motors with the same HP. What happens, is the max rpm is limited. navistar does this a lot with the DT 466, ie they will have two 225hp motors, one with around 625 lb ft of torque, the other with 850. BUT< one will rev to say 2800, the higher torque one will only rev to say 2400.
GM did this as an option for the dmax for a few years, as does Navistar with ALL of the V8 motors they have produce, having at least 4 or 5 hp/torque ratings. Last I checked Cummins had 12-16HP/torque ratings for the B5.9, I would swag that the 6.7 is similar, starting as low as 160/400 or so, and going upwards of 300-350 with 800 or so max torque.
So it is doable frankly! How Cummins does it, I will not guess nor try to cause issues, other than to say with the puter controlled engines of today, anything is possible with how things are fueled etc.
Along with, again, as stated, the J8207 spec is strictly that, a BASE on how to rate something. No different than how SAE specs how to rate HP in a given motor, which will also vary based on the GVWR of the rig too! IE actual flywhell hp, or rearwheel hp with drive train loss included or not! Hopefully obvious, rear wheel can vary based on trans, ie manual does not use as much as an auto. Size alternator ore ven two alternators, if the motor is turning an AC pump.... to even how long the driveline is, diam tires, size of axel gear........
13percent driveline loss vs 18 percent, tween the dodge and ford, very possible frankly! again depending upon numerous things ford does vs dodge. I hve yet to see a GM percentage loss, but would swag on the lower end of things based on mag tests and them seeming to win. Or a better puter control setup to keep HP to the rear wheels..... No actual link, data to show my feelings on this, just past experience, things I've read thru the years etc.
Marty
05 Chev CC D/A LS Dooley
92 Navistar dump truck, 7.3L 7 sp, 4.33 gears with a Detroit no spin
00 Chev C2500, V5700, 4L80E, 4.10, base truck, no options!
92 Red-e-haul 12K equipment trailer
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Blt2ski wrote: Actually it is not hard for a motor manufacture to tweak the programing per say so their are different torque motors with the same HP. What happens, is the max rpm is limited. navistar does this a lot with the DT 466, ie they will have two 225hp motors, one with around 625 lb ft of torque, the other with 850. BUT< one will rev to say 2800, the higher torque one will only rev to say 2400.
As far as I know, the rpm did not change on the Ram with the increase in torque. This should have resulted in a increase in HP as well. Of course with todays computers, anything can be tuned...I just don't see a reason to tune out a HP increase.
One is far more likely to break things from a increase in torque than a increase in HP.
Huntindog
2010 Palomino Sabre 30BHDS TWO bathrooms...No waiting!
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2011 Silverado Big Dually 3500 4x4 CC D/A
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As far as limiting power RAM limits the amount of power to the wheels until 4th gear. Not because they feel the downstream parts are weak it is because the engine developes so much low end torque. Again conservative approach for long lasting truck.
THe Dmax has limited power in 1st gear since 2001. The Ram limiting power thru 4th is not all that surprising. It has a 4.10 rearend vs. the Dmaxes 3.73.. And if I recall correctly also has lower tranny ratios in most if not all gears. I haven't done the math on this, but the torque multiplication difference will be startling. This will make a HUGE difference in the torque to the rear wheels..Much more than the small difference at the flywheel.
Actually the GM and Ram transmission ratios are very close to each other. It's the Ford transmission that has gearing advantage in all 4 lower gears. Go here to see the truck specs.
Rich
'09 Dodge/Cummins 6.7 3500 Quad Cab DRW SLT Laramie Auto, Timbrens & Overload Bump Stop Spacers; Tork Lift Super Hitch, Tiedowns and Fastguns, ExtremeAir 12 Volt Air Compressor
'04 Arctic Fox 990; 91 Jeep Wrangler ARB's TeraLow 4.5" Rubicon Express Lift
As far as limiting power RAM limits the amount of power to the wheels until 4th gear. Not because they feel the downstream parts are weak it is because the engine developes so much low end torque. Again conservative approach for long lasting truck.
THe Dmax has limited power in 1st gear since 2001. The Ram limiting power thru 4th is not all that surprising. It has a 4.10 rearend vs. the Dmaxes 3.73.. And if I recall correctly also has lower tranny ratios in most if not all gears. I haven't done the math on this, but the torque multiplication difference will be startling. This will make a HUGE difference in the torque to the rear wheels..Much more than the small difference at the flywheel.
Actually the GM and Ram transmission ratios are very close to each other. It's the Ford transmission that has gearing advantage in all 4 lower gears. Go here to see the truck specs.
Rich
Don't forget the rear end ratio. Both the Ford and GM use 3.73.
The Ram uses 4.10.
THe Ram has a slight advantantage in the tranny ratios in 4 of the 6 gears, which is multiplied by the rear end ratio of 4.10, which is also lower.
THe Ford has lower tranny ratios in every gear with the 1-2 gears being subtantially lower,,,,,,,But they are multiplied by the 3.73 rear end,,,same as the Dmax.
So the difference is solely in the tranny with the Ford, whereas in the Ram you gotta take the rear end into account.
I hven't done the math between the Ford and Ram yet to see which one has a gearing advantage..and where.
Naturally, when I say advantage,,,,there is also a disadvantage.
I agree Ford did because they did not have a leg to stand on. GM did because some of their lighter duty trucks ratings went down but their HD line was fine. Like I said I got it from the horses mouth that RAM already meets the spec.
@Cummins, please go back and read what I wrote.
WHS
05' Layton Lite 170LT Cascade edition
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