Cats have always been known to have better lugging ability then cummins or detroits, with that I mean most guys that run them figured they had better low end grunt then the latter 2, however in recent years detroits and cummins have somewhat figured out how to make thier engines pull better down low, what do you guys think? Is cat still the undisputed champion of low end torque or have the competitors finally caught up, lol keep in mind we are talking stock hp and torque levels here,
Best to NOT LUG ANY ENGINE. Select the proper gear to keep the RPM in the powerband that the engine was built for.
Guys running ISX's should be in the 1200-1800 RPM range, and use transmission neutral more often to save fuel.
Low RPM's cause low flow of the oil and coolant systems. Low RPM's have low exhaust flow and build up heat in the turbo.
The last couple years of Detroit's pull very well down low. Most guys I know drive them down to 1000rpm almost. The 500 Paccars are supposedly similar to cats in that sense as well. But as VIN mentioned I really don't think it's a good idea to constantly lug any engine. I used to be part of the lower rpm the better camp but if you really think about the dynamics involved higher rpm is less strain on components and controlling your fueling with your right foot inside of those higher rpms well be more economical.
I think the notion of higher rpms being less efficient and damaging to components is from company drivers only knowing one throttle position, this is why many companies are gearing their trucks with 10 speed trucks and tall rear end gears and limiting rpms electronically to force a more sensible and economic driving style. They are dummy proofed in a sense.
Here is the problem Detroit thinks they can, but they can't. The compounding turbos make it pull down low but the engine isn't built strong enough for the heat dissipation.
Cummins can't lug worth a shi#t.
If you want cat lugging but you want a new engine there is only one choice. ..... wait for it......
Volvo D16. Yes that's right. Volvo did a major overhaul to the bottom end of the D16 in order to meet the demands of the XE16 140,000lbs version. They have what they called oversized bearings and connecting rods which help with the heat. I do not know if there is any difference between the normal D16 and the XE16 because Volvo is a bunch of retards who can't answer anything but I do know I have a 2014 XE16 hauling super b with half a million and 3:21 gears and never a stitch of issues, truck is flawless and runs at 1200rpm all day everyday.
Of course it still doesn't pull as savage as my cat does down low buy it doesn't fall flat on its face after 1600rpm either like the kitty does.
It seems to me the newer commen rail cummins with 2050 torque and @m*m^2 pull a bit better down low, the first generation of isx cm570 were totally gutless and sluggish under 1500 rpm, the low rpm response improved a bit on the 870, the 871 had a electric actuater on the turbo which improved response a bit, they all pulled ok if you kept the rpms above 1400 or so, the 2250 with their smaller turbo are quicker responding, but due to the smaller turbo can not build and serius hp, however with @m*m^2 and 2050 torque I would say the 2250 has almost cat like torque below 1500, just my experience, I may not know what I am talkin about
(09-28-2016 )Running rough Wrote: [ -> ]It seems to me the newer commen rail cummins with 2050 torque and @m*m^2 pull a bit better down low, the first generation of isx cm570 were totally gutless and sluggish under 1500 rpm, the low rpm response improved a bit on the 870, the 871 had a electric actuater on the turbo which improved response a bit, they all pulled ok if you kept the rpms above 1400 or so, the 2250 with their smaller turbo are quicker responding, but due to the smaller turbo can not build and serius hp, however with @m*m^2 and 2050 torque I would say the 2250 has almost cat like torque below 1500, just my experience, I may not know what I am talkin about
Being able to pull down low and being able to withstand pulling down low are 2 different things. Cummins has never been able to withstand the abuse in lower rpm because they've never tried to build the engine to do so.
Forman at a Cummins shop put it real clear for me. he said you drive below 1300 and I'll be rebuilding your bottom, bring it above 1800 all the time and I'll be doing your top end. He said throughout the 20 plus years he's been working on solely Cummins, he sees it over and over like clock work.
Byfar the old cat motor had the most low end torque. How ever you have to look at the liner set up on them too. Very think and alot of block support. These newer engine have thin liners and very little block support therefore allowing liners to "dance" in the block.
two words
mack maxidyne
mic drop.....
The isx piston rod combo looks somewhat similer to a c15 piston rod set, however like it has been stated, the cat block has more beef in it