BLASPHEMY!!
Good advise on hill pulling heavy! More than one way to keep boost up/EGT's down.

"Never have to downshift" ....Guess there are no long 6% grades in the Dakotas!

RJ

 

Wish I didn't have to downshift either, but that's not gonna happen out here in AZ. We have quite a few hills out here that dont care what you have under the hood, they require downshifting or your going nowhere real fast........

 

I remember going over the top of the Four Sisters (think that's the name) in first gear...empty. But that's another story.

RJ

 

My 05 will hit 1550 at just about any freeway on ramp empty---but elevation is bout 5500 here

 

Not much for long 6% grades but some short ones. The problum is the never ending 40 mph wind.
I have pulled some grades in Montana stayed in 6th
Fact is with a good diesel like the 5.9/6.7 cummins people shouldn't be afraid to let the engine pull down and work a little. Sure their come a time when you need to downshift but atleast let it pull down first.

 

Sounds to me like you have a really good baseline, time to buy the goodies.

 

I'm ready! Just need to knock the Credit Card down just a tad! You all are a big help. For the record these hills in Az are pretty steep and hell yes you better down shift.especially with a stick.If you dont shift quick you will drop down real fast.
Thanks all

Phil

 

a free flowing aftermarket exhaust 4 or 5 inch with a mild fueling box that adds timing will cool your motor down quite a bit. It will easily drop you 200+ degrees pre turbo. My truck is an '01 but you should have similar results. I can pull a 6-7% grade for an extended period in 5th gear(1:1) with a trailer and only see a max of about 1150 degrees pre turbo now.

 

Thats not true.

Cummins definition of lugging is likely different than yours. You can lug a Cummins at more than 1500 rpm.

 

Exactly..Most of the hills out here I can hit them at about 1900rpm then before I know it the motor is lugging big time, while still at 1900rpm and my egt's go sky high. Then I downshift to raise my rpm's and everything comes back down.

 

So running your engine near peak tq is lugging it's called pulling, that!!

 

It is when you have a 10k+ toyhauler behind you going up a 6% grade for miles on end. You bet your a** it's lugging it. That has been my experience with my truck. I dont have a billion hp or 2 trillion lb/ft of tq. It's virtually stock. 2400-2500 rpm's are just perfect for pulling the hills out here for me. Using the hp instead of the tq for pulling the hills keep's thing a LOT cooler in my truck.

 

You've got it right.

A lot of guys think its all about the torque. They don't always get it.

The torque curve on the Cummins is virtually flat from 1500-1600 all the way to 3000. IIRC on a stock truck its within 10-15 ft-lbs the entire rpm range.

What some guys don't get is that when you are making HP to go along with the torque,your truck is going to pull better.

Like you said,you can lug along in 6th gear for miles on end making 600 ft-lbs of torque and low HP. With low rpm comes high EGTs.

Or,you can run along like you do at more rpm,you'll still be making the same amount of torque but have way more HP to go with it.

Me,I'll take 300 HP with 600 ft-lbs of torque over 200 HP with the same torque anytime.

 

If you don't believe me,give Cummins a call. Get their take on pulling a heavy load at peak Torque. I'll guarantee they tell you its not a good idea.

 

Well said! "truck is going to pull better"... and cooler (the original topic of this thread).
All my dyno runs have shown "table top" torque curve from 1700 rpm to about 2800 rpm!
Would expect 3rd gen to be similar?

RJ