2 questions
01-12-2020, (Subject: 2 questions ) 
Post: #19
RE: 2 questions
(01-12-2020 )Chamberpains Wrote:  Damn, I missed that link Rawze removed. I was curious what crap habits they are pushing these days. If someone can PM that link, I'd appreciate it. Sometimes knowing what bad habits people use can help a guy diagnose problems with the truck.

it hammered using the cruise control as much as possible + the lowest rpm you can get away with. -- sounds just like a fleet manager at a mega-fleet wrote it.

--There are 2 ways to reduce overall fuel consumption in an already healthy truck/engine. They BOTH involve the same thing ... REDUCING POWER OUTPUT of the engine.

1) - lug the crap out of the engine at as low rpm as it will let you and hold your foot to the floor. <- this is the mega-fleet way of forcefully making their drivers who only know one position on the fuel pedal to reduce power output. Hence, why a tall geared truck is more fuel efficient when you got some moron who can't keep his foot from the floor ... because the thing can't get out of its own way because it cannot produce full power to the wheels when driven like that. The higher torque demand is hard as hell on the engine, shortening its life significantly, and saves fuel at the expense of the engine and drive train.

2)- Backing off the accelerator when using a better rpm range that is not damaging to the engine.

550-hp truck can go up the same hill, 2 different gearing, get to the top at the same exact time, have the same fuel consumption when say ...

A - geared tall) - running 1200rpm, 1850 torque (423-hp applied to the wheels). Foot to the floor. Tall gearing. hard on enigne/driveline/truck.


B - not geared tall) - running 1650rpm, 1346 torque (same exact 423-hp applied to the wheels). Foot backed off to about 70% on the pedal, reduced boost. - Better gearing ratio. reduced engine/driveline wear.


A- geared tall)- Is hard on the engine, driveline, and produces a lot more heat in the enigne/drivetrain. it saves a bit of fuel, but long term maint. costs go way up / engine life cut almost in half usually.

B- not geared tall)- Same fuel consumption. Same time to arrive to the top of the hill. - The output power to the wheels is the exact SAME as "A"!.

So,.. for someone not knowing how to drive without their foot all the way to the floor + can;t drive it much above about 1400rpm even if they wanted to (geared too tall for anything useful)...> A) would be more fuel efficient (hence all the goddamn tall geared trucks these days that can't get out of their own way). It is idiot proofing the truck, gutting its full power output potential at the expense of the life of the truck/engine. - ALSO why I would not buy a used truck with those ridiculous tall rears. <- It is already slated for an inframe at 450k - 500k miles / slap worn out.

B - not geared tall)- ON THE OTHER HAND -- DOES TAKE SOME ACTUAL DRIVING SKILL and some discipline to NOT USE that extra power if it is there for use, if a person wanted to save the same (or more) fuel as the idiot proof truck. -- IT BECOMES A CHOICE, delegated by ONE'S OWN RIGHT FOOT!

So... The next time you got someone arguing with you about how all his buddies with their taller rear trucks use less fuel ... -- IT IS THAT SAME SOMEONE THAT CANNOT FIGURE OUT HOW TO DRIVE A BETTER SPEC'D TRUCK PROPERLY! -- THAT IS THE PROBLEM! -- Don't blame it on the gearing... it is NOT THE ISSUE!. - IT IS THAT PERSON'S RIGHT FOOT that is the issue. -- ALSO, THE BETTER SPEC'D TRUCK WILL PERFORM MORE OVERALL WORK OVER ITS LIFETIME THAN THE CRAPPY SPEC'D ONE! --- it has a higher up-time because it is not being abused. Engine will last longer and have less issues + all sorts of other benefits long term that are not seen from day to day.

A TRUCK GEARED AND SPEC'D PROPERLY FOR THE OPERATION AT HAND and dicipline, slowing down BY CONTROLLING ONE'S OWN RIGHT FOOT, driving by your BOST GAUGE (instead of some terrible tall gearing is forcing you to do) === HIGHER PROFITS BY A LONG SHOT above some crappy nut-less garbage rear ended P.O.S. destined to be in a shop getting inframed 2x more often than it should be.

tall rear, tall gearing, geared too tall, rear ratio

User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
 Thanks given by: Waterloo , farmer70 , Brock
01-12-2020, (Subject: 2 questions ) 
Post: #20
RE: 2 questions
So true what Rawze stated, these motors like that 1700+ rpm range. Been able to really drive the truck since rebuilding the motor. Been nearly two years of little to no work with this truck, been through multiple carriers, etc, just terrible.

Anyhow, I have been going West, running I-80, and had a chance to really break her in and play around with my pedal skills vs fuel mileage. I played around with 1400 to 1500 rpm, run a tank full, fuel up, etc.

Running that 1400-1500, she was a slug, just did not feel right. I did not last long, mileage was right around 5.8-6.0 in a fairly wind free trek across Nebraska. Yes, wind free, that's a first! Calm as I have ever experienced it going across there, very rare.

Then did the same running her at 1700+ rpm in a lower gear. I found 1700 rpm, which put me at roughly 65-67 mph in low 8 (18 Spd, 3:42 gears) seemed to be the sweet spot. In High 7 I found the same results with a tad bit better fuel mileage. That had me running at 59 to 61 mph and getting closer to that 7 mpg, 6.7-6.8'sh range.

This is a mid roof ProStar, CM-871 pulling a dry van. Wind has a huge effect on my fuel economy, along with ambient temps and of course the winter blend. I found my average fuel economy in the 5 mpg range heading West, and 6 mpg heading East, this is on I-80, Reno to Detroit, round trips on paper with the Tri-Pac.

That Tri-Pac sucks quite a bit of fuel vs my old one this new Evolution replaced. I did idle the truck a few times when the temps were hovering at zero and below.

If I put an air dam on the top, I think 7+ would easily be obtainable. A flat bed, I know I can get close to 9, which I have hit in the past with a blown head.

These numbers are on paper, fuel in the morning and fuel in the evening, taking the Tri-Pac out of the equation and then an overall everything accounted for trip average. I did use cruise in the flats, like Nebraska, my foot is old, needs a break now and then. LOL!

Overall, running at that 1700+ appears to be where the motor is happiest, and has really loosened her up, she feels like she is breathing now, the power (torque) feels stronger and she is very snappy on the pedal. She moves, and pulls like a freight train with little effort just feathering the throttle and keeping the boost low once the correct gear is found.

Honestly, this is one of the strongest motors I have ever driven, much stronger than those old Cat 550's or older Detroit or Cummins 500 hp motors I have driven or owned. Very happy, very sad I am parking her.
 Thanks given by: farmer70
01-12-2020, (Subject: 2 questions ) 
Post: #21
RE: 2 questions
You should do a egr tune up. And nox sensors. Then forced regen. Or if in the hills with load on 1900rpm climbing the hill. These filters need to be hot and have a lot of volume of air going through them to open them up. Emissions engines are hard to get mileage out of. Some guys will say driving them faster actually gets better mileage. I don’t think that’s the case but the engine will do better being driven hard under a crap preventative maintenance program then one babied. Your truck gears are two high. I just bought a truck with 3.36 gears on low pro 22.5. 1250 rpm at 60 or so. I knew what I was buying and knew I wouldn’t be able to use cruise much because of always downshifting. I’m empty half my miles so I wanted the legs when empty. I run cattle out of state seasonally so I wanted legs for that also. Seasonal cattle I’m empty half my miles. It just a theory I have and I could be dead wrong but empty 13th gear. Lower rpm maybe not fighting emissions system as hard, trying to get fuel mileage. But gonna need to change sensors yearly or so. Your sensors are critical to maintaining fuel mileage.
 Thanks given by: farmer70
01-13-2020, (Subject: 2 questions ) 
Post: #22
RE: 2 questions
(01-12-2020 )Rawze Wrote:  
(01-11-2020 )farmer70 Wrote:  {removed =-- BAD INFORMATION!}
Found this on search for proper driving techniques for a Cummins ISX. I’m not arguing with you guys I’m just find it interesting

See this is why I’m confused

Take it from an actual hypermiler -- that is some of the worst info I have seen yet. <- some dumbarsse fleet company driver must have wrote it!. =-- I deleted the link!.. not having garbage like that on my forum for others to spread around like a stale, mouldy sandwich.

here is some better info..

just for a perspective any ways.

Thanks for your advice! Today I ran in the Texas Panhandle and across Northern Ok rolling hills all day. OOG and tried to keep boost under20 running around 60-65 I can tell just by looking a t fuel gauge it did before on fuel kept RPM 1500 and above. Its a lot different driving this way. This truck’s gear ratio isn’t worth a darn. Thanks again.
01-13-2020, (Subject: 2 questions ) 
Post: #23
RE: 2 questions
You lost me somewheres in the middle.

User's Signature: 2015 Kenworth T660
 Thanks given by: farmer70
01-14-2020, (Subject: 2 questions ) 
Post: #24
RE: 2 questions
(01-13-2020 )Mattman Wrote:  You lost me somewheres in the middle.
My main question how to increase my milage was answered I didn’t run the cruise up the hills. I’d downshift and back off the throttle. You just barely press on the throttle and manifold pressure shoots up there. Takes some patience and work to get the. MPG but I think I see how this works. I wish my tall rear ends were 3.55-.3.70 not 3.25.
 Thanks given by: Mattman
01-22-2020, (Subject: 2 questions ) 
Post: #25
RE: 2 questions
(01-11-2020 )farmer70 Wrote:  With the truck set up as I described What gear RPM and speed should I try to obtain the best mileage and safe on the engine? I’m used to Cats and my C12 will out pull this ISX. I’m trying to learn and appreciate all advice. Specifically 12th gear 11th gear? 12th an 1500 would probably put me about 66.

just my 2cents but 1700 on up hills, if you have a piro gage and intake psi gage use them low on piro and the lower the better on intake psi,i run heavy and a lot of hilly sh#$%#t so 30-35 psi on the up but other than that trying to keep intake to baer min. like 8-15 on most hwys. im learning it
and im doing better. head winds and big hills is a killer 4.2- 5 mpg on flats low or no wind 6-6.3
hope it helps you

User's Signature: Just my 2 cents + -

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