2014 isx 15 gearing question

[Purplehaze]

So I am trying to figure out how to improve my fuel mileage I have an isx15 de-mandated engine tuned to 485hp and 1750 tq a13 speed transmission 3.42 rears with 22.5lp tires and at cruising speed of 70mph I'm at 1510rpm. My question is do I need to get it brought down some by changing my gears or
is that where I should be. I have thought about putting 3.25 gears in but would like some input before I do. I can't seem to get over 5.8mpg with this setup unless I run at 60mph. Also trying to find someone who knows more about engine tuning than I ever will

[Rawze]

first and foremost, who did the de-mandate programming. More than 90% of any programs seen are going to tear that engine up, and that should be your biggest concern far above any fuel mileage issues.


NEXT>... The taller you gear it ... All your going to do is severely shorten the life of the engine by lugging it everywhere and severely limit its power output to the ground (hence the artificial fuel mileage savings by gearing it way too tall like the mega-fleets do). You need to get that garbage idea out of your head real fast there. You are already geared too tall for any kind of heavy weights... taller will only make your situation much worse.

THE BIGEST KEY to getting better fuel mileage is not by torturing your engine but learning to control your right foot!. Learn to drive the thing by a boost and pyro gauge and stop using the damn cruise control combined with trying to drive it 70+ everywhere.

SLOW THE HE$LL DOWN, BE MORE DISCIPLINED BY KEEPING THE DOOR SHUT AND LEARNING TO DRIVE AT A SLOWER PACE WITH MORE CONSISTENCY so that you can make the same delivery times. Pick loads up early, deliver them up to an hour late .. etc... and stop racing the clock by going fast... but by slowing down and driving more steady with less stopping instead.


-- NEXT... you need to do everything to that truck to keep the fuel mileage in tip top shape. THIS MEANS tune-up work, ensuring the truck is spec'd for best fuel mileage, making sure aero is as best possible, truck matches trailer, etc. etc.etc.

Some more detail in what you got, what you haul, what make/model truck, etc. and what you do would likely help others with some real recommendations towards higher profit margins. - More info is needed.

YOU SERIOUSLY NEED TO START BY CONCERNING YOURSELF WITH THE DE-MANDATE AND ITS PROGRAMMING!@!!>>> AS MOST THAT ARE SEEN ARE HORRIBLE!.
ref: http://rawze.com/forums/showthread.php?t...5#pid13255

ALSO: Most delete shops DO NOT PROPERLY HOLLOW OUT the exhaust cans and that can cost you fuel mileage big-time. Many shops do not do the mechanical work properly and it causes fuel mileage, power loss, and eventually tears up the engine. here is a fine example.. http://rawze.com/forums/showthread.php?t...3#pid63743

[Purplehaze]

I have done all I can to improve the aerodynamics so it will match the trailer which is a conastoga I have a mid roof pete 579 and have installed the tail on top and that helped I think. Then the de-mandate program was done remotely and seems to need some work but I don't know anyone else that can help that knows how to do a correct tune. Also all the cans have been removed completely even tho I don't know about programming I have done enough wrench turning to know to get rid of all the things that can plug up lol. Also any advice as to who can help with the program and to help make it last longer would be greatly appreciated! I normally run 63 to 65 but out west I get that led foot also I don't haul over like maybe 40k on the deck ant that's rare most of the time I haul ac units or machinery

[Rawze]

(04-07-2021 )Purplehaze Wrote:  I have done all I can to improve the aerodynamics so it will match the trailer which is a conastoga I have a mid roof pete 579 and have installed the tail on top and that helped I think. Then the de-mandate program was done remotely and seems to need some work but I don't know anyone else that can help that knows how to do a correct tune. Also all the cans have been removed completely even tho I don't know about programming I have done enough wrench turning to know to get rid of all the things that can plug up lol. Also any advice as to who can help with the program and to help make it last longer would be greatly appreciated! I normally run 63 to 65 but out west I get that led foot also I don't haul over like maybe 40k on the deck ant that's rare most of the time I haul ac units or machinery

do you have an adapter and insite? -- if not, that is your next investment. Stop relying on idiots with remote tuning and get set up to do things for yourself.

If not then you can get an inline-6 adapter kit (from china) off ebay on the cheap.

[Purplehaze]

That's what I am getting next for sure. But for the time being there is one I can use when needed. But I am pretty stupid when it comes to programming I don't even know where to begin

[Waterloo]

Get a load to Atlanta an go see Mr Hagg...

Haggai Automotive And Diesel Repair
1228 High Falls Rd,
Griffin, GA 30223
Hours: Opens 8AM
Phone: (678) 688-8107

[Purplehaze]

Will do and appreciate the info Waterloo