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Are you a Big-Rig Hypermiler ?... - Printable Version

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RE: Are you a Big-Rig Hypermiler ?... - Zondo956 - 05-12-2020

(05-12-2020 )Paccardude Wrote:  Hi All,

I have an isx15 2350 engine. I'm not sure what's going on with the acceleration from 9th to 10th gear. 9th gear won't climb past 1500 rpm and change to 10th gear it falls back to 110p - 1200 rpm and lugs the shi#t out of the engine before getting back over 1450 rpm. I have Cummins insite is there a vid or does someone know how to change the parameters so 9th can climb over 1500 rpm before shutting off, and accelerate quicker in 10th with less speed? 10th gear is only 1500 at 70-75 mph and and 13 at 65. I'd like to be at 65 max speed but 1500 rpm. Hope this makes sense and any help would be most obliged.

Mine is the same. Only goes past 1500 for a few seconds when pulling a hill. I have insite but don’t know what to mess with. Don’t want to mess things up


RE: Are you a Big-Rig Hypermiler ?... - Chamberpains - 05-13-2020

Grow some balls, do some reading, ask some questions and get rid of your problems. Stop being paralyzed by a lack of knowledge. We were all there.... until we decided not to be.


RE: Are you a Big-Rig Hypermiler ?... - Paccardude - 05-15-2020

(05-12-2020 )Zondo956 Wrote:  
(05-12-2020 )Paccardude Wrote:  Hi All,

I have an isx15 2350 engine. I'm not sure what's going on with the acceleration from 9th to 10th gear. 9th gear won't climb past 1500 rpm and change to 10th gear it falls back to 110p - 1200 rpm and lugs the shi#t out of the engine before getting back over 1450 rpm. I have Cummins insite is there a vid or does someone know how to change the parameters so 9th can climb over 1500 rpm before shutting off, and accelerate quicker in 10th with less speed? 10th gear is only 1500 at 70-75 mph and and 13 at 65. I'd like to be at 65 max speed but 1500 rpm. Hope this makes sense and any help would be most obliged.

Mine is the same. Only goes past 1500 for a few seconds when pulling a hill. I have insite but don’t know what to mess with. Don’t want to mess things up

Delete the ECM value for gear down protection, like Rawze said. The shifting is like a dream. 9th gear can go from 45 to 65 now 65 around 1800. Although, I am curious as to why they set the specs the way they did... Not a response as like they are f**k tards. Did they think the driver would not pay attention and run over 2000 RPMs in 9th, or was there problems with the designs of the isx15, that they thought it would be better to set the gear down at 55 and 71??


RE: Are you a Big-Rig Hypermiler ?... - Rawze - 05-15-2020

(05-15-2020 )Paccardude Wrote:  
(05-12-2020 )Zondo956 Wrote:  
(05-12-2020 )Paccardude Wrote:  Hi All,

I have an isx15 2350 engine. I'm not sure what's going on with the acceleration from 9th to 10th gear. 9th gear won't climb past 1500 rpm and change to 10th gear it falls back to 110p - 1200 rpm and lugs the shi#t out of the engine before getting back over 1450 rpm. I have Cummins insite is there a vid or does someone know how to change the parameters so 9th can climb over 1500 rpm before shutting off, and accelerate quicker in 10th with less speed? 10th gear is only 1500 at 70-75 mph and and 13 at 65. I'd like to be at 65 max speed but 1500 rpm. Hope this makes sense and any help would be most obliged.

Mine is the same. Only goes past 1500 for a few seconds when pulling a hill. I have insite but don’t know what to mess with. Don’t want to mess things up

Delete the ECM value for gear down protection, like Rawze said. The shifting is like a dream. 9th gear can go from 45 to 65 now 65 around 1800. Although, I am curious as to why they set the specs the way they did... Not a response as like they are f**k tards. Did they think the driver would not pay attention and run over 2000 RPMs in 9th, or was there problems with the designs of the isx15, that they thought it would be better to set the gear down at 55 and 71??

it is to prevent the company drivers form utilizing full output power of the engine.


RE: Are you a Big-Rig Hypermiler ?... - Bigboyt01 - 02-09-2021

I worked with U S Xpress in a 2016 International prostar sleeper with the isx 15 and auto transmission. I personally put 180k miles on that truck and not once did I break down and didnt know why until Rawse said it in his video. I made that truck get on it every where I went and back down once I was back flat when I went up a hill 1800 rpm was where I was and manually shifted it I didnt pamper it nor was I abusive you find that right spot with a diesel. I averaged 9 to 10 gpm as a company driver. You might say bulls### but a lot of what he said is the truth. Maintenance and how you drive it determine a lot. Thank You Rawse for your insight on the cummins isx and will continue to be a member.


RE: Are you a Big-Rig Hypermiler ?... - Business School Dropout - 03-03-2021

(05-12-2020 )Zondo956 Wrote:  
(05-12-2020 )Paccardude Wrote:  Hi All,

I have an isx15 2350 engine. I'm not sure what's going on with the acceleration from 9th to 10th gear. 9th gear won't climb past 1500 rpm and change to 10th gear it falls back to 110p - 1200 rpm and lugs the shi#t out of the engine before getting back over 1450 rpm. I have Cummins insite is there a vid or does someone know how to change the parameters so 9th can climb over 1500 rpm before shutting off, and accelerate quicker in 10th with less speed? 10th gear is only 1500 at 70-75 mph and and 13 at 65. I'd like to be at 65 max speed but 1500 rpm. Hope this makes sense and any help would be most obliged.

Mine is the same. Only goes past 1500 for a few seconds when pulling a hill. I have insite but don’t know what to mess with. Don’t want to mess things up

My 2012 ISX was the same. Last time it was in the shop I had them turn the Load Based Speed Control off.


RE: Are you a Big-Rig Hypermiler ?... - SquareOne - 08-09-2024

Thought I'd revive an old thread as it def pertains to hyper-miling. As a refresher, I'm running 2 trucks, a daycab Freighiner Cascadia w/ 190in WB and a sleeper International LT625 (newer Prostar version is all the fancy numbers really mean) w/ a 226in WB. Both with new sets of drives BTW.

I try to squeeze every dime I can, especially when it comes to fuel. My Cascadia has very often achieved high 8-9.0's mpg since I've owned it with the International always staying about .15-.2 behind. I figured the taller roof and approximate 2k lbs of additional weight was to blame.

However (and I'll get to the point of the post), these last 3 tanks, I've actually beaten the Cascadia by a hair in the MPG race. The only difference - - - I've been IN GEAR (IG) coasting rather than OUT-OF-GEAR (OOG) coasting. The last 3 hand calculated tanks were 9.04, 9.05, 8.99mpg. I've always been an OOG coasting guy when I had to bring my speed back down to 60 from a decline which pushed me faster, but just recently I tried leaving it in gear with no throttle input.

Whenever I'm OOG coasting, the instant MPG (which I know isn't perfect) hovers around 45-60mpg depending on speed. The IG coasting immediately maxes out the instant mpg at 150.5mpg until I touch the pedal. My question after all of this is...

- Does the ECM go to near zero fueling when IG coasting due to the speed vs engine load and rpm, whereas OOG coasting requires the ecm to command enough fuel to stay at idle?

I may be waayyyy off with this assumption, but this is literally the only change I've made in order to try to achieve the Cascadia numbers. Loads, 60mph speed, weather, route, times driven, even the same truck stop and pump, etc. have all been nearly the same. I hand calculate each and every tank from both trucks, so any anomalies will be caught early on. Each tank is typically about 1250-1270mi between fill-ups, so if what I'm assuming is true, that's a pretty damn good improvement for just one small change. I waited for the 3rd tank numbers to come in before making this post, because it just seems too good to be true. In this case, I don't see how the numbers could lie.


RE: Are you a Big-Rig Hypermiler ?... - Mal4shtf - 08-09-2024

Your assumption is probably correct. Year and power plant type slash transmission? Also an FYI I've seen {advertisement removed by Rawze}. The fuel standards in this country are junk.


RE: Are you a Big-Rig Hypermiler ?... - Rawze - 08-09-2024

the rule of thumb for OOG (out of gear) is anything more than 1/4 - 1/2 mile, especially when the truck is heavy loaded.

OOG is more effective when your heavy vs. when your empty and light ... this factors in as well.

and no ... OOG is always more efficient than in being gear and off the throttle down a hill. The engine always consumes more energy slowing down the truck, than it does consuming the 18-20 mg/stroke idling when in neutral.

Its just matter of getting good at when to OOG ... and when not to go OOG for the benefits.