Load Based Speed Control Issue

[Unilevers]

(10-19-2019 )Signature620 Wrote:  At 120,000lb, the LBSC will not have any effect. It only limits max engine speed at low load.

im sorry but this is very much not true. It hinders it greatly especially if the settings are set lower for high and low breakpoints. there is also a software glitch in some of the calibrations that even if LBSC is turned off it still adheres to the upper break point. To truly make 100% sure its off raise the breakpoints to above your RPM range and then turn off LBSC interaction/enable.

[jakebank]

(10-19-2019 )Unilevers Wrote:  

(10-19-2019 )Signature620 Wrote:  At 120,000lb, the LBSC will not have any effect. It only limits max engine speed at low load.

im sorry but this is very much not true. It hinders it greatly especially if the settings are set lower for high and low breakpoints. there is also a software glitch in some of the calibrations that even if LBSC is turned off it still adheres to the upper break point. To truly make 100% sure its off raise the breakpoints to above your RPM range and then turn off LBSC interaction/enable.

But if it won’t let you change the breakpoint you anything above 1800, and it won’t let you simply disable the setting, what’s the fix?

[Unilevers]

you can change the breakpoint to whatever you please, just have the have the right programs.

[Chamberpains]

The LBSC greatly screws with proper smooth shifting. I left mine on after MommaBurt tuned my cm870 for me. I was still trying to figure out how to keep my rpm's up and drive the truck differently at the time.

I set the break point to max 1800 rpm and drove it that way for months. I would take the rpm's up to about 1700-1750 and then shift. Which with my 10 speed, would drop me down to about 1200-1250 after shifting. Which was still too low. And if I mistakenly got anywhere close to 1800, it would fall flat on its face and totally screw up the next shift, bad. Forcing me to stay in the current gear and fumble around trying to recover.

Once I found the the LBSC toggle and turned it off... I'll be damned, I was able to take it right up to 1800-1900 rpm nice and gentle. Leisurely shifting into my next gear and I fall right into 1300-1350 range and continue pulling with boost and momentum on my side. This is where I finally started to seeing an extra .5 mpg or so. It took me from the high 6's low 7's to solidly in the 7's all the time. Plus pulling and shifting in the hills I live in was a lot easier.

Im glad I left it on when MommaBurt tuned it. He wanted to disable it but I told him to leave it on because I thought I still needed to have that high RPM governor for engine safety. Boy was I wrong. I was glad I left it on because it allowed me to experience the enormous difference in drivability, fuel mileage and pulling power with and without it.

I'll tell anyone to shut that stupid thing off. Take it right up to 1800-1850, grab your next gear smoothly and keep on tugging. The cm870 loves it. I've purposely taken it up to 1950 and shifted in a couple of ass kickin hills and it didn't hurt a thing. It appears there is an over all engine governor at 2100 rpm that I've mistakenly bounced off of when I've missed a gear and that didn't hurt a thing either. Though I really don't try to take it above 1900 ever. My goal is to shift at 1850 every time. It works extremely well for me.

[Rawze]

* max mechanical rpm limit for the ISX is 2700.
* Max safe rpm to hold for extended periods is 2400, and is their publicly listed max rpm.
* Factory will often set them governed to 2100 for safety.
* The engine has its highest longevity at 1650 or thereabouts when pushing 100% engine load.
* Anything much above 50% or so engine load below about 1500 rpm takes its toll rapidly on the engine.

* Driving it only 1100 - 1500 rpm(Where the mega-fleets set them and gear them wrong) its whole existence can shorten its life by as much as 50%, as this is only the bottom 1/3 of the engines working range.


- It is not unusual for us to run at 1500 - 1800+ rpm, a gear or 2 down from top gear for 10+ hours at a time when loaded to 80,000 lbs and running in terrain like the Pennsylvania hill country.

[SquareOne]

I run a 10speed mated to a 2350, so I'm not sure if this applies (excuse the ignorance if so) and I've always wondered how a newer or a better 'taken care of' 10 speed Eaton felt.

- I purchased this one with 360k (a hard 360 according to the load that the previous engine experienced). Currently it has 425k. Although I have no where near the experience as majority of you on this forum, it just feels like sometimes I can't get into the groove. Other times, I can float flawlessly like I've been doing it a lifetime. I don't (well very rarely at least) just blindly miss a hole...it just seems like I'm a beat or so off tempo at times. I do run it up higher on in the range, since I pull near gross most of the time when loaded, and it feels much smoother when shifting to the next gear.

Would LBSC (again if it applies to my application), assist or hinder shifting as Chamber described?

[Lonestar10]

LBSC just stops your RPM growth basically you hit a wall on power. 10speeds to me seem to be finicky bastards when i drove for Crete every now and then ied buzz a gear while accelerating. some of it also has to do with terrain if you get used to shifting alot in city/flatland traffic you might have a hiccup or 2 on hills because the RPM drops the same but the truck sheds speed during the shift faster lowering the RPM which the gear slammer will just fall into the hole that your used to. i do it from time to time used to how fast i can shift then hit a big hill while accellerating and try to upshift like i was still on normal ground.

[Chamberpains]

LBSC feels like someone took the throttle peddle away at what ever RPM it's set at. It is the epitome of feeling like the truck falling on it's face. It will only do this when you're putting a load on the engine. You can gently go right on by the RPM it's set at if you're light enough on the peddle. This is how I began to teach myself how to use less off the pedal to pull hills, accelerate gently, and keep my boost down. It wrangled in my driving habits a lot.

But it came at a cost because I was running lower RPM's (in the 1200-1700 range) frequently because in the hills its REALLY hard to be disciplined all the time and triggering or slamming into the LBSC was seriously bad. This lead me to running low boost all the time. This is how I was able to run under 10 psi up and down hills all day long. But I was still lugging the engine at 1200 a lot more than I wanted while trying to keep the LBSC from being triggered.

Then I turned off the LBSC and took the RPM's right up to 1850 and shifted. I stopped worrying about boost levels being so low because once you get up to about 1700+ you can't keep boost under 10.

Now when pulling hills I take it up to 1850-1875, boost at around 12-15 psi and keep my fuel pedal at no more than 60 TPS often times fluttering at 50-55 TPS. Then when the hill drags my RPM's down to 1350, I downshift, RPM's back up to 1850, boost flies up to 20-21 psi, fuel pedal goes to about 60 TPS, boost drops accordingly to 12-15 psi and on up the hill I go with any load 80000# and under gross weight. Up any mountain, steep, goat trail, incline, quarry path that the continental US has. I seriously have never NOT pulled some serious inclines, 12-15% quarry road grades, at full gross weight, driving this way. The lowest gear I've used is 3rd. So that left me with 2 more gears and a whole lot of throttle pedal if I happen to find the challenge that needs it. But to date, I haven't found any. This is with 450 hp Uni-tune. I definitely don't need any more. I often contemplate if I really need less. Being that I only use 3/5th's of the throttle or less, 95% of the time. I wonder if there is even more fuel savings if I had less. I guess I can start that in a new topic though.

Most of the time I'm in high range and occasionally on a long steep climb I find myself in 4th and 5th to keep within the restrictions I put on myself.

I'm now starting to see 7.5+ mpg's a lot in the N.E. and when the load is lighter and the road a bit flatter, I'm seeing in the 8's. That's a pile of money coming from 6.4 mpg before I changed driving habits.

Oh, and if you're having a bad day shifting. Grinding gears, missing gears, fumbling like its your 1st day driving... Pull over take a nap, take a break, take some time off. This is a very obvious sign of mental and or physical fatigue and stress. A good nights rest will help tremendously at correcting the problem. I know this and what it looks like all to well.

[Mattman]

I need this lsbc mess turned off on my truck. Can't stand it. I am used to driving CAT and Mack motors your foot is the governor until you rev too high. I am not a high revver. 1800 rpm is plenty, after that power is falling off and all you are doing is my opinion is making noise.

Now the CAT and Mack motors have more hang time when shifting. Cummins has to be about speed shifted to keep from engine rpms dropping to much before you slide it in the next gear. Is there any way to slow the return to idle speed while shifting?