Load Based Speed Control Issue
10-20-2019, (Subject: Load Based Speed Control Issue ) 
Post: #17
RE: Load Based Speed Control Issue
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.
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 Thanks given by: Rawze , JimT


Messages In This Thread
RE: Load Based Speed Control Issue - Unilevers - 10-19-2019,
RE: Load Based Speed Control Issue - Unilevers - 10-20-2019,
RE: Load Based Speed Control Issue - Chamberpains - 10-20-2019



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