Fuel mileage

[Rawze]

(10-07-2019 )DDlighttruck Wrote:  Ok, how the heck do you drive down the road at under 10 pounds boost? I was on US-2 today across the UP, which is fairly flat going. The best I could consistently hit was in the 11-13 pounds boost range. Unless it was downhill. I was 15-1600 rpm, 60-62 mph, light load on a stepdeck. Barely stepping on the fun pedal with one toe.

sounds to me like you might be also fighting some excessive drag somewhere. Maybe wind, maybe aero drag on the trailer or load, rolling resistance,.. who knows.

[Chamberpains]

11-13 ain't bad. You don't get great right away. Im a year and a half at this and still working at it.

A little help from neutral on the down hills and over those slight up hills (like overpasses) helps a lot out on the flat parts of the country. Use that throttle as little as possible. Lose a mph or 3 on the up hill side and nice and gently with the throttle, get it back on the down hill side.

[DDlighttruck]

(10-07-2019 )the missing link Wrote:  Running from Seattle to prince goerge the long way ( dejong) with a low profile step . I am running light but have a 15` wide and 16 ' tall box on the back .I am getting 5.5 loaded and 8 the way back .this is with a 4900 star with a 2250.
My 08 9900 was around 5.5 us pulling super B's .I had better days and way worst days .
The tune is not the end of the world , your right foot is everything .it takes a long time to get used to every trick in the book and to be able to back out .

I am having a very hard time getting this star to hit what my 9900 did .
I still have a few more things to check . Running big heavy loads (9 axel) this truck is running roughly .5 lower loaded and 1 empty less then the 08 9900 driving the same .
Maybe this helps.

When did you sell your 9900?

Every little bit helps. Thanks!

[the missing link]

Still have it .
Good a really good deal on the star and a heavier truck for what I do is not a bad idea .
I put the star to work 2 months ago

[DDlighttruck]

(10-07-2019 )Rawze Wrote:  

(10-07-2019 )DDlighttruck Wrote:  Ok, how the heck do you drive down the road at under 10 pounds boost? I was on US-2 today across the UP, which is fairly flat going. The best I could consistently hit was in the 11-13 pounds boost range. Unless it was downhill. I was 15-1600 rpm, 60-62 mph, light load on a stepdeck. Barely stepping on the fun pedal with one toe.

sounds to me like you might be also fighting some excessive drag somewhere. Maybe wind, maybe aero drag on the trailer or load, rolling resistance,.. who knows.

Ok, even empty today across US29 in Wisconsin, I could barely get it in the mid tens for boost. Low pro step deck.

What number am I shooting for? Or just anything under ten?

[DDlighttruck]

(10-08-2019 )Chamberpains Wrote:  11-13 ain't bad. You don't get great right away. Im a year and a half at this and still working at it.

A little help from neutral on the down hills and over those slight up hills (like overpasses) helps a lot out on the flat parts of the country. Use that throttle as little as possible. Lose a mph or 3 on the up hill side and nice and gently with the throttle, get it back on the down hill side.

I kind of get it. Going uphill or even just accelerating watch the boost gauge, if it hits 17-18 lift your foot just a hair and it drops to 11-12, but you’re still accelerating.

It takes a lot of discipline to drive it this way, I’m not sure yet how this will work loaded heavy in hills. I’ll keep working at it. Thanks!

[DDlighttruck]

(10-08-2019 )the missing link Wrote:  Still have it .
Good a really good deal on the star and a heavier truck for what I do is not a bad idea .
I put the star to work 2 months ago

How are you liking the star car?

[Chamberpains]

When pulling hills, its more important to keep your RPMs up. So keeping boost down at 10 isn't gonna happen.

When you down shift, you should see a spike in boost to somewhere a little over 20 psi. Then it's up to you to do the dance of pulling the hill and yet trying to keep boost as low as possible. I can keep mine under 15 pretty quick after the initial downshift spike. But it takes some serious discipline. And I downshift a lot till i find the gear that keeps my RPMs above 1500 and gets my boost at around 15 psi. I also monitor my tps reading and I can now say I can pull every mountain in the states by using no more than 60 tps or 3/5ths of the pedal and never pushing it any further. This is done with full 80000# gross using a Cummins cm870 450hp Uni-tune, 10 speed, 3.55 rears. I actually have very little need to use more throttle pedal. Except on the occasional short on ramp in heavy traffic. My fuel mileage is in the mid 7's and im just now starting to see 8's after I replaced my transmission and exploded pilot bearing.

[DDlighttruck]

(10-08-2019 )Chamberpains Wrote:  When pulling hills, its more important to keep your RPMs up. So keeping boost down at 10 isn't gonna happen.

When you down shift, you should see a spike in boost to somewhere a little over 20 psi. Then it's up to you to do the dance of pulling the hill and yet trying to keep boost as low as possible. I can keep mine under 15 pretty quick after the initial downshift spike. But it takes some serious discipline. And I downshift a lot till i find the gear that keeps my RPMs above 1500 and gets my boost at around 15 psi. I also monitor my tps reading and I can now say I can pull every mountain in the states by using no more than 60 tps or 3/5ths of the pedal and never pushing it any further. This is done with full 80000# gross using a Cummins cm870 450hp Uni-tune, 10 speed, 3.55 rears. I actually have very little need to use more throttle pedal. Except on the occasional short on ramp in heavy traffic. My fuel mileage is in the mid 7's and im just now starting to see 8's after I replaced my transmission and exploded pilot bearing.

I’m a relatively new driver, but I’m used to the “hurry up and deliver so you can turn around and grab the next one” type trucking, or the “leave on Thursday and deliver 1000 miles away Friday morning” type of trucking

I pulled a 715 mile day a couple weeks ago limited to 62 mph (by my choice). So it’s still doable to make miles, it just takes keeping the left door shut.

I swear dispatch thinks I can pull triple digits which is another subject altogether

I’ll keep working on it, thank you.