[TomB985]

Wow...I'd take gutless for those kind of MPGs... thanks for the specs...

[tracer]

okay, did the dyno tuning on monday. they worked on the truck almost an entire day (from 6 am to 3:30 pm). I got exactly what I asked - lots of power at my cruising RPMs: between 1300 and 1400 RPM. I drove back from Toronto to Guelph, and this is not the same truck I drove from Guelph to Toronto The increase doesn't look that much on paper, but they really put the joy back into the driving. I'm going back on the road on thursday and will report on how this extra horsepower will affect my fuel mileage.

Here's some technical info from the dyno report.

RPM 1,188; 1,419; 1,634; 1809;
Fuel GPH 21.2; 24.5; 25; 26.7;
Old HP 436; 509; 501; 501;
NEW HP 442; 547; 538; 540;
Wheel 1 400; 477; 452; 425; old HP at the wheels
WHEEL 2 405; 516; 462; 437; new HP at the wheels

I'll be crusing at 1325 rpm which according to a graph attached to the dyno report, should give me about 475 hp (450 at the wheels).

The truck has 2004 Cat C15 Acert (dual turbo), 3.73 rears, 18913 tranny, 2000 lb-ft torque LIPE clutch, low pro 295 yokohoma tires. 1325 RPM makes me cruise at 58 MPH.

[tracer]

Originally Posted by allan5oh

What gets better fuel mileage, the low revving v8's or higher revving 4 cylinders?

My 2008 Chevrolet Cobalt Sport with 175 HP engine and 5 speed manual gets 7 liters per 100 km at 120 km/h! To translate into U.S. units, that's 34 mpg at 75 MPH. At that road speed this high efficiency 4-cyl engine turns at 2700 RPM. I got a custom K&N air intake and performance muffler from GM. Everything else is stock. I noticed for this car it doesn't matter whether I'm doing 60, 65, 70 or 75 mph: as long as I"m on an interstate (here's it's called "401") and driving in top gear, the fuel mileage stays close to 34 mpg at all speeds. Weird...

[solo379]

Originally Posted by luckyky00

Just wondering if I'm okay running the RPM'S that high....

If you don't mind paying extra few grand for fuel.... And of course you could run CAT at 18-1900 RPM,tho it's not really a "sweet spot". But if you are going to keep this truck, and operate at those speeds, it's cheaper to replace tranny, or rears....

[rank]

Originally Posted by TomB985

Wow:bow:...never met someone who averaged that on paper...what RPMs and speed to you cruise at? Also, what HP and torque are your engine rated at?

now you've met two.

[rank]

Originally Posted by tracer

okay, did the dyno tuning on monday. they worked on the truck almost an entire day (from 6 am to 3:30 pm). I got exactly what I asked - lots of power at my cruising RPMs: between 1300 and 1400 RPM. I drove back from Toronto to Guelph, and this is not the same truck I drove from Guelph to Toronto The increase doesn't look that much on paper, but they really put the joy back into the driving. I'm going back on the road on thursday and will report on how this extra horsepower will affect my fuel mileage.

Here's some technical info from the dyno report.

RPM 1,188; 1,419; 1,634; 1809;
Fuel GPH 21.2; 24.5; 25; 26.7;
Old HP 436; 509; 501; 501;
NEW HP 442; 547; 538; 540;
Wheel 1 400; 477; 452; 425; old HP at the wheels
WHEEL 2 405; 516; 462; 437; new HP at the wheels

I'll be crusing at 1325 rpm which according to a graph attached to the dyno report, should give me about 475 hp (450 at the wheels).

The truck has 2004 Cat C15 Acert (dual turbo), 3.73 rears, 18913 tranny, 2000 lb-ft torque LIPE clutch, low pro 295 yokohoma tires. 1325 RPM makes me cruise at 58 MPH.

where did you take it and what did they charge you?

[rank]

that M11 that I drive? I used to drive it 70, then 65, now 60. Mileage got better every time. Even at 60, it screams 1700 rpm with that 4.55 rear gear and 22.5 LP tires. I can't drive slower than 60 so I think I'm going to swap some tall rubber on there for fun. Should drop the rpm's to ~1400.

I bet it gets me .7 mpg

[tracer]

Originally Posted by rank

where did you take it and what did they charge you?

You need a CAT dealer that has a dyno machine. In the area where I live there's 3 such places: Stony Creek, ON; Concord, ON, and London, ON. I went to the Toromont CAT in Concord at Hwy 7 and 400. The flat fee is Cnd$799 plus tax.

[TomB985]

Originally Posted by rank

that M11 that I drive? I used to drive it 70, then 65, now 60. Mileage got better every time. Even at 60, it screams 1700 rpm with that 4.55 rear gear and 22.5 LP tires. I can't drive slower than 60 so I think I'm going to swap some tall rubber on there for fun. Should drop the rpm's to ~1400.

I bet it gets me .7 mpg

Wow...that efficient at 1700 RPMs...

We heathen company drivers don't have much choice of equipment, and thus I drive what I'm given. The only two engines I've ever had for any length of time were 14L Series 60s, and this Cat C15...both of which like 12-1400 RPMs.

It's amazing the figures you guys are getting with smaller motors, you have to wonder why many fleets prefer the large ones. My last employer tried the MBE4000s for a bit, then went back to the 14L Detroits. My current employer has a few '06 Volvos with D12s left over from a merger, and they are getting rid of them and replacing most of them with T660s with ISX motors. Not sure why, though, with what the cost of fuel is...

[tracer]

Originally Posted by TomB985

It's amazing the figures you guys are getting with smaller motors, you have to wonder why many fleets prefer the large ones.

Large engines last longer and have a better resale value. You can get good fuel mileage from big engines as long as you don't abuse the horsepower. Keeping the RPMs in her sweet spot is the key.