8V-71 HP?

[buswarrior]

The trick is to look at the torque curve, with an eye on the horsepower curve.

Satisfaction with the way the coach pulls is tied to the torque curve, not horsepower.

You want the torque curve to be climbing behind you, as the revs drop off, if you want it to have some driveability, that is, that it will still pull with a slight rise in the road or a headwind.

When choosing a cruise RPM, gearing your coach, or choosing to be running at the torque peak will produce unhappy results: anything that slows the coach a little, the torque falls off, and it will feel like it has no power.

In the chart, cruising at 1600, any drop in RPM will have a drop in pulling power, cruising at 1800, the torque rises behind you as the revs drop to 1600, there is some "pull" left in the pedal to combat that rise in the road.

You will note the drop in torque up at the higher rpm. As we start climbing, the coach readily drops in speed from top RPM, then sets to pulling, often a downshift to 3rd, and there's a little more speed drop, and then in 3rd, it loves to pull the interstate slopes at 40 to 45 mph.  Most stock gearing puts the engine at 1800 rpm, which is no coincidence.

The compromise is, an engine is most fuel efficient at peak torque, but gearing to run there makes the driver unhappy with how the coach slows as it approaches hills and headwinds.

happy coaching!
buswarrior

[rampeyboy]

When choosing a cruise RPM, gearing your coach, or choosing to be running at the torque peak will produce unhappy results: anything that slows the coach a little, the torque falls off, and it will feel like it has no power

wow that makes a lot of sense! Never even considered this before. This explains a lot about my old gasser's inability to hold speed on a hill. It would easily run 70 on the flat (with a lot of rpm) but any hill would just kill it!

[5B Steve]

  Thanks guys, for all of your responses.  After reading the post and seeing the charts, seems to me if you keep

your foot in it on that engine and the right injectors that's a good engine to have. Like Clifford mentioned, and

Tom C. (in a previous post) the right AIR has alot to do with the performance. I have the 8V-92N in mine,  on a

trip to Fl. and back home for bike week, my engine just sipped fuel.  Just like the BLACKBIRD SR-71 the faster

you go the less fuel you burn! LOL!

Steve 5B......

[DaveG]

8V92N..did I miss something ?.

[5B Steve]

  Hey Dave,

   You didn't miss anything, mine is the 92 series less the turbocharger guess that why it's a natural (boat motor)

    Steve 5B....

[luvrbus]

Nope you are not missing anything DaveG lot of the green 8v92 were N/A the Sliver not so much but you do see them a friend of mine in the charter business had some sliver 8v92 in his Eagles 14 to be exact he said it kept the drivers under control lol but when he sold out to Arrow the bus he kept for a RV I installed a turbo and a cooler on that one in a hurry  


good luck

[DaveG]

Okay, thanks all...still learning...hard to believe! I thought all 92s were Turbo'd