Mileage with a Motor Home

[Bernie Jacobsen]

-----Original Message-----
From: Eric Elliott <eelliott at arkansas.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Monday, March 30, 1998 9:05 PM
Subject: Re: Mileage with a Motor Home
>All fuel, HP, torque and BSFC curves that I have been able to find specify
>operation @ WOT. No curves ever describe part throttle operation. WHY?

It seems to me that for a gasoline engine to have a meaningfull part
throttle BSFC curve, there would need to be a SET of curves for that engine
i.e.  WOT, 2",4",6",8".....16".... Does this exist?  I've searched the web
and only found the SAE site with its unending lists of seemingly random
papers... that seems a little too harsh, I do respect the SAE, I was just
alittle frustrated.  In the end, I still didn't find anything.


>
>Cummins sales sheets show their 5.9 L engines from 160 to 300 HP all get
>best BSFC near 1100 RPM. Even a short drive in the ram will show the turbo
&
>torque happen at 1900. Go figure.


In your short drive, you probably felt a combination of torque and HP.  I
haven't looked at the 5.9L curves, but I'm guessing the HP has a very steep
rise between 1100 RPM and 1900.  Also, it wouldn't surprise me if the motor
in the pick up doesn't match 100% to the Cummins 6BT sales sheet (changes
for emissions: cam, timing....) Just a guess.

^Bernie