Mileage with a Motor Home

[Bernie Jacobsen]

Andris,

There is one HUGE variable that's hard to account for: POWER.   how much
power does it take to propel your buggy down the road at 60 or 70 mph.

Now you can look at driving the same speed in different gears. This would
presumably require the same HP, so it would cancel out.   If you had an
infinite number of gears, you could travel a constant speed and select the
most efficient RPM.

On paper you can do this only if you have a fuel consumption curve [bsfc]
for your engine (although if you've modified the cam, heads... this may not
be true anymore). in that case, you can look for the lowest point on the
curve for your operating conditions.

Where can you find this curve?  I don't know.  I've only seen and used them
for diesels. I have been looking for one for a gas engine, but I'm still
empty handed.

^Bernie



-----Original Message-----
From: Andris Skulte <askulte at emerald.tufts.edu>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Monday, March 30, 1998 4:42 PM
Subject: Re: Mileage with a Motor Home


>Bernie Jacobsen wrote:
>>
>> I want to get more reliable data!
>> My plan as of now,  is to run the GB headers cruising at about 2700-2800
>> and check mileage. The next step is to lower the cruising rpm with OD
(found
>> one used for $400) and torque converter.
>
>Can you figure out mileage if you know the vehicle speed, rpms, fuel
>pressure and injector pulsewidths? This way I could figure out the best
>cruise gear/rpms for my Camaro... Everyone's mentioned best cruise at
>max torque, so should I be cruising at 3,000 rpm (off dynojet runs)? Do
>I want the most vaccuum? If I go WOT at 3,000 rpm, my torque peaks at
>475 ft-lbs, which propels me up to ludicrous speed in no time... I get
>nervous cruising at more than 90 anyways... TIA!
>
>Andris
>