28' 1981 Excella- Isuzu Diesel RPM's?

[Jeremy Krug]

I recently acquired a 28' 1981 Excella motorhome. It has the original Isuzu 5.9 with 60K miles, when I got it. I've tightened things up and taken two long trips (2K miles each) and I'm hooked!!

I was running 2600 rpm's at 57mph, getting 12.5-13 mpg. My question is, does anyone know what RPM's this motor is happy with? I'd like to run at 2800-3000 and go 62-65mph from time to time, but don't want to push the motor too hard. Any advice on this rig and motor would be awesome!

Thanks!
Jeremy

[Magnet18]

Nice looking RV!

I recommend you repost in this section, where there is more traffic-

https://www.airforums.com/forums/f311/

The section you posted in here doesn't get a lot of traffic

[mayco]

I run my Isuzu between 28 - 2900 rpm at about 62 mph. Seems to be a sweet spot. I keep it under 3000 always. We’ve put around 40,000 miles on the rig running at those numbers without issue.
Mike

[Smartstream]

Welcome to the forums and to the world of Airstream moho ownership. You have joined a rather interesting group of people.

Your Isuzu will be quite happy running 2800 to 3000 rpm. Mine did so for many miles. I on the other hand was not so happy. I installed a Gear Vendors overdrive unit. It brings the rpms down and gains some road speed. 2300 to 2400 rpm provides 63 to 65 mph. Now the Isuzu and I are both happy.

[Jeremy Krug]

Thanks Dan! I was checking out the gear vendor gear splitter as well. Have you ever towed a vehicle once you installed the spitter? I was curious if this would give me the power to tow while keeping my RPM's reasonable at 55mph.