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MileHiGuy · 12-07-2014, 08:44 PM

Quote:

Originally Posted by OB-One

We have an 04 Signature with a 525HP 14 Liter Detroit Series 60. This thing will pass anything but a diesel pump. We have not yet defeated the EGR. From what I have read, defeating the EGR will improve fuel mileage 0.3 to 0.5 mpg. We've averaged 5-5.5 mpg over the past 5000+ miles. Our cruise speed has been 65mph most of the time with a few excursions to the 75mph range. The mileage drops to 4.8-5.0 mpg at 75mph.

We pulled an 8300 pound diesel pickup for the first 2500 miles and have now switched to a much lighter Ford Explorer.

It's hard for me to keep the speed down on the Interstates, even using cruise control, because this thing just runs and rides so nice at 75mph.

Thanks for the informative post. Sounds like the Seris 60's are runners just a little on the thirsty side.

The ISM did turn out to be manufactured in Sept of 2002 and is pre EGR. Just afraid the small stacker I would like to get needs more torque. (assuming I can update the hitch and stay below GCWR)

OB-One · 12-07-2014, 08:59 PM

A note on my stated mpg; I did not factor out generator or Aqua-Hot fuel consumption. Most of our travels have been pole to pole, but in warm weather the generator ran 100% of the time to run the 3 A/C units.

super_rep · 12-08-2014, 08:59 AM

We have an 04 45' Signature Castle IV with the 515 Detroit Series 60 ERG engine. Got it with 71,000 miles on the odometer and now have 94,000. This engine is one fantastic workhorse. It really pulls, but does drink the fuel. We are running about 6.25 mpg ave. It seems to be most comfortable at about 1475 rpm-64-65 mph. We tow a 5300# Jeep GC diesel and don't even know it's there. Talk about a stable coach-this thing is rock solid at 65mph.

We crossed the Salt River Canyon on Rt 191 earlier this year. It handled the 7-8% grades and multiple switchbacks effortlessly with only a 10deg increase on engine temp.

I run with SilverLeaf VMSpc real time engine and transmission monitoring and you can see all the data change as the engine is running. It sure is easy to keep the engine running in the "sweet spot".

We're full timers and this coach is probably one of the best for full time living on the road.