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engine rpm & HP

I have a question about why the manual that came with the FT has a different governed rpm. See pics below. Has anyone else noticed this and why would the engine be governed 300 rpm lower than the specs?
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: engine rpm & HP

Reply #1 –
Quote from: craneman –
I have a question about why the manual that came with the FT has a different governed rpm. See pics below. Has anyone else noticed this and why would the engine be governed 300 rpm lower than the specs?
Engine produces max hp at 1800 rpm. It will go 2100 rpm max, but does not necessarily produce anymore hp or torque at that speed.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: engine rpm & HP

Reply #2 –
Quote from: jcus –
Engine produces max hp at 1800 rpm. It will go 2100 rpm max, but does not necessarily produce anymore hp or torque at that speed.
Correct.

There are couple of important RPM numbers for any engine:

Peak torque RPM:  Do not operate engine below this RPM under anything but very light load

Peak HP RPM: Just what is says

Max operating RPM/Governed RPM: Highest operating speed UNDER LOAD

Maximum RPM on overrun/Max RPM, no fueling:  Just what it says-- most engines are OK running a little faster when "not working" than when working.  Important information for engines with exhaust or engine compression brakes, and even with coaches with retarders, as more engine RPM when on the retarder turns the water pump faster, so transmission temperatures are lower.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: engine rpm & HP

Reply #3 –
Quote from: wolfe10 –
Correct.

There are couple of important RPM numbers for any engine:

Peak torque RPM:  Do not operate engine below this RPM under anything but very light load

Peak HP RPM: Just what is says

Max operating RPM/Governed RPM: Highest operating speed UNDER LOAD

Maximum RPM on overrun/Max RPM, no fueling:  Just what it says-- most engines are OK running a little faster when "not working" than when working.  Important information for engines with exhaust or engine compression brakes, and even with coaches with retarders, as more engine RPM when on the retarder turns the water pump faster, so transmission temperatures are lower.
The engine tag states engine has governed rpm at 1800 there is no mention on the engine tag about 2100 rpm. That is what is confusing me.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: engine rpm & HP

Reply #4 –
I think the 1800 RPM limit on the tag was the over the road truck limit. Cummins gave off road, emergency equipment and RV's an additional RPM, explained to me at Cummins NW.
As illistrated in you Foretravel Manuel , perhaps Fortravel should have made that change to the data plate.
I wonder what other M11/ISMcoaches have on the data plate?
Cummins can pull up your engine in their data base and tell you what your engine can do.
It looks like with your engine 1800 would be a good long hill climbing RPM.
JD.
John Duld
1995 U320C SE 40'

Re: engine rpm & HP

Reply #5 –
Update, called Cummins and according to my S/N the governed rpm is 2100. The engine tag is incorrect Foretravels info is correct. They flash the ECM for the motorhome and don't always change the tag.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: engine rpm & HP

Reply #6 –
Before I read any replies, I thought the engine plate meant the max horsepower, not max rpm, was achieved at 1800.  I think if you have the owners manual you will find a hp and torque curve, and on it it shows the peak hp.  Maybe that is at 1800.  I have not pulled out the graph to check.

My engine/tranny will shift automatically at about 2000 rpm

I think...hope....I am saying the same as Bret.

mike
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches
 

Re: engine rpm & HP

Reply #7 –
Yes, Mike we are saying the same thing.

While the engine can be operated at above peak HP (i.e. before reaching governed RPM), HP does drop off.  Same with virtually all engines, gas and diesel.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020