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Topic: Regulating water temp on mountain uphills (Read 986 times) previous topic - next topic

Re: Regulating water temp on mountain uphills

Reply #25 –
To add to the power vs lack of power. My 1977 GMC General had a 855 cu. in Cummins making 350 H.P. and weighed 53,000 lbs. It would go over the 405 grade here in Los Angeles at 55 MPH in high gear at partial throttle and got 7.5 MPG. My '81 International with a 466 cu. in. engine weighing 31,000 lbs. came over the same grade at 40 MPH 11th gear full throttle and only got 5 MPG. No replacement for displacement.
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: Regulating water temp on mountain uphills

Reply #26 –
14 liters! What Cummins is that? N14? Supposed to be an excellent engine. Huge torque.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Regulating water temp on mountain uphills

Reply #27 –
Yup, since diesel do NOT need to have a stoichiometric fuel ratio (i.e. they can happily run LEAN) a large displacement engine at lighter throttle (and therefore more air than fuel mixture) does not give up MPG to a smaller engine at higher throttle making the same HP.
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: Regulating water temp on mountain uphills

Reply #28 –
Quote from: Pierce & Gaylie Stewart –
14 liters! What Cummins is that? N14? Supposed to be an excellent engine. Huge torque.

Pierce
Never needed any parts so not sure what model they called it. In the business we just called them Cummins 350's same cu. in eventually went to 650 HP. with 2 turbos
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: Regulating water temp on mountain uphills

Reply #29 –
Some Allison tranny's like ours are programed to normally be in power mode and when we press mode button tranny shifts change to economy staying in higher gears longer.

And some Allison's like Chuck's are programed to normally be in economy mode and when they press mode button, tranny changes to power mode.

I am not sure but maybe the smaller Cummins engines like our C8.3 normally are in power mode and larger M11 normally in economy mode.

BTW, we never change to economy as it tends to stress/lug engine a little more.  Our hill climbing downshifts are usually manual and paying little more for fuel is less expensive than fixing engine & tranny.
 

Re: Regulating water temp on mountain uphills

Reply #30 –
Quote from: wolfe10 –
Yup, since diesel do NOT need to have a stoichiometric fuel ratio (i.e. they can happily run LEAN) a large displacement engine at lighter throttle (and therefore more air than fuel mixture) does not give up MPG to a smaller engine at higher throttle making the same HP.
Brett has it. At idle, a diesel engine may burn 140 parts air to 1 part diesel. At full load, the ratio is more like 15/1.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)