Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 06-03-2013, 11:26 AM   #1
Member
 
Join Date: Sep 2011
Posts: 35
Class A Diesel Performance on Grades

I'm looking at mid to late 90's diesel coaches and would like to know if the Cummins, CAT or Detroit engines which range between 275-350 HP have decent power to pull 6% or better grades pulling a 3000# toad. I'm asking those who have had experience with this combination to please share their comments.

My wife who was an over the road trucker for 25 years says we should be looking for no less than 400 HP, but pulling a 53 ft trailer weighing 80,000 # is different than a motorhome.

It seems that the majority of coaches I have looked at are in the 275-350 range.

Thanks!
__________________

__________________
datedd is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 06-03-2013, 11:39 AM   #2
Senior Member
 
Skip426's Avatar


 
Join Date: Apr 2011
Location: Powell River, B.C.
Posts: 14,972
Best description I've seen , and one that I agree with is.
At least 1 HP per 100lbs of total weight.
With torque of 3X that of HP.
With peak torque and peak HP within 1000RPM of one and other
Example MH with toad 30,000lbs
Engine HP 300, torque 900ftlbs.
Peak torque 1400 RPM peak HP 2400.
My coach fits this profile and I'm happy.
Could use more power at times , but as is I'm able to pass loaded semis when climbing hills.
MH, HP race didn't really get going till the 2000's and the fuel economy suffered, I have gotten 9+mpg on trips for the last 3 years, the 400+ HP MHs most times are reporting 7>7.5.
__________________

__________________
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Skip426 is offline   Reply With Quote
Old 06-03-2013, 11:39 AM   #3
Senior Member
 
dons2346's Avatar
 
Country Coach Owners Club
Join Date: Dec 2010
Posts: 4,491
Well, my 350 Cummins hauls 32,000 pounds up a hill fast enough to pass the 80,000 pound trucks. I wouldn't say you absolutely have to have 400HP at a minimum
__________________
dons2346 is offline   Reply With Quote
Old 06-03-2013, 12:55 PM   #4
Senior Member
 
csrrsr's Avatar
 
Freightliner Owners Club
Join Date: Jan 2013
Location: Spokane, WA
Posts: 692
In the NW we have several long....steep grades ie, Big Sandy, Lewiston Grade, Vantage Grade along with several mountain passes. I usually pull a boat making our total weight about 31,000 lbs. Seems most grades run between 5-6%. The 330 Cat does a great job, but the 6 sp Allison transmission gets all the credit. I usually manually adjust the gears from 6 down to 4 based on 1500 RPM being where I do the down shift. I've never had to go below 4th gear. My MPH is 45 at that point. As the RPM's increase over 1500 I take it to the next gear. On long grades there's points where the grade decreases which allows me to shift up and when the grade increases I down shift again. The engine stays cool and I'm not over powering the drive train. I'm very happy with the torque of the 330 Cat.
__________________
02 Fleetwood Discovery 37U, 330 Cat pulling a 2006 diesel Liberty..or..2011 4dr Wrangler..or..20' Lund Salmon/Halibut Hunter
csrrsr is offline   Reply With Quote
Old 06-03-2013, 01:26 PM   #5
Senior Member
 
rdownward's Avatar
 
Alpine Owners Club
Join Date: Sep 2011
Location: Leeds, Utah
Posts: 199
I have owned 2 coaches with the 275 h.p. Cummins and was extremely frustrated with the performance on grades with both of them. I now have a 350 h.p. Cummins rated at somewhere over 1,000 lbs of torque and I'm a happy camper. The fuel mileage overall is about the same (unless I was driving for long stretches on level highway with no headwind - then the 275 h.p. got better mileage than the current 350 gets). My suggestion would be to look for a coach with a minimum of 300 h.p. and 900 lbs of torque. The brand shouldn't make that much difference (IMHO).
__________________
Roger & Diana
'03 Alpine 36MDDS
Leeds, UT
rdownward is offline   Reply With Quote
Old 06-03-2013, 03:22 PM   #6
Member
 
Join Date: Sep 2011
Posts: 35
Thanks for the quick replies, this is giving me something to work with. It's not like I'm looking for a 60 MPH jaunt up a grade, but 20 MPH would be ridiculous.
__________________
datedd is offline   Reply With Quote
Old 06-03-2013, 03:44 PM   #7
Senior Member
 
wimberleyman's Avatar
 
Join Date: May 2012
Posts: 224
X2 to Skip426. Similar set-up, same engine, similar results.

WM
__________________
Wimberleyman
2001 Cruisemaster/300 Cat
wimberleyman is offline   Reply With Quote
Old 06-03-2013, 03:48 PM   #8
Member
 
Huck's Avatar
 
Join Date: Feb 2000
Location: Galveston,Texas,USA
Posts: 33
Quote:
Originally Posted by datedd View Post
I'm looking at mid to late 90's diesel coaches and would like to know if the Cummins, CAT or Detroit engines which range between 275-350 HP have decent power to pull 6% or better grades pulling a 3000# toad. I'm asking those who have had experience with this combination to please share their comments.

My wife who was an over the road trucker for 25 years says we should be looking for no less than 400 HP, but pulling a 53 ft trailer weighing 80,000 # is different than a motorhome.

It seems that the majority of coaches I have looked at are in the 275-350 range.

Thanks!
Well I am going to go against the masses and say I side with the wife, 400 HP is the least I would want but then again I think at times what I have now is under powered When you hit Loveland or Vail or Wolf Creek Pass not to mention Monteagle or The Grapevine you will want twice whatever you have . But I am a Hot Rodder at heart and you can never have too much HP or Money............
__________________
2012 Newell Quad Slide ISX 650
12sp ZF AS Tronic Trans
and all the goodies they would put in it
Huck is offline   Reply With Quote
Old 06-03-2013, 04:01 PM   #9
Senior Member
 
becks's Avatar
 
Join Date: Sep 2006
Location: Fulltime/ SE Minnesota
Posts: 2,544
I too agree with the wife ,and Huck above. And I would realy like an ISX. But for us when shopping it was a minimum of an ISL 400 hp which is what we ended up with and are happy with. Get the 400 if budget allows, and you and the wife will both be happy. Good luck shopping.
__________________
06 TS-42-DS04
1040 watts of solar
2014 Jeep Rubicon/2003 Honda CRV
becks is offline   Reply With Quote
Old 06-03-2013, 04:49 PM   #10
Senior Member
 
EDALLSAILS's Avatar
 
Thor Owners Club
Freightliner Owners Club
Join Date: Apr 2011
Location: Port Charlotte, FL
Posts: 727
Had a 280 Cummings and it could be frustrating in a 36 ft MH. Now have a 350 CAT in a 40 ft and haven't had any problems with grades here in the So East USA. Can tell a difference between the two engines. Not in a hurry, don't care if I can pass or not, just don't want to be the reason that backs traffic up behind me for miles. Safe Travels ed
__________________
EDALLSAILS is offline   Reply With Quote
Old 06-03-2013, 05:23 PM   #11
Senior Member
 
CampDaven's Avatar


 
Join Date: Jul 2012
Location: Fulltime, USA
Posts: 14,463
Blog Entries: 1
On a 10 mile 6% grade, I crest it at about 45mph.
If the rig next to me crests it at 55, he will be a couple minutes ahead of me.

If his flat road speed is 70 and mine is 60, and he Wal-docks after 12 hours and I go to camp after 300 miles to have a campfire, a fine meal, family time, a great nights sleep, who wins?
__________________
Dave and Nola, RVM1
The Journey is Our Destination!

http://davenola.blogspot.com/
CampDaven is offline   Reply With Quote
Old 06-03-2013, 05:30 PM   #12
Senior Member
 
GaryKD's Avatar
 
Newmar Owners Club
Join Date: Jul 2006
Location: Wellington, Florida
Posts: 12,324
Hi dated,
I'm weighing in at 37K pounds, coach and toad. The engine is a Cummins ISC 330 HP and 950 ft lbs of torque. On long grades, momentum is everything. Because of traffic, I usually loose the momentum. The ISC will not retrieve the lost momentum. Patience is required. I go back and forth across the Smoky Mountains (I40) quite a bit. If there is no traffic, I can zip along at 45-50 MPH. However, what usually happens, I am in the truck lane putzing up the hill at whatever speed the lead truck is going.
__________________
Gary
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
The Avatar Is Many Times Around The USA
Nobody Knows Your Coach Like Somebody Who Owns One Just Like Yours
GaryKD is offline   Reply With Quote
Old 06-03-2013, 06:53 PM   #13
YC1
Senior Member
 
YC1's Avatar


 
Holiday Rambler Owners Club
Join Date: Jun 2011
Posts: 5,582
Wife, Huck, Becks, I agree. Even with 400 hp I have it upped to close to 500. The Grapevine or Donnor summit are tough hills. What would be nice is a couple more gears but 6 is enough. I get excellent mileage and acceleration from a stop is surprising. My FIL used a 350 for years and was very happy with it but his rock truck had 18 gears.

In any case, if the wife ain't happy, no one is happy. She has the experience and will be doing a lot of the driving I suspect. Let her smile. If you get a rear radiator 400 ISL I can show you how to get more power and better mileage and put a smile on her face.
__________________
Myron & Deborah
08 HR Endeavor 40 SKQ
2012 Ford Edge Limited FWD 3.5L
Aluminator tow bar, Demco base plate
YC1 is offline   Reply With Quote
Old 06-03-2013, 07:02 PM   #14
Member
 
Charrua72's Avatar
 
Join Date: Apr 2013
Posts: 56
Quote:
Originally Posted by datedd View Post
I'm looking at mid to late 90's diesel coaches and would like to know if the Cummins, CAT or Detroit engines which range between 275-350 HP have decent power to pull 6% or better grades pulling a 3000# toad. I'm asking those who have had experience with this combination to please share their comments.

My wife who was an over the road trucker for 25 years says we should be looking for no less than 400 HP, but pulling a 53 ft trailer weighing 80,000 # is different than a motorhome.

It seems that the majority of coaches I have looked at are in the 275-350 range.

Thanks!
Man I wish my wife would try and talk me into having more power! Lol if she says so with all her experience then just get one with more power....
__________________

__________________
Charrua72 is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:13 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.