Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > MH-General Discussions & Problems
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 01-28-2023, 06:10 PM   #1
Junior Member
 
Join Date: Jan 2023
Posts: 3
Question Transition from gas to diesel

My wife and I have owned four gas RV's over 25 years, but are strongly considering a diesel pusher (specifically a Tiffin RED 340 38LL in our case) for long range national travel. My question is not about make/model/chassis, etc, at this time, but I need guidance in the driving and monitoring of diesel engines compared to gas. I know nothing about temperatures or pressures monitoring or about air brake systems. I need some pre-purchase tutoring before I invest in the change. Thanks for any guidance
hll60 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 01-28-2023, 06:52 PM   #2
Senior Member
 
bhammond1980's Avatar
 
Join Date: Feb 2019
Posts: 478
I doubt you will find the change difficult. As for the engine you monitor temp and oil pressure, same as gas. You will most likely have either an exhaust or engine brake of some sort. You will find this the largest change and a major benefit. The air brake system works just like a hydraulic system from a drivers perspective. There will be additional dash gages to monitor system air pressure.
The diesel engine will have much more torque than a gas engine. For a motorhome that weighs north of 30K lbs. it's the only way to go.
Some other differences:
Diesel costs more than gas
Oil changes will be 30 - 40 quarts depending on engine size
Fuel filters need to be changed frequently and you should carry a spare
Normal annual service for chassis $800-1000
__________________
bhammond1980
2007 Haulmark 3301ds
2019 Ram 1500
bhammond1980 is offline   Reply With Quote
Old 01-28-2023, 07:34 PM   #3
Senior Member
 
tmw188's Avatar
 
Monaco Owners Club
National RV Owners Club
Workhorse Chassis Owner
Join Date: Dec 2013
Location: St. Charles MO
Posts: 4,920
Send a message via AIM to tmw188
Transition from gas to diesel

Air bags, their systems and sensors are one thing when working but when and if they act up could affect ride height and leveling. Lots of systems and filters depending on models. Coolant maintenance is very very important.
__________________
2002 Monaco Windsor 40PST 2019 Equinox 1.5L, Blue OX Aventa LX tow bar, Roadmaster EZ5 baseplate, SMI Stay-In-Play Duo, TireSafeGuard TPMS
tmw188 is offline   Reply With Quote
Old 01-28-2023, 09:04 PM   #4
Senior Member
 
capnqball's Avatar
 
Join Date: Mar 2012
Location: NW OREGON
Posts: 537
We had a 340 powered 38 Newmar LE prior to the current 360 hp we now own. I would advise driving that Tiffin on a variegated road test. Then drive other potential choices which have larger hp. We found the 340 a bit too weak to satisfy our needs. Make sure your potential toad is under 5K as that is the limit due to the Alison 2500 transmission which may be in the Tiffin 38.
Just my .02.
__________________
Ron in NW Oregon
2017 Ventana 3436
2021 Chevrolet Spark LT
capnqball is offline   Reply With Quote
Old 01-29-2023, 06:31 AM   #5
Senior Member
 
Join Date: Oct 2020
Posts: 495
Quote:
Originally Posted by capnqball View Post
We had a 340 powered 38 Newmar LE prior to the current 360 hp we now own. I would advise driving that Tiffin on a variegated road test. Then drive other potential choices which have larger hp. We found the 340 a bit too weak to satisfy our needs. Make sure your potential toad is under 5K as that is the limit due to the Alison 2500 transmission which may be in the Tiffin 38.
Just my .02.
I’m familiar with the Tiffin model line, your assumptions are all correct. The RED 340 line uses the Cummins ISB in 340/660 tune with the Allison 2500 transmission. Accordingly it has a tow limit of 5,000lb.

Also, it is built on the Freightliner XCS straight rail chassis so does not have passthrough storage, so something to check out and make sure it is adequate.

The OP doesn’t say what in what state they are licensed. Moving to a coach with a GVWR above 26k may require them to secure a higher license classification - it does here in Texas. Regardless, I suggest finding your states CDL study guide online and learning the air brake section. How they work, how to perform a test, routine maintenance, etc.
Shadow5501 is offline   Reply With Quote
Old 01-29-2023, 06:57 AM   #6
Senior Member
 
Triangle Drifter's Avatar
 
Join Date: Jan 2007
Location: Bermuda Islands
Posts: 1,469
Diesels run hotter than gas. Usually 165-185, depending on engine & to some degree how hard it is working.

Diesels like clean fuel, clean oil & clean air. I have had three diesels used in marine applications & now the Isusu in my truck. Oil is cheap mechanic repellant. Use a better than specified grade of it & a better than specified filter. Get into a routine of checking fluids before a long drive.

Diesels are simple beasts but when something goes wrong hang on to your wallet.
__________________
Home: Bermuda
US RV base, MD
2007 Alpenlite 34RLR
Triangle Drifter is offline   Reply With Quote
Old 01-29-2023, 08:57 AM   #7
Senior Member
 
Tiffin Owners Club
Join Date: Jul 2014
Location: Cedar Falls, IA
Posts: 2,226
I have a Tiffin 37PA with a 360 HP engine and the Alison 3000 transmission. The 38LL would be much better with the same setup. That rig is too heavy for the smaller engine, and the 2500 transmission limits your towing too much. And I also have a XC chassis, and it does have pass through storage in the two big bays. That being said, the transition to a diesel isn’t too hard. You need to learn about engine braking and exhaust brakes, but temps and pressure limits are well marked on the dash instrumentation. The exhaust brake along is worth its weight in gold if you travel a lot in mountains.
__________________
2018 Tiffin RED 37PA
2023 F-150 carrying a RZR 570 Trail UTV toad
https://toobusyforwork.com
UTTransplant is offline   Reply With Quote
Old 01-29-2023, 10:18 AM   #8
"Formerly Diplomat Don"
 
Dutch Star Don's Avatar
 
Newmar Owners Club
Join Date: Apr 2005
Location: Moorpark, Ca.
Posts: 23,931
Quote:
Originally Posted by hll60 View Post
My wife and I have owned four gas RV's over 25 years, but are strongly considering a diesel pusher (specifically a Tiffin RED 340 38LL in our case) for long range national travel. My question is not about make/model/chassis, etc, at this time, but I need guidance in the driving and monitoring of diesel engines compared to gas. I know nothing about temperatures or pressures monitoring or about air brake systems. I need some pre-purchase tutoring before I invest in the change. Thanks for any guidance
The newer diesel coaches are just like the gas coaches. The computer monitors all of your engine functions and will let you know if there is an issue. A modern diesel will not have overheating issues and again, the computer will watch for all of this. The big difference will be how the coach accelerates. A gas coach likes to have the pedal "mashed' for instant acceleration, but a diesel will just fall on its face if you try the same thing. Diesels are powerful but need to gain momentum versus accelerating.

Your gas coach uses hydraulic fluid, under pressure, to activate your brakes by putting pressure on the pads or shoes (drum brakes). A diesel (air brake) coach works differently. In the most basic description, springs are always applying the brakes on an air brake coach. It's the air that puts pressure against the springs, releasing the brakes. This is why it's important to know and maintain your air brake system. If the air fails, the brakes are applied, and the coach will come to a stop. This sounds serious, but rarely ever happens in the lifetime of people operating air brakes, especially in an RV.

Lastly, a diesel coach will come with an exhaust brake or engine brake. Similar to some of the grade brakes on newer gas coaches, the exhaust and engine brake basically block the exhaust from exiting the engine and cause a diesel to slow down. This is done in combination with the transmission downshifting. It's a useful feature when descending grades and towing a car or trailer. Operation of the exhaust or engine brake has a short learning curve, but can't be done wrong, just done better as you get more experienced.
__________________
Don & Mary
2019 Newmar Dutch Star 4018 (Freightliner)
2019 Ford Raptor
Dutch Star Don is offline   Reply With Quote
Old 01-29-2023, 10:43 AM   #9
Senior Member/RVM #90
 
MSHappyCampers's Avatar


 
Monaco Owners Club
Join Date: Nov 2002
Location: Columbus, MS
Posts: 54,626
Hi ! Welcome to IRV2! We’re sure glad you joined the gang here!

I don't know that much about Tiffin, but isn't the RED the one with the engine up front? If so, I would not want it, but that's just me. Hope you fine the perfect rig for your needs!

Good luck, happy trails, and God bless!
__________________
Joe & Annette
Sometimes I sits and thinks, sometimes I just sits.....
2002 Monaco Windsor 40PBT, 2013 Honda CRV AWD
MSHappyCampers is offline   Reply With Quote
Old 01-29-2023, 11:35 AM   #10
Junior Member
 
Join Date: Jan 2023
Posts: 3
Thanks for the feedback. I did not think the license situation would be an issue with a non-commercial vehicle in Alabama, but I'll check that. Sounds like I need to rethink the 340hp. We like that specific floorplan, but it sounds like it will be under-powered.
hll60 is offline   Reply With Quote
Old 01-29-2023, 11:48 AM   #11
Senior Member
 
JerryP's Avatar
 
Tiffin Owners Club
Join Date: Sep 2008
Location: Dallas TX
Posts: 522
Tiffin 360 RED

We have a 2020 Tiffin 33AA with the 360 engine and Allison 3000 transmission. These are a great match. Our RV is 35 feet long. Yours would be almost 40 ft. long. I think the 340 might be underpowered.

Good luck with your purchase.
Jerry
__________________
2020 Tiffin 33AA with 2 rear Vroom Slides - towing 2016 Toyota 4Runner Trail Premium, Options: Roadmaster Sterling Tow bar, RVIbrake2
JerryP is offline   Reply With Quote
Old 01-29-2023, 12:19 PM   #12
Senior Member
 
jarwiebe's Avatar


 
Newmar Owners Club
Spartan Chassis
Join Date: Jul 2012
Location: Manitoba, Canada
Posts: 553
Quote:
Originally Posted by Dutch Star Don View Post

Your gas coach uses hydraulic fluid, under pressure, to activate your brakes by putting pressure on the pads or shoes (drum brakes). A diesel (air brake) coach works differently. In the most basic description, springs are always applying the brakes on an air brake coach. It's the air that puts pressure against the springs, releasing the brakes. This is why it's important to know and maintain your air brake system. If the air fails, the brakes are applied, and the coach will come to a stop. This sounds serious, but rarely ever happens in the lifetime of people operating air brakes, especially in an RV.
To clarify what Dutch Star Don said above, only the parking brake is spring applied and air released. The service brakes are air applied and spring released.
__________________
Jake
2005 DSDP 4024, Cummins ISL 370, Spartan MM Chassis / 2018 Ford Taurus, Roadmaster Base Plate, Blue Ox Aventa LX Tow Bar, RVI 2 Brakes
jarwiebe is offline   Reply With Quote
Old 01-29-2023, 05:48 PM   #13
Junior Member
 
tundratech's Avatar
 
Newmar Owners Club
Freightliner Owners Club
Join Date: Aug 2013
Posts: 16
Hey jarwiebe, I think you need to take an air brake course.
Dutch Star Don is correct, the air works against the spring applying the brakes.
The park brake release the air from the brake chambers and the coil spring applies the brakes. You must have seen the twin skid marks on the highway. Generally caused by air loss to a set of highway trailer brakes causing full application by the spring and locking up the brake on that wheel
__________________
2012 Newmar Dutch Star 4353
tundratech is offline   Reply With Quote
Old 01-29-2023, 06:00 PM   #14
Senior Member
 
Newmar2856's Avatar
 
Join Date: Jan 2013
Posts: 881
If I recall correctly, and I could be very wrong, when we looked at this model I thought the salesman said that the coach has air leveling and no hydraulic levelers. Again, I could be wrong, but it stuck in my head and was one of a number of things that caused us to cross the model off our list.
__________________
John, Laurie & the 3 Schnauzers
2019 Newmar Bay Star 3609
Ford V10 - 24K Chassis
Newmar2856 is offline   Reply With Quote
Reply

Tags
diesel, gas



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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Transition from Gas to DP? What To Look For. Sky_Boss Class A Motorhome Discussions 19 07-22-2012 11:38 PM
Transition to LED Bulbs gdbontly Excel Owner's Forum 5 03-31-2011 09:58 PM
Dog House Carpet Transition Solutions iRV4FUN Damon 3 07-09-2008 01:17 PM
Alternative for Adapting To Digital Broadcast Transition vicsryd Technology: Internet, TV, Satellite, Cell Phones, etc. 7 03-01-2008 07:08 PM
DTV Transition and Cable TV vicsryd Technology: Internet, TV, Satellite, Cell Phones, etc. 6 01-09-2008 09:11 AM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 03:56 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.