275hp cummins enough?

[Big A]

I could use some advice fellas.

My father-in-law is looking at a 37ft holiday rambler coach. It's powered by the 275/660 version of the 5. 9l. This thing has to weigh around 25000lbs or more. He wants to pull a small car behing it. I love these engines, but I don't think it's going to have enough to pull well over the mountains. He really likes the setup, and asked me about bombing it, but he's not the type to worry about gauges. Any experienced info would be greatly appreciated.

Thanks

Big A

 

[dan_gilson]

My dad has had both a 235 and a 275. He says both are OK for the coach and pulling a car (toad) behind it. My dad also says that you will not know that a small car is back there.



Most motorhomes only have a 5K# hitch.



If you are thinking about puling a RAM or something heavier than a small car, you will probably have to up put an air over hydralic for the toad.



M&G makes an adapter for your normal brakes so that you can just plug in a motorhomes air brakes line.

 

[Barry]

If the unit he is looking at has the 1000 Allison, it will not take bombing as the over torque limiter will kick in and throw the trannie in limp mode.

If it is a 6 speed allison, it will take what you throw at it. EZ has an RV adapter and that will take it over 300 hp.

 

[dan_gilson]

The 275 may be able to be "up-rated" to a 300 or 305. You will have to pay to have the warrenty extended by Cummins. My did checked in on this and it was in the $300 ballpark. You should verify that the Allison will handle that. I believe that it will otherwise Cummins would not offer. The best thing there is that Cummins will continue to warrenty if up pay for the up-rate.



My dad decided against because the 275 has more than enough to pull it and the toad with out problems.

 

[Big A]

Originally posted by Barry

If the unit he is looking at has the 1000 Allison, it will not take bombing as the over torque limiter will kick in and throw the trannie in limp mode.

If it is a 6 speed allison, it will take what you throw at it. EZ has an RV adapter and that will take it over 300 hp.

Barry,

The unit does have the 6spd Allison in it. I drove it. It actually has a lot of power. It is really slow in 1st gear though.

Big A

 

[Barry]

The first gear is a little deep but when it hits 2nd and 3rd, you think someone has rearended you. It goes!



I am glad it has the 6 speed... ..... it's a real trannie!

 

[K_Arts]

Big A, did you have the change to drive it up a couple of good hills or passes. How was the powerband while climbing?



IMO, that sounds like a pretty heavy Motor home for an engine only having 275hp. I'd be very curious to see how that bad boy does going up Floyd Hill or Eisenhower unloaded. Please give us some feedback on how it drives.



I am curious though, what makes that engine rated at 275 when ours is only 235? What is physically different about that motor then the ECM?



Kev

 

[ProspectorTim]

Originally posted by K_Arts

... I am curious though, what makes that engine rated at 275 when ours is only 235? What is physically different about that motor then the ECM?



Kev

Where do you think we get "RV275" injectors from?



From what I've read, in addition to the bigger injectors, I think the RV motor also has better pistons.

 

[ecv2001]

In addition to having the bigger injectors I think the motor coaches have better exhaust systems already installed.

If i had a motor home and it still had the resinator in it , and the restrictive muffler I would change it to the 4 or 5" pipe and truck muffler that most muffler shops would be able to install.

Also suggest the k&n filter.

If you start doing much more you will need to monitor gauges when making steep climbs so you dont hurt anything.

 

[K_Arts]

Originally posted by firemanemt

If you start doing much more you will need to monitor gauges when making steep climbs so you dont hurt anything.

This brings up another question in my head. . LOL (Scary I know). I know pending on the type of motor home the motor could either be in the front (chassis motorhome) or the back (big ole bus motorhome). If the engine is in the back, being that this is a 37 footer, how in the world would you find an EGT gauge for that bad boy? I've never seen a probe with longer then a 10 foot lead. Autometer once told me when I was having problems with my EGT gauge if I messed with the wiring to the probe and I said no of course. They rebuttled with saying that if you change the length of the wiring that this knocks the probe calibration off. Is this true? Again, I've never seen a probe with over a 10 foot lead.



Thanks



Kev

 

[drees1]

You can extend the probe wire by using the correct wire and wire nuts.



A thermocouple works on the principle of dis-similar metals producing a voltage based on temperature at the junction where they are joined. The business end of the probe has a junction where 2 dis similar metal wires are welded together.



You must use compatible wire, either J or K type is most common. Then you must match your extension lead so the red is to red and white to white, or what ever your colors are. If you use plastic wire nuts then you do not introduce another conductor metal or create a false junction, so your gage will be correct. There may be a very small error due to the increased resistance of the extension but it will not be noticeable. The important thing is not to use screw terminals or junction blocks to make the connection, where the screws are a different material then the wire. They do make terminal strips with screw materials the same as the wire, but using plastic wire nuts is common. Just be sure the wire nut does not have a metal insert that will touch the wire!!

 

[dan_gilson]

I checked to see if K&N had a air filter for my dad's motorhome. The filter is about 1 foot in diameter and almost 3 feet in length. K&N said no.



After a trip throught the southwest my dad's filter minder was way up there.

 

[Briman]

Big A, My father in law had a Pace Arrow with a 8. 3 250 horse Cummins. It had enough beans for the rig. He then traded it in for a '97 HR Endeavor. We thought the 5. 9 wouldn't be enough. The upgrade in that chassis was a V6 Caterpillar, which he ordered. The Freight liner chassis must not have as much room as some others for larger engines. He likes the power but the cooling system is not as good as what he had in his Pace with the Cummins. I would be leery of the 5. 9 in such a large vehicle.

 

[Big A]

Thank you guys for all the advice. I think he's going to buy it. He will be travelling to Florida with it. He wants to see how it pulls stock. If he feels he needs a little more, we will put an EZ in it. I was going to talk him out of it, but he's a big boy. I think he'll be ok with it.

Big A

 

[rtaylor102]

I have a 275 turbo diesel H/R, 37 ft. I pull a jeep liberty and have had no trouble climbing hills. On mountains it slows a little. It is for sale. Has 55K miles and is a 1998.

Ray Taylor

Also, where do I find the ECM control to check for faults.

 

[jhenderson]

Power is relative. Our fire dept has a tanker we built out of an International 10 wheel dump truck. It's got a 160 cummins. Now weall think 275 isn't enough.

 

[SnoKing]

When will people get over the K&N kookaid. It is pretty dusty in the rear of a motorhome and a K$N is the last thing you want. They already have Big Hooking Air Filters! Big intake and big exhaust!

It will not win races but should do just find!

SNOKING

 

[RustyJC]

In motorhome apps, the 275 probably won't be first to the top of the hill, but it'll eventually get there and, as a bonus, has a reputation of using substantially less fuel than the 500-600 bhp rigs. Reports of 10 to 10.5 MPG are commonplace in the 36-38' rigs.

Rusty

 

[SnoKing]

No kidding Rusty, my friend has a HR Navigator tag axle with 525HP Cummins. He tows a Chevy SSR when it does not fall off, but that is another story. He gets 6ish+ MPG give or take.

The SSR came off on a bump in an on ramp in California this spring and someone flag him over 2 miles down the road to tell him he lost his tow car! Another three miles to get turned around!

Guys with fence and hedge that it went through said it happens often on that on ramp, and this time he was not putting the fence back up so do not worry about that!!!! SSR spent a month in the hospital!

SNOKING