Motor Size vs. Trailer Size

[Cayman Dave]

Hi All,
I would like to tow a trailer (stacker v nose) that will weight 16000 lbs loaded. I have looked at several different coaches 39/40 feet with mostly cat 330 HP motors. I talked to a Cat Motor guy he thought that this engine C-7(which is not discontinued) " might not do the job.
Does anyone have any imput?

[Cayman Dave]

Hi All,
I would like to tow a trailer (stacker v nose) that will weight 16000 lbs loaded. I have looked at several different coaches 39/40 feet with mostly cat 330 HP motors. I talked to a Cat Motor guy he thought that this engine C-7(which is not discontinued) " might not do the job.
Does anyone have any imput?

[Gary RVRoamer]

The rule of thumb is that you want at least 1 hp for every 100 lbs for adequate performance, so figure the gross combined weight of coach and trailer and divide by 100 lbs for a minimum horsepower figure.

I agree with the Cat guy - 330 hp isn't going to make you happy. Not only will the HP be low for the load, the torque (I think it is 925 ft lbs for a 2007 C7) is also on the light side. You need a larger Cat or a Cummins ISL or ISM.

I pushing 37,500 lbs down the road with a 370 hp, 1200 ft lb Cummins ISL and it is fine on the highway and adequate for the steep hills. I wish I had a bit more power for steep grades but it's OK. You will likely be over 40,000 lbs GCW, so an even larger engine would be better. The ISL is available in a 425 hp version but an ISM (500 and up) would be better yet. The Cat C9 is similar to the Cummins ISL and the C13 is competitive with the Cummins ISM.

I'm surprised that you are finding the C7 engine in a coach that has the GCWR for the size trailer you want to pull. Look at the GCWR on the coach as the very first thing - even a 26,000 lb coach will gross at least 42k with your 16k trailer, so you need a really strong chassis and power train.

[Cayman Dave]

Roamer,
We have decided on a Damon with the ISC Cummins Engine 360 HP. The total trailer weight is about 16,000 lbs. The GVWR is 32000 lbs CGWR is 42000 lbs. Total weight would be 48000 lbs.
So from what you are saying I should have 480 HP motor for this job. The hitch that Damon installs is 10,000 lbs which is too small.
Think this rig is marginal for the stacker. Is that your take? I appreciate your ideas.
David

[Pusherman]

Dave, my take is that your coach is not marginal for the stacker, but inadequate. You state you will be 6K lbs over GCVW. Have you considered your safety and the safety of others towing a trailer which causes you to exceed GCVWR?

If you ever get into an accident with this rig, watch out for the attorney who will take you to the proverbial cleaners.

[Route 66]

I agree with Don.

Having enough horsepower to move the load is secondary.

Controlling that load is the primary issue.

Your trailer is 60% over the capacity of the hitch and motorhome rating.

We have a member on this forum whose 15,000# hitch broke from towing his stacker.

[Shanwick]

My opinion is that you should be paying more attention to chassis and hitch capabilities. Even a coach with a 15k towing capacity is going to be undersized for your needs.

Jeff

[Cayman Dave]

To all,
I have given much thought and guidance to this question. Because I have purchased a motorhome that cannot accomodate a stacker or at least a standard stacker this is a mute point. I have found a company that is interested in building a stacker with a fiberglass body which will reduce the weight substantially and maybe make this idea work after all.
Regards

[Gary RVRoamer]

Sorry to be late getting back to you, Dave, but the others gave good advice. Definitely do not exceed the GCWR or the hitch rating. And a bigger hitch does not mean the frame is strong enough for the extra load either.

A lighter trailer is you only option, so I hope it comes through for you. Still think it will be an overload, though.