2005 Safari Panther C-13 525hp fuel mileage

[slemnah]

I am considering purchasing a 2005 Safari Panther with C-13 525hp with 295/80R22.5 tires which need replacing. The Alladin system shows that it is getting 5.5mpg over the life of the vehicle. It has a 4.30 rear axle ratio and I believe that due to the ratio the motorhome runs in the wrong RPM at highway speed causing this terrible fuel mileage. The tires need replacing before I purchase the vehicle and I found a Michelin tire (295/60R22.5) that is 4" shorter with a higher load range that will give me a numerically higher rear axle ratio (575 revs per mile vs 503 revs per mile) and change the rpm sweet spot on this CAT engine and hopefully improve my fuel mileage. What are your thoughts?

[slemnah]

I appreciate all the info. I also found out that another member went to look at this motorhome and he stated that it wasn't what was advertised and he walked away from it. I will be out looking at it on Tuesday and from everything that I have seen I think I will be walking away from it also.
Thanks for all the info.
Steve

[Twomed]

Steve my advice is same as before. The guys answering on this one are former Safari/Beaver/Monaco owners who have run these for a long time. Several of us sat through the seminars at rallys back in 05/06 when CAT and Monaco were trying to placate owners of these beasts. The solution was trade or buy oil futures. 🙂 🙂 Good Luck...keep looking. JMHO

[Ivylog]

You are going the wrong way as the sweet spots (IF THERE IS ONE) is at less than 1550, not the 1800 it's probably turning. Even going with a 315/80/22.5 is not going to gain you enough. STOP looking at the Panther with the CAT engine as the 5.5 is all you'll get out of a C13 and find the same MH with a Cummins or Detroit and it's called a Monaco Exe that will get 7+ mpg. As I posted previously, my Aladdin system is very accurate and unfortunately 5.5 is NORMAL for a Acert C13..

[wolfe10]

Actually, questions on gearing are a lot more complex than "one ratio fits all".

First question: At what speed do you wish to cruise? Gearing for best MPG at 55 will do very poorly for you if you drive 70 MPH.

Looking at it from another prospective, some coaches are geared such that there really isn't any "economic speed". If geared to cruise at 70 MPH (where aerodynamic drag is HIGH) they likely would not even be in 6th gear at a reasonable "economical speed" like 55-60.

[2bzy2c]

powderman426 wrote:
Either I am not understanding (which is something that happens a lot it seems) or your moving the wrong direction. If you want to lower your rpm it would require larger tires not smaller. What am I missing here?
:h

I had to read it twice. I think he is trying to find the "Sweet Spot RPM" which may be at a higher rev than what is currently on the coach. If that is true, then smaller diameter tires will do just that.

[lanerd]

You sure don't want to go to smaller dia tires....however, I would think that the tires on the mh are stock tires that the mfg put on there and would be matched to the weight, rear end ratio, and engine torque specs. Going to a smaller dia tire will lessen the mpg, not increase it due to the engine rpms being higher for the same speed.

I don't think I would vary from the stock size/load range of tire.

The previous owner could have had a heavy foot and didn't care about mileage; hence, the low overall mileage. He also could have been pulling a rather heavy trailer/toad.

I myself, will drive fast enough to get the trans to shift into 6th and then back off two or three mph still keeping the trans in 6th. This seems to work best for me and my cat has an overall average mpg of about 8.5.

[powderman426]

Either I am not understanding (which is something that happens a lot it seems) or your moving the wrong direction. If you want to lower your rpm it would require larger tires not smaller. What am I missing here?
:h

[Altern]

I see now that it is a load range "J" tire.
You present an interesting question and while I have no experience to offer here - I'm certainly interested in what conclusions may be in the offing.
Good luck