Cummins 300 Power

[James C. Wheeler]

Well I just returned from my first venture in my 1993 Beaver Contessa.  The Beaver has the 300 Cummins engine and seems a little weak in the mountains and on acceleration from the traffic light.  I was told that the engine could be turned up, ANY HELP in this from you folks in the know?   Other than that, I am very happy with my new ride, got a lot of questions and good comments on it and it's condition.

Thanks,
J.C.

[Richard And Babs Ames]

More power means more heat and torque. Be sure your transmission and cooling system can handle additional torque and heat.

[Gerald Farris]

James,
Your engine is mechanically injected, and not computer controlled, so increasing the horsepower and torque ratings on your engine will require engine modifications. It will by no means be as cheap or simple as reprogramming one of the newer computer controlled engines. In other words, you can not just turn-up the engine, it will require modification to get more power than it is rated for.

Gale Banks Engineering is the largest marketer of modification kits to increase the performance of Cummins engines in RVs. I think that there are two different kits to modify your engine, depending on how much more performance you want.

One thing to check before you start spending time and money trying to get more power from you engine is the throttle linkage. Since your engine has a mechanical throttle linkage, the linkage can get out of adjustment so that when you are applying full throttle, the engine throttle is only opening 1/2 to 3/4 of the way. It is a common problem on those engines, and if yours is one of them, you have a lot more power than you think, and you just need a simple adjustment to use it.

Gerald  

[Tom and Pam Brown]

Gerald,

I believe a Cummins dealer can change the fuel map of the engine without a engine reconfiguration.

it is simply a fuel pump change and possibly a turbo change if a great deal of horsepower is desired.

I believe that the 300 can be changed to a 330 with only a fuel pump change any higher will require deeper pockets.

[James C. Wheeler]

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Thanks gentlemen for your response I really appreciate it.

J.C.
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[Edward Buker]

James,

With any increase in horse power you add stress to all the components. You gain HP by metering more fuel per cylinder when you need it climbing hills. That is also the time when your coach slows some and air flow through the cooling system also slows to some extent. You have to recognize that the engine HP, chassis weight, and the cooling system are a matched system by design. As you change one parameter you would like to be able to change some of the others to accomidate the extra heat. That is not redily possible. Excessive heat will stress and shorten the life of engine components.

You have a fine vintage coach and the head gaskets, exhaust manifolds, turbo, fuel injection components may very well be original. It may be time to go easy on the "old girl" and be happy that she is still cruising in her retirement years like us.... Just one persons opinion.

Later Ed

[Wayne Tull]

James,

I have the 300 hp turbo charged 8.3 mechanical with Allison 6 speed transmission in my 94' Marquis 40 ft. coach, with the Banks stinger (adds 50+ Hp) put on by a previous owner eight  years ago. I have had no heating problems (fully loaded and pulling a 3,000 lb. toad) in the Rockies or otherwise. That said it is still slow on the grades (not sure what slow is for you) although acceleration from stops seems OK.   I'm normally a speed freak, but in the RV I've gotten past that (might have been the blown tire on a previous RV on the highway) at least while driving the RV.

Cheers,

[James C. Wheeler]

[size=14]Hello Wayne and Ed,

Thought I should respond to you entry.  Don't know if either of you have traveled Arkansas Highway 7 south of Jasper Arkansas or not but this is I believe a 7 percent climb which I was able to do at about 30-35 mph once I got started up.  From what I am reading that is probably what I should expect???

AnyWho,  Thanks for the response.

J.C.

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[Edward Buker]

Jim,

I had a 1989 Contessa with a Cat 3208 in it that we owned for 10 years. You have slightly more HP but are a bit heavier. Those speeds on a long grade of 6 to 7% are what I remember. I would just leave it floored, put on the flashers, and make the climb. It takes some time but we always crested the top and the old coach never let us down. The only thing we could do to help is gain a little extra speed before starting the climb....Safe travels.

Later Ed

[Richard And Babs Ames]

Be sure to keep the rpms up on long climbs as it keeps the engine cooler. We gross about 33,000 lbs and with 830 lbs of torque can maintain about 40 on a grade like you describe. Your transmission will run a lot cooler if it has Transynd (or equivilant) fluid than Dexron III.