C-12 425 HP to 455 HP.

The torque stays the same at 1550lbs. You will notice no difference going up the hills. Horse power is for acceleration and torque is what pulls you up the hill. That is directly from a Cat tech at one of the class 8 truck test tracks that I use to work at.

I believe the torque stays at 1550 for either HP rating.

Interesting, a friend upped his ISM from 450 to 500 and needed a new turbo plus some other parts to get it done. He also did a resonator too. He loves the difference. I did just the resonator on my ISM and the difference was pretty noticable. Sure it was only ten miles per hour faster on the hilks and more pickup due to a faster turbo spook up, but it was almost a mile a gallon better milage too. Upping the programming will have a effect and you heed to see what is is. Are you pumping in more fuel so your milage will go down cross the board? Questions abound.

wolfe10 wrote:
Questions to make sure this "upgrade" is relevant to you/your coach:

Any change in torque? If so, how much and at what RPM?

Those extra HP-- are they are RPM's I normally run the engine, or only at close to governed RPM?

Is my cooling system adequate to accommodate the additional heat load. Let's face it, the time you will want those extra HP are on long, sustained grades-- just the time that your cooling system is already stressed. So, if you overheat on those conditions already, probably a bad idea. If you don't go over 200 degrees F on those long sustained climbs at high ambient temperatures, you may have the reserve to accommodate the additional heat load.

I honestly don't know if the torque changes or not but the Beaver C-12 came in the 425, 455, and 505 hp versions. To the best of my knowledge the cooling is the same in all model but the 505 had some internal changes which wouldn't be practical. All run the same 2100 rpm limit.

As for temps, on long grades I can keep the temps below 205 at 110F ambient as long as the rpm is around 2K.

Again, no first hand knowledge but Cat said it is only a program change so I'm thinking it's simple remapping the injectors.

If a 7% increase in HP isn't noticeable, it's not worth my effort just to pass slower traffic on a grade. I'm not in that big of a hurry. I've found that if I have to drop to 45 or so before I can pull out to pass, it take a while to get back to 60ish.

Getting a 20-35 hp gain would only be noticable for a very few gear heads who know their equipment, however the hp is the minor part, if you can gain 100 ft lb torque, most would notice that.
I had my ISM changed from 450 hp @ 1450 ftlb, to 500 hp @ 1550 ft lb, that is very noticable. Cost about $3,400.00, yes would do it again;. Required a turbo change, hardware for the turbo control (waste gate) and ECM reprogram.
Dave M

I had mine done to increase from 500 to 525HP....my advice...:h... use the money for better things....I didn't see much of a change.....Dennis

Questions to make sure this "upgrade" is relevant to you/your coach:

Any change in torque? If so, how much and at what RPM?

Those extra HP-- are they are RPM's I normally run the engine, or only at close to governed RPM?

Is my cooling system adequate to accommodate the additional heat load. Let's face it, the time you will want those extra HP are on long, sustained grades-- just the time that your cooling system is already stressed. So, if you overheat on those conditions already, probably a bad idea. If you don't go over 200 degrees F on those long sustained climbs at high ambient temperatures, you may have the reserve to accommodate the additional heat load.

Never heard anyone say they have too much power.