My '06 Beaver Patriot Thunder has a C-13 Cat rated at 525hp. The guy parked next to me last week had a similar size MH (looked like a Prevost but wasn't). It also had a Cat C-13 but it was rated at 475hp but with more torque. I know Cat can change engine ratings both mechanically and electronically (i.e., injector timing?) but I don't know why the coach builders' design specs call for different ratings.What I don't understand is how the torque/horsepower trade off affects vehicle performance and if there would be any advantage to going back and paying Cat to making a change to my engine specs (what would I ask for?). How do the changes affect hill pulling, towing, city vs country driving, fuel mileage, etc? Could the average Joe sitting in the driver's seat even feel the difference if the modifications were made?

Torque horsepower 2010Torque horsepower 2012

thgoodman wrote:My '06 Beaver Patriot Thunder has a C-13 Cat rated at 525hp. The guy parked next to me last week had a similar size MH (looked like a Prevost but wasn't). It also had a Cat C-13 but it was rated at 475hp but with more torque. I know Cat can change engine ratings both mechanically and electronically (i.e., injector timing?) but I don't know why the coach builders' design specs call for different ratings.What I don't understand is how the torque/horsepower trade off affects vehicle performance and if there would be any advantage to going back and paying Cat to making a change to my engine specs (what would I ask for?). How do the changes affect hill pulling, towing, city vs country driving, fuel mileage, etc? Could the average Joe sitting in the driver's seat even feel the difference if the modifications were made?your C13 525HP should be around 1700lbs torque? I doubt the 475 vertion is higher or as high?you at 525/1750 have more hp/torque than most any RV out there as it sits now so doing anything would be a waste of time and money

2oldman wrote:Torque horsepower 2010Torque horsepower 2012I'm curious to see an answer to the OP's question as well but not curious enough to read through 75 pages of text.Maybe someone can provide a more condensed or specific answer to the OP's question on his C-13.

Here: C-13 specs are Hp/torque specs. It looks to me like you have 100 lb/ft more torque than the 470 version (?).

ScottG wrote:2oldman wrote:Torque horsepower 2010Torque horsepower 2012I'm curious to see an answer to the OP's question as well but not curious enough to read through 75 pages of text.Maybe someone can provide a more condensed or specific answer to the OP's question on his C-13.Well said, Scott. Thank you. I guess I should have been more clear. My actual question was kind of buried it the end of the post. "Could the average Joe sitting in the driver's seat even feel the difference if the modifications were made? "

Torque vs. Horsepower | Good Sam Community

neil57
Explorer
Mar 09, 2014
Cat engines come in many power levels,some ratings are motorhome specific or because of cooling or transmission capacity. If you feel you are lacking power(525 is probably lots) Cat can put it on their chassis dyno and give you a detailed report. A reflash of your computer is $5-600 plus cost of dyno time. Your right foot and road speed has more to do with fuel economy than any engine rating. Unless you are pulling a large trailer behind,100 lbs. torque would not be felt in the drivers seat. Hope this answers your questions.
wolfe10
Explorer
Mar 09, 2014
hone eagle wrote:
wolfe10 wrote:
hone eagle wrote:
Nobody mentions that Cat 'gives' the power it thinks the chassis can cool,the better they think the cooling system is the higher they will set the power.
Check out marine installations ,much much higher power and boats are always going uphill.

Common across the industry. Same goes for Cummins. In marine applications where cooling capacity is infinite and engine load is much more constant, AND emission standards are lower, indeed power is higher than in on-highway applications.

OK the OP asked if the power can be changed ?He was comparing his installation to another different builder ,its possible his at the limit for his chassis and the other has a higher capacity cooling system?
apples and oranges but still fruit ?

Absolutely. Cooling system, transmission, etc could certainly be different. And, different year models of the same engine (but with different emission specs) can and are often different.

Since this is a Caterpillar, I would start with a call to Caterpillar (877 777-3126) with the engine serial number. They can tell you exactly what HP your engine made on the dyno before leaving the Caterpillar factory. Not just what is SHOULD make, but what it actually made.

They can also tell you if an upgrade is possible.

Be sure to ask if it changes torque and HP at "normal RPM"-- many higher-HP engines only make the additional power way up in the RPM range.
hone_eagle
Explorer
Mar 09, 2014
wolfe10 wrote:
hone eagle wrote:
Nobody mentions that Cat 'gives' the power it thinks the chassis can cool,the better they think the cooling system is the higher they will set the power.
Check out marine installations ,much much higher power and boats are always going uphill.

Common across the industry. Same goes for Cummins. In marine applications where cooling capacity is infinite and engine load is much more constant, AND emission standards are lower, indeed power is higher than in on-highway applications.

OK the OP asked if the power can be changed ?He was comparing his installation to another different builder ,its possible his at the limit for his chassis and the other has a higher capacity cooling system?
apples and oranges but still fruit ?
wolfe10
Explorer
Mar 09, 2014
wny_pat wrote:
And it really gets complicated when one manufacturer measurers torque/horsepower at the flywheel and another measures it at the wheels.

Not aware of any engine manufacturer who measures at the wheels. Not even sure how that could be done. With the same engine, the chassis builder makes many decisions that affect HP at the rear wheels:

Alternator size/output-- the larger the output, the more HP it takes.

Dash A/C compressor size-- same issue.

Rear mounted fan (solid) vs clutched fan vs hydraulic pump for side radiator.

Air compressor for air brakes and/or suspension vs no air pump.

Bottom line, WAY too many chassis builder options for an engine manufacturer to rate "at wheel HP" even if they wanted to.
wolfe10
Explorer
Mar 09, 2014
hone eagle wrote:
Nobody mentions that Cat 'gives' the power it thinks the chassis can cool,the better they think the cooling system is the higher they will set the power.
Check out marine installations ,much much higher power and boats are always going uphill.

Common across the industry. Same goes for Cummins. In marine applications where cooling capacity is infinite and engine load is much more constant, AND emission standards are lower, indeed power is higher than in on-highway applications.
hone_eagle
Explorer
Mar 09, 2014
Nobody mentions that Cat 'gives' the power it thinks the chassis can cool,the better they think the cooling system is the higher they will set the power.
Check out marine installations ,much much higher power and boats are always going uphill.
wa8yxm
Explorer III
Mar 09, 2014
Gee, I always thought Torque was a measure of how much "Twist" (Torque) it could put on the output shaft and Horse Power was how many 33,000 pound train cars it can lift one foot in one minute... (A very very old way of measuring horse power). (NOTE: I actually looked this up. 33,000 foot pound/minute

So torque is foot pounds but static, HP is dynamic.
wny_pat1
Explorer
Mar 09, 2014
And it really gets complicated when one manufacturer measurers torque/horsepower at the flywheel and another measures it at the wheels.
Koop
Explorer
Mar 09, 2014
As someone already mentioned, torque is force that can be measured on a dyno. Horsepower is a calculated value that represents work over time (power).

The formula for SAE horsepower is torque (measured in lb/ft) X RPM /5252
(torque times RPM divided by 5,252)

This formula illustrates how two engines with the same peak torque can have different horsepower ratings. It depends on what rpm that peak horsepower is achieved at. The torque curve influences which at which RPM we achieve maximum horsepower.

I hope this simplified explanation helps.
wa8yxm
Explorer III
Mar 08, 2014
Oldme wrote:
Another analogy I like:
HP= how fast you can hit a wall
Torque- how far you can push that wall.

I like it Oldme. I like it.. A good rewrite of what I posted. :)

Kind of like what I say about 4-wheel drive in bad weather.

Yes, A 4-wheel drive can "Go like the wind" on roads where a 2-wheel drive would be stuck.

Problem is: it also STOPS LIKE THE WIND (When it hits something).

Forum Discussion

Torque vs. Horsepower

About Motorhome Group

Related Content

HP vs Torque

Engine torque

Lug Nut Torque

Duramax Torque Management

Lug nut torque specs?