On Mar 26, 9:56*am, " wrote:
On Mar 26, 7:55*am, Opus wrote:



On Mar 25, 4:58 pm, " wrote:

snip

I looked around and saw a lot of pages touting "certified SAE
Horsepower" but I did not find anything that actually stated the
actual testing procedure without paying for it. *I am highly skeptical
that a gasoline automobile motor could last 15 minutes on a dyno at
full power where as it quite well established that a commercial diesel
motor can do this for hours even days on end...

Jon

Jon

Be skeptical all you want, I forgot the exact number of hours the test
requires the engine to stay at full power, but several manufacturers
have used those test results to project 100.000 mile record runs,
particularly Subaru and Benz. That's 100,000 miles at full power only
stopping for gas or diesel, driver changes every 4 hours as required
by the FIA for safety, and oil changes and air filter replacement. The
used to allow for spark plug changes, but as I haven't been involved
in that kind of testing in more than 20 years I don't know what the
rules are for changing spark plugs. I know that when Subaru did their
record attempt they changed spark plugs at 50.000 miles but that was
last century. Benz' last attempt was with a diesel so they didn't have
any plugs to change.

Opus

This is really off topic but full power for over a long period of time
doesn't mean accelerating and slowing as one does in a fast moving car
but rather continuous full output at maximum rpm as one can do in a
truck climbing a grade or boat/ship on a long voyage. *I am skeptical
that you could put a "400hp" motor out of an SUV or sedan, gear it
correctly so that it could maintain maximum rpm and maximum HP and
have it actually put out that 300hp hauling an 80,000 pound rig up the
GrapeVine..

Think about that the next time you see an unloaded semi breeze by you
at 75mph up a long 6% grade and then realize that truck weighs around
30,000 lbs.

Jon

correction: I meant to write "I am skeptical that you could put a
"400hp" motor out of an SUV or sedan, gear it
correctly so that it could maintain maximum rpm and maximum HP and
have it actually put out that 400hp hauling an 80,000 pound rig up the
GrapeVine.."