OK, the ANCIENT debate
between Torque and Horsepower is one that never seems to get
resolved. I will try and give a VERY general explanation of why you
can NOT have one without the other and which one is really putting a
smile on your face,,,,
1) Given 2 engines running at the same
rpm.. if one engine has more HP, it automatically has more torque..
ALWAYS!! Torque is measured and HP is calculated via mathematical
formula using TORQUE as one factor.
2) HP and torque can NOT be separated in terms of what is doing what
with respect to how your engine runs (see #1).. They are connected
ALWAYS and can not be separated..
3) Stating that torque is what is accelerating you down the track is
simply incorrect.. Why? See #1 and #2 above..
Now, here is where the "FUN" begins...and hopefully, I can related
to this Big Bore topic..
1st.. a few basics... CVT Equipped Engines should be clutched ALWAYS at peak HP rpm..
ANY good engine will have a peak torque output rpm 200-500 rpm LOWER
than the peak HP output rpm. WHY.. Because you clutch for peak HP..
NOT peak Torque..
So, when your engine is heavily loaded and it begins to drop a few
hundred rpm.. It will fall into its PEAK Torque realm and have a
much easier time at recovering and returning back to peak HP rpm...
Hence, the reason for having the engine's peak torque rpm lower
than its peak HP rpm.. Without this relationship.. the engine would
be VERY hard to clutch in a full load situation. Make sense?
When people talk about engines, they like to quote and cite peak HP
numbers..For example.. RK Tek 860R makes 180HP at 8300 rpm. Peak
torque is closer to 7900/8000 rpm.. OK, so, those are the peak
numbers.. What MANY fail to realize is that the area under the
torque curve is what really makes one engine stand out over another.
Different engines build TORQUE at different rates.. Some
build torque rather rapidly and then hold the torque across a very
wide rpm band.. This is a good engine and one that will accelerate
very hard and will be very easy to clutch.. The area under this
torque curve would look like a bumpy straight line with very little
Some engine builds do not build torque quite as fast but can get to
the same torque numbers as another engine.. This engine's torque
curve will look like a side of a mountain.. So, while the 2 engines
can make roughly the same torque and HP, their torque curve can look
completely different. So, the area under the curve really tells you
how the engine will "perform" under real-world operation.
In flat land racing, this curve is not so important (note: I did NOT
say NOT important. just not as)..
because you come out of the gate and immediately hit the desired
rpm and stay there for the duration of the race. so, what the curve
looks like BELOW the rpm you are running are inconsequential.
Now, boon docking and mountain riding.. Different story.. It is very
common to have your engine quickly lose rpm because you are on and
off the throttle. So, the flatness of the torque curve becomes a big
This is where the Big Bores really shine... I will speak to my BB,
because it is , obviously, the one I know the most about...
The 860R builds torque at a very rapid rate when compared to the
stock engine. It builds it faster and builds much more of it.. So,
you have a very broad and very flat torque curve.. So, when on and
off the throttle OR when your sled hits a super "Deep" spot and
drops some rpm.. The BB is MUCH less effected and can recover much
faster than the stock engine.. WHY?? Much more TORQUE AND HP at ALL
rpm.... Simple as that.. Where the stock engine will get
overloaded.. the Big Bore will be much less effected by it and
continue to pull...
The RKT 860R has massive torque and HP increases in the 6500-8000
rpm band. So, it has a much easier time handling anything "HIGH
LOAD" situation it encounters. This becomes very apparent when
banging a steep hill with 3ft of fresh and deep powder.. There is no
comparison between the Big Bore and the stock engine.
Getting into the mathematics and physics
behind the relationship of torque and horsepower was never the
intent of this article.. I wanted to keep it very simple and refrain
from the physics involved.. However; there are some very good
articles on this very subject all over the web.. Just search for
"Horsepower vs. Torque" and you will have a grundle of hits that
will keep you reading all night...