...Which one will get you to through the traps fastest...and why?...

 

HP. Do a search on this one and then sit back and barf!

 

Have we done this one before?

Grumpy used to say it was HP, but it's more average HP and TQ in the highest RPM band you can run the motor in.

But if the question is "fastest" rather than quickest it's HP

Bret

 

Your question makes no sense to me.
Horsepower is basically a result of an equation of torque and rpm.
It's not a "one or the other" kind of thing.
Horsepower is a measure of power, which is a technical term in physics. It measures the amount of work that a force does as it acts over time. Work is another technical term in physics. It measures the actual effect of a force in moving an object over a distance. If we move an object one foot by applying a force of one pound, we are said to be doing one foot-pound of work. If it takes us one second to move the object, we have exerted one foot-pound per second of power. A horsepower is 550 foot-pounds per second.
For a more detailed explanation, go to http://home.inu.net/davidstua/horsepower_and_torque.htm

 

I understand everyone's concern with the question but I purposely simplified it b/c it is a very complicated subject...
What made me post is the thread on the 10.8 second 350 turbo diesel posted in the lounge. Lots of torque, lots of extended hp (for a diesel) but a low mph...never the less a respectable et. Some builders spin the engines up higher relying on hp. Others don't concentrate on the rpms so much and go for the torque. It's been done both ways (winning), but I really want a discussion on what makes a vehicle cross the traps "faster"....

 

Well, RPM x Torque/5252 = HP.

It's easier to think of it as "which one will get you through the traps fastest, high rpm or low rpm torque".

Higher horsepower is just the ability to produce more torque at higher rpm.

For example, if you have 500ft/lbs at 5000 rpm's you have 476hp at the same rpm.

If you can make 500ft/lbs at 7000 rpm's you have 666 hp at the same rpm.

A diesel is by nature a low rpm machine. AFAIK, they will never even reach 5252 rpm, therefore always having higher torque than horsepower.

 

Well said.

 

Good answer=>
Grumpy used to say it was HP,
but it's more average HP and TQ
in the highest RPM band you can run the motor in.
------------------------------------

Good answer=>
Your question makes no sense to me.
Horsepower is basically a result
of an equation of torque and rpm.
It's not a "one or the other" kind of thing.
---------------------------------

Torque without motion produces no work
No work..no power
No power ..can't win anything

Torque = ( HP * 5252 ) / RPM

HP = ( Torque * RPM ) / 5252

whenever you have more Torque
at a given RPM
you also have more HP at that RPM

whenever you have more Horsepower
at a given RPM
you also have more Torque at that RPM

increasing Torque is the same thing
as increasing Horsepower at the same RPM

Which engine will accelerate down the DragStrip the fastest ET/MPH ??
a 1250 HP engine with 800 Peak Torque
or
a 1150 HP engine with 800 Peak Torque

(if the amount of Peak TQ was the real answer)
then how can any engine on Earth
ever accelerate past its peak Torque RPM ??

next time you go to DragStrip
shift at peak Torque point
and see if you go faster

next time you go to DragStrip
don't let the engine past peak Torque RPM point
and see if you go faster

does NASCAR go around the Track the "fastest" at
Peak Torque RPM ??

does NASCAR "gear" their race cars to go around
the Track at Peak Torque RPM ??

does a Drag Boat go faster in the water
at Peak Torque RPM ??

Peak Torque is basically "LOCKED" into
2 major components ;
1-engine size in cubic inches
2-Compression Ratio
so after you have pretty much
exhausted peak torque gains
you have to then find a way
to shift the same peak torque
higher in rpms

so, in all forms of MotorSports
the only way to go faster
is to find a way to make the
same peak torque
but at a higher RPM (which is HP)
and ultimately=> HP/CID Ratio
and HP/Weight Ratio rules

(example=> Formula 1)
does a Formula 1 race engine
go the fastest around the Track at Peak Torque ??

does a Land Speed record streamliner keep the
engine at peak torque RPM point ??

why do Formula 1 engines turn so high??

why do ProStock Cars / Bikes / etc turn so high ??

why "doesn't" NHRA rate SuperStock and Stock Eliminator
on rated Torque/Weight Ratio ??

Will any of the above examples ever win races
keeping the engine at peak torque RPM ???
-----------------------------------------------

so whats the answer ?
it's the highest average HP and TQ amounts
in the highest RPM band you can sucessfully
run the engine in, that is ultimately capable
of wining races

 

This is the best discussion I've seen of power vs. acceleration:

http://mclements.net/mrc-PowerTorque.html

 

That is just plain wrong. It would make some sense if you had a continuously variable transmission that could keep the engine at its peak hp rpm at all times. But you don't. So you have to choose component specs so that your engine has power characteristics that work best for your application. Any engine builder can pick up more hp at the expense of powerband.

 

Bud ;

if you could move the very same power curve to a higher RPM band ..you could go faster without having to use a variable ratio transmission

and last statement in that same post was ;
so whats the answer ?
it's the highest average HP and TQ amounts
in the highest RPM band you can sucessfully
run the engine in, that is ultimately capable
of wining races

 

Yeah, but that's a big if, isn't it? Wouldn't every engine builder love to find a way to maintain the same power spread at a higher engine speed?
But you last statement sounds logical.
BTW, I was just reading about Kenny Roberts and the TZ750 powered flattracker. His remark about having a that bike (which had way more peak hp than any of his competitors) was "They don't pay me enough to ride that thing!"

 

MaxRaceSoftware,

You pretty much said it all. Even though it seems simple not too many people get it for some unknown reason. I don't even worry because it's the people that argue about stuff like this who's money you can always take in any race!

CAJUN-Z,

RWTQ, which is what is accelerating your car is proportional to the engine power at that point so you will always accelerate fastest when you keep the motor in it's "power" band and gear appropriately.

Getting a car down a 1/4 mile is WORK and doing it in a given time period is POWER, so POWER is where you're looking if you want to get somewhere FAST!

 

I tried opening the link several ways. Won't open...
BTW, HP vs. Torque is really what I want...

 

In layman's terms...
Horsepower is how fast you hit a wall. Torque is how hard you go through it.