HP vs Torque!?!

[Y2KPewterSS]

Some excellent info posted in this thread. One theory I have always heard and used that I didn't see mentioned was that your 60' time is an indicator of your Torque and your MPH in the 1320 is an indicator of your HP.

[Pythias]

Some excellent info posted in this thread. One theory I have always heard and used that I didn't see mentioned was that your 60' time is an indicator of your Torque and your MPH in the 1320 is an indicator of your HP.

But 60" vary so much depending on traction, unless you are very consistent.

[chevyguy8413]

I know this is gonna sound like a retarded beginners question.....
But what is the difference between Horsepower and torque?

I understand torque, that it is the power to push ur car off the line, and its what gets you down the track.....

But what is the point of horsepower?

When accelerating, the engine is out of its maximum torque range, but the longer the torque curve "hangs in there" ...i.e. horsepower...the better the acceleration. horsepower is actually a term of convenience linking the force produced by the engine (torque) ,and the rpm at which it is observed,
by the formula horsepower = observed torque (at any particular rpm) times the rpm at which it is observed..all divided by the constant 5252....
(rpm x torque)/5252

The point is, in acceleration, its necessary to rev the engine higher than its torque curve sweet spot...so upper rpm range torque (i.e. HP) is needed to achieve good acceleration.

[chevyguy8413]

But 60" vary so much depending on traction, unless you are very consistent.

60' is really about the launch...chassis tires etc..and is used to set up the chassis
trap speed is totally about horsepower....and varies very little regardless of the 60'...it is used by tuners to assess the performance...run to run etc..as with air/fuel ratio, ignition timing etc

[Frankthetank]

is it always divided by 5252 or is that just on ls1's?

What about big blocks that dont rev that high?

[stevegrizzle]

Ok in physical terms , think of torque as the force produced (how intense the combustion cycle is) and horsepower is the accumulative effect of these cycles as RPM increases. Torque is frequently thought to be a function of displacement, when, in fact, other factors weigh heavily, as well....they all relate to air flow into the engine/cylinder filling. Horsepower is an indication of how high on the RPM curve the torque values are being maintained. Torque is measured; horsepowr is calculated from the torque and rpm by the following: BHP = (RPM x Torque)/5252

thanks for explaining it first......i didnt want to have to write the book

[shady milkman]

is it always divided by 5252 or is that just on ls1's?

What about big blocks that dont rev that high?

no every engine i believe

[Phlash_riot]

tourque is how much you can do HP is how fast you can do it.... if oyu have 1000ft/lbs of tourque and 10 hp you can haul a couple semis down the road but you won't do it very fast....

Or if you have say a Honda S2000 with almost double the HP vers the tourque you can't pull as much but you can do a little very fast.

My .02 but They go hand in hand with each other in the grand scheme of things. and like building an engine you have to balance every thing out for your car as a whole.

[BlackLT1Z28]

is it always divided by 5252 or is that just on ls1's?

What about big blocks that dont rev that high?

Yes, ALL engines (well car engines) are rated using the constant 5252. I don't remember exactly how that term came to be, but it has something to do with assumed travel, crank swing, and piston inertia that all engines inverably have. I won't get into that. But it's a constant based on the physics of a 4 stroke engine.

As for the second question, big block don't rev that high because of the amount of torque they can produce. Torquey pushrod engines are limited to their lower rev limit because of physics and their characteristics. That's why OHC engines have the ability to rev so much higher, but they don't make as much torque (power) down low.

And this will be a life-long debate, which is better, high-revving OHC motors or the lower revving monster torque engines? Both have trade-offs. But the thing that us GM pushrod guys enjoy is the fact that we DON'T have to rev so high to achieve max power. Why rev all the way to 9,000+ RPM's when we only have to get to 6,200 RPM's to reach maximum horsepower?

But torque and horsepower are essentially used to measure the same thing; go-juice.

[chevyguy8413]

Some excellent info posted in this thread. One theory I have always heard and used that I didn't see mentioned was that your 60' time is an indicator of your Torque and your MPH in the 1320 is an indicator of your HP.

I think you are right on...cuz torque is what overcomes inertia and (together with chassis setup..tires etc) will be reflected in the 60'; horsepower is very closely calculated from the trap speed and weight using tables and charts. Trap speed will vary minimally regardless of the "quality" of launch and of course and is also dependent on the vehicle's Cd.

[chevyguy8413]

HOw bout the LT4 upgrades are they worth the trouble or are aftermarket sources better for the $$??

[djvaly]

with 2.73, 3.23 vs 3.73 or 4.10 gears one accelerates faster, with a stall converter one has more torque because of the torque multiplier effect. they usually lock up at 45mph.

[shady milkman]

with 2.73, 3.23 vs 3.73 or 4.10 gears one accelerates faster, with a stall converter one has more torque because of the torque multiplier effect. they usually lock up at 45mph.

i know with tc and gears it gets nasty at launches

[djvaly]

true dat.

[BlackLT1Z28]

HOw bout the LT4 upgrades are they worth the trouble or are aftermarket sources better for the $$??

I wouldn't get the LT4 package. You can get better gains with the same amount of money going other ways. The LT4 kit is ok in that all the parts all work well together, but you can find other stuff out there that can outflow and outperform the LT4. From what I'm told, it is a decent daily driver setup with a nice kick in the pants, but there are other options. And good luck trying to get some of those parts new, GM doesn't make the LT4 intake manifold anymore, probably the heads too.

[BlackLT1Z28]

i know with tc and gears it gets nasty at launches

All about the torque.

[chevyguy8413]

I wouldn't get the LT4 package. You can get better gains with the same amount of money going other ways. The LT4 kit is ok in that all the parts all work well together, but you can find other stuff out there that can outflow and outperform the LT4. From what I'm told, it is a decent daily driver setup with a nice kick in the pants, but there are other options. And good luck trying to get some of those parts new, GM doesn't make the LT4 intake manifold anymore, probably the heads too.

thank you for the heads-up...i remember seeing some comparison dyno runs LT1 vs LT4, but from what you say, now there are better 'avenues to power'...thanks again

[chevyguy8413]

with 2.73, 3.23 vs 3.73 or 4.10 gears one accelerates faster, with a stall converter one has more torque because of the torque multiplier effect. they usually lock up at 45mph.

man from your stats, my LT must really be anemic...mabe
230 rwhp or so?? any of u run yours stock on chassis dyno??

[BlackLT1Z28]

man from your stats, my LT must really be anemic...mabe
230 rwhp or so?? any of u run yours stock on chassis dyno??

That's because he is running a newer LS1.

[djvaly]

LS1 engines put out 345-350 to flywheel (285-295rwhp) depending on year. GM under rated TA LS1 engines so our good vette friends can keep buying, but in reality the same engine as C5, different application..