xs650

Nope, Hp is equivilant to Watts, 1 HP = 746 Watts.

A Volt is a unit of electromotive force so is roughly equivilant to torque, while Amps are flow quantity and more equivilant to RPM.

C8-Vette

I said KEEP IT SIMPLE!!

xs650

Einstien said "make it as simple as possible, but no simpler."

troy144

Wow. I haven't thought about this type of stuff, in these equation forms, since college physics. I thought I would never revisit this stuff.

Velocity Steve

Do a google search on horsepower vs torque and read the first couple of dozens sites. By the way, when you get the revs up in an S2000, your not just making torque, you're making horsepower.

VET4LES

After reading all of these post I think I have it. When my wife and I go grocery shopping I should shift at around 6000 RPM and keep the rev's above 4500 at all times. That will make the trip a lot more fun.

Irv

I'm sorry, but this analogy is incorrect. RPM is analogous to voltage, torque is analogous to amps, and horsepower is defined by physics as being convertible to watts, at ~746 watts/hp.

Contrary to Car & Driver's frequent misuse of the term "horsepressure", there's also a water analogy. RPM = water pressure in psi, torque is equivalent to the pipe size, and horsepower = flow-rate, like gallons per minute.

Onyasix

Oh he!!, just put it to the floor and hang on. That's why you've got an automatic anyhow. . . Oh you just might want to watch out when launching and ease it to the floor, those P285/35ZR's are rather expansive.

catpat8000

You guys need to draw the line at making analogies
with voltage and current. As someone who works with
electrons for a living, I can tell you the comparisons
between HP, amps, voltage, water pressure, and RPM
make absolutely no sense whatever. It's confusing
but, worse, it's incorrect.

Pat

catpat8000

The best explanation I've found on the web for this
question is here:

http://www.vettenet.org/torquehp.html

Pat

tommy1727

Yeah, that's the ticket, I'm sure your wife will really appreciate it. At least that's one way to get out of having to go grocery shopping!

Irv

Excuse me? It's frightening to think you work with electrons for a living and don't know that 1hp = 746 watts. That part is not really an analogy, that is a fact. Since horsepower can be calculated from torque and rpm, or from volts and current, these transformations are not incorrect, they are commonly taught in high school physics.

UBETRUN

You LAUNCH at peak torque (make chassis mods as necessary for traction) and SHIFT at peak HP. Proper gearing keeps the engine in the powerband between shifts. I drag race ATVs and they are very sensitive to minor changes, everything is amplified in a 3lb/HP chassis.

UBETRUN

That is absolutely correct except for the launch, torque gets the chassis moving.

catpat8000

That's a nice bit of sophistry. Yes, if I did work with electrons
and didn't know about HP and watts, you might wonder. But
that wasn't what I was trying (admittedly poorly) to say.

To be clearer, I had two main points:
1. For someone trying to understand HP and torque, the
electrical power/voltage/current analogy is, in my opinion,
unenlightening and does not advance their
understanding significantly. It might be a useful analogy
to someone who does understand electrical engineering
but isn't a car nut but that's probably not the majority of
posters on this forum.

2. The post near the top of this page, to which I thought
I had responded, but after re-reading see that I didn't,
claimed that current was analogous to rpm, which I claim
is erroneous. I now see I responded to your posting which
also made the same point I am trying to make. Sorry for
the confusion - I read your posting too quickly.

Pat

catpat8000

Absolutely. And having driven two vehicles with CVTs,
I can tell you that's exactly what they do. You launch,
there's an initial period where the engine climbs up to
the max HP rpm, near the top of what would normally be
a first gear, and then it stays at the max HP rpm while
the car accelerates.

It's actually very weird driving such a vehicle. You keep waiting
for a shift which never comes...

Pat

P.S. The two vehicles were an Audi A4 and a Nissan Murano.

jschindler

Interesting. We had a Murano for about a year (my wifes "driver"). You are correct - they are very odd. Also, due to the lack of a torque converter, many people (my wife included) don't feel like it's accelerating as fast as it is. It worked, but my wife never liked it. She's back in a Tahoe now.

orca1946

WOW !! Just be happy that you have both!

catpat8000

Not sure if this refers to my post of having driven two
CVT cars. If so, I don't own either one. Both drives
I referred to were in friend's cars. I only own a C6.

Pat

Velocity Steve

Yes but not engine torque. It's REAR WHEEL TORQUE! As previously stated by others, an engine that develops it's power at a higher rpm can be geared lower than one that makes it's power at a lower rpm. Not sure why I didn't state it this way before but the obvious way to prove the point is to change the rear axle ratio in your car and watch how much quicker it accelerates without changing the engine torque. There are currently threads in this forum about changing from a 3.42 rear axle to 3.73, 3.90 or 4.10 for quicker acceleration. Back in the 50's and 60's, you could order a Corvette from the factory with a choice of 3.08, 3.36, 3.55, 3.70, 4.11 or 4.56 rear axle ratio. The difference in acceleration is quite remarkable by only changing rear wheel torque and nothing else. Going from a 3.42 rear end to a 4.11 has the same rear wheel torque increase as increasing an LS2 motor from 400 to 480 ft lbs.