i have a friend who tells me torque really makes no difference in how fast a car can go other than the first 0-30 mph. what would you say to this?

essentially, by this thinking, a 450 hp, 300 lb/ft engine would run hand in hand with a 450 hp, 560 lb/ft engine through the quarter mile, or from a "60 roll" as he puts it. :confused:

can someone enlighten me on how torque comes into play, cause i tend to think what he's saying is a load of crap. graemlins/clonk.gif

Ok....Hp is a derivative of torque...essentially hp is torque at a given rpm. Torque is what makes street cars drivable. It takes lots of torque (power) to move heavy objects i.e. chevelles. More torque yields higher hp so your 300hp might have 300hp at 8000 whereas my bbc has 300hp at 2500. Needless to say you can see that my torque bbc that makes power down low has the advantage of not having to rev sky high to make power. For a drag only car low end torque doesnt matter much its about high end hp...bc thats what keeps you accelerating. A drag only car will launch at 5000 plus rpm and stay their the whole trip down the strip so the torque doesnt matter.

What it comes down to is a torquey car like a big block has the advantage over the hp only car bc you want to accelerate as hard as you can so when the little s2000 has 100 ft lbs and has to dump the clutch or do a 5000rpm roll to ahve nay power you can start from a dead stop and let the torque bring you into your power band(between peak torque and peak hp)

Torque and horsepower go hand as torque increases so does horsepower. Horsepower is torque measured over a particular amount of time and the tq./hp. lines cross at 5252 RPM. They are inseparable. Believe me a car making more torque down low and having less horsepower up the scale will generally walk all over one with little tq. and more upper end horsepower. My son's car was outpowered by another similar '70 Chevelle at Springfield, Mo. on the Dynojet last year but 636-700 ft. lbs. vs 679-655 ft. lbs. but has easily outrun the higher H.P. car on two seperate occasions because it has more TQ.

The first sentence should read "torque and horsepower go hand in hand".

keep in mind too much torque can be bad you dont want to spin and unload the rear suspension. You want all the torque to keep your tires wrinkled and just about to spin i.e. accelerating as hard ad traction allows without adequate torque this is impossible with these huge rpm clucth dumps that spin tires.

with 3900 lbs of GM iron,,,I'll take ALL the torque I can get, just gimme some stickier tires :D

Originally posted by four o two:
i have a friend who tells me torque really makes no difference in how fast a car can go other than the first 0-30 mph. what would you say to this?

essentially, by this thinking, a 450 hp, 300 lb/ft engine would run hand in hand with a 450 hp, 560 lb/ft engine through the quarter mile, or from a "60 roll" as he puts it. :confused:

can someone enlighten me on how torque comes into play, cause i tend to think what he's saying is a load of crap. graemlins/clonk.gif Four 0 Two--- I am not directing this at you at all

LMFAO -------------- graemlins/clonk.gif graemlins/clonk.gif

Your Friend is severely mis-guided and you are right, he is full of crap.

.

Torque is the only thing that matters.

Originally posted by four o two:
i have a friend who tells me torque really makes no difference in how fast a car can go other than the first 0-30 mph. what would you say to this?

essentially, by this thinking, a 450 hp, 300 lb/ft engine would run hand in hand with a 450 hp, 560 lb/ft engine through the quarter mile, or from a "60 roll" as he puts it. :confused:

can someone enlighten me on how torque comes into play, cause i tend to think what he's saying is a load of crap. graemlins/clonk.gif =
Chris,
If your friend really believes this I would suggest you keep him or her as far away from your engine as possible graemlins/sad.gif

I believe the last part of your last sentence pretty well says it all :D

What Tom,Mike,Bob and Brian said :D

Ever heard "Torque moves cars - horsepower sells them"?

Back in the day when guys built hot street cars, remember the gears you'd hear about ( I was too young to participate!), 5.13, everone has a minimum of 4.10 or 4.56 and many ran 4.88s. Why. Making HP-built motors ET well.

I threw 4.33s at my 'old style HP' mill and came up with a respectible ET for a street car.

But to answer your Q, don't debate anyone who doesn't have even a modest understanding of what is going on. He surely hasn't a clue. You can use gearing/rpm to match a low end torque motor. Idid it. Ricers running quick times do it. But his example shows ignorance. Beleive he is trying to equate 4 cyl screamers to 8 cyl thumpers?

high horsepower numbers make for dyno bragging rights,torque wins races. tongue.gif

Torque is HP. Put as much of it as you can in the RPM range you run.

You can't make hi RPM HP without torque! HP=Torque x RPM/5252.

If you never see below 6000, make all the torque you can above that. If your engine never sees above 5000, make all the torque you can below that and the HP will be what it will be.


As far as his "rationale", tell him to put a Honda engine in his Chevelle. Then he'll understand what torque it. Unless he puts a 15 speed diesel trans in it too..

Doug hit the nail right on the head b/c I've been saying it for years.

ALL that is happening is that due to cam changes, the torque curve is moved over up the rpm scale for a HP motor and down lower like stock for a torque motor!! That's all..

Take a family of cams and run them through D2K using any particular motor combination that is held constant and watch the torque curve go to the right up the rpm curve as cams get bigger...

You will see just what Doug and the rest of the guy's and I are talking about!!!!!!

You have to match intake valve closing point with your compression, (head chamber design, piston top design, headgasket thickness and quench number), so that you can run a certain octane grade of gasoline, then match your gearing and tire size to get her down the road like you want!!!!

pdq67

Four o two, the different Chevelles in my post ran these times: Yellow Chevelle #1 made 679 H.P. and 655 ft. lbs. of torque on the Dynojet and ran 9.77 @ 137 MPH while my sons Green Chevelle # 2 made 646 H.P. @ 700 ft lbs. of torque and ran 9.56 @ 140 MPH. The higher H.P. car has never beaten the higher torque car (four trys). All these are rear wheel numbers.

Within the last year or so someone posted a pic of an old 1/4" (?) car that was lifing a tire or two with a 283. I think the R&P was a 6 something. Cool car, but geared towards high RPM HP and not low end torque. It's a math thing.

Anyone remember Modified Production drag racers with the tiny little small blocks in them that would REV to 8000+RPM and ate valvetrain parts like popcorn at the movies? I'll take the torque route anyday. Only reason I did not go big block when I swapped motors is I couldn't afford to replace all of the stuff that goes with it.

Doug has the formula. HP is just a calculation from the torque and it is a measurement of how quickly the engine can do a certain amount of work.

For me, I really want the most area under the torque curve that I can get and the curve has to be high in the operating rpm range of the engine. Achieve this and the car will be fast compared to other similar sized engines that don't. GM has been building some of the new small blocks (LT1 and LS1) with very wide and flat torque curves. The mid 90's Camaro's all had ~280hp but they still run well due to their big fat torque curve.

Another good example is the Honda S2000. Tons of HP for the size of engine but they're still fairly slow cars. Stick a 250hp 350 engine with a nice fat torque curve in that car and it will be faster.

Peter

It's really all about horsepower if you think about it. Power is the rate of doing work, so the rate of moving a car is determined by power.
The problem is, a car's rated horsepower is it's PEAK horsepower, and you're not always at that RPM.

We really should be concerned with average horsepower. Take 2 identical cars with different engine combos - the one that wins is the one that delivered the higher average horsepower over the course of the race.

You need torque to get you out of the hole.........and you need hp to carry you on down the track. If your racing.......chances are your above 5200 rpm where your torque starts dropping off and hp starts picking up ;)

I think David Vizard puts it best by saying: "Let's drop the word 'horse' because the term 'horsepower' just relates to how much power so many horses would make....there's no need for us to tack a prefix on to the front of the word 'power', it's stlil a legitimate term if we just say power." "If we exclude the term 'horse' then the relationship becomes very simple. Power= Torque x RPM. That's all there is to it." -David Vizard, How to build max performance Chevy small blocks on a budget! Vol.3

Originally posted by ScottC:
It's really all about horsepower if you think about it. Power is the rate of doing work, so the rate of moving a car is determined by power.I deal with electric motors a lot and the acceleration of an electric motor with it's load and the acceleration of a car can both be calculated the same way. No hp curve is required. It's all about the torque curve. The difference between the engine torque and the load (all the losses) torque is the accelerating torque. The accelerating torque is what accelerates the car. I co-wrote a program that calculates electric motor acceleration so I've more than just casually looked at the theory. Think about this. When you first energize an electric motor while it is stopped it isn't developing any hp. Hp always = 0 at 0 rpm. Yet, it will still accelerate. If it was all about the hp, then electric motors could never start from rest.


Originally posted by SSMAN69:
You need torque to get you out of the hole.........and you need hp to carry you on down the track. If your racing.......chances are your above 5200 rpm where your torque starts dropping off and hp starts picking up ;) I believe this argument is always used because the hp numbers are higher above 5250 rpm so it seems by the numbers that the hp is helping the car at the top end. The engine is still creating torque even if the hp number is higher.

Peter

Naturally torque does matter. Its the only thing measureable on a dyno. HP is a mathematical conversion of torque at a given RPM. BUT in defense of his "torque dosent matter" I will have to look at his perspective...too much low end torque CAN be a bad thing. For instance Chevy Hi Performance BUTCHERED GM's new crate 572. Took a motor that already made somthing like 550 lb/ft of torque{over 450 probably from 2500 up} and somthing like 650hp, and basically reversed numbers to somthing along the lines of 680 ft/lbs of torque and 525 hp or somthing like that by putting a Pansy ass cam in it and screwing everything that was good about the motor up. OK that was STUPID!!!! Who here can dead hook a 700 ft/lb motor with a stock style street car chassis that they DROVE to the track 250 miles. Probably no one. BUT everyone here would love to have 650 ponies on top. {if you call 6,500 rpm on top} So to say lower RPM torque is everything is a bit over stated. I respectfully argue. I personally drive around with 4.11 gears, and my little 350 dosent make peak torque till around 5,500 but it still drives around the highway, city, anywhere just fine. Of course thats when im not having stupid problems with the son of a bitch and the big local cruise/show and shine is this weekend!!!!! :mad: Oh and my car only weighs 3,250 so thats a big difference from a 4,000 lb chevelle. To be put simply, the heavier the car the more emphasis that should be put on low RPM torque.

[QUOTE] When you first energize an electric motor while it is stopped it isn't developing any hp. Hp always = 0 at 0 rpm. Yet, it will still accelerate. If it was all about the hp, then electric motors could never start from rest. [QUOTE]

It's at 0 RPM then you apply power and it moves.
What you are talking about is the rate of applying force, which IS power!

If you take identical cars each with 250HP, they'll have the same top speed. It doesn't matter if it's 454 with an RV cam or a high revving 4 cylinder. It's the power that's meaningful here. Why? Because we can use gears to convert torque to whatever we want.

Give me a breaker bar and I can generate more torque than a Honda S2000 engine. I sure as hell can't take that amount of torque to 7000 RPM's because I don't have the power. Give me enough pulleys and I can hoist a Chevelle in the air. I can't do it fast!

Anway, if we all had CVT's and could start at redline, torque wouldn't be a factor. In the real world, we need to measure torque because it tells us a lot about how the engine will act.
Believe me, I don't like the S2000. I'm quite sure it feels like a dog unless you rev the hell out of it.

For the most part, everyone seems to be violently agreeing here. It just seems that people can relate to torque as being the strength of the engine, but strength is not the same thing as power.

one more thing on the electric motor deal...That electric motor isn't going to move unless you put current to it...and how is current measured? in amps. and how do you figure out how many amps it will take to move it? by watts divided by volts.. how many watts will it take to move a 1HP motor? 746...so you have to use 1hp of electricity to turn the motor..not 1 ftlb of torque

Which is more important? The chicken or the egg?

Originally posted by gwbutch:
Which is more important? The chicken or the egg? Depends on whether your cooking breakfast or dinner. :D

PeterF and Bigjimzlll, I like the comparison with electricity. Its that comparison that got me through the electricity part of physics.
Watts = Amps x Volts
HP = Tq x RPM

very similar equations.
there's a constant involved in the hp one that I left out because its not important for this comparison. The constant is there convert the power into horses.
Bigjim you lost me on how it takes a hp of electricity,not tq to move the engine? Watts is a measure of power, such as hp is. I didn't think you could supply a number of watts to a motor, just amps and volts to it. The motor would draw x number of amps and y number of volts, those we can measure (much like tqu and rpm) and we can then calulate the watts. Or am I looking at this all wrong?

Now I'm going to go home and look at my meter on my house as my house dyno. lol

Torque does matter..look at my best ET and gear ratio..and my car weighs 3945

Here's another good example.

Dave (Sheetmetal) did dyno testing with his engine before racing it.

One of the changes he made was to see what ignition timing the engine liked.

On the dyno the motor made the same HP with 34 degrees as it did 36 degrees, but with 36 degrees the motor made more torque....same HP, more torque.

At the track the car went .15 quicker with 36 degrees as it did 34 degrees.


A simple misconception is that many dont realise you need to accelerate the car into its RPM range. if you can footbrake it to 2500, and the converter flashes to say 5200 rpms, you still need a lot of power on the low side of the RPM range.

The initial Hit is what Matters! You need to hit the tires at or above peak torque to get the car moving!

You need to power on the low side of the RPM range to recover from the shifts!

here is another Tid-Bit, in a converter comparison, A converter that was made to minimize the initial hit, and MPH high was backed against a converter that was set-up as a slightly tighter D/SA stocker converter.

The converter that minimized the initial hit ended up being .17 slower in ET!

Darin Morgan of Reher Morrison made a quote that sticks out in my mind. He said that he doesnt want more low end power, and doesnt want more top end power, but wants more Power in the Whole RPM range that he's using.

Make note that he doesnt call it HP he doesnt call it torque, he calls it power.

Originally posted by ScottC:
If you take identical cars each with 250HP, they'll have the same top speed. It doesn't matter if it's 454 with an RV cam or a high revving 4 cylinder. It's the power that's meaningful here. Why? Because we can use gears to convert torque to whatever we want. That may be true, but that doesn't mean that both cars will get to their top speed in the same time. Acceleration is all about the amount of torque that is available to accelerate the car.

If you're concerned with maximizing your cruising mpg then you need to look at the hp required to move the car and the efficiency of the engine running at the rpm required to run the speed you want. But, usually the discussion deals with how fast the car can accelerate and that's all torque.

Originally posted by bigjimzlll:
how do you figure out how many amps it will take to move it? by watts divided by volts.. how many watts will it take to move a 1HP motor? 746...so you have to use 1hp of electricity to turn the motor..not 1 ftlb of torque I wish your example was that simple in real life. Add in efficiency and power factor and you're close. At any rate, trust me on this, the motor is taking the electrical power and converting it to torque. When it turns at it's operating rpm it just takes so much power to keep it turning. I've never seen a hp curve for an electric motor but look at torque curves almost every day. If the hp was so important wouldn't it be used for more than just sizing the motor?

Originally posted by Nickel333:
BUT everyone here would love to have 650 ponies on top. {if you call 6,500 rpm on top} So to say lower RPM torque is everything is a bit over stated.I understand what you're saying but maybe everyone would like the torque to come on later once they're rolling? I agree that low end torque isn't everything. The area under the torque curve is everything. You can always argue that if you can't hook then the torque you have is useless no matter what rpm you're operating in.

Peter

If torque was the only thing that mattered, we'd all be building diesel engines. Monster torque, but low power.

As has been said here, power is a function of torque and rpm. What you want, is the most power under the curve in the rpm range you will be using. Assuming identical cars, you can have a low torque small block that makes 400 AVERAGE hp in the 4k-7k range, and it will stomp all over a 500 lb-ft Big Block that makes 350 AVERAGE hp in the 3-5k range, provided that both cars are geared to take advantage of thier usable powerband.

Average Horsepower in the useable rpm range is what really matters.

I'm sure there's some discussion going on in some motorcyle forum about how it's all about RPM's.

"I gotta make RPM's.
Horsepower is nothing.
RPM's are all that matter!"

Originally posted by ScottC:
I'm sure there's some discussion going on in some motorcyle forum about how it's all about RPM's.

"I gotta make RPM's.
Horsepower is nothing.
RPM's are all that matter!" And in some import/honda forum there's some discussion going on about how it's all about adding more stickers and bigger wings to their car to go faster :D

I think people make this debate way too complicated. Keep in mind no matter what you do, what you say, or how you look at it... torque and horsepower have two things in common: They both are a measure of power and they are both equal at 5250 rpm. If you have a street car or a motor that spends very little time above 5250 rpm you should care less about horsepower and go for the best possible torque curve. If you will spend most of your time 4,000 rpm and higher due to gearing and the powerband of your motor you should be more concerned with your horsepower curve. Notice I say CURVE.... not peak numbers. Peak numbers mean nothing if your curves look like a mountian peak. Also keep in mind that weight, gear, and converter are HUGE factors in deciding what way to build a motor for peak performance.

I dunno... that philosophy has worked for me for over 10 years of building cars for myself, others, and customers.

They both are a measure of powerNot true in the textbook definitions of "torque" and "power".

EVERYONE:

Consider this mandatory reading... it will explain this stuff in detail:

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

Best explanation Ive read :D

thanks for the input guys - pretty much what all of you have said is what i had thought to be true about the relation of torque to horsepower.

i kinda played dumb in my post, just to see what you guys had to say, because i really didn't know where to go about replying to this guy... as far as i understand it, torque = ability to do work, & horsepower = rate at which the work is done. sound about right?

To the guys that bash the imports, have you ever really looked into the stats for an intelligent comment? For comparison, a 2004 Honda Civic 1.6 litre engine makes 120HP net at very civil 6000 RPM. By comparison, a 454 {7.4 litre} would have to make 555HP to have equivalent power/displacment ratio. Having an '04 Civic in the house, I would bet you that I could beat a 555HP 454 Big Block out of the hole everytime if both cars were run on OE equip tires in a stock chassis.

I am one of the HP skeptics that also agree that peak claimed HP means little, what counts is where the power comes on and how/if you put it to the ground.

Originally posted by GRN69CHV:
To the guys that bash the imports, have you ever really looked into the stats for an intelligent comment? For comparison, a 2004 Honda Civic 1.6 litre engine makes 120HP net at very civil 6000 RPM. By comparison, a 454 {7.4 litre} would have to make 555HP to have equivalent power/displacment ratio. Having an '04 Civic in the house, I would bet you that I could beat a 555HP 454 Big Block out of the hole everytime if both cars were run on OE equip tires in a stock chassis.
Joe,with all due respect,I beg to differ.A 550 HP 454 in a 4000 lb. car running,say 4.10 gears/TH400,and hooking well (low 1.6 high 1.5 60 ft.) would be a low 11 second/possible high 10 second car..now,go put street tires on it and watch the 60 ft. go out the window..down to a 2.30 or so..it would still go low 12's in 1/4..a stock 1.6 litre/120 HP Honda is NOT going to be anywhere near that neighborhood.Even with a crappy 60 ft. the 0-60 acceleration would be take 3.9-4.10 seconds.Again,I don't see a stock Honda doing that.Even my 2.73 geared car can do 0-60 runs in 4.5 seconds on street tires.Unless I'm missing something in your comparison...

Originally posted by GRN69CHV:
To the guys that bash the imports, have you ever really looked into the stats for an intelligent comment? For comparison, a 2004 Honda Civic 1.6 litre engine makes 120HP net at very civil 6000 RPM. By comparison, a 454 {7.4 litre} would have to make 555HP to have equivalent power/displacment ratio. Having an '04 Civic in the house, I would bet you that I could beat a 555HP 454 Big Block out of the hole everytime if both cars were run on OE equip tires in a stock chassis.

I am one of the HP skeptics that also agree that peak claimed HP means little, what counts is where the power comes on and how/if you put it to the ground. My P455 makes 130hp at an extremely civil 2000rpm. :D The curve goes up from there. Thats because it has enough displacement to make a lots of torque (350 lbs/ft) at that rpm. so from a dead stop you'd have to dump the clutch at 6000rpm in the civic while I just ease into it for us to launch at similar hp levels. I see what you were trying to say, and the stats are impressive as how much hp/liter they are getting. I just think your comparison was a little too extreme to be realistic. I do agree that the peak means little, its the average, and with 130hp at 6000rpm, there really isn't much average hp compaired to a much bigger engine.

" on OEM tires ", I would give the Honda the nod over the first 100' or so.

Hey fourfiddyfowar, I know what you mean. In order to get a decent 60' from my HP motor, you need to launch it at a pretty high rpm, NOT 2000.

Some of you definitely missed the point. I made reference to 2 points. 1 - power/litre. 2 - usable power. We had this discussion late last year on this board, a thread that I had started "How much is enough". I am not debating the "more power is better theory", only stating that overall engine power is only as good as the balance of the package.

I will give you a good first hand example. Many of you may have heard of the "Rolling Stone" Funny car that ran during the 70's now runs Nostalgia shows. That car was campaigned by my cousin of the same name. The cars of those days ran in the 7's and high 6's. Today these cars run in the 4's. What changed? Subtle changes in tire technology and suspension, and advanced development of clutches. They had experimented with running more boost way back when and putting out a lot more horsepower. Moot point though, excessive HP is just that "excessive".

My example of the Civic vs a BBC is only to demonstrate that a defined level of "power" is only as good as the package into which it is installed. 427L88 is the only one that picked up the OE tire as a reference. A stock '70 454 LS6 Chevelle was only a 13.8+(?) car on stock tires. I rememeber seeing these on the street in stock form back them. Out of the hole the cars would dance all over the place if you tried to launch it. Like it or not, a bone stock 120HP Civic could beat it out of the hole. How far would it keep the lead? I don't know, 20', 30', maybe 50'? Now at 60' that's another story, the big power will keep it running and accelerating down the track.

" on OEM tires ", I would give the Honda the nod over the first 100' or so...nah..no way smile.gif
These Hondas aren't terrors..ever get next to a 15-16 second Honda car at the track? I have,and even at my ET level they are always in the rearview mirror :D

Chris, I'm not talking down the track, I am only referring to the first 50', if both cars have the OE tires. Like it or not, the 120HP car most likely will beat you off the line every time, unless you get your car to hook. By the same token, do another comparison, {2} '70 Chevelles - identical trim/specs to your car, except for the motor. Car A - your spec 454 motor as a baseline - runs 12.99's. Drop a 540CI 600 HP motor in it with no other changes. I would bet your current 454 combo will get it out of the hole everytime. 100' mark, different story. It's all about usable power.

Joe,its all in the 60 ft.
Example:my car on street tires spinning to a 2.20 60 ft. vs. a Honda running a 2.68 60 ft.
He isn't getting to that 100' quicker than me.

Chris,

You may be right, I don't have hard data to rely on, plus there are too many variables to deal with to validate the comparison. But the comparison I had made was a 555HP BBC on stock OE tires compared to the Honda on stock OE tires. Obviously too extreme of a comparison.

Like they say -- stick a fork in it, I think its done!