Let's talk TORQUE

[gregshin]

Ok folks...i always hear about HP this HP that...but i never hear anything about TORQUE. My question is this...say i have a SR20DET S13 blacktop with a front mount I/C, down pipe, turbo exhaust system with piping, Air filter, and other misc goodies, maybe later on add a fuel pump and bigger injectors, STOCK turbo....and i boost to about 9 PSI...how much TORQUE would i gain?

better yet...how much TORQUE do you gain for each level of PSI that you boost? does it depend on the effeciency of the setup? is there a rule of thumb?

[DuffMan]

What, do you haul a trailer with your 240? Who cares about torque. The car with the most HP will be fastest.

[Silviaholic]

Is that entirely true?  I thought torque had a good deal to do with launching?  Secondly, wouldnt torque make it easier for that HP to be effective?

[gregshin]

why do you guys always neglect torque? if you notice how the v6s and v8s have insane amounts of torque usually pull in faster times with less mods and with NA power. My goal is to spank mustangs and camaros off the line at a stop light...

[Krunko]

if you can combine great torque and great HP, then that's great.

Notice Supras and Grand Nationals.....6cyl turbo....fast.

[Titan]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (DuffMan @ June 10 2002,12:59)</td></tr><tr><td id="QUOTE">What, do you haul a trailer with your 240? Who cares about torque. The car with the most HP will be fastest.</td></tr></table><span id='postcolor'>
And you're incorrect... HP is only a fraction of making a car quick. Other factors are weight, gearing ratios, and torque.
Torque matters immensly in getting a good launch. Considering:

Horsepower = Torque * RPM / 5252

Therefore HP is a manifestation of torque at peak rpm efficiency.

Don't listen to Duffman, toruqe is very important.. many times more so then HP.

[gregshin]

can someone please answer my question about how many lbs of torque do we gain for each level of PSI boost?

[nrcooled]

The only way you will find out is to put in a SR and drop a controller on the it and slap her a dyno. &nbsp;Each engine will be a little different considering you have mods and different mods make different power gains

[rampid360]

The subtitle said sr20 or kaT. &nbsp; If a turbo'd engine retains some of the basic characteristics of the non turbo'd version...then a nicely set up KaT should spank an sr20 torque-wise. &nbsp;

Im sorry i cant answer your question about torque gains by psi increase.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">What, do you haul a trailer with your 240? Who cares about torque. The car with the most HP will be fastest.</td></tr></table><span id='postcolor'>
jesus christ I hope you are joking <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> &nbsp; Torque has EVERYTHING to do with the usability of your HP.

[gregshin]

well i said SR and KA-T cuz i wanna know both engine owners feedback

[Kreator]

Ok here is the way i relate hp and torque. Take a honda s2000. Lot's hp, not much torque. result: that thing goes up to 9000rpm and gets it peak at 8300. Now consider our cars. The torque and hp are about the same. The result: we max out at around 6K. Now finally consider a trailer. Those things have approximately 400hp and 1000+ftlbs of torque. their redline is at 3000rpm. Conclusions: if your hp is much higher than you torque, you are gonna be reving high up. If it's much lower, you max power is at low rpms. Now relating back to kat srs: Since sr is a higher revving motor, you'll basicly have less torque at the same rpm compared to a kat. The torque is directly related to your hp. So basicly diff between hp and torque is how high you rev (sorta) and the torque is your actual acceleration you feel. And there is no need to talk specifically torque, as you can always relate to torque from hp if you know wtf you are talking about

[DuffMan]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Titan @ June 10 2002,2:29)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (DuffMan @ June 10 2002,12:59)</td></tr><tr><td id="QUOTE">What, do you haul a trailer with your 240? Who cares about torque. The car with the most HP will be fastest.</td></tr></table><span id='postcolor'>
And you're incorrect... HP is only a fraction of making a car quick. Other factors are weight, gearing ratios, and torque.
Torque matters immensly in getting a good launch. Considering:

Horsepower = Torque * RPM / 5252

Therefore HP is a manifestation of torque at peak rpm efficiency.

Don't listen to Duffman, toruqe is very important.. many times more so then HP.</td></tr></table><span id='postcolor'>
Well we're talking about 240's here so gearing and weight should be similar.

Torque is usefull on dyno graph to determine shift points, but PEAK torque is a rather useless number. Some cars will be at their fastest shifting at points where they always stay below peak torque, by being at higher revs than their peak.

But PEAK HP is a usefull number because it, like you said, combines torque and revs. Torque and revs are equally important. Take 2 cars moving at the same speed. One is currently producing 100ft lbs of torque, and is revving at 8000 rpms. The other has 200ft lbs of torque and is revving at 4000 rpms. The cars will accelerate at the exact same rate (assuming eqaul weight, ect.). HP is the combination of these 2 equally important factors, and that is why tuners use it as the benchmark for performance.

Even for launching torque isn't that important. Traction is way more important. Cars with low torque will still launch well due to their shorter 1st gear ratios. S2000's get drag numbers that are comparable to other cars with the same power/weight ratio because of their gearing.

A stock Honda Civic Si (99-00) will wail on a stock 240 all day long in drag racing with its puny 111ft lbs of torque. Power is what determines acceleration.

[KiDyNomiTe]

Ok this is sort of off topic, but still deals with torque.

I was looking at some JUN products and was wondering how much of a difference Stroker kits make. I saw in the new SCC an ad that said that they increase torque and hp, but how much (ballpark figure).

Would it be a good thing to get for an Auto-X/Daily driver?

[gregshin]

AWESOME discusision...KEEP'EM coming

[misnomer]

The general consensus is the KA is all in all a torquier motor. You get that from a longer stroke and bigger displacement among other factors. The torque vs HP arguement is pretty much a moot point, as it's been pointed out, because one is a function of the other. Basically what I'm seeing the root of this discussion is power verses revs. "Torquey" cars have power at lower RPMs, but typically don't rev as high. They can be equally capable on the track or the strip as cars that rev to the moon, with lower torque output. It all comes down to personal preference. Some folks like the feel of power building and building as they get faster, others like to hit the gas pedal and "boom" they're there.

All personal preference, neither way to build is better than the other.

However, it would be good to discuss how to get which way :-)

[flipboi13]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (DuffMan @ June 10 2002,12:59)</td></tr><tr><td id="QUOTE">What, do you haul a trailer with your 240? Who cares about torque. The car with the most HP will be fastest.</td></tr></table><span id='postcolor'>
I still find that reply offensive... &nbsp;

And no, 99-00 si will not wail on this stock 95 ka 240sx, no way in hell..i beat one the other day from a red light, didn't think much of it as a great car to begin with.

[s13driver]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (DuffMan @ June 10 2002,1:59)</td></tr><tr><td id="QUOTE">What, do you haul a trailer with your 240? Who cares about torque. The car with the most HP will be fastest.</td></tr></table><span id='postcolor'>
that's not exactly true.. i mean it is true that the car with the most hp is going to be the fastest.. but we gotta think that without the torque to keep it moving. how can it be the fastest ? for example let's say there is a car with like umm... 1000hp but totally torqueless with let's say... 50. and the car weights about 3000lb tell me if it is even possible to get it moving to the point of its limit ? and also how long does it take to get there ?

[DuffMan]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">I still find that reply offensive... &nbsp;</td></tr></table><span id='postcolor'>
Well get over it. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">And no, 99-00 si will not wail on this stock 95 ka 240sx, no way in hell..i beat one the other day from a red light, didn't think much of it as a great car to begin with.</td></tr></table><span id='postcolor'>
Your anecdotal evidense is not convincing. My point is that stock for stock, all other things being equal, the Si is a faster car. Reason: HP.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">that's not exactly true.. i mean it is true that the car with the most hp is going to be the fastest.. but we gotta think that without the torque to keep it moving. how can it be the fastest ? for example let's say there is a car with like umm... 1000hp but totally torqueless with let's say... 50. and the car weights about 3000lb tell me if it is even possible to get it moving to the point of its limit ? and also how long does it take to get there ?</td></tr></table><span id='postcolor'>

I don't think you understand the physic of how torque and HP work. Assuming the car is geared properly, no matter how high revving/low torque a motor is, there will be more torque of the wheels on the ground than a lower HP car due to the gear ratios.

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (DuffMan @ June 09 2002,8:40)</td></tr><tr><td id="QUOTE">Well we're talking about 240's here so gearing and weight should be similar.

Torque is usefull on dyno graph to determine shift points, but PEAK torque is a rather useless number. Some cars will be at their fastest shifting at points where they always stay below peak torque, by being at higher revs than their peak.</td></tr></table><span id='postcolor'>
Torque is useful on a dyno graph because:
a: it's the measurement used to calculate HP, since the dyno itself is measuring torque, not HP.
b: peak torque shows you where your torque dropoff starts, and your initial torque value for your useable powerband.
c: shifting: i have no idea what the hell you're trying to say, but the general consensus is to stay within the powerband, which is usually described as the area between peak torque and peak HP.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">But PEAK HP is a usefull number because it, like you said, combines torque and revs. Torque and revs are equally important. Take 2 cars moving at the same speed. One is currently producing 100ft lbs of torque, and is revving at 8000 rpms. The other has 200ft lbs of torque and is revving at 4000 rpms. The cars will accelerate at the exact same rate (assuming eqaul weight, ect.). HP is the combination of these 2 equally important factors, and that is why tuners use it as the benchmark for performance.</td></tr></table><span id='postcolor'>

The cars will NOT accelerate at the same speed if they weigh differently. &nbsp;Thus, the Civic Si has "faster" numbers than the stock 240sx.
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">A stock Honda Civic Si (99-00) will wail on a stock 240 all day long in drag racing with its puny 111ft lbs of torque. Power is what determines acceleration.</td></tr></table><span id='postcolor'>
I'd say the weight difference is the most important factor in this race. &nbsp;That and the comparison of a decade old car to one within a few years.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">
Even for launching torque isn't that important. Traction is way more important. Cars with low torque will still launch well due to their shorter 1st gear ratios. S2000's get drag numbers that are comparable to other cars with the same power/weight ratio because of their gearing.</td></tr></table><span id='postcolor'>
The S2000 doesn't necessarily have shorter gearing because of it's lower torque, it's more of the close ratio 6spd transmission, which it NEEDS since the powerband is smaller. &nbsp;Just exactly what cars of the same power/weight ratio are you comparing it to, anyways??

[luey02]

I really wanted to quote one of you but all of you have the wrong idea, at least not perfectly correct.

Ok, torque and HP are functions of RPM of each other (stated before), that mean by knowing one of them at certain RPM, you can know the other. &nbsp;they are just different means of representing the power of specific motor. &nbsp;

1000 hp with 30 torque? that's not possible, unless you're making 30torque around 17000rpm. &nbsp;

Since determining HP depends on what RPM you're talkin about, peak HP is important since rpm is taken into account. &nbsp;But for torque, it's merely the amount of torque pushing the car at any instant, regardless of what rpm. &nbsp;So it's import to have a fat torque curve on a dyno sheet. &nbsp;that means you 're pushing your car all the way from 2k to 6k rpm the same amount force; which is better than a sloping one. &nbsp;Area under the torque curve the the total energy spend pushing the car. &nbsp;

now you know

[luey02]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (DuffMan @ June 10 2002,8:40)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Titan @ June 10 2002,2:29)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (DuffMan @ June 10 2002,12:59)</td></tr><tr><td id="QUOTE"></td></tr></table><span id='postcolor'>
.</td></tr></table><span id='postcolor'>
But PEAK HP is a usefull number because it, like you said, combines torque and revs. Torque and revs are equally important. Take 2 cars moving at the same speed. One is currently producing 100ft lbs of torque, and is revving at 8000 rpms. The other has 200ft lbs of torque and is revving at 4000 rpms. The cars will accelerate at the exact same rate (assuming eqaul weight, ect.). HP is the combination of these 2 equally important factors, and that is why tuners use it as the benchmark for performance.


A stock Honda Civic Si (99-00) will wail on a stock 240 all day long in drag racing with its puny 111ft lbs of torque. Power is what determines acceleration.</td></tr></table><span id='postcolor'>
maybe I'll quote you, hell no car's acceleration is determined by power, it is determine by force excerted by tires to ground and since that force is delivered by rotating shaft (drive shaft, axle, tires), it's correct to measure that force by torque. &nbsp;

HP is missleading and is used to fool grandma's looking for cars, and people like you.

[DuffMan]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">maybe I'll quote you, hell no car's acceleration is determined by power, it is determine by force excerted by tires to ground and since that force is delivered by rotating shaft (drive shaft, axle, tires), it's correct to measure that force by torque. </td></tr></table><span id='postcolor'>
The force of the wheels on the ground determines accleration. The force is determined by torque AND GEAR RATIO. Doubling the torque and doubling the gear ratio have the same effect on force. This is basic physics here people. If you understand the relationship between revs and gear ratio you can see why HP (Torque X Revs) is a good measure of accleration.

You see cars have these little things called TRANSMISSIONS that fuck up your assertion that there is a constant mathematical relationship between torque and force at the wheels.


</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">HP is missleading and is used to fool grandma's looking for cars, and people like you.</td></tr></table><span id='postcolor'>
There have been a lot of stupid things said in this thread but this one wins the prize. Why dont you go buy a powerstroke diesel, with your 600+ ftlbs of torque you'll rule the strip, dude!

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Torque is useful on a dyno graph because:
a: it's the measurement used to calculate HP, since the dyno itself is measuring torque, not HP.</td></tr></table><span id='postcolor'>
Actually the dyno is measuring force and then using the gear ratios to compute torque. It can determine the gear ratio by comparing engine RPM to the speed of the roller.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">b: peak torque shows you where your torque dropoff starts, and your initial torque value for your useable powerband.</td></tr></table><span id='postcolor'>
Where your torque dropoff starts is interesting to know, especially if you are making modifications to the car trying to raise the rpm where that dropoff occurs. But it doesnt effect shift points.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">c: shifting: i have no idea what the hell you're trying to say, but the general consensus is to stay within the powerband, which is usually described as the area between peak torque and peak HP.</td></tr></table><span id='postcolor'>
Ask a professional drag racer if he just trys to "stay within the powerband" and see what he tells you.

Actually I'll save you the trouble, as you approach the ideal shift point, your accleration rate is slowing down rapidly, because you are way past the torque peak. The acceleration rate you COULD have by shifting is either decreasing or increasing (increasing if you would end up before peak torque), but if it is decreasing, it is doing so at a slower rate than your current gear.

When the force of acceleration in you current gear is equal to the force you will be at after shifting, it is time to shift. The reason is if you stay in your current gear, your force will be decreasing faster than the next gear.

Torque is usefull for making this calculation.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">I'd say the weight difference is the most important factor in this race. &nbsp;That and the comparison of a decade old car to one within a few years.</td></tr></table><span id='postcolor'>

Civic Si is 2612lbs. Thats not much less than a base S13 coupe. Yet the Si's torque is only about 2/3 that of our cars. If torque were as important as everyone here says, shouldn't they be slightly better than 2/3 as fast as us instead of beating us?

[DuffMan]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ June 11 2002,12:08)</td></tr><tr><td id="QUOTE">The S2000 doesn't necessarily have shorter gearing because of it's lower torque, it's more of the close ratio 6spd transmission, which it NEEDS since the powerband is smaller. &nbsp;Just exactly what cars of the same power/weight ratio are you comparing it to, anyways??</td></tr></table><span id='postcolor'>
Lower torque doesn't automatically = shorter gearing, but there is a relationship.

Cars are generally designed to shift arround the same speeds. Most cars will redline in first at about 40mph. Some cars are geared shorter (for sport) or some longer (like for fuel economy), but usually there is a relationship between the redline and the gear ratios.

The S2000 with its high redline, is given short gears. By short I don't mean the ratios are close together, i mean the ratios themselves are higher, (talking about the combined final drive and gear ratio). This effects the actual force of the wheel on the ground.

Force = MA so A = F/M right?

The S2000 produces more force to the ground in 1st gear compared to it's mass than a Grand Prix GTP with its massive 280 ft lbs of torque. This is why peak torque isn't that important &nbsp;even for launching. Lack of torque can be made up for in gearing.

[luey02]

Ace, I think you need to correct this idiot..

[Zemus]

How is the 180sx torque wise, i dont really know the specs. i take it isent to great

[adey]

...but doesnt throwing a turbo onto a car make a whole lot of difference? at all?

All I've noticed (and the last time I've taken a physics class was freshman year in college) is that on turbocharged cars, peak torque tends to be close to peak HP whereas on n/a cars, peak HP tends to be much higher than peak tq.
Through this observation, I'm led to believe that a turbocharger has something to do with it, regardless of the rev-nature (high or low) of an engine.

[flipboi13]

Civic Sis have 160 hp compared to our 155 hp. &nbsp;This gives them the advantage over our higher torque and the fact that we have RWD? &nbsp;Yeah, they have a higher compression ratio than us fitting in that 1.6L crap engine but on a stock civic si, that is very restricted.

[KyoLo]

wow...very good analysis
so...are you guys saying SHIFT POINT = Torque Peak?
so after torque peak, acceleration or in other word, total force exerted, will decrease?!?
give 97 240SX as an example, its peak torque 160lb/ft @ 4400rpm, that means after passing 4400rpm the car starts to decrease its max acceleration(force) @ 4400rpm?

[camppain]

in a 1/4 mile torque will get you down the road faster dont say its not needed that you only need traction your logic is semi there.

if you have 100ft lbs of torque but no way to deliver it to the ground you'll just be spinning your wheels all day thru gears with a 20 sec time

but ask hot rod guys what gets you donw hp or tq? tq would win in a 1/4 mile race

but this question is even debated with hotrodders. but like i said in a 1/4 torque. dont say it has nothing at all to do with it

[DuffMan]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (KyoLo @ June 12 2002,12:18)</td></tr><tr><td id="QUOTE">wow...very good analysis
so...are you guys saying SHIFT POINT = Torque Peak?
so after torque peak, acceleration or in other word, total force exerted, will decrease?!?
give 97 240SX as an example, its peak torque 160lb/ft @ 4400rpm, that means after passing 4400rpm the car starts to decrease its max acceleration(force) @ 4400rpm?</td></tr></table><span id='postcolor'>
no, your force will be decreasing for almost the whole time in a drag race.

What matters is whether it is decreasing at a faster rate than it would, were you to shift. So after peak torque, your acceleration rate is slowly decreasing, but were you to shift you would end up below peak torque and, more importantly, you would loose the mechanical advantage of the lower gear.

Maybe I could drum up some visual aides to make this easier to understand.

Camppain - No serious drag racer would say that torque would win a race. Drag cars have higher flowing heads and insane cams to increase the top end power. Higher flowing heads and wild cams do nothing for peak torque and might even decrease it.

[WaKeMaN]

Let's try a different approach.

Let's say hypothetically that we have:

Two cars, Same HP, Same Weight, Same Gear Ratios, Same Tires, Same Drive Wheels. &nbsp; One car has more tq for whatever reason, (larger displacement, etc.) &nbsp;Will not the car with more tq win a 1/4?

[Kreator]

Ok i'll, try again. I've read this whole 2 page article that was trying to explain relationship between torque and hp based on example of a 93 corvette compared to the 2002 corvette.

Some info:

2002:
&nbsp;350 @5200rpm
&nbsp;360 @4000rpm

1993:
&nbsp;300 @5000rpm
&nbsp;340 @3600rpm

ok so you see the difference. first off, notice that the peaks for the 93 corvette are lower. As i tried to explain in my first post, that directly depends on the difference between the hp and torque. The second thing, that the article emphasized, was that while the two cars accelerated basicly at the same speed, the newer vette won, because at the point where 93 vette shifted, the 02 vette kept going. Again try to see it. When you shift, you kinda lose hp. So suppose you are at 5400rpm and you have 110hp at the wheels. When you shift, you drop back down to about 4900 and get something like 100 hp. So when you hit peak torque at 6400 or whatever, and have 120 hp at the wheels and shift, you go down and lose some of that hp. But, if you keep going in the same gear, you'll be losing it cuz you already passed the peak torque. So as i see it, you gotta shift at the point when the hp is equal (suppose if you shift at 6400, you go from 120 hp to 110, but if you shift at 6700, you'll be down to like 118, but shifting will get you higher in the powerband, and you'll have 118 hp at after you shifted as well). Again, this is in perfect conditions. Don't forget the air drag. So in short words, torque is how fast you accelerate, and hp is how long you can keep accelerating without shifting. Thats my view.

But honestly, i think we should all shut up, cuz i don't think any of us (including me) know exactly what they are talking about or understand it correctly, and those that do aren't able to explain it to the others.

[Kreator]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (adey @ June 11 2002,2:09)</td></tr><tr><td id="QUOTE">...but doesnt throwing a turbo onto a car make a whole lot of difference? at all?

All I've noticed (and the last time I've taken a physics class was freshman year in college) is that on turbocharged cars, peak torque tends to be close to peak HP whereas on n/a cars, peak HP tends to be much higher than peak tq.
Through this observation, I'm led to believe that a turbocharger has something to do with it, regardless of the rev-nature (high or low) of an engine.</td></tr></table><span id='postcolor'>
Well most upgrades actually increase your torque rather than hp. Like the air intake gives you only 2hp, but about 4-5 ftlbs of torque... So my guess would be that throwing on a turbo increases the toque alot and hp somewhat. Therefore peak torque gets peak closer to hp <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

[rubbersidedown]

taken from http://www.howstuffworks.com/horsepower2.htm - ( "Another thing you can see from a car's horsepower curve is the place where the engine has maximum power. When you are trying to accelerate quickly, you want to try to keep the engine close to its maximum horsepower point on the curve. That is why you often downshift to accelerate -- by downshifting, you increase engine rpm, which typically moves you closer to the peak horsepower point on the curve. If you want to "launch" your car from a traffic light, you would typically rev the engine to get the engine right at its peak horsepower rpm and then release the clutch to dump maximum power to the tires." ) This kind of explains things as far as horsepower and torque goes. So horsepower is very very useful and its not used to "fool grandmas" or whatever but rather it is used because its generally a more impressive number. Horspower, torque, and the engine speed are all import factors in figuring this out. Without torque, or rather the concept, there would be no horsepower and you still need to know the engine speed to figure all this out. But together this still doesn't mean that much. You still have to account for gearing, weight, drag, and all that other happy bullshit. I hope this helped.

[blaqsilvia]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (flipboi13 @ June 11 2002,01:33)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (DuffMan @ June 10 2002,12:59)</td></tr><tr><td id="QUOTE">What, do you haul a trailer with your 240? Who cares about torque. The car with the most HP will be fastest.</td></tr></table><span id='postcolor'>
I still find that reply offensive...

And no, 99-00 si will not wail on this stock 95 ka 240sx, no way in hell..i beat one the other day from a red light, didn't think much of it as a great car to begin with.</td></tr></table><span id='postcolor'>
I have a 95 KA 240sx and I have beat every civic except for my friends who has a NOS in it... &nbsp;he did blow his engine a few weeks ago though &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

[obruT ES 41S 79&#39;]

Geez, all these folks trying to downplay torque, hp, SR, KA etc...

All you guys are missing the big picture. Yes some of you know that HP is a function of torque, but fail to know that torque produced by an engine varies with rpm, causing HP to vary with rpm. Can never separate HP from torque and vice versa. It's all the samething. HP is torque produced over time. You can load 100ftlb on an object, but if you are not spinning the object, then there is no work done over time, hence zero hp. But if you load 100ftlb on an object constantly while it's spinning, then there is HP exerted.

The typical figures car manufacturers are useful to understand the powerband of the engine. Most folks that doesn't understand the concept of the powerband will instead focus on the peak numbers for torque and hp.

Example:
Two cars, same gearing, same weight.

One have a flat torque curve, let's say 150ft from 2krpm to 8krpm. The power band on this car will be linear. Peak hp will be at 8krpm.

The other one a peaky torque curve. 100ftlb from 2krpm to 5krpm, and 6krpm to 8krpm. 200ftlb from 5k to 6k. Power band is peaky, just like the torque curve. Peak hp will be @ 6krpm.

If racing both cars from 2krpm to 5krpm, the first car will pull ahead. Why? It's got more torque &nbsp;in more parts of it's rpm range, thus more hp from 2k to 5k. The rate of accelaration through out each gear will also be constant and linear.

From 5k to 6k, the 2nd car will pull faster than the 1st car, but in the rest of the rpm range, it will lose. The acceleration of the car will be linear for the lower torque are, and a sudden jolt/increase in accelaration between 5k and 6krpm. But since it's effective powerband is so narrow, the car is slower.

Typically, car manufacturers that have engines that are peaky like the 2nd car will regear the transmission such that the driver can take advantage of the narrow power band. The gears will be close ratio, such that, when the next gear is selected, the rpm will drop to a point where it's near the peak power.

Big broad power band cars can make do with wider ratio gears since any part of it's powerband still makes plenty of good power. Makes it easier to drive too.

Another example:
This is a classic battle of the KA+T vs SR. This is my favorite example that I use quite often. This actually took place during 2001 1st annual 240SX national meet in KC, Mo. Both cars, dynoed with 210 rwhp. Same peak numbers, around the same rpms. The S14 with a KA+T and 7,000rpm redline. The other, redtop SR in a fastback.

They held an informal drag race at a secure location. Race 3 times, and all 3 times, the heavier S14 KA+T won. The driving skills were equal, and the S13 driver actually took more weight out of the car than originally agreed upon.

Guess what? It's the fatter powerband of the KA+T that allowed it to win. The engine made more torque throughout more of the rpm range than the SR. Both cars, same gearing, and if not, the SR tranny would actually be more advantages for the SR since it would be a closer ratio.

So, don't just talk peak numbers, it's the curve that matters.

For those who are into stereos, just think about advertised peak wattage vs RMS... Which one tells the bigger story? RMS... or in the engine's case, power curve (includes the HP and torque curve since it's all related), and not peak numbers.

tyyap
'97 S14 SE Turbo

[flipboi13]

Daaaaamn... You're the man!!! &nbsp;I just learned soo much.. &nbsp;Thanks...

[camppain]

ok this is straight from the book

torque is a turning or twisting force. the engines crankshaft rotates with a torwue that is transmitted through the drivetrain to turn the wheels of the vehicle. horsepower is the rate at which torque is produced.

engines produce power by turning a crankshaft in a circular motion. to convert terms of force aaplied in a straight line to a force applied in a circular motion, the formula is

torque= force x radius

ex a 10 lb force is applied to a wrench 1 foot long will produce 10 ft lbs of torque

if the torque output of an engine at a given speed is known horsepower can be calculated by the following formula

hp=(torque x rpm) / 5,252

horsepower basically overcomes friction or resistance created by the internal parts of the engine rubbing against each other

what moves a bolt when you need to remove it? the torque applied. now i understand you cant apply hp to a wrench. unless you want to say that is how fast you turn it. but lets say usiing that example you try to turn a wrench to loosen a bolt with just speed no force or better yet torque. the bolt wont move. apply the torque to it and it will move. once it gets moving the faster you spin the wrnech (hp) you will loosen it faster

and im just trying t say you cant dismiss torque i never once dismissed hp just for the mere fact that torque starts to move a car not hp.

try moving your car from a stand still in 4th gear
it wont cause there isnt enough force to do so the gears are smaller for higher hp not more torque. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sly.gif" border="0" valign="absmiddle" alt=':sly:'>

lemme guess was that your s14 that won obruT ES 41S 79'?

[luey02]

actually, stock ka has closer gear ratio than stock sr transmission. &nbsp;

YOu guys should've switched drivers...to find out the truth..

[obruT ES 41S 79&#39;]

All that verbage... Don't copy directly. You need to be able to explain it without copying others words. That shows much more understanding.

Nope, it's not my S14, because it wouldn't have been a fair race if it was my S14. My car puts down much more than that. My car puts down over 200rwhp from 4,000rpm to 7,000rpm. Not a fair race against a car that only have a peak 210rwhp. At the time, I was suppose to race Greaser, but since it rained out the track event, we never got to race.


And for the record, I can move my car from a standstill in 4th gear... My clutch won't like it, but it does get going. I can also move around in 1st gear without my foot on the gas, and foot off the clutch. The car will cruise at about 3mph, no juttering, etc. Pretty fun actually. My car makes 330ft-lb of torque @ 4,300rpm. Go ahead and calculate the hp there. (270rwhp). Peak hp is 318rwhp @ 6,000rpm to 6,500rpm. Go ahead and calculate the torque there. (278 ft-lb @ 6,000rpm and 257 ft-lb @ 6,500rpm). You can see how the torque curve is. If I wanted to raise peak HP, I'll have to improve the higher rpm torque. (But can you see that the engine puts down over 200rwhp from 4,000rpm to past the peak hp?)

Let's say that I successfully increase the torque at 6,000rpm to 6,500rpm by 10ft-lb. Resultant HP would be. 329rwhp @ 6,000rpm and 330rwhp @ 6,500rpm. But the peak torque at 4,300rpm hasn't change.

Or lets say the engine puts out 330ft-lb of torque at 6,500rpm. That would be 408rwhp @ 6,500rpm. Peak torque would still be the same.

Anyway, hope the examples will show folks that looking at the peak numbers isn't everything. What's really important is to see the torque curve over rpm or HP over rpm. That says a lot more than peak numbers. I personally prefer to have a wider power band. It's much easier to drive. Don't have to shift that often, and don't have to take it to redline all the time to go fast. Like I pointed out twice, the engine put down over 200rwhp (~240hp crank) for a large rpm range. That makes the car easy to drive. I rather have that than an engine that only does it in a narrow range.