How to read torque curve graph

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>>16489018
>automatic

>>16489018
yes torque is on
don't try to understand horsepower it's not a really tangible unit
torque is the force applied to turn your wheels at a precise moment/rpm

horsepower is the overall energy your engine is producing

>>16489018
Torque is irellivent as the torque at the road changes with the gear so ignore it.

>>16489044
So in circuit racing and drag racing, drivers shift at redline, no?

That graph shows that peak torque is at 4000 rpm. Why would you stay in gear as the torque drops off?

>>16489018
Horizontal axis shows RPM.
Left vertical axis (orange) shows torque, so yes, orange line.
Right vertical axis (white) shows HP
You just read it like any other grap, you have a value on the horizontal RPM line and you look at the corresponding value on the graph, only there are 2 graphs, so enjoy.

I can't explain the exact difference between torque and HP, or rather, torque is pretty straight forward but HP is a little more abstract.

>>16489062
What? These tests row through the gears.

>>16489044
>don't try to understand horsepower it's not a really tangible unit
Lol you mean dont try to understand torque. Especially not when gearing is a thing.

Horsepower is the rate at which work is done...

>>16489070
Power increases. Power is what matters.

>>16489079
No a dyno pull is only done in one gear.

>>16489079
4th is 1:1, is the gear dynos are done in

>>16489070
>Why would you stay in gear as the torque drops off?
because horsepower is what matters :^)

>>16489070
By shifting at redline it makes you more likely to be in peak torque when you get to that next gear.

>>16489085
So torque is what gets the car moving, but once you have the momentum built, it doesn't matter as much?

Aren't torque and horsepower more or less the same thing? Or at least you get horsepower from torque, right?

>>16489096
Then what is this?
https://www.youtube.com/watch?v=lpB1yR9Sz9Y

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>>16489018
horsepower is a measure of torque overtime

Torque times RPM divided by 5252 equals horsepower

That means that at 5252 RPM on any engine horsepower ALWAYS equals torque
this assumes torque is in lb-ft and mechanical horsepower

>>16489106
Torque is a derivitive of power. Engine torque dosn't matter at any speed only wheel torque and thats just related to engine power and speed.

>>16489119
Anon getting BTFO is what

>>16489070

But torque at the tires is affected by gearing. Since horsepower is a measurement of work over time, the peak horsepower is more important for getting the mass of the car to increase velocity as fast as possible. Peak torque is irrelevant for drag racing, you want torque to stay up in higher rpms for more power.

>>16489098
Jesus, this is confusing.

HP is torque x rpm / 5252, right? I would have assumed that hp would be linear, but as torque drops off and rpm increases at a stead rate, I would think that HP would also drop, but it doesn't. It continues increasing at a linear rate. What gives?

>>16489102
Okay, that makes sense. An explanation in understandable terms.

So why does torque drop off if you keep the engine revving?

>>16489119
That's an ad... lol It's to show off sound.

>>16489119
An advert not a dyno pull.

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>>16489119
>>16489106
>>16489098
wrong 4th is not always 1:1

Also torque is meaningless without an RPM number next to it.
My impact wrench can do 700lbs of torque does that mean its a hand held hellcat? No

Horsepower is the only number that actually matters for performance.Torque is a useless stat meant to self trucks
Diesels make a ton of torque and little horsepower because they dont rev for shit due to the fuels flame speed.
You can always get more torque by simply changing the gear ratios but you cant get more horsepower by change the ratio because its connected to an element of time. IE RPM

>>16489070
it's more complicated than that
the graph shows how torque you have at the crank you need to multiple that by the ratio of each of your gears
when the torque in the next gear is greater than the one in gear your in then you shift but redline usually comes first that why on most engine you shit at red line for optimal acceleration

>>16489080
torque is pretty tangible to me more than horsepower
but horsepower isn't complicated either

>>16489018
You don't need to know, it's obvious you'll only use it for more shitposting

>>16489144
Ignore the 5252 as that's hust unit conversion. If you multiply 1000rpm by 20 units of torque tos get 20,000 units of power if you multiple 1500rpm by 15 units of torque you get 22,500 units of power.

>>16489168
>torque is pretty tangible to me
Yeah okay mr, you have a dynamometer inside your head do you?

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>>16489144
HP goes up because RPM goes up

If torque is flat then the HP will ramp up with RPM
If torque is falling at a steady rate HP will be flatish
If torque is flat then suddenly ramps like on a high boost small engine with a big turbo HP will ramp even faster

More air in means more fuel in means more power out
Notice as boost pressure in this chart comes up the power follows almost exactly?

>>16489152
>So why does torque drop off if you keep the engine revving?

Normaly due to restrictions in air flow through the valves.

>>16489164
Okay, that adds some perspective.

>>16489144

Because the rpms increase. Torque is a force. Think of a single cylinder 2-stroke engine. Every time it does one revolution, it gives one torque pulse. If it is spinning faster, it gives more torque pulses per second. As the engine spins faster, the torque pulses are also stronger due to the engine being designed to make power at higher rpms. Once a certain rpm is reached, the peak force of each torque pulse has been reached. After this, each one gets less and less as rpms go higher and higher. But, even though the pulses are getting weaker, the engine is spinning faster, so there are more torque pulses per second, which means more overall torque is applied. Eventually the dropping force of torque pulses is too much, and power starts to decrease as rpms increase.

>>16489180
dude you can feel heat but you don't have a thermometer inside your head

you can feel a force and torque is just a force that turns

>>16489204
>you can feel a force
You are feeling horsepower. Fuck off.

>>16489183
jesous that must be a shit drive.

>>16489018
>Measuring torque in newton meters while measuring power in horsepower
Wew lad. When will you cucks learn that metric is a steaming pile of feces?

>>16489214
Hey there trailer trash underage rapist

Okay, then can someone explain this to me?

I'm using these because they're the only figures I can think of off hand.

S550 Mustangs:

V6 models makes 300HP & 280 ft/lbs of torque.

Ecoboost makes 310HP and 320 ft/lbs of torque.

Does that mean that the only tangible performance gain is 10HP?

I feel like the torque has to mean something because if not, what's the point of offering the Ecoboost as an engine, especially since it weighs more than the V6?

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>>16489187
This
Race engines pull all the way to mechanical limits say 9,000 RPM

street engines need enough low end torque/power to lug the car around at non racing speeds hence mild camshafts and small intake and exhaust ports

More aggressive cams add a shit load of power to most american V8s because they come with mild cams stock
The bigger the cam(mainly duration not lift) the more torque the engine makes at higher RPM so... the more horsepower it makes because the torque band is shifted right.
Honda VTEC is cool because the engine has basically two sets of cams a mild cam lobe for fuel efficiency driving but when you hit higher RPM like 5,500 it hits vtec which switch the cam profile to basically a race cam grind which allows you to rev to 8,500 and make power.
If you had a single cam profile and needed high rpm the car would run like shit at 2-3,000 normal street driving rpm and idle like aids

>>16489018
Why arn't you using KW to measure powet Impirial is shit and should have been dumped decades ago. Only an idiot wouldn't know SI is superiour in every way.

>>16489232
Notice the PS next to the HP?
That's metric horsepower.
That's how metric power is actually measured you fucking coon.
I swear Australians are fucking retarded.

>>16489187
Is there any way to combat that? Forced induction should be able to fix that, right?

>>16489226
>Does that mean that the only tangible performance gain is 10HP?
No not necaseraly it may make more power over the V6 at other points in the rev range, you can't tell a lot from a single data point for each engine.

>>16489228
I kinda like it though, but they suck in traffic.

>>16489210
try touching anything you know what you feel ?
the force in Newton that you apply to this object
try picking up any object now make it turn with one hand and hold it with the other do you know what you feel ?
it's torque in N.m

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>>16489226
yes sort of 10hp but also the shape of the powerband

The ecoboost engine has a much MUCH flatter torque curve so its making more torque at a lower rpm which is great if you have a two or three speed transmission. Modern transmissions are 6+ gears so you only need a narrow power band to stay in the torque curve when you shift.

If you tried to race say in 5 gear from 1,500 rpm to say 6,500 rpm the ecoboost would rape the mustang but if you raced from 4,000-6,500 in 1st 2nd 3rd 4th it would be a very close race
>>16489211
dont be made fag

>>16489202
Okay, I understand your explanation.

It's just an odd thought that each "pulse" would get weaker as the rpm increases, past a certain point.

>>16489255
When you press the gas pedal, the car picks up acceleration, thats horsepower you are feeling kid

Just stop posting

>>16489238
What has metric HP got to do with SI units? I'll give you some time as you are hard of thinking.

>>16489242
Yes forced induction helps but there is what is ckown as choked flow in fluid dynamics, above a flow rate you have progressivly more losses due to internal friction within the air. It's one of the main reasons F1 engines have huge bore to strok ratios as a big bore lets you have big valves, it's also why multiple valve heads are common as you can get nore valve area with 4 valves per cylinder than 2.

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>>16489255
torque means nothing

Sustained torque at the wheels is what moves a car not just single blip of torque ones

Sustained wheel torque is called horsepower

>>16489228
Is that why cammed cars have that irregular clanking sound at idle? Because it's just not designed to run at such a low rpm?

>>16489106
Horsepower is a unit of power, like watts.
Power is energy over time, or in other words, how much energy you're putting out per second.
In order to get a car moving you need to give it kinetic energy. Kinetic energy is the energy of movement. So how fast you accelerate is related to how fast you're adding kinetic energy to the car. Energy per time. Power.
Torque is rotational force. It doesn't really matter to the driver, except that more force can make it easier to overcome the frictional force holding the tires to the road (i.e. spin the wheels.)
Anyone who talks about how you can 'feel the torque' of an engine doesn't know what they're talking about.

>>16489261
What he is actualy feeling is a linear force causd by horsepower.

>>16489261
not you fucking retard what you feel is your inertia try to resist the acceleration of the car
it's a fucking force
you just don't feel energy you dumb fuck
and i was talking about what you feel in a car but what seems more tangible to me
just start thinking

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>>16489275
flow is increased squarely with pressure
Only reason you cant run 200 psi of intake pressure is because heat not because the engine reaches a certain max flow potential
Remember ALL engines are boosted even NA ones. NA means naturally aspirated that is atmospheric pressure is what the "boost" pressure is which is around 14.5 psi. Engines pull a near perfect vacuum at the head of the valve. More pressure behind that means more air pushing into the vacuum

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>>16489246
Good point. Here are the two side by side.

hp = torque * rpm / 5252 (iirc)
but that's when you measure torque in freedom units not in this commie garbage.

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>>16489183
>~1500hp @7500 @~2bar boost

>>16489257

This is because the engine is running out of breath. It is spinning faster, thus the piston is going up and down faster, burning a mixture of air and fuel faster, and the intake port, fuel metering, air intake and all that can only flow so much air. Purse your lips and inhale sharply, there is a restriction and you can only inhale so much air so quickly. Now open your mouth and inhale sharply. Your restriction is less. Think of that in terms of adding your cold air intake, headers, exhaust, ect. Now, imagine you were inhaling sharply with a leaf blower sealed to your face. Your lungs would inflate pretty fast, but you might rupture something and die. Think of that in terms of adding a turbo kit.

>>16489299
You keep saying tangible, you have no idea what youre fucking saying.

Stop posting

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Here's your standard Mustang lineup.

You're talking about a $12k CAD difference from top to bottom.

>>16489276
i wasn't talking about what you feel in a car
but you don't feel energy you feel how it act which is acceleration

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>>16489283
cammed cars idle poor because they dont have enough vacuum at idle when you add in a large cam
normally you have 18+ inches of vacuum at idle but with aggressive cams this can drop to as low as 5 inches

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>>16489312
Dont fuck with 4g63 bruh

http://technologyandracing.blogspot.com.au/2011/02/one-robust-4g63-engine.html

>>16489283

Exactly. And, they often blow some of the intake charge right out the exhaust port at low rpm. Cams meant to move lots of air at high rpm are very inefficient at low rpm.


It's a trade off, like anything else.

>>16489319
maybe tangible isn't the right word
i mean it's something more concrete than Horsepower because you can feel it

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>>16489301
>not because the engine reaches a certain max flow potential

thats not true at all. valves are pseudo-laval nozzles and there exists an inlet pressure such that the flow would be supersonic. so there is an upper limit to intake pressure.

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>>16489312
KG per CM not PSI
its about 80psi of boost

>>16489338
i don't mean you can feel it in your car
i mean you can apply torque with your hand

>>16489338
>i mean it's something more concrete than Horsepower because you can feel it
Kill yourself. If anything is 'concrete' it is power because its what makes the car fucking move.

>>16489336
to make 1500hp at 2 bar it would need to make 500hp NA.
what are the chances a 4G63 can do that at 7500rpm

>>16489255
When I pick something up, I feel its weight in pounds, not kilograms.

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>>16489339
sure at that far extreme but engines are designed like you said with large bores to allow large valves which given the cylinder volume I dont think you would ever hit that limit

Some diesels are running 250+ PSI of boost pressure with very linear gains still happening

>>16489353
>to make 1500hp at 2 bar it would need to make 500hp NA.
volumetric efficiency doesnt work like that. you can stop posting too.

>>16489256
SO looking at the torque curves and your explanation, the Ecoboost was designed to have more low end torque?

>>16489338
Horsepower's made from gasoline and forged steel, not concrete.

>>16489341
ottomh 1kg/cm ~ 1bar.
so no.

>>16489314
I love that explanation.

>>16489354
oh god dude now you're just trolling
you don't feel the mass of an object anyway you feel it's weight in newton
>>16489346
i won't bother to explain my point of view anymore

>>16489368

Yes, it's designed to drive better.

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>>16489353
The side is not in bars its in KG per CM

Again its like 80 psi of boost

>>16489367
Volumetric efficiency absolutely does work that way.
Come back when you finish high school and do this shit day in day out.

>>16489368
Which gives it more horsepower over the rev range.

>>16489385
fucking hell you are one illiterate piece of shit, i'll give you that.

>>16489369
gasoline and air
and what your produce is pressure which apply a force on a piston then a crankshaft which convert it to torque which spin your wheel s

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>>16489303
Yes... all that space between the two power curves is important.

And the difference between the two power curves is a function of the torque.

I can't believe no one posted this equation yet.

>pic related (units in HP and Ft-lbs)

>>16489398
ALL AMERICAN AIRCRAFT SPEC FORGED STEEL

I have to say that I'm proud of you, /o/ anons. Usually these threads go straight to bro-science. Keep up the good fight.

>>16489386
Nope.

>Come back when you finish high school and do this shit day in day out.
I learned how to read units of measurement in primary school. 3.2 kg/cm is not 2bar.

>>16489405
Did your college professor write that equation out?

>>16489324
You've got a good point.

>>16489393
Thread on the entire setup
Says it made 1400~ on 57PSI
IIRC it ended up like 2khp at 80~ psi

http://www.evolutionm.net/forums/evo-dyno-tuning-results/447351-highest-hp-4g63-engine-2007-a.html

>>16489386

No. In a boosted engine, higher pressure is a result of more overall restriction to flow through the engine and the turbine in relation to how much air the compressor wheel is forcing in. So, an engine with large cams and a more efficient and usually larger turbine will have less restriction, and lower pressure when running the same compressor, yet make a shitload more power. This is why on say, a Civic Si, the cheaper turbo kits make like twice the pressure of the better kits and a lot less power. They have cheap, restrictive turbos.

>>16489422
kg/cm is torque though i think the graphic doesn't display the 2
that being said 1 bar is roughly 1kg/cm2

>>16489431
Its all about the exhaust flow with a bigger turbo
Pressure is pressure on the intake assuming its the same temp. Smaller turbos will run a higher pressure ratio of exhaust PSI to intake PSI. 3:1 is pretty high but normal for a small factory turbo that is if you have 20 psi intake you would have 60 psi pre turbo exhaust back pressure. Some very good medium size turbos will run near 1:1 at least up to 15ish psi of boost depending on the engine size ect

Turbo flow rate tells you the amount of air in lbs the turbo flows and gives you a rough estimate of the power the turbo can support. Remember air = fuel = power.

>>16489378
I didn't say mass. I said weight.

>>16489422
Oh it's those Greek guys, yeah they're generally regarded as being full of shit.
Even 1400@57psi seems like an exaggeration. That would be 350hp NA which again would be highly unlikely at 8500rpm, even on race gas.
Assuming it's still a 2 litre. I don't know how high you'd have to rev to make those numbers it but it would be over 10k.

>>16489422
3.2kg/cm2 abs = 3.1 bar abs = 2.1 bar boost
so yeah, it pretty much is you dumb faggot.

>>16489498
disregard this, it would be 280hp NA, which actually might be possible.

>>16489490
pounds is mesure of mass
weight is mass x gravity but it's being use incorrectly by every one which doesn't really matter because gravity is almost the same everywhere on earth

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>>16489498
IIRC it was nearly 11,000 rpm

If I member right it was also being sprayed which changes everything
Nitrous is cheating in terms of engine dynos ect
Spraying more oxygen without having to deal with VE or any other issues associated with cramming more air in is fake news to me.

>>16489471
I can tell you've shitposted about this before.

>>16489431
this. the compression process is not adiabatic.

>>16489228
I never got why people ragged on Vtec other than ricers pretending only Honda had variable valve timing. Alot of retarded kids in V6 mustangs talk shit on it not realizing how revolutionary it was.

>>16489018
better wuestion is how do i read compressor map and P-V plot

>>16489516
Oh okay at 57psi and 11k it's definitely possible. Very impressive too, but there were a lot of question marks about the honesty of those guys claims.
I was only going off the graph initially, which has very implausible figures.

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>>16489517
??
The turbine(hot side) is always the biggest restriction in a turbo setup
Cheap turbo kits have nothing to do with turbine size or AR ect
Cheap turbos are fine and can make good power but the real reason they make less than an expensive newer style turbo is mainly due to the use of billet compressor wheels. These are normally cut closer to the shaft so in effect act like larger turbos than what they are. They run less back pressure because they dont nee to spin as fast/hard as a similar cheap turbo to produce the same amount of flow.

So here's another question. What does engine volume have to do with horsepower?

>>16489546

There is no doubt they are full of shit. Did you see the pictures of the head? They randomly removed metal and created strange hot spots.

>>16489549
I'm not agreeing or disagreeing, just commenting on your posting style :^)

>>16489552
More boom-boom room = more hp

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>>16489537
It was and still is amazing tech that has be copied tons of times.
Most modern VVTI setups are inferior to the early honda ones in that they dont actually change the lift just the duration. But they are nice because they can constantly vary the duration vs the early VTEC setup was on/off
Also these days its not for performance but more for emissions shit

>>16489367
Volumetric efficiency is the biggest meme

>>16489560
Why do some smaller engines make more power than larger ones?

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>>16489552
bigger engine = more air flowing = more fuel flowing = more power

As far as horsepower? Nothing remember we had 5.7 liter + v8s in the 70s and 80s making 130hp
Today we have 1.0L I3s making the same amount of power

But bigger engines if setup right will make more power its simple physics

>>16489549

I meant the cheap turbo kits in just the Civic Si world. Let me clarify, by "cheap" I meant like a GReddy kit, which comes with shit components and management, which is about as cheap as you can go. It has a puny ass turbo. The really cheap knockoff kits actually have good turbos and manifolds, but you have to replace all the hardware and supply your own engine management, which is expensive. So the really cheap kit becomes expensive by the time the car is running, and makes more power.

But you obviously didn't read what I originally said thoroughly, since you're trying to make the same argument right now. You are correct about the turbine restriction, and that is what I originally said.

>>16489587
because they flow more air and burn more fuel in a given time

>>16489587
Tarbos

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>>16489572
VE is just an expression an air pump or how good the engine acts as one
Its a dank meme
>>16489587
Because power is a function of work done. Smaller engines can do more work if they spin harder OR spin faster.
Most small engines making dank power are spinning very high rpm and the big OLDs 455s of the 70s making 150hp only revved to like 2,900 rpm. A lot more work can be dont at 8.000 rpm than at 2,900 rpm
You can adjust the gear ratio and have more torque if you have more rpm to play with

>>16489601
Specifically talking about NA engines.

>>16489591
What was the main cause of them being so inefficient? A restrictive exhaust can only do so much

>>16489594
https://www.youtube.com/watch?v=ckNayDBWFi4

GReddy makes cheap shit? I though they were cool.

>>16489609
poor design
we didn't have the tools we have today to get peak efficiency and power

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>>16489609
they were not inefficient actually they were way more efficient at least compared to the big cammed 427s 429s ect of the late 60s

They had extremely small cams and were designed to lug massive cars around at 1500rpm Also transmission back then had mostly 3 speeds with a few having 4 gears.
You needed an engine with a broad powerband so reducing the RPM but making it have good power within that range was easy so they did that. Those engines had an awesome torque curve from like 800 rpm to 2,800 which was great for the shit 3 speed transmissions of the day

>>16489613

Their kit for the Civic Si is junk. Over $3k and it's non-intercooled with a tiny turbo and poorly designed manifold. Also comes with a less than ideal fuel management solution. You're paying for brand marketing with them.

>>16489641
Also when I said efficient I mean their BSFC is much better than a big cammed race engine
Basically how much fuel is being used vs how much work is actually being done.
Turbo engines are generally very poor in terms of how much fuel is burned vs how much work is done same with big cammed NA race engines

>>16489671
Got it

>>16489511
Pounds are force you retard. Grams are mass.

>>16490243
you silly fuck

>>16489070
The more power you make, the better te gear ratios can be without sacrificing torque. A 100hp car can have a good 0-60 time ife the gears are short enough, the drawback would be a top speed of 60 mph at 9000rpm

>>16489285
>doesn't know what they're torque-ing about.

I see what you did there you cheeky cunt.