So, I did a little math on Subaru's new 2.0...

[iggyhop9]

Well, the stock FB20 is: 1995cc, 84mm bore x 90mm stroke, 10.5:1 Compression Ratio. I don't know if that helps.

[Chemist]

Yeah, so I made this graph the other day for the "Interesting" thread. Shows what torque/RPM combination(s) will produce 200 hp.



My guess will be 150 ft-lbs of torque at 7000 RPM (again, only applicable for 200 hp). Of course, it may make over 200 hp so who knows. It's definitely possible.

[Matador]

here we go again.

[nate89]

I still don't agree with that graph. No (i.c.e.) car has that torque curve. Did someone make that graph cause I'd like to know how they derived their data. It looks more like a torque curve for and electric motor than anything. I can post torque curves all day long (both real and ones I can make up) and we'll still know nothing about the engine, yet we'll continue to argue about it lol.

Edit: After looking at the graph, I assume whoever made the graph set the max power to 200hp, and calculated torque from the known rpm. If this is the case, it should have been made more clear a the beginning of the thread when it was posted. Of course even then the graph is still wrong...Power is calculated from torque and rpm ie power is dependent on torque. You have to know two before you can find the other one.

Example: The car makes 200hp. What is the rpm and torque?

Well, if the car makes 200 hp at 6000 rpm, then the torque is 175.066 ft-lbs.

If the max power is produced at 3000 rpm, then torque is 350.13 ft-lbs.

The fact of the matter is that neither torque, nor power are linear when dealing with an internal combustion engine (though there is a linear relationship between hp and torque). So again, all we're doing is guessing (and putting out false information).

[NESW20]

Originally Posted by nate89

blah blah blah

holy shit you fail.

it's a graph showing how much torque at each RPM will produce 200hp. so when we "know" we WANT 200hp, we can look at the graph and see how much torque is required at a particular RPM to achieve the desired power level. it's not reasonable for any production 2.0L n/a 4 cylinder to make 350ft.lbs, but it's entirely reasonable for it to make 130ft.lbs and rev to 8000rpm.

[overvolting]

If I asked you a question in the form of:

"Hey nate, my engine makes peak power at X RPM. I wanna hit 200HP out of this tune so I can brag to my buddies I make 200HP. How much torque should I aim for?"

It might make your life quite easy to refer to this graph.

I know algebra and maths is hard and it's for the nerds, but it is kind of a simple basic form of maths that has been used since AT LEAST 1700BC. That's almost four thousand years ago. I mean, it's like there's counting and then there's algebra and anything that's worth thinking about is kind of beyond that...

Power[hp] = (Torque [ft.lb] * RPM[w])/5252

Power*5252 = Torque*RPM

Torque = (Power*5252)/RPM

The graph simply plots Torque = (200hp*5252)/RPM

It represents more than a single car.

It represents ALL cars. ALL engines. In fact, ALL OBJECTS that can rotate and have a coupled force of 200hp.

It's a pretty big axiom.

[nate89]

Originally Posted by NESW20

holy shit you fail.

it's a graph showing how much torque at each RPM will produce 200hp. so when we "know" we WANT 200hp, we can look at the graph and see how much torque is required at a particular RPM to achieve the desired power level. it's not reasonable for any production 2.0L n/a 4 cylinder to make 350ft.lbs, but it's entirely reasonable for it to make 130ft.lbs and rev to 8000rpm.

First, way to make an ass of yourself.

Second, If we are wanting 200hp, we still don't know what torque or rpm that 200hp occurs at. In other words, we have one known, two unknowns, and one equation; which means we cannot solve the equation exactly. Read up on engines and learn some math before you post shit.

Originally Posted by overvolting

If I asked you a question in the form of:

"Hey nate, my engine makes peak power at X RPM. I wanna hit 200HP out of this tune so I can brag to my buddies I make 200HP. How much torque should I aim for?"

It might make your life quite easy to refer to this graph.

I know algebra and maths is hard and it's for the nerds, but it is kind of a simple basic form of maths that has been used since AT LEAST 1700BC. That's almost four thousand years ago. I mean, it's like there's counting and then there's algebra and anything that's worth thinking about is kind of beyond that...

Power[hp] = (Torque [ft.lb] * RPM[w])/5252

Power*5252 = Torque*RPM

Torque = (Power*5252)/RPM

The graph simply plots Torque = (200hp*5252)/RPM

I know math can be tough, but I'm an engineer and have been teaching calculus on the side for the past four years, so I'm competent in my math skills. All your equations are correct, but the thing is that the relation ship between torque and rpm is not linear. Torque varies with rpm, increasing, then decreasing. What that graph is saying is that ass rpm's increase, torque decreases, and vice versa. However, torque does not increase as rpm decreases past a certain point.

It represents more than a single car.

It represents ALL cars. ALL engines. In fact, ALL OBJECTS that can rotate and have a coupled force of 200hp.

It's a pretty big axiom.

This is incorrect for several reasons. Not all cars are the same. Not all engines have the same torque curve (in actuality, no engine has the same torque curve as another since there are slight deviations in machining and assembly-this is the reason Nissan didn't post HP numbers for their engines since it could deviate by 15hp). With spinning objects, things get more complex with mass concentrations, moments, etc.

[Snaps]

^ I said this in the other thread, and I'll say it again:

THAT IS NOT AN ENGINE DYNO GRAPH SHOWING TORQUE OF AN ENGINE.

The graph shows what combinations of torque and rpm are required to achieve 200hp (200hp is the whole curved line), using the equation:

Power = (Torque x RPM)/5252

We know all the variables we need to know too... we know how much power we want to achieve (200hp), and then we plot points on a graph according to the rpm values going from 5000 to 9000 in this particular graph, we rearrange the equation to find the torque (using substitution for the rpm values) needed to produce 200hp at those rpm points between 5000 and 9000, and then we plot them on the graph.

Once again, THIS IS NOT AN ENGINE DYNO GRAPH.

[70NYD]

yeah but we dont know when peak torque occurs.. what if peak torque occurs at 4000rpm? and then it stays virtually flat, only dropping a little.. untill it drops totaly around lets say 7000 rpm
you need the ACTUAL torque curve of the engine to get the power.. guessing doesnt do anyone good :p

[nate89]

Originally Posted by 70NYD

yeah but we dont know when peak torque occurs.. what if peak torque occurs at 4000rpm? and then it stays virtually flat, only dropping a little.. untill it drops totaly around lets say 7000 rpm
you need the ACTUAL torque curve of the engine to get the power.. guessing doesnt do anyone good :p

Thank you!

We have no idea what the specs of the engine are, so why are we arguing about it? Let wait till we hear some official news and then discuss the engine.

[Snaps]

Originally Posted by 70NYD

yeah but we dont know when peak torque occurs.. what if peak torque occurs at 4000rpm? and then it stays virtually flat, only dropping a little.. untill it drops totaly around lets say 7000 rpm
you need the ACTUAL torque curve of the engine to get the power.. guessing doesnt do anyone good :p

If peak torque occurred at 4000rpm and it was virtually flat until a rev limiter of 7500rpm, then you would only need about 150ft-lbs of torque to achieve 200hp at 7000rpm (where torque begins to drop). If Toyota can manage to pull more torque out of the engine than that (which I'm sure they will), then you don't need to rev the engine as high to get to 200, and it also means (if the torque curve stays flat) you will get a higher power at a higher rpm.

As you both said, we don't know the specs of the engine, but we can hazard a guess at them... An example: The 2011 Subaru Impreza (Using this because it's a boxer engine) - produces 170ft-lbs of torque, cut another .5L off of it and it should produce about 140 ft-lbs (without D4-S). This means that you only need to keep that figure until about 7000rpm to achieve 200hp. If you increase the torque (which D4-S will do), you don't need to rev it as far to achieve that number. I think this should be easily doable for Toyota/Yamaha.

Edit: Nate89, we're arguing because it passes the time until we get more info!

[70NYD]

Originally Posted by Snaps

If peak torque occurred at 4000rpm and it was virtually flat until a rev limiter of 7500rpm, then you would only need about 150ft-lbs of torque to achieve 200hp at 7000rpm (where torque begins to drop). If Toyota can manage to pull more torque out of the engine than that (which I'm sure they will), then you don't need to rev the engine as high to get to 200, and it also means (if the torque curve stays flat) you will get a higher power at a higher rpm.

As you both said, we don't know the specs of the engine, but we can hazard a guess at them... An example: The 2011 Subaru Impreza (Using this because it's a boxer engine) - produces 170ft-lbs of torque, cut another .5L off of it and it should produce about 140 ft-lbs (without D4-S). This means that you only need to keep that figure until about 7000rpm to achieve 200hp. If you increase the torque (which D4-S will do), you don't need to rev it as far to achieve that number. I think this should be easily doable for Toyota/Yamaha.

Edit: Nate89, we're arguing because it passes the time until we get more info!

exactly!!! hehe its fun

[NESW20]

Originally Posted by nate89

First, way to make an ass of yourself.

Second, If we are wanting 200hp, we still don't know what torque or rpm that 200hp occurs at. In other words, we have one known, two unknowns, and one equation; which means we cannot solve the equation exactly. Read up on engines and learn some math before you post shit.

you're the one who started tearing apart a decent post without understanding a SHRED of what the graph was for. i know plenty about engines, thank you. and i've done enough math in my day. you don't know a THING about me, but thanks for trying.


I know math can be tough, but I'm an engineer and have been teaching calculus on the side for the past four years, so I'm competent in my math skills. All your equations are correct, but the thing is that the relation ship between torque and rpm is not linear. Torque varies with rpm, increasing, then decreasing. What that graph is saying is that ass rpm's increase, torque decreases, and vice versa. However, torque does not increase as rpm decreases past a certain point. this is all true, however, THAT'S NOT THE POINT OF THE GRAPH. IT'S NOT A DYNO GRAPH.

This is incorrect for several reasons. Not all cars are the same. Not all engines have the same torque curve (in actuality, no engine has the same torque curve as another since there are slight deviations in machining and assembly-this is the reason Nissan didn't post HP numbers for their engines since it could deviate by 15hp). With spinning objects, things get more complex with mass concentrations, moments, etc. again, you're missing the entire concept of that graph.

you seem to be determined to be obtuse, so this will likely be my last post directed to you.

[nate89]

Originally Posted by NESW20

you seem to be determined to be obtuse, so this will likely be my last post directed to you.

That's probably for the best...:happy0180: