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Old 06-18-2013, 03:31 PM   #51
GrumpyPitbull
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As Mrkyle3 stated above, with upgraded suspension the late model WRX and STI feel almost exactly the same on a track.

The STi does not have some magical properties due to the red STI emblem, nor the obvious performance increases it did in previous years. Its a WRX with LSD, 6 spd, bigger wheel bearings, brembos, all black interior, and better factory suspension and TMIC. The engine internal differences are so small as to be completely irrelevant. This has been proven many times on the recent models.

Most of us know the differences between the cars I stated above, yet these threads continue to fester because some people think that red STi badge adds 40hp .... It doesn't. Its been proven several times that the two models dyno the same, and have an almost identical power curve. Some attribute it to more drivetrain loss in the STi, others to the WRX being under rated. Either way, they are about the same in the power department.
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Old 06-18-2013, 03:40 PM   #52
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Originally Posted by GrumpyPitbull View Post
Most of us know the differences between the cars I stated above, yet these threads continue to fester because some people think that red STi badge adds 40hp .... It doesn't. Its been proven several times that the two models dyno the same, and have an almost identical power curve. Some attribute it to more drivetrain loss in the STi, others to the WRX being under rated. Either way, they are about the same in the power department.
So because they have the same whp on a dyno, you think they have the same whp on the street in all scenarios, even when the drivetrain inertia, which influences whp, isn't a factor?

The STI just magically can hit 158mph, while the WRX can only muster 142mph, but they 'must' have the same whp on the highway because they have the same whp on a dyno.

Maybe this is a better anology, picture a bucket loader on a dyno... the whp will be read waaay lower than crank because what you're measuring is the acceleration of the rollers, which is being hindered by the acceleration of the masssssively heavy wheels, flywheel & entire drivetrain.

Now picture that bucket loader towing something, steady state drivetrain, power passing straight through. HUGE power making it out the wheels, doing work, because it's not being robbed by /invested into the dynamics of the system.

These scenarios exist in cars, like overcoming wind resistance, increasing elevation, etc and crank hp will play a bigger factor because drivetrian loss is playing less of a factor. And dynos cannot account for it. Crank horsepower is real power in the right scenario.

Last edited by blehhh; 06-18-2013 at 03:59 PM.
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Old 06-18-2013, 04:28 PM   #53
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Quote:
Originally Posted by blehhh View Post

So because they have the same whp on a dyno, you think they have the same whp on the street in all scenarios, even when the drivetrain inertia, which influences whp, isn't a factor?

The STI just magically can hit 158mph, while the WRX can only muster 142mph, but they 'must' have the same whp on the highway because they have the same whp on a dyno.

Maybe this is a better anology, picture a bucket loader on a dyno... the whp will be read waaay lower than crank because what you're measuring is the acceleration of the rollers, which is being hindered by the acceleration of the masssssively heavy wheels, flywheel & entire drivetrain.

Now picture that bucket loader towing something, steady state drivetrain, power passing straight through. HUGE power making it out the wheels, doing work, because it's not being robbed by /invested into the dynamics of the system.

These scenarios exist in cars, like overcoming wind resistance, increasing elevation, etc and crank hp will play a bigger factor because drivetrian loss is playing less of a factor. And dynos cannot account for it. Crank horsepower is real power in the right scenario.
It's governor limited to 142. People have reported in the 150s after removing the governor.
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Old 06-18-2013, 04:36 PM   #54
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Originally Posted by blehhh View Post
The STI just magically can hit 158mph, while the WRX can only muster 142mph, but they 'must' have the same whp on the highway because they have the same whp on a dyno. .
Not sure why you keep bringing this up. Top speed has literally nothing to do with the power the motor creates. Top speed is purely dependent on gearing (at this level of performance we aren't talking about land speed record cars). And again, they DO have the same power on the freeway as they would on a dyno. I don't know why that's so hard to grasp that dynomometers calculate power post drivetrain and rolling resistance loss.

Keep arguing what you want about crank hp, because where it matters is at the wheels.

Last edited by sc00by4life; 06-18-2013 at 04:46 PM.
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Old 06-18-2013, 04:52 PM   #55
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Quote:
Originally Posted by blehhh View Post

So because they have the same whp on a dyno, you think they have the same whp on the street in all scenarios, even when the drivetrain inertia, which influences whp, isn't a factor?

The STI just magically can hit 158mph, while the WRX can only muster 142mph, but they 'must' have the same whp on the highway because they have the same whp on a dyno.

Maybe this is a better anology, picture a bucket loader on a dyno... the whp will be read waaay lower than crank because what you're measuring is the acceleration of the rollers, which is being hindered by the acceleration of the masssssively heavy wheels, flywheel & entire drivetrain.

Now picture that bucket loader towing something, steady state drivetrain, power passing straight through. HUGE power making it out the wheels, doing work, because it's not being robbed by /invested into the dynamics of the system.

These scenarios exist in cars, like overcoming wind resistance, increasing elevation, etc and crank hp will play a bigger factor because drivetrian loss is playing less of a factor. And dynos cannot account for it. Crank horsepower is real power in the right scenario.
I get what your trying to argue regarding the crank horsepower, but what I'm telling you is that the STi probably does not have 40 more crank horsepower than the WRX on the 2011+ models. I don't buy the STi is losing 40 more hp over the WRX in drivetrain loss .. I think the WRX is under rated.

As Scooby4life stated, the top speed difference is about gearing, not that magical STi badge power.

Anyways, believe what you like .. but the factual evidence does not support your belief. The STi has become a "track pack" handling upgrade to the WRX, and its not the massive upgrade it used to be.
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Old 06-18-2013, 05:15 PM   #56
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Originally Posted by sc00by4life View Post
Not sure why you keep bringing this up. Top speed has literally nothing to do with the power the motor creates. Top speed is purely dependent on gearing (at this level of performance we aren't talking about land speed record cars).
Top speed is power-related if you literally don't have enough power to travel at a faster rate due to the wind & rolling resistance. Gearing comes into play, but if properly geared, a vehicle can match the power available with the power required.

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Originally Posted by sc00by4life View Post
And again, they DO have the same power on the freeway as they would on a dyno. I don't know why that's so hard to grasp that dynomometers calculate power post drivetrain and rolling resistance loss.

Keep arguing what you want about crank hp, because where it matters is at the wheels.
I'm literally saying that interia drivetrain loss, which influences the whp reading on a dyno, varies with the driving scenario, therefor the whp you see on a dyno is not always what you will experience on the street. Bringing it back around the sti vs wrx debate, it is conceivable that those different levels of drivetrain loss that make them have 'equal' whp may or may not be relevant in all scenarios.

Lighter wheels, flywheel, driveshaft, etc might all spin up a lot quicker than an STI's bulky drivetrain, resulting in more whp, but when that inertia is not a real factor, like when you're already doing 80mph and only asking for another 20mph, that whp gain / inertia advantage will no longer be relevant.

Last edited by blehhh; 06-18-2013 at 05:24 PM.
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Old 06-18-2013, 05:33 PM   #57
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Why's so hard to understand that whp is what counts here?

The WRX has a speed limiter. That's why it can't go any faster. It can do lower 150s without the limiter. The gearing of the STI really isn't that much of an advantage because 6th isn't geared much deeper than 5th on the 5MT.

If the STI was truely the faster car, we'd see it in the acceleration numbers. From 0 to 120mph, both cars post very similiar numbers, many of times of which fractionally favor the WRX.
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Old 06-18-2013, 05:41 PM   #58
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Why's so hard to understand that whp is what counts here?
Why is so hard to understand that dyno whp doesn't always translate into real-world whp?

The drivetrain losses that account for the whp aren't always relevant.

Last edited by blehhh; 06-18-2013 at 05:46 PM.
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Old 06-18-2013, 05:42 PM   #59
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Wait, the seat warmers are different in the 11+ WRX Limited and STI Limited?
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Old 06-18-2013, 05:49 PM   #60
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Originally Posted by blehhh View Post

Top speed is power-related if you literally don't have enough power to travel at a faster rate due to the wind & rolling resistance. Gearing comes into play, but if properly geared, a vehicle can match the power available with the power required.
Note part about land speed cars. The motor is not the limiting factor between the two.


Quote:
I'm literally saying that interia drivetrain loss, which influences the whp reading on a dyno, varies with the driving scenario, therefor the whp you see on a dyno is not always what you will experience on the street. Bringing it back around the sti vs wrx debate, it is conceivable that those different levels of drivetrain loss that make them have 'equal' whp may or may not be relevant in all scenarios.

Lighter wheels, flywheel, driveshaft, etc might all spin up a lot quicker than an STI's bulky drivetrain, resulting in more whp, but when that inertia is not a real factor, like when you're already doing 80mph and only asking for another 20mph, that whp gain / inertia advantage will no longer be relevant.
The sti experiences more drivetrain loss and is a couple hundred pounds heavier than the wrx.
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Old 06-18-2013, 06:06 PM   #61
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Blehhh. Engineer here. I understand what you're trying to say, it's just that you are incorrect in this case. The WRX and STi actually have very similar power levels no mater which way you want to measure it. They just do, as shown in the real world. Also, note that the 142 mph top speed of the WRX is electronically limited, not drag limited. If the difference between the two was as pronounced as you're claiming, then using the relationship of aerodynamic drag power being proportional to velocity cubed, then if 265 hp can only 142 mph, then that would mean that the STi would have to be putting down 364 hp to hit 158, which we all know is incorrect. If there really was a 40 hp difference between the two cars (which there's not) then at 150 mph, 40 hp equates to an 8 mph higher top speed.
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Old 06-18-2013, 06:25 PM   #62
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Blehhh. Engineer here. I understand what you're trying to say, it's just that you are incorrect in this case. The WRX and STi actually have very similar power levels no mater which way you want to measure it. They just do, as shown in the real world. Also, note that the 142 mph top speed of the WRX is electronically limited, not drag limited. If the difference between the two was as pronounced as you're claiming, then using the relationship of aerodynamic drag power being proportional to velocity cubed, then if 265 hp can only 142 mph, then that would mean that the STi would have to be putting down 364 hp to hit 158, which we all know is incorrect. If there really was a 40 hp difference between the two cars (which there's not) then at 150 mph, 40 hp equates to an 8 mph higher top speed.
I'm an engineer as well. The top speed was a bad example. I didn't know they were electronically limited. I haven't done the math in years, but a lot of cars are actually drag limited given their power levels. And many cars have to be in lower gears to achieve their top speeds because in their top gear the engine isn't making enough power to overcome the drag at the given speed, at the geared rpm.

And the power to speed relationship is squared, so it does take exponentially more power.


While I'm not sure if the empirical differences are substantial, there is a conceptual difference in whp measured on a dyno under acceleration, and the whp actually put down in a steady-state system, in which drivetrain inertia is not a factor.
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Old 06-18-2013, 08:40 PM   #63
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Originally Posted by GrumpyPitbull View Post
I don't buy the STi is losing 40 more hp over the WRX in drivetrain loss .. I think the WRX is under rated.
Apparently so:

http://forums.nasioc.com/forums/show....php?t=2071237
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Old 06-18-2013, 09:45 PM   #64
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Originally Posted by blehhh View Post
.

And the power to speed relationship is squared, so it does take exponentially more power.
Wrong.

Drag FORCE is proportional to the square of velocity. Drag POWER is proportional to the cube of velocity.

You're simply misinformed in this situation, that's all.
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Old 06-18-2013, 10:41 PM   #65
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Wait, the seat warmers are different in the 11+ WRX Limited and STI Limited?
Lmao, but yes, this?
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Old 06-18-2013, 10:48 PM   #66
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Wait, the seat warmers are different in the 11+ WRX Limited and STI Limited?
I believe the STI uses a multiple level warmer similar to the Legacy and the WRX uses a 2 level warmer similar to the Forester.
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Old 06-19-2013, 12:58 PM   #67
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Wasn't this thread revived regarding a seat question?
Yes, yes it was. But don't let that stop people from highjacking a thread for two pages and then others for coming in and b!tching about redundancy.

Thanks to all who replied about the seats!
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