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Discussion Starter #1
Has anyone had the opportunity to drive a Honda K20A2 based Spyder vs a stock 1ZZ Spyder. Mostly interested on how each pulls up to 4000 rpm, or beyond for that matter.

Also interested in Honda vs 2ZZ.

All comparisons appreciated.
 

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Anything below lift is essentially the same for the 1zz vs 2zz, just FYI
 

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k is significantly more. always. 2zz is more comparable to a b18 only far less reliable and vastly more expensive to use.
 
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Has anyone had the opportunity to drive a Honda K20A2 based Spyder vs a stock 1ZZ Spyder. Mostly interested on how each pulls up to 4000 rpm, or beyond for that matter.

Also interested in Honda vs 2ZZ.

All comparisons appreciated.
I removed a healthy 1zz and swapped a K20a2 into my 2003. Huge difference at all engine speeds, but when lift kicks in on the K, the feeling is just incredible. My K is stock with headers, 2.5 custom exhaust, CAI, Hondata, and RSX 6-speed.

If you compare the power curve of the 1zz to any new engine, you can calculate the % difference in acceleration you will feel at any engine speed. The difference will be precisely the % difference in Power at any rpm, not Torque. Let me emphasize, the torque differences will not tell you anything. this is why: Power or Torque? – Roth Automotive Science

Dave
 

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Dave, I am surprised by your Power or Torque? analysis.

Power is the rate of performing work, or the rate of energy transfer, which is a very important metric that connects the various engineering fields together, but it is not mutually exclusive from torque or velocity in rotating machines.

You cannot have a high HP engine without increased torque (rotational force at the wheels) at a given RPM. Torque is measured directly and many dyno's use this value either directly or indirectly when creating the performance curves.

IMHO, a nearly flat torque curve is where its at for a performance car, while trucks need increased torque at the low end.

Just thought I would throw a little water on your fire. 😁
 

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Power is everything. You can increase torque with gearing but not power.
LOL, power cannot be generated in a wheel without torque... These metrics are not mutually exclusive, therefore power cannot exist in your car without torque since they are directly proportional to each other...
 

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Discussion Starter #10
Simplist answer is, if you have to ask then you haven't driven a k. There is no comparison.

Personal MR-S experience: 1ZZ, K20, K24
Actually I haven't driven a normally aspirated K, just a turb'd version. I asked the question because I'm trying to figure out how much difference is there between a 1ZZ (or 2ZZ), before the K20 starts making boost (~ 3300 rpm). From the different responses, sounds like a lot of difference.

Thanks to everyone for their insights.
 

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Discussion Starter #11
LOL, power cannot be generated in a wheel without torque... These metrics are not mutually exclusive, therefore power cannot exist in your car without torque since they are directly proportional to each other...
You all seem to understand the concept of 'power' better than I do. When I look at a dyno sheet, I get a pretty good sense of how a car will perform and 'feel' based on the HP and torque curves. How does 'power' factor in relative to interpreting a series of dyno runs?
 

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You all seem to understand the concept of 'power' better than I do. When I look at a dyno sheet, I get a pretty good sense of how a car will perform and 'feel' based on the HP and torque curves. How does 'power' factor in relative to interpreting a series of dyno runs?
Power (watts) = torque (N-m) x angular velocity (radians/sec)

or HP = (RPM x Torque (lb-ft)) / 5,252

So, calculations are simple.
 

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Discussion Starter #13
In pragmatic terms, does calculating power, help in tuning a car? When I view HP and torque curves I can infer certain things about how to improve aspects of performance. Does calcualting 'power' help in a practical way?
 

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You can change performance (power at the wheels) with gearing since the car is not just an engine. The only way to increase engine power is to improve the combustion process in the engine - air, fuel, spark, etc... Power (joules/sec) is a byproduct of these physical changes and not a metric that is directly measured.
 

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Only at the flywheel. The drive ratio to the rear wheels increases torque substantially but doesn't change the power one little bit. If you have an engine that makes double the power but only 50% the peak torque you can simply reduce the final drive ratio to make up for the loss of torque and still have double the power.
 

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"Torque" has become a metonym for the type of tune the engine has. A "high torque" engine that has a large peak torque relative to peak power also has a rather blunt tune. That means that it has a relatively broad power peak, it is not picky about exactly which gear it is in, and it may launch well. An engine with a high ratio of peak power to peak torque has a very peaky power curve. It will be picky about which gear it is in, and will underperform its power rating if it is not in the right one.
 

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Discussion Starter #17
I think of torque as the ability of a vehicle to perform work and hp is how rapidly the vehicle can perform that work. A sports car that operates at high rpm may have high hp but low torque. A pickup truck that can pull stumps out of the ground may have lots of torque but low horsepower. Of course these are both boundary conditions.
 

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Torque is just force. You can multiply it with a lever. Horsepower is power which is the ability to do work, which is force over time. Certainly some high power lower torque engines are peaky but not all. Most important factor is the area under the power curve between the shift points.
 

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HP is just a number that relates energy to time or joules/second.

81583

Lets examine the picture HP definition.

Horse A is 1 HP horse and can move a 550lb object 1ft in 1s.
Horse B is 1 HP horse and can move a 55lb object 10ft in 1s.
Horse C is 1 HP horse and can move a 5.5lb object 100ft in 1s.

All three horses have the same HP rating and can theoretically perform the same work, but in reality, they are all quite different.

HP is a derived term that looses its meaning without knowing the details of the numbers that created it.

You can argue all you want about the great HP number, but ponder this -> Everything has the capability to produce energy but nothing is energy. So the rate of energy conversion is meaningless without knowing the details related to the specific conversion.
 

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Only at the flywheel. The drive ratio to the rear wheels increases torque substantially but doesn't change the power one little bit. If you have an engine that makes double the power but only 50% the peak torque you can simply reduce the final drive ratio to make up for the loss of torque and still have double the power.
Power at the flywheel is a theoretical value and will be zero if no work is being performed. Once the engine is connected to a load, power can be calculated since Linear Force or Torque and Linear Velocity or Angular Velocity can be measured. Once these variables are known, a specific HP value can be determined at a specific operating point.

If your assumptions were correct, I could measure HP in first gear and it would be exactly the same as HP measured in high gear but this is not true since the work would be quite different.

The Dyno operator puts in corrections for the final gearing, the drivetrain losses, and other small variables all in an effort to predict HP but since the HP readings are dependent on torque and velocity, the only accurate reading will be what is measured at the wheels, which is a torque and velocity reading.
 
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