How does Nissan get away with publishing those HP and TQ numbers for the Z?
#41
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I understand HP can be underrated... but people are ALWAYS claiming that BS and I almost never see real evidence that supports it... people always come up with some stupid explanation as to why and it just never makes sense... They say the new mustang GT is underrated... that's funny I run with them just fine.... they say the STI is underrated... that's funny.. I run with them just fine.... they say the EVO is underrated.... that's funny.. I run with them just fine....
I also just noticed that was also from a dynapack... which will always read higher than a typical dyno.... so that explains the inflated numbers... but still... gimmie a break...
I also just noticed that was also from a dynapack... which will always read higher than a typical dyno.... so that explains the inflated numbers... but still... gimmie a break...
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Originally Posted by CAN0802
You guys crack me up. You think this would be the first time in history that manufacturers claimed less power for a particular car? Maybe Honda did it to not overshadow their "premium" Acura. Others have been well documented cases, such as Ford, Chevy, and Dodge in the 60s and 70s lowering output numbers for insurance purposes. Ever stop to think that maybe.....just maybe, that Honda was trying to keep their published number below that magical 200hp for a reason?
#43
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Originally Posted by laswyguy
Porshce's all under rate their HP.. check out this cayman dyno.. 270 whp on the dyno, but 295 rated at the crank. Thats why they so damn fast.
http://www.caymanclub.net/topic.asp?...le=Cayman+Chat
http://www.caymanclub.net/topic.asp?...le=Cayman+Chat
![](http://www.caymanclub.net/UserFiles/dyno3(1).jpg)
Porsche jacked our wheel design!!! Or did the 35th come out after the Cayman?
A dyno is just a dyno... but even with variations in dyno, if it dyno's at the WHEELS close to what its supposed to at the CRANK, then its underrated. Bottom line.
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With a dyno one has to be careful because there are many correction factors for power conversion, altitude, air temperature to consider.
The SAE regulation for determing HP and Torque is to have a standard of all the essential and working parts of your car/engine connected to provide real-time crank power. This is to keep it fair. A civic can produce 300 crank HP if the power steering/air condition/alternator/radiator belts and components are not connected and running on the timing belt.
Yet, with the SAE requirements, the minimum number of components in place and running would yeild the HIGHEST possible HP and torque numbers for a given car and power application. With this method, the gap between - Crank HP and actual Wheel HP will be quite wide as the CHP numbers were very optimal and with little stress on the engine.
On the other hand, if the automotive manufacture runs and tests the car with maximum components running and connected, the yield gap between CHP and actual WHP will be smaller- IE Porsche- thus the UNDERRATED power cars.
Even with rather stringent standards set forth by the SAE - cars are sometimes not what they appear to be.
As a general finding across the board (this is by no means a blanket indication, but rather a general finding and observation through time)-
Japanese cars seem to have the highest Yield gap between CHP and WHP- thus OVERRATED.
While Euoprean cars seem to have the lowest yield gap between CHP and WHP- thus UNDERRATED.
Domestic cars are in between Japenese and European.
Yet, these factors tend to balance out the power curve becausae the power to weight ratio of japanese v. domestic. euoprean is still supreme that Japanese and RECENTLY domestic cars have higher PTWRs. So, even though European cars are mostly underrated with power ratings, their conservative power ratings are probably rather accurate becuase the extra power that is no rated in their numbers goes to compensate for the fact that they weigh a few hundred pounds more than Japanese cars.
Last thing.
Torque is measured
HP calculated
Given a choice, you'd probably want more torque rather than more HP- take the RX-8 for example. Not picking on it, but the torque range doesn't start until about 5000 RPM, where most of us peak in power, the RX-8 has just started to take off. At the same time, too much torque and not enough HP, will yield gains like a V12 van. It can spin tires all day and smash any car on the street for the first 0-60 ( now this is 0-60 FEET)- but after the Vtec picks up in a honda, the Van will be SOL. Left in the mud with 500 lbs/TQ but no HP.
It's a balancing act. A good measuring stick is to drive the car in all circumstances and terrains to see how it responds and drives- in traffic, on the freeway, up hills, down hills, in the wet. etc...
Cheers,
Allen
The SAE regulation for determing HP and Torque is to have a standard of all the essential and working parts of your car/engine connected to provide real-time crank power. This is to keep it fair. A civic can produce 300 crank HP if the power steering/air condition/alternator/radiator belts and components are not connected and running on the timing belt.
Yet, with the SAE requirements, the minimum number of components in place and running would yeild the HIGHEST possible HP and torque numbers for a given car and power application. With this method, the gap between - Crank HP and actual Wheel HP will be quite wide as the CHP numbers were very optimal and with little stress on the engine.
On the other hand, if the automotive manufacture runs and tests the car with maximum components running and connected, the yield gap between CHP and actual WHP will be smaller- IE Porsche- thus the UNDERRATED power cars.
Even with rather stringent standards set forth by the SAE - cars are sometimes not what they appear to be.
As a general finding across the board (this is by no means a blanket indication, but rather a general finding and observation through time)-
Japanese cars seem to have the highest Yield gap between CHP and WHP- thus OVERRATED.
While Euoprean cars seem to have the lowest yield gap between CHP and WHP- thus UNDERRATED.
Domestic cars are in between Japenese and European.
Yet, these factors tend to balance out the power curve becausae the power to weight ratio of japanese v. domestic. euoprean is still supreme that Japanese and RECENTLY domestic cars have higher PTWRs. So, even though European cars are mostly underrated with power ratings, their conservative power ratings are probably rather accurate becuase the extra power that is no rated in their numbers goes to compensate for the fact that they weigh a few hundred pounds more than Japanese cars.
Last thing.
Torque is measured
HP calculated
Given a choice, you'd probably want more torque rather than more HP- take the RX-8 for example. Not picking on it, but the torque range doesn't start until about 5000 RPM, where most of us peak in power, the RX-8 has just started to take off. At the same time, too much torque and not enough HP, will yield gains like a V12 van. It can spin tires all day and smash any car on the street for the first 0-60 ( now this is 0-60 FEET)- but after the Vtec picks up in a honda, the Van will be SOL. Left in the mud with 500 lbs/TQ but no HP.
It's a balancing act. A good measuring stick is to drive the car in all circumstances and terrains to see how it responds and drives- in traffic, on the freeway, up hills, down hills, in the wet. etc...
Cheers,
Allen
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Originally Posted by roast
I'll call BS on that guys post just the same. You're going to go with some jokers dyno numbers over what the manufacturer claims? First of all, it's the internet, and second of all it's a DYNO!! You really think he's making more at the wheels than his car is even supposed to have at the crank?? That's a MIGHTY big under-rating. Think about it. 205hp at the wheels... let's say 15% drivetrain loss... thats edit:240hp at the crank.... from a 4 bangin 2 liter...
Uh huh.... I'll have some of what you're smoking.
Uh huh.... I'll have some of what you're smoking.
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Yeah my Z was underrated too. It's putting down 300whp stock. Yeah it's believable...S2000's with 4 bangers have 240 crank hp, add 2 cylinders..you figure it out...360 at the crank! Just give me a minute to make a dyno sheet from my Windows Paint program.
I WILL RAPE A STOCK SI. Even if his B.S. #'s were correct, he's still got only 140 tq...that ain't hsit.
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Originally Posted by pecora55
Any of you guys have any of these dynos? Would love to see them...
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Originally Posted by CAN0802
You guys crack me up. You think this would be the first time in history that manufacturers claimed less power for a particular car? Maybe Honda did it to not overshadow their "premium" Acura. Others have been well documented cases, such as Ford, Chevy, and Dodge in the 60s and 70s lowering output numbers for insurance purposes. Ever stop to think that maybe.....just maybe, that Honda was trying to keep their published number below that magical 200hp for a reason?
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Some people are just igonorant about what they call ricers and 4 bangers. Ever hear of an S2000 2.0 liter with 240hp at the crank. I love my Z but, but I am also a honda fan.
Roast is bringing all sorts of brilliant insights to this thread. Value has been added to my day. ::sarcasm::
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BTW, the dynapack attatches to the wheel so there is no contact loss like with a typical dyno, hence the inflated numbers.
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Originally Posted by CAN0802
You guys crack me up. You think this would be the first time in history that manufacturers claimed less power for a particular car? Maybe Honda did it to not overshadow their "premium" Acura. Others have been well documented cases, such as Ford, Chevy, and Dodge in the 60s and 70s lowering output numbers for insurance purposes. Ever stop to think that maybe.....just maybe, that Honda was trying to keep their published number below that magical 200hp for a reason?
IMO the new Si has the same exact engine as the new 210hp RSX-S (obviously), but right down to the ecu and it's programming
That's not the first dyno I've seen pushing over 190 at the wheels but this one had intake and exhaust mods. Video, charts, original baseline, step by step mod install documented etc. Others see more conventional numbers - a lot posted at clubsi.com.
I almost bought one - had a deposit down 2 or 3 months before their initial release.
Finally came to my senses and realized if I was going to drop 22-23K on it, why not dig a bit deeper and move up to a 350Z?!
No regrets - but would still like to take a new Si for a nice long spin.
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Last edited by Todd-350Z; 04-30-2006 at 01:06 AM.
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By the way, it was the 1999 Cobra Mustang. Ford underestimated the power. Because of the bad publicity, Ford recalled the car to improve HP. Also Ford did not make a 2000 cobra (except for the "R") probably because of this reason. Ford now has a third party test the performance of their vehicles so the data is correct the first time. The '03-'04 cobra is rated a 390 fly wheel hp but actually dynoed at about 365-370 rwhp stock. That brought the fly wheel power to more than the Z06 at the time. Probably around 420 fwhp.
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