Do car manufacturers rate their horsepower and torque by the wheels or crankshaft?

[Zone47]

I know back in the day with the old rear wheel drive cars and no accessory load, it was measured as crankshaft horsepower but moving forward, I found an interesting video from Hondata where they run a wheel horsepower baseline on a non-modified FL5 type R and it exceeded the factory ratings. Padding the factory numbers is nothing new but it's surprising how much additional power a stock type R makes over the factory ratings (unless this is a differently tuned Euro version)?? (I'll include screen shots at the bottom).

So this sort of answers my next question which is; when you buy a tune that is rated for so much horsepower and torque, are they talking about wheel horsepower or crank horsepower? After seeing the video I have to assume whp, but some tuners don't always say ... or maybe I missed it?

325 wheel horsepower is incredible as is 360 ft lbs of torque!!

Here is the video:

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[Jester04]

I know back in the day with the old rear wheel drive cars and no accessory load, it was measured as crankshaft horsepower but moving forward, I found an interesting video from Hondata where they run a wheel horsepower baseline on a non-modified FL5 type R and it exceeded the factory ratings. Padding the factory numbers is nothing new but it's surprising how much additional power a stock type R makes over the factory ratings (unless this is a differently tuned Euro version)?? (I'll include screen shots at the bottom).

So this sort of answers my next question which is; when you buy a tune that is rated for so much horsepower and torque, are they talking about wheel horsepower or crank horsepower? After seeing the video I have to assume whp, but some tuners don't always say ... or maybe I missed it?

325 wheel horsepower is incredible as is 360 ft lbs of torque!!

Here is the video:

Manufacturers rate at crank, I got 356whp and 368tq out of mine with just a intercooler and a tune at the wheels. On the stock tune the car made around 290whp.

If you check out my thread there is a bunch of info.

 

[Zone47]

Manufacturers rate at crank, I got 356whp and 368tq out of mine with just a intercooler and a tune at the wheels. On the stock tune the car made around 290whp.

If you check out my thread there is a bunch of info.

Alright, thanks!

 

[AZCWTypeR]

Manufacturers rate at the crank. SAE provides a specific procedure that manufacturers are supposed to follow in regard to losses from accessories, water pump, etc. and the test engine is supposed to be representative of typical build vs. a blueprinted prototype.
Twenty years ago Honda was called out for optimistically rating HP by a USA auto company and most Honda cars were derated a few HP the following year.
Now Honda wheel horsepower often comes close to crank ratings on some dynos. Rule of thumb used to be about 15% difference between crank and wheel HP.

 

[Pekingduck]

unless if it German. For some reason their claim horsepower is very close to or exceed whp. I notice this to be a trend with turbo cars though. It really annoy me when I watch car video showing anything but German car against a non German car with similar power and the German car kills the other.

 

[Zone47]

Manufacturers rate at the crank. SAE provides a specific procedure that manufacturers are supposed to follow in regard to losses from accessories, water pump, etc. and the test engine is supposed to be representative of typical build vs. a blueprinted prototype.
Twenty years ago Honda was called out for optimistically rating HP by a USA auto company and most Honda cars were derated a few HP the following year.
Now Honda wheel horsepower often comes close to crank ratings on some dynos. Rule of thumb used to be about 15% difference between crank and wheel HP.

If you watched that dyno video at the top, I don't quite understand something>

They are bolting the Honda's hubs directly to the dyno. The car has all it's accessories connected along with transmission losses, yet the baseline run is showing 325hp and 360 ft lbs of torque. They must have some sort of transmission and accessory loss calculation to arrive at those numbers.
If this is the case, why the higher than advertised numbers? Is this a ROW car and does Honda tune the ROW cars hotter than the USA cars?

And then wheel horsepower is simply the rubber tires on a roller without any losses calculated out... that's my guess anyway.

I've never had a car dyno'd, so trying to get up to speed with the latest. Thanks.

 

[Clark_Kent]

If you watched that dyno video at the top, I don't quite understand something>

They are bolting the Honda's hubs directly to the dyno. The car has all it's accessories connected along with transmission losses, yet the baseline run is showing 325hp and 360 ft lbs of torque. They must have some sort of transmission and accessory loss calculation to arrive at those numbers.
If this is the case, why the higher than advertised numbers? Is this a ROW car and does Honda tune the ROW cars hotter than the USA cars?

And then wheel horsepower is simply the rubber tires on a roller without any losses calculated out... that's my guess anyway.

I've never had a car dyno'd, so trying to get up to speed with the latest. Thanks.

Chassis dynamometers are tuning tools. Nothing more, nothing less. Comparing numbers on this dyno, to that dyno, to this car or that car is an exercise in futility. The numbers in a vacuum mean absolutely nothing. Some dynos read "higher", some read "lower".

The dyno in the video posted above is a Dynapack. It measures mechanical power via the vehicle's hubs unlike a DynoJet, Mustang, or Maha that uses a roller interface. Again, the intended purpose is a test and measurement tool for tuning, period.

 

[Jester04]

If you watched that dyno video at the top, I don't quite understand something>

They are bolting the Honda's hubs directly to the dyno. The car has all it's accessories connected along with transmission losses, yet the baseline run is showing 325hp and 360 ft lbs of torque. They must have some sort of transmission and accessory loss calculation to arrive at those numbers.
If this is the case, why the higher than advertised numbers? Is this a ROW car and does Honda tune the ROW cars hotter than the USA cars?

And then wheel horsepower is simply the rubber tires on a roller without any losses calculated out... that's my guess anyway.

I've never had a car dyno'd, so trying to get up to speed with the latest. Thanks.

So adding to what @Clark_Kent said.

They are a tool and no 2 dyno’s can be compared so chasing numbers is a pointless endeavor. Whatever dyno you choose the best way to do it would be to get a baseline some dyno’s read higher than others. As long as you can get a delta tuning the car and see the difference that is all that matters.

Virtual Dyno racing is pointless and anybody that tunes these cars and sells tunes if you try to dyno the car at a different dyno you will get a different reading from advertised.

Most hub dyno’s read higher since they don’t have the weight of the wheel added. Some people calibrate it better than others. But like I previously stated baseline and tuned should be all that you need. But people get blinded by numbers. They see ahh this tune makes 390whp when it reality a lot of factors come in when you get on a dyno and realistically the chances of replicating the numbers are slim.

 

[Zone47]

So adding to what @Clark_Kent said.

They are a tool and no 2 dyno’s can be compared so chasing numbers is a pointless endeavor. Whatever dyno you choose the best way to do it would be to get a baseline some dyno’s read higher than others. As long as you can get a delta tuning the car and see the difference that is all that matters.

Virtual Dyno racing is pointless and anybody that tunes these cars and sells tunes if you try to dyno the car at a different dyno you will get a different reading from advertised.

Most hub dyno’s read higher since they don’t have the weight of the wheel added. Some people calibrate it better than others. But like I previously stated baseline and tuned should be all that you need. But people get blinded by numbers. They see ahh this tune makes 390whp when it reality a lot of factors come in when you get on a dyno and realistically the chances of replicating the numbers are slim.

Yeah, I get the baseline and tuned off the same dyno, where you'll get the delta and know the gains during a particular session. Too bad there isn't any kind of gold standard to calibrate these things, then again there is temperature, humidity, quality of fuel and other variables from day to day. Thanks for your answer, it makes good sense.

 

[Higgs Boson]

Manufacturers are using steady state power ratings where they hold the RPM, take the measurement and move to another data point then form a curve based on these steady state points.

Using a dyno at a shop is a sweeping pull across the RPM range and on turbo cars always reports higher figures than steady state measurements.

None of these manufacturers are sandbagging, the testing methods are just different (aside from crank vs whp).

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