In Europe, it is standard to measure the engine output (some say crank HP), which is roughly speaking wheel horsepower plus powertrain loss. In the US people measure whp.
So how is the power loss measured?
Many dynos just calculate the power loss, which is inaccurate. Only few dynos, such as our MAHA dyno, really measure the power loss. Therefore, directly after the wheel horsepower measurement, a coast down test (deceleration test) is conducted. This test measures the power loss accurately. Naturally, several factors affect the power loss (e.g. AWD or how firm the vehicle is fixed on the dyno). Anyway, comparing the results of different dynos is vague. Only a real before-and-after comparison under exactly the same circumstances creates reliable results. Moreover, please keep the standard factory model variation in mind. A stock Stinger does not necessarily have exactly the same power output as another stock Stinger.
I really appreciate the information and am learning more everyday, however I'm slightly confused by this explanation. Sorry in advance for the long response, but I'm a perfectionist and just want to clearly understand as many facts as possible.
My understanding is that it is standard for all manufacturers to directly measure engine output(crank HP), since they test the engines before installing them into the chassis. However, since "engine dynos" are rare and few people pull an engine out to run further tests, "chassis dyno's" are widely used everywhere. I believe all of these measure WHP so I'm unclear where Racechip or others in Europe would be directly measuring engine/crank HP?
If I'm not mistaken the MAHA dyno you reference is also a chassis dyno and it too measures wheel HP. Your description sounds like it actually measures WHP and then drivetrain efficiency in order to make a calculation of engine output/crank HP, correct?
If so, then any confusion simply lies in the use of terminology. It sounds like you may have intended to describe the standard "unit of measure" in Europe is engine output or crank HP, not that its standard to measure the engine output or crank HP? If this is correct, then its the same standard in the US as it is in Europe. Engine output/crank HP/brake HP, SAE HP, Net HP, etc., are all standard units of measure, but are much more difficult to provide accurately without an "engine dyno."
I'm sure the MAHA dyno is more accurate than the estimated 15-20% drivetrain loss most use as a rule of thumb, but its still not directly measuring engine power. This is why most tuners use and generally compare WHP.
I do agree comparing different dynos is vague, and the best way to see accurate modification results is with a direct comparison on the same dyno. I also understand the standard deviation between production vehicles, but for general comparisons both of these would only account for 2-3% variation of HP/TQ. Although nobody can provide a 100% direct comparison of different tunes I believe most people will be happy with only a few % difference in tested HP numbers.
Lastly to clarify, are you saying the 444HP in the dyno test you listed above is true engine/crank HP, or WHP+tested drivetrain loss to determine HP?
Either way this is very impressive and sorry for the lengthy message trying to clarify. Thanks in advance and I look forward to your responses.
Here is one example from another thread, "430 WHP and 463 lbs.ft of Torque (64 kg.m) with a dual chip and an exhaust from 343whp 376 lbs.ft before the tune". Thats about 520-540HP, and insane is an understatement!
