SAE HP testing methods
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09-22-2016, 08:02 AM
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#2
09-25-2016, 12:09 AM
The engine is fully dressed, breathing through the full intake/exhaust systems with all accessories on the front of the engine in place and operating on its designated computer. Horsepower is measured at the flywheel, not the rear wheels.
Keep in mind, it takes horsepower to overcome the frictional losses in the transmission and differential. There may also be some loss turning the hubs on a full floating axle.
When I taught as Sequoia Institute (defunct now), we had a road speed simulator for transmissions. While it didn't apply a load, it was useful to see if the automatic transmissions/transaxles would shift correctly and to verify pressures. It was powered by a Datsun (Nissan) A12-1200cc engine. When a C6 or a TF727 would shift 2 to 3, the motor had to be under throttle or it would almost stall out. If the shift was slightly out of sequence and the 2nd gear band would release too slow, the motor would stall regardless.
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09-25-2016, 07:50 AM
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SAE horsepower testing is all done to the same standards by all the manufacturers.
The engine is fully dressed, breathing through the full intake/exhaust systems with all accessories on the front of the engine in place and operating on its designated computer. Horsepower is measured at the flywheel, not the rear wheels.
Keep in mind, it takes horsepower to overcome the frictional losses in the transmission and differential. There may also be some loss turning the hubs on a full floating axle.
When I taught as Sequoia Institute (defunct now), we had a road speed simulator for transmissions. While it didn't apply a load, it was useful to see if the automatic transmissions/transaxles would shift correctly and to verify pressures. It was powered by a Datsun (Nissan) A12-1200cc engine. When a C6 or a TF727 would shift 2 to 3, the motor had to be under throttle or it would almost stall out. If the shift was slightly out of sequence and the 2nd gear band would release too slow, the motor would stall regardless.
The engine is fully dressed, breathing through the full intake/exhaust systems with all accessories on the front of the engine in place and operating on its designated computer. Horsepower is measured at the flywheel, not the rear wheels.
Keep in mind, it takes horsepower to overcome the frictional losses in the transmission and differential. There may also be some loss turning the hubs on a full floating axle.
When I taught as Sequoia Institute (defunct now), we had a road speed simulator for transmissions. While it didn't apply a load, it was useful to see if the automatic transmissions/transaxles would shift correctly and to verify pressures. It was powered by a Datsun (Nissan) A12-1200cc engine. When a C6 or a TF727 would shift 2 to 3, the motor had to be under throttle or it would almost stall out. If the shift was slightly out of sequence and the 2nd gear band would release too slow, the motor would stall regardless.
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09-25-2016, 01:14 PM
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09-25-2016, 01:17 PM
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09-25-2016, 01:33 PM
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#7
09-25-2016, 01:33 PM
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#8
09-25-2016, 01:45 PM
There may have been a change. More research would be needed, but it's a start.
"U.S. automakers continue to use SAE net ratings, but in 2005, the SAE issued a new standard, J2723, which clarified and amended the existing methodology, among other things requiring that a suitably qualified independent observer be present during the rating procedure."
Understanding Gross Versus Net Horsepower Ratings - Ate Up With Motor
"U.S. automakers continue to use SAE net ratings, but in 2005, the SAE issued a new standard, J2723, which clarified and amended the existing methodology, among other things requiring that a suitably qualified independent observer be present during the rating procedure."
Understanding Gross Versus Net Horsepower Ratings - Ate Up With Motor
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