Harley measures engine torque at the crank, right?

If a stock 114 measures 119 lbs-ft @ 3000 RPM at the crank, how is parasitic loss determined to get an approximation of rear wheel torque?

 

they display "corrected rear wheel" on their Stage Kits compared to Stock

 

It's a shell game with them. What does that mean and how is it calculated?

 

They pick a number they think the customer would like to see...

 

I'm not sure how they calculate it, but there are lots of dyno sheets out there showing around 106-107 TQ at 3K RPM for a stock 114. That's observed I suppose.

 

No its not a shell game. Corrected rear wheel torque or HP simply means its adjusted to standard temp, humidity and barometer conditions so dyno runs at different places and times can be compared for the same setup. For instance, a dyno run at sea level will produce more torque then the same engine dyno'd at 5500 ft altitude.
Here is some more info, this is standard practice at reputable dyno shops.
"SAE J1349 is the current gold standard of dyno testing and represents the newest widely accepted industry standard correction factor. Reengineered in 1990 (yeah, a long time ago), the SAE correction factor standardizes temperature to 77-degrees F, 29.23inHg and dry, 0-percent humid air."

 

hellifino..I simply showed their display..they do run good though

EDIT: well got curious so did some searching

here's what HD uses

ENGINE TORQUE TESTING METHOD J1349

here's what SAE says about that..what it all means I'll need to defer to the experts here..it's all farble garble blah blah blah yada yada yada mumbo jumbo to me

https://www.sae.org/standards/develo...rtified-power/

About SAE J1349Ž Certified Power

Power and torque certification provide a means for a manufacturer to assure a customer that the engine they purchase delivers the advertised performance. This SAE Standard has been written to provide manufacturers with a method of certifying the power of engines to SAE J1349Ž or SAE J1995Ž. Document SAE J2723 specifies the procedure to be used for a manufacturer to certify the net power and torque rating of a production engine according to SAE J1349Ž or the gross engine power of a production engine according to SAE J1995Ž. Manufacturers who advertise their engine power and torque ratings as Certified to SAE J1349Ž or SAE J1995Ž shall follow this procedure. Certification of engine power and torque to SAE J1349Ž or SAE J1995Ž is voluntary, however, this power certification process is mandatory for those advertising power ratings as "Certified to SAE J1349Ž".

SAE Engine Rating Standard Prevents Numbers Fudging (an article on how GM will use SAE J1349Ž Certified Power, AEI May 2005, Vol 113 No.5, p 59 )

General Motors has become the first manufacturer to certify an engine's power and torque ratings using a newly adopted SAE standard (J2723), James Queen, GM Vice President, Global Engineering, announced during his keynote address at the SAE World Congress and Exhibition in April 2005. The world's largest automaker plans to certify all of its engines to the voluntary standard, and is encouraging its competitors to do the same. The LS7 engine for the 2006 Chevrolet Corvette Z06 was certified under the new standard this month. The 7.0-L V8 unit produces 505 hp (377 kW) at 6300 rpm and 470 lboft (637 Nom) at 4800 rpm. "The new voluntary SAE power and torque certification procedure ensures fair, accurate ratings for horsepower and torque as it uses third-party certification," said Queen. "SAE technical standards level the playing field, and this certification procedure is just the latest example of the value SAE has offered over the past century." To tout power and torque ratings as "SAE-certified," engine manufacturers must have an SAE qualified witness watch over the entire testing procedure to ensure that it is conducted in conformity to SAE standard J1349Ž. Third-party witnessing is the main provision of J2723. An existing SAE standard, J1349Ž, spells out how the actual testing is to be done. J1349Ž was updated last year to eliminate some ambiguities that allowed engine makers to cite power and torque ratings higher than the engine's actual capabilities. Engine makers are free to cite power and torque figures drived from testing conducted outside the scope of the SAE standards, but they may not claim the figures are SAE-certifed. "We feel that both the consumer and industry are well served by having accurate, consistent ratings from all manufacturers," said David Lancaster, a Technical Fellow in GM Powertrain and Chairman of the SAE Engine Power Test Code Committee that updated J1349Ž and wrote J2723. Data from a wide array of parameters (e.g., air:fuel ratio) will be collected during testing conducted to the SAE standards. SAE will create a database and offer it to industry in different packages and at different price points.

 

I agree, and I understand.

However, look at the 114 engine torque as published by Harley - 119 lbs-ft @ 3000 RPM

Now look at the chart posted by MJ. - 110 lbs ft @ 3000 RPM (Corrected)

If Harley wants me to believe that the parasitic loss is only 9 lb ft of torque from crank to rear wheel, I have a hard time with that. That's why I said it's a shell game with them, or if you prefer, it's marketing trickery.

 

I think I got it...

 

it's simple really, just multiply EPA AFR 14.7:1 by PI 3.1415926535