Getting my 2014 R/T Supercharged
#41
I thought HP ratings -- since 1972 -- were supposed to be net, not gross meaning the HP rating is taken at the wheels not at the crank. Dodge advertises 360HP on the Hemi so I assumed the dyno would reflect that, yet it is only 268HP. As you said, that represents a 25 percent driveline loss, which is a pretty typical loss rate for most cars.
So did the manufacturers go back to gross ratings or am I missing something?
So did the manufacturers go back to gross ratings or am I missing something?
#42
I thought HP ratings -- since 1972 -- were supposed to be net, not gross meaning the HP rating is taken at the wheels not at the crank. Dodge advertises 360HP on the Hemi so I assumed the dyno would reflect that, yet it is only 268HP. As you said, that represents a 25 percent driveline loss, which is a pretty typical loss rate for most cars.
So did the manufacturers go back to gross ratings or am I missing something?
So did the manufacturers go back to gross ratings or am I missing something?
Most AWD drivetrains lose 30% or more
Most 2wd's lose about 20% so its really not that bad.
Gen 1 Durangos lost about 33%-35% hp thru drivetrain
STEVE
#43
When manufacturers made the switch from gross to net numbers they simply used a fully dressed engine with all accessories. However this also coincided with a massive power loss from manditory emissions equipment. This is why a chevy 350 in a vette went from 375hp to 155hp the next year. THANK YOU EPA
#44
#45
I thought HP ratings -- since 1972 -- were supposed to be net, not gross meaning the HP rating is taken at the wheels not at the crank...
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#46
This is a gross misunderstanding of the terms. Net differed from the gross rating because the former had the exhaust, air filter, alternator, fan, water pump and all normal accessory drives in place. The old gross hp was with all these removed. For example the old direct drive clutchless fans could suck up over 20 hp just by themselves.... .
Yeah, and pity the poor Ford -- or any manufacturer -- salesman who had to explain to customers why their new '73 Mustang 302-2V was rated at 155hp (net) vs the identical engine in a 1972 car was rated at 210hp (gross).
At the time we were told the switch from gross to net was a government mandate to ensure that customers got "accurate" information. The lower rating was also blamed on the new emissions equipment. While the emissions equipment DID reduce performance the reduction was no where near the 20-25 percent evidenced in 1973 models (55HP in the case of Ford's 302-2V).
Which makes me wonder: was the switch from gross to net a government mandate or was it simply and agreement among the manufacturers? I still don't know.
So somewhere along the line the manufacturers apparently have gone back to advertising gross HP?
#47
So somewhere along the line the manufacturers apparently have gone back to advertising gross HP?
Bottom line, if wanting to measure power differences you need to use the same dyno, same vehicle before and after installing any power adder and compare the results across the entire rpm range.
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#49