what does "to the wheels" mean???

xcaliber264

New Member
I recently stated my car (an estimate) has about 160 horsepower and someone said to me yea but not to the wheels..... I have no idea what this means I thought it might be a reference to torque but wasn't completely sure so I kept my mouth shut. I know torque, up, and vehicle acceleration are 3 different things so If anyone can clarify what "to the wheels" means. Any help would be appreciated.
 

dc2GS-R

Super Moderator
Vehicles are rated by the manufacturer as horsepower at the crankshaft. It doesn't not compensate for drivetrain losses due to friction, inefficiency and the weight of rotating parts. Power to the ground is the amount of power that is actually transferred to the pavement at the wheels as measured by a chassis dyno

For example, the G3 Integra GS-R is rated at 170hp by Acura. It typically puts down about 150hp at the front wheels on a chassis dyno.
 

TegSox

Super Duper Moderator
Yep, power "to the wheels" is the power actually making it to the ground after a chunk of it is taken away by the transmission, mainly. Car companies list the power an engine makes right at the crankshaft because it's a bigger number than the actual wheel HP rating, for marketing purposes.
Most car amplifier companies do the same type of thing for marketing purposes when they announce their amplifier makes 1000 watts in an advertisement, when that is merely a peak wattage rating, and the actual wattage is 500 RMS watts. The RMS rating is a much more meaningful number as to what the amp can do, but the bigger 1000 watt number makes people go oooh and aaahh.
 

heykosal

Angkorian
In addition to what Barry says, don't forget that automakers strap the engines to engine dynos minus all of their ancillary accessories. So in addition to the driveline losses experienced, the manufacturer advertised power number is further degraded by our luxuries.
 


dc2GS-R

Super Moderator
Don't forget that SAE also revised the method of calculating horsepower ratings in 2006 to show more accurate numbers. Hence the reason the 2005 RSX Type S is rated at 210hp while the 2006 RSX Type S is rated at 201hp.

The same reason that my new car was advertised with 330hp during it's introduction but came to showroom floors with only 306hp.
 

dc2GS-R

Super Moderator
heykosal said:
So you got the IS??? WHere are the picssss?
Click to expand...
They're coming. I'm sparing everyone the typical crappy cell phone pics. I'm going try and get some time to use the D40x we have at work.
 


You must log in or register to reply here.
Top