what is the difference between BHP and RWHP

what does bhp stand for? buliding horse power?

 

Brake Horsepower... goes back to the days when hp was measured at the flywheel with a torque-wrench-type device (as best as I understand it).

Rear Wheel Horsepower... always less than BHP because power is robbed on its way to the rear wheels by the tranny, ring/pinion, etc.

 

i see... then how come on magazines some people put hp and other put bhp

 

because the brake horse power value is higher and looks better

just playing with numbers

 

Brake horsepower was a term commonly used before the 1970s in the US, and is still common in the UK. It indicates the brake, the device for measuring the true power of the engine. Stating power in 'bhp' gives some indication this is a true reading, rather than a calculated or predicted one. However, several manufacturers started to strip their engines of essential ancillaries for the purposes of getting a high horsepower figure to use in marketing the car.

hp (SAE)
In the United States the term fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use "hp (SAE)" to indicate the power of the engine, given that particular car's complete engine installation. This may also be stated as "SAE net hp" or simply "net hp".

 

so i was reading road and track and it said the new GT 500 puts out 475 bhp... that trasnlates to how much hp and how much rwhp?

 

Like I said, it's hard to know if the 475 bhp was done with or without the ancillaries.

RWHP will have drivetrain loss of 12-15%. So if we take 15% off the 475 you would get 413 rwhp.

 

considering the mustang ran 12.9 in the 1/4 mile that seems a bit high 415rwhp

 

yeah, but what kind of traction issues did it have?

could have been a 12.9 at 120mph....

and is it an IRS? cause those absorb more hp than standard rears. if you figured a higher number like 20% (probably overkill) the hp numbers at the wheels is more like 380. still high for the track time, but again...traction?

 

If they are selling it by advertising it at 475 HP with a referenced SAE standard, its got to be rated in terms of "SAE net", as explained in the post a few above. That's a requirement set by the government. The test procedure for the "SAE net" standard was recently adjusted, resulting in a small gain in rated HP for some US cars (e.g. the new Z06 increased from 500HP to 505HP SAE net), and a decent reduction in HP for several Japanese cars. Use of the newer SAE J1349 standard, in place of earlier SAE standards is voluntary.

Some additional info:

http://www.sae.org/certifiedpower/details.htm

 

true.... ill have to check out the mph....