I was talking to a guy at work who's really into cars and has had several Vettes of different styles over the years. I was telling him about my mods and the guesstimates about how much HP I've picked up. When he asked me how much HP the C5 now has stock, I said 350 at the block, since that's the rating Chevy always puts out. But, he told me that when that number is stated, that it's referring to and based upon RWHP, and that most auto makers went to that convention of specifying HP years ago. Well??? :confused: :confused: :confused:

Also, to keep the HP theme going, from what I understand from what I've done with the Blackwing, power duct, and PRT's, I've picked up about 25 HP. Did I really pick up that much or more or less? Whatever I picked up, say the 25 HP, was that a 25 HP gain at the rear wheels, or the block???
:confused: :confused: :confused:

Thanks, and remember, "There's no such thing as a stupid question. Just stupid people asking questions." :lol: :D :lol:

 

350hp not rwhp....and you picked up 25hp not rwhp if even that much...

 

He's wrong. The 350 HP that Chevy states is SAE Net BHP (brake horse power) and is measured at the crank with all accessories attached and exhaust system in place. With your mods, you probably only picked up 16 BHP, which will be less than that at the rear wheels.

 

I agree.... Way back when (1971 or 1972 - I forget?) the powers that be changed the way automobile horsepower was measured. In the old days it was measured at the motor, with no accessories ( no alternator, a/c power steering...). So the mighty 427 cube v-8 put out 435 hp (this was "gross hp")
Then after the change, horsepower was still measured at the engine, but with all accessories attached - that same 427 would measure something like 390 hp (this was "net"), this obvioulsy reduced the advertised horsepower rating. Today car makers still use the "net" horsepower. Rear Wheel horsepower is a measure taken at the rear wheels, you literally run the car on a big roller system called a dyno that measures horsepower. While this is the most practicle way to measure horsepower to the road, it is really only used in the aftermarket and by tuners or hot rodders. For example your Vette has a claimed net horsepower of 350, it would have about 390 hp gross, but only around 300 hp at the rear wheels or RWHP. (obviously these numbers are estimates and each car is uniquq, and my conversion from net to gross is an estimate but you get the idea)


[Modified by Ragtop_Rob, 7:47 AM 4/4/2003]