Can someone please explain this?
I was always under the impression that the hp rating of pre 1971ish cars were based on gross horsepower (hp at the flywheel?) and ratings from '72 and on were based on net horsepower (rear-wheel ratings?). Is this accurate?
I ask because I was glancing at the MT Dec. 2001 issue which compares the 2002 Camaro SS vrs the '01 SVT Cobra and they had a little sidebar regarding horsepower ratings. After reading it, I took it to mean that the 325 HP rating was not the rear wheel hp rating (similar for the cobra) and was actually closer to the flywheel HP or some corrected HP rating.
When did they start doing this? and if so, is my 245 factory HP rating on my '92 Z28 rear wheel or flywheel?.
Thanks

 

Your rating of 245HP is at the ffywheel and NOT RWHP.
I) Gross horsepower was the engine without any accessories or drive train.
2) Net horsepower was with accessorie to the fywheel.
This is my understanding of the two, anyone else with anything to add.

 

I was also looking at my '67-'93 Camaro White Book and in the description for the '72 model, they mention, "1972 horsepower ratings were released at "net" ratings, the power actually delivered to the rear wheels after accessories and driveline losses".
I used to drive a '72 Old with a 350 in high school and at the time, it felt pretty quick and had some good power (heck I was in high school and I never got to drive a Camaro until I was out of college and I bought my own). I recall the Old was rated at 200 HP. If that's the case, does that mean my '92 Z28 has only about the 195 to 200 rwhp (I recall seeing a .8 factor in another post).
I don't know. Maybe my definitions are still all screwed up.
If it is the case, that sure sucks, but at least it handles a hell of a lot better that the Olds.
Thanks

 

That 200 horsepower is net, and your camaro was net. So it has 45 more horsepower.

"Fast" depends on a lot of things. Weight for one.. the olds could have weighed a lot more and still the camaro is quicker with less power. There is also a big difference between your perception of fast when you were in high school and out of college. I thought my car was pretty fast until I drove a 12 second camaro.

 

z28-92
Your right 245HP x .80 drive train loss=est 196 rwhp. Your actual
RWHP can only given by a Dyno Test. You may get more or less
depending on your engine and Mods. Now are you

 

Nah, I'm not that bummed. The power on my car is what it is. I still enjoy driving it as it is more of a street /weekend cruzing car and I'll probably honestly never take it to the track. To me, it just gives me more room for inprovement
My neighbor across the street is a cop and drives a police issue 2000 camaro for his job (traffic division). He used to drive a '92 police issue prior to his current car. He tells me that the 2000 has way more power but he liked the handling of the '92 alot better. In his garage, he has a cherry 1968 SS/RS Camaro with a 396. That's his weekend play car. His daily driver is a lightly modified late model fox body Mustang. As you might guess, his garage is the local hang-out for all the guys on our street. (p.s. his neighbor just "inherited" his father-in-laws '71 Z-28 so on our street, on any given day, you'll find a 1 gen, a 2nd gen, a 3rd gen and a 4th gen camaro either in our garages or on our driveways.)At least our wives all know we're probably all together huddled over one of our cars when they can't find us. Just one of life's many pleasures.

 

No no no. Gross was the engine with no accessories and dyno facility exhaust manifolds (headers) - no driveline. Net is with all vehicle model specific accessories and stock manifolds - no driveline. The ZZ4 is rated at 355HP by Chevrolet. BUT, in a thirdgen Camaro/Firebird it only produces 308HP as rated by Chevrolet. RWHP means nothing in HP ratings.

 

I thought, I answered that question.