I thought HP measurements have been SAE since the early 70's which meant the dyno readings were taken at the rear wheels.

 

The SAE has put in new regulations that require that all engine manufacturers do their ratings while under the same conditions. So there's no chance of someone testing under conditions suitable to make more power. They must also report the exact hp/tq they get. So no rounding or under/over rating.

BTW, just to make sure you're clear. SAE stands for Society of Automotive Engineers. Its not just a name for a rating or requirement.

 

So what are the conditions that SAE requires? I always figured it's been the same all this time, at the drive wheels. That's one reason I was always amazed at the HP ratings of today's cars.

If the new engines are rated at a higher HP than the gross HP ratings of the 60's AND they are supposedly net (SAE as I called it) HP, then they must be extremely powerful compared to the old engines.

 

See here for definitions of gross, net, and SAE certified (about 3/4 down):
http://en.wikipedia.org/wiki/Horsepower#SAE_horsepower

All are measured at the crank. Not sure what the conditions are exactly for SAE certification.

 

GM has a long history of using milder, more fuel efficient versions of the same basic engine when teamed with automatic transmissions in the F-body. The thinking is basically, the people who buy automatics aren't the "hard core" crowd. If they can trim a few HP that the non-hard-core buyers won't miss and pick up some fuel economy, that helps them with CAFE standards. They sell a LOT more automatic trans cars than they do manual trans cars, so it makes a difference when you're selling tens of thousands of them.

I can buy the technical explanation that cylinder deactivation technology isn't a good match for a manual trans. Makes perfect sense to me. But you know that whiz-bang valvetrain technology can't be cheap. And there is only one reason it exists in the first place- fuel economy. If that wasn't on the table and that technology didn't even exist, I can imagine an alternative scenario where you'd be seeing the automatic trans cars getting the 6.0L engine and the manual trans cars getting the 6.2L. Fuel economy is a big consideration for GM on a car like this that they intend to sell a lot of.

 

HP has never been rated at the wheels. The only time you get that is when they're put on a dyno by individuals.

Net ratings started in 1971 and were universal in 1972. Differences in ratings varied widely. A big contributor was intake and exhaust. A big 455 with a single exhaust could lose 100hp or more from gross to net, but with a dual exhaust and non-restrictive intake, maybe only 50hp.

Then some engines were underrated and others were overrated.

Still, the top engines from 1970 would probably be around 375hp under today's system. But there were very few of those sold. A 440/4 barrel in 1970, which was the highest performance Mopar engine sold in high volume, produced around 310 net hp.

 

Doesn't make Sense yet.

 

You mean you don't understand why 2 v8s?

Simple. They don't want a guzzler tax on the Camaro. With the 6 speed, you can activate the 1-4 skip shift to avoid that. On the auto, you can use AFM.

No one has gotten AFM to work smoothly with a manual, so you won't see that one offered there. They won't offer the non-AFM on the auto, because who'd want to pay a $2000 gas guzzler tax for 22 more hp? But maybe Chevy will offer that in the future as a special edition.

 

Not sure if this is going to be the case , I guess time will tell . I think mod vs. mod , the L99 will make more power because it has VVT , so as you mod it , you can control the VVT with tuning and we should be able to make more power ultimately with this platform as you start modding becasue of this . I have done all the testing with the G8GT in development for AFM camshafts and what needs to be done to make them work still utilizing the AFM , even though the G8GT does not have VVT , I have seen how beneficial this can be , the L99 is going to be very similar and I can't wait to get into it .

Mike

 

Not sure if they still do this, but in the late 70's(last hp rating I looked up that had it explained) they had dyno'd the engine and the rating was at the tail shaft of the transmission with all accessories installed. This was on a 79' Formula with the 403 Olds that was rated at like 175 hp or something rediculous.

 

They're all rated at the flywheel- even in 1973. They switched from SAE Gross to SAE Net ratings, but both were always at the flywheel. Gross was with open exhaust & intake, no accessories and (often) optimized tuning. Net was a lot closer to "as installed" with air cleaner, full exhaust, spinning all accessories, factory tuning, etc. But they were always rated at the flywheel. Doesn't mean they didn't cheat in other ways (picking specific RPMs for the published numbers, rather than listing the peak numbers, for example).

In recent years they tightened the specs even further (plus some other changes to how HP was measured and under what conditions) because certain "foreign" competitors were using setups for testing that were fairly far from "as installed," but still within the old rules. Quite a few "foreign" engines lost 10-15HP from their ratings while the Z06 Corvette actually benefited from them, getting a small bump from 500HP to 505HP.

 

185! Zoom!

If you lived in a low altitude state that wasn't California, you could get a Pontiac 400 with 220hp.

Emission controls strangled those engines, in spite of what the sticky topic in this forum might say.

 

I'll probably get the 400hp motor w/ auto tranny just for gas reasons. We never know when the gas prices will go up again, so having that AFM will be nice to have while at the same time having a 400hp motor to stomp on.

 

so are they callin the auto a l99 or ls3 n do u think insurance will be diff if u have a l99 compared 2 the ls3

 

si, d auto s l99 n stk s ls3