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Originally Posted by DGthe3
You don't understand engineers very well, do you? They say that the fastest way to get something done is to tell an engineer its impossible. Its a game for both sides. The SAE creates the rule book to even out the playing field. But like any other rulebook, its a paperback not chiseled in stone. There are ways to bend it which ever way you want. The manufacturers will try and get around the test procedure (in many cases, they help to write the procedure) and engines will be under rated (or over rated as the case may be). Then a new procedure will be created and the cycle will continue.
For reference, the 5.7L hemi in the Challenger (370 crank hp rating) dynos at about 335 to the wheel. The LS3 in the G8 has dyno'd 370 to the wheel (415 crank rating). This is approximately a 10% driveline loss. One of three this is going on here:
1. Those engines were unsually strong
2. They have very low drive line losses
3. They're under rated.
I'm leaning towards #3 because if you assume the standard 15% driveline loss from the 'regular' versions (390 hp Hemi, 436 hp LS3) you get . . . 332 and 371 which within error margin of what they dyno'd at.
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I remember reading the way GM used to get around certifications was to not referrence power at the power peak but lower. For example, I believe the ZL1 was rated by GM at 430 horse' at 5800 (for example) but it actually came closer to 500 at like 6500. I can't find the literature on-line (I think I have it in a
Hot Rod article from back in the day, but it goes along what DG' said. I mean, the LS3 will make what GM certifies it to make at that RPM, but it could make more.
Quote:
Originally Posted by DGthe3
Actually, I have a membership that expires March 31
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You're a P.E.?