power ratings?

[THE EVIL TW1N]

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.

Are you even a member at SAE? have you even checked out the site or read up the complete process and tolerances the manufacturers must meet? Based on your answer, it's obvious you haven't.

Your assuming 15% which is outrageously high. MAYBE for a modern automatic. The typical manual transmission car will lose ~11-13%. Some as low as 10% with the right set up.

I will agree, engines can be underrated. They just can't be underrated and SAE Certified at the same time.

BTW, according to SAE.org, the hemi is not SAE Certified.

[GOT PSI]

Originally Posted by DGthe3

GTR: Get Transmission Replaced

No sh1t! I just saw this in another thread and it all became clear. LoL

[DGthe3]

Originally Posted by THE EVIL TW1N

Are you even a member at SAE? have you even checked out the site or read up the complete process and tolerances the manufacturers must meet? Based on your answer, it's obvious you haven't.

Your assuming 15% which is outrageously high. MAYBE for a modern automatic. The typical manual transmission car will lose ~11-13%. Some as low as 10% with the right set up.

I will agree, engines can be underrated. They just can't be underrated and SAE Certified at the same time.

BTW, according to SAE.org, the hemi is not SAE Certified.

Actually, I have a membership that expires March 31

[MerlinZero]

Originally Posted by 1982camaro

i heard the gtr is underrated at 480 hp, i heard its really 500 plus hp

Beyond not being SAE rated. they are individually cast and hand built making each one its own unique system....

They only averaged that ratings... The one that did the Nurburgring lap was dyno'd at 515HP... the one Motor Trend god was dyno'd at 550HP...

Some I've seen out at 460HP... so yeah... its all different.

[Crowley]

I'll go with #4 which is .... different dynos and different readings .. he could take that same G8 to another dyno and dyno lower .. or higher ... the good thing is that he got a baseline and can use that dyno to attempt to figure out gains of his mods ...

I do believe that there will be a certain % error in ratings .. Even if the LS3 in the G8 was certified at 415hp .. I think % error will have this rating fluctuate as well ..

I also do believe that most manual drivetrains will see around a 12% loss these days and a little higher for Automatics ..

Crowley

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.

[radz28]

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.

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.

Originally Posted by DGthe3

Actually, I have a membership that expires March 31

You're a P.E.?

[THE EVIL TW1N]

Originally Posted by radz282003

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.



You're a P.E.?

The SAE Certification process didn't start untill a few years ago (2006 I believe). That same dancing around and manipulating that worked before won't work anymore. Talk of rating at a specific/different RPM with the SAE Certification process is how rumors and wrong information is spread.

[DGthe3]

Originally Posted by radz282003

You're a P.E.?

Not yet, it is a student membership that I received for last year in order to compete in an SAE design challenge (mini Baja). But I do have membership to the Society of Automotive Engineers.

Originally Posted by THE EVIL TW1N

The SAE Certification process didn't start untill a few years ago (2006 I believe). That same dancing around and manipulating that worked before won't work anymore. Talk of rating at a specific/different RPM with the SAE Certification process is how rumors and wrong information is spread.

GM was the first to adopt it in 2005, I believe the first engine they certified with it was the LS7.

[radz28]

Originally Posted by THE EVIL TW1N

The SAE Certification process didn't start untill a few years ago (2006 I believe). That same dancing around and manipulating that worked before won't work anymore. Talk of rating at a specific/different RPM with the SAE Certification process is how rumors and wrong information is spread.

I meant to add that, but do you know if they are completely tied to listing the highest output? I mean, like my post, where the ZL1 was stated as making power at a certain RPM, it really made more power at higher RPMs. I know that SAE didn't test like this back then, but do they now? I'm asking in all seriousness, not to be difficult

Originally Posted by DGthe3

Not yet, it is a student membership that I received for last year in order to compete in an SAE design challenge (mini Baja). But I do have membership to the Society of Automotive Engineers.

GM was the first to adopt it in 2005, I believe the first engine they certified with it was the LS7.

[SoFlaZ]

Originally Posted by DGthe3

Not yet, it is a student membership that I received for last year in order to compete in an SAE design challenge (mini Baja). But I do have membership to the Society of Automotive Engineers.

I had one too. I was with the formula team, but that didn't last long as the whole program here is very disorganized and I ditched. Then I switched to a business major lol.

I think it still might be possible to get around a few things still to underrate the power, the thing we need to know is the real drive line efficiency.

[THE EVIL TW1N]

Originally Posted by SoFlaZ

I had one too. I was with the formula team, but that didn't last long as the whole program here is very disorganized and I ditched. Then I switched to a business major lol.

I think it still might be possible to get around a few things still to underrate the power, the thing we need to know is the real drive line efficiency.

if they want to underrate, the manufacturer just wouldn't certify the engine. it's as easy as that.

[THE EVIL TW1N]

Originally Posted by radz282003

I meant to add that, but do you know if they are completely tied to listing the highest output? I mean, like my post, where the ZL1 was stated as making power at a certain RPM, it really made more power at higher RPMs. I know that SAE didn't test like this back then, but do they now? I'm asking in all seriousness, not to be difficult

SAE has all the dyno's with all the related information (engine/coolant temps, oil temps, etc.) for download. They are expensive, but the information is all there.

[radz28]

Originally Posted by THE EVIL TW1N

SAE has all the dyno's with all the related information (engine/coolant temps, oil temps, etc.) for download. They are expensive, but the information is all there.

So SAE posts all of the results then? If that's the case, I understand now; yeah, it wouldn't really be possible to underrate an engine in that case.

[mp11]

Originally Posted by THE EVIL TW1N

if they want to underrate, the manufacturer just wouldn't certify the engine. it's as easy as that.

Then just what is the purpose of certifying? Is there a benefit to the car company?