580 HP Dyno Tunes

[330toSRT8]

Originally Posted by SlingShot

I guess great minds think a like...

You do know the preferred method of testing is with all accessories attached to the engine. These accessories can and do include things like, water pumps, steering pumps, alternators, A/C compressors. Any electrical accessory is not included in the test, eliminating them from the equation. If the accessories are not available at the time of testing, a 85% efficiency is used to calculate the power. This power is the NET HP, that the drive train loss in calculated from.

The accessories are not part of the drive train loss. The drive train loss comes from the drive line from fly wheel to rear end.

OMG! Read it more slowly. If a car uses an electric water pump, then the engine will be more efficient. It's not as if something normally taking power is being excluded from the test, it's that the electric water pump is never taking power from the engine in this scenario. It's electric. It doesn't need a belt. Maybe I'm just crazy.

[detltu]

Originally Posted by 330toSRT8

OMG! Read it more slowly. If a car uses an electric water pump, then the engine will be more efficient. It's not as if something normally taking power is being excluded from the test, it's that the electric water pump is never taking power from the engine in this scenario. It's electric. It doesn't need a belt. Maybe I'm just crazy.

You need to read his responses more slowly.

SAE Gross Horsepower (J1995 and J245, used prior to 1972)- rated engines with open headers, no accessories and used correction factors for air temp, humidity,etc. Gross numbers varied widely and there were plenty of ways to game the system including ignition timing.

SAE Net Horsepower (J1349 used after 1972) rated engines with stock ignition timing, stock fuel delivery system, full exhaust, and all accessories. There were still ways to game the system so numbers could still be fudged.

SAE certified net horsepower (J2723 debuted in 2005) - This testing is done with all stock accessories added and is done with an SAE certified tester present and allows for no fudging of numbers. Whatever numbers are reported are what the actual engine makes. If someone pulls the LSA out of their ZL1 and tests it to L2723 specification, they will get exactly 580 hp (maybe a few hp different either way depending on the engine).


While you are correct that an electric water pump would make the engine more efficient, what you are missing is where that efficiency will show up.
The efficiency is already included in the SAE certified net horsepower. For example HP with regular pump = 570, HP with electric pump = 580.
When RWHP is measured, the difference between the SAE net hp and the rwhp is the drivetrain loss. This includes losses in the transmission, rearend, etc. It has nothing to do with the power steering.
To answer MA2010 SS's question, yes they would both have the same drivetrain loss (percentage wise). They would have a different accessory loss which would show up in the net hp.

[detltu]

Originally Posted by Camarowguy

Chevy always underrates, ford usually over rates.

If it is SAE certified, it's not over or underrated. Its the number and it can be compared between Ford, Chevy, and whoever else has their numbers certified.

When the certification came out, almost all of GM's numbers went up (proving that GM underrated their engines prior to the certification), many other companies including Toyota had their numbers go down (proving that they were overrating their engines).

Most of the changes weren't very drastic, because there is little reason to over or underate engines these days. Insurance companies don't care if your car makes 400 hp vs 426 hp. Fudging the numbers to make yourself look better against the competition would open GM or Ford up for lawsuits. The only reason I could see GM underrating engines is to prevent a Camaro from having more hp than a Corvette, but the certification pretty much prevents that.

[newb]

With that being said ( insert thread jack here) the 1LE will make more than the advertised 426hp since the LS3 was cert'd using a hydraulic PS pump. The switch to electric should free up 1-2% Hp. Correct?

[chain777]

Originally Posted by newb

With that being said ( insert thread jack here) the 1LE will make more than the advertised 426hp since the LS3 was cert'd using a hydraulic PS pump. The switch to electric should free up 1-2% Hp. Correct?

It won't "make" more horsepower, but more of the 426HP will be available to propel the car since there will be less parasitic loss. I would imagine that will apply to the SS's too, unless only the 1LE is getting the electric pump.

[newb]

But if the 426 Hp was achieved with all subsystems attached then the rating is different with electric power steering correct? With that being said, a 1LE or new SS if they all have electric power steering will make more Hp at the rear wheels than '12. Correct? Not arguing, just trying to make sense of the certification process.

BTW, I understand that true flywheel HP of an LS3 or LSA does not change given that it is what it is. We are talking parasitic losses prior to driveline loss which all affect RWHP. I am not sure everyone understands true engine hp vs parasitic loss vs driveline loss. If someone has an easy explanation please share.

[SlingShot]

Originally Posted by detltu

You need to read his responses more slowly.

SAE Gross Horsepower (J1995 and J245, used prior to 1972)- rated engines with open headers, no accessories and used correction factors for air temp, humidity,etc. Gross numbers varied widely and there were plenty of ways to game the system including ignition timing.

SAE Net Horsepower (J1349 used after 1972) rated engines with stock ignition timing, stock fuel delivery system, full exhaust, and all accessories. There were still ways to game the system so numbers could still be fudged.

SAE certified net horsepower (J2723 debuted in 2005) - This testing is done with all stock accessories added and is done with an SAE certified tester present and allows for no fudging of numbers. Whatever numbers are reported are what the actual engine makes. If someone pulls the LSA out of their ZL1 and tests it to L2723 specification, they will get exactly 580 hp (maybe a few hp different either way depending on the engine).


While you are correct that an electric water pump would make the engine more efficient, what you are missing is where that efficiency will show up.
The efficiency is already included in the SAE certified net horsepower. For example HP with regular pump = 570, HP with electric pump = 580.
When RWHP is measured, the difference between the SAE net hp and the rwhp is the drivetrain loss. This includes losses in the transmission, rearend, etc. It has nothing to do with the power steering.
To answer MA2010 SS's question, yes they would both have the same drivetrain loss (percentage wise). They would have a different accessory loss which would show up in the net hp.

Thank You !!! Finally someone that understands ...

[KKreme15]

Can we all agree that the engines aren't making 620 HP

[newb]

Absolutely agree. There will be some Hp found after a full break in but not 40hp

[b_williams_82]

Originally Posted by KKreme15

Can we all agree that the engines aren't making 620 HP

I think I can say that! Well I know I can say that!! Haha No way does it make 620hp! I just think the engine could still be a little underrated by 10 horses or so. But that's neither here not there. That's just a transfer of maybe 7-9 horses to the wheels. I just kinda figured we see rwhp around the 485's and seeing them at and above 500 just made me think a little, and maybe my percentages were wrong too!! I don't know, it just seemed like it could be possible they were underrated a little.
The 13's may have 620! Boy wouldn't that be nice!

[stymie]

I'm still following recommended break-in procedures (cough cough), but I'd just about swear that the craftsmen who built #61 tweaked it to perfection. Oh yeah, PRM-GRN has a sweet "burble", but absolutely NO popping, which kind of surprised me a bit from all the videos I've been watching.

My heartfelt thanks to the guys & gals who put my baby together... even the vendor's dark gray stripe kit to match the exposed weave CF extractors did a FLAWLESS job. She's very special!

[b_williams_82]

Originally Posted by stymie

I'm still following recommended break-in procedures (cough cough), but I'd just about swear that the craftsmen who built #61 tweaked it to perfection. Oh yeah, PRM-GRN has a sweet "burble", but absolutely NO popping, which kind of surprised me a bit from all the videos I've been watching.

My heartfelt thanks to the guys & gals who put my baby together... even the vendor's dark gray stripe kit to match the exposed weave CF extractors did a FLAWLESS job. She's very special!

Do you have pics of this?? I'd be very interested in seeing them! Thanks!

[toehead93]

It is not underated. It is not overated. There will always be some type of difference in power of each one because of so many variables and the range of acceptable tolerances in the assembly process. But please, please, please, please, please, please, please, please, please, please, please, please, stop believing that a chasis dyno is more accurate than SAE certified numbers performed on an engine dyno in a lab! I have no more hair to pull out.

GM advertises 580HP because that it how much power the engine makes in lab conidtions under SAE guidelines. All of these chasis dyno numbers and % deviations (13% here-15% there, etc) are not aywhere close to being as accurate as SAE numbers. This is not an opinion, this is a fact. Chasis dyno numbers are just another one of several pieces of imformation that we use to determine how and where a car is making power, but people who get the most out of these numbers take them with with a grain of salt and understand what they really are.

So, I beg you all to please take a deep breath and calm down the next time you read anything about dyno numbers. And for the sake of my hair please think about this before you post again.

[chain777]

Originally Posted by newb

But if the 426 Hp was achieved with all subsystems attached then the rating is different with electric power steering correct? With that being said, a 1LE or new SS if they all have electric power steering will make more Hp at the rear wheels than '12. Correct? Not arguing, just trying to make sense of the certification process.

BTW, I understand that true flywheel HP of an LS3 or LSA does not change given that it is what it is. We are talking parasitic losses prior to driveline loss which all affect RWHP. I am not sure everyone understands true engine hp vs parasitic loss vs driveline loss. If someone has an easy explanation please share.

You're right, they will make more power at the rear wheels. It's possible the '13 will be re-rated to a slightly higher number because of the electric steering, or the new exhaust. I wouldn't be surprised at all, since the '13 5.0's got a small power bump. I don't think you need an explanation of the different hp ratings, you seem to understand fine.