SteVTEC

I posted this at Maxima.org yesterday, but since people seem confused here too I'll copy-pasting here also.

Since this has been confusing to a lot of people, and Nissan/Infiniti still has a mix of rating systems in use, here is some real quick basic information.

SAE J1349 JUN 1995 = OLD
SAE J1349 AUG 2004 = NEW
SAE J2723 = cerftified = "voluntary" and based on top of J1349

http://www.sae.org/certifiedpower/details.htm

About SAE J1349 Certified Power

Power and torque certification provide a means for a manufacturer to assure a customer that the engine they purchase delivers the advertised performance. This SAE Standard has been written to provide manufacturers with a method of certifying the power of engines to SAE J1349 or SAE J1995. Document SAE J2723 specifies the procedure to be used for a manufacturer to certify the net power and torque rating of a production engine according to SAE J1349 or the gross engine power of a production engine according to SAE J1995. Manufacturers who advertise their engine power and torque ratings as Certified to SAE J1349 or SAE J1995 shall follow this procedure. Certification of engine power and torque to SAE J1349 or SAE J1995 is voluntary, however, this power certification process is mandatory for those advertising power ratings as "Certified to SAE J1349".

SAE Engine Rating Standard Prevents Numbers Fudging (an article on how GM will use SAE J1349 Certified Power, AEI May 2005, Vol 113 No.5, p 59 )

General Motors has become the first manufacturer to certify an engine's power and torque ratings using a newly adopted SAE standard (J2723), James Queen, GM Vice President, Global Engineering, announced during his keynote address at the SAE World Congress and Exhibition in April 2005. The world's largest automaker plans to certify all of its engines to the voluntary standard, and is encouraging its competitors to do the same. The LS7 engine for the 2006 Chevrolet Corvette Z06 was certified under the new standard this month. The 7.0-L V8 unit produces 505 hp (377 kW) at 6300 rpm and 470 lboft (637 Nom) at 4800 rpm. "The new voluntary SAE power and torque certification procedure ensures fair, accurate ratings for horsepower and torque as it uses third-party certification," said Queen. "SAE technical standards level the playing field, and this certification procedure is just the latest example of the value SAE has offered over the past century." To tout power and torque ratings as "SAE-certified," engine manufacturers must have an SAE qualified witness watch over the entire testing procedure to ensure that it is conducted in conformity to SAE standard J1349. Third-party witnessing is the main provision of J2723. An existing SAE standard, J1349, spells out how the actual testing is to be done. J1349 was updated last year to eliminate some ambiguities that allowed engine makers to cite power and torque ratings higher than the engine's actual capabilities. Engine makers are free to cite power and torque figures drived from testing conducted outside the scope of the SAE standards, but they may not claim the figures are SAE-certifed. "We feel that both the consumer and industry are well served by having accurate, consistent ratings from all manufacturers," said David Lancaster, a Technical Fellow in GM Powertrain and Chairman of the SAE Engine Power Test Code Committee that updated J1349 and wrote J2723. Data from a wide array of parameters (e.g., air:fuel ratio) will be collected during testing conducted to the SAE standards. SAE will create a database and offer it to industry in different packages and at different price points.

By Patrick Ponticel


So far ONLY GM is making it a point to officially "CERTIFY" their engine's power ratings across the board. DCX has done so but only on the 8.3L Viper engine. You can see the documentation below. And the whole "certification" process is entirely optional to begin with. Using the "NEW" standard (J1349 AUG 2004) is mandatory, however on all new or updated powertrains. Nissan and other manufacturers have gotten away with using older ratings since if you do not change the engines you are not required to restate the numbers. You MUST use the new standard on any new or updated powertrains though.

http://www.sae.org/servlets/epcdAppl...PAGE=epcdIntro



PLEASE DO NOT SAY that SAE J1349 AUG 2004 is "OLD". That is wrong period. It is in fact the NEW standard. J2723 simply tells a manufacturer how they go about officially "certifying" an engine.



2007 G35: http://www.nissannews.com/infiniti/2...35/specs.shtml

LexFather

Can car makers basically ignore getting a 3rd party for the accurate newer rating and just say to heck with being SAE certified?
I wonder would the consumer care?

Thanks for the explanation

SteVTEC

The extra certification step is and always was "optional." SAE J1349 AUG 2004 is what's required. J2723 "SAE certified" is really going the extra mile, and it's also an enormous expense for manufacturers which is why it's optional. And the Germans can still use their DIN specs too. This is just tightening up the SAE specs.

I don't think anybody will really care if things are officially certified or not, but it'd be nice to see especially on pricier high dollar cars. I read an article that said it'd also be useful for people in the tuning world who want to get credibility for their performance modifications and especially turbo/supercharger systems. If "Joe Blow S/C Systems" is offering an S/C for a car and claims 300hp, and then "Racetek S/C Systems" has a similar S/C for the same car that also claims 300hp but theirs is officially "SAE certified" then who has more credibility? So it offers incentive to people in the tuning world to actually certify their power ratings since it could give them a big marketing advantage.

spwolf

did GM actually retest all of their car with new sae ratings?

SteVTEC

Yes they did, and they're also going the extra step of certifying the engines too.

At least in GM's case, they had very legitimate reasons for doing that as well from a marketing perspective. Toyota was fibbing so big on their engines, the MZ V6 engines in particular, that the Camry which was rated at 210 hp went all the way down to 190hp on the new standards. OTOH, the Chevy Malibu which is the direct competitor to the Camry was rated at 200hp even on their 3.5L V6, and actually went up to 201 hp I believe on the revised/certified standards.

So to somebody looking at the Malibu and Camry, they see the Camry's 3.0, think it's great that it makes 210 hp from only a 3.0L and wonders why Chevy can only get 200hp out of a larger 3.5L engine (import fanboy flawed HP/L logic). But the reality is the Malibu 3.5 makes MORE power than the Camry does, not less. Suddenly the Malibu becomes a lot more attractive, especially considering that it also has more torque (220 vs 210), and gets better fuel mileage also (23/32 mpg from a V6 on the Malibu, vs 20/28 mpg on the Camry.

DOHC, VVT-i, 5AT, smaller engine? Where'd all the power and efficiency go? Especially with all that "advanced" technology?


Good thing Toyota got their GR engines when they did.

LexusLuver

No GM did not rerate their old engines. But they were accurate so it really doesn't matter.

hp debates are a waste of time. What only matters is acceleration #'s provided by magazine comparos.

LexusLuver

Honda and Toyota rerated all engines.

SteVTEC

Not only did they re-rate a lot of their new engines, but they also officially certified them with J2723.

http://www.sae.org/servlets/epcdAppl...PAGE=epcdIntro

You cannot certify the engines on the old standards, so yes they did re-rate a lot. Some of these were new, but many were carryover.


I'm not going to touch your mag racing comment. Yes I agree that when it comes down to it actual acceleration is what matters, but there can be just as much fibbing going on in mag times as there was in previous SAE ratings. But that's a whole nother thread.