shevchenko

SAE new horsepower rating system
This has been discussed many times by many people already, but I want to clear up all the issues with this new standard and concerns with the power “decline” of your automobiles.
I worked as a mechanic for some time and currently studying to become a mechanical engineer.
Many people think that horsepower is horsepower, and in a way it is. It’s the measurement of power, which we took more conveniently to measure the potency of the gasoline engines in automobiles instead of Watts. There are different measurements of horsepower. There is an American horsepower (derived by using English units, such as Pound (lb), Feet (ft) and Slugs) and there is metric horsepower (derived by using metric units of the SI system: Newtons (N), meters (m) and kilograms (kg). One metric horsepower PS (PferdeStärke in German) equals to 0.9862 of American horses (hp) or 1 hp equals to 1.0139 PS.

There are different organizations that standardize the horsepower measurements:
DIN (Deuchland Istitute) – German Institute of standards
ECE – European Commission of Economy of EU
ISO – International Standard Organization
JIS – Japanese Institute of Standardization
SAE – Society of Automobile Engineers, USA
Standard ISO 1585 tries to bring all of those standards together, but the difference up to 10 percent still exists.
Power measured by DIN is 1-3 % smaller if recalculated to ECE or ISO. This explains BMW M3’s 333 PS and 325 HP, 2.5 percent difference.
There are also two different types of power: Netto power and Brutto power. Netto power is the power produced by the engine on the dynometer at the flywheel with all of the needed equipment, such as alternator, exhaust with catalytic converters and all the pulleys. Brutto power is the “laboratory” power produced by the engine, where the engine is not equipped with all the needed equipment for the vehicle operation. Typically Brutto power is 10-20 % higher than Netto horsepower.

New J1349 changes the SAE method. Old SAE standard of measuring horsepower measured the Brutto power of the engine, MINUS the calculated by engineers frictional losses on pulleys, alternator, power steering pump and thermodynamic loses of slow down of the gases by the exhaust system. Any oil level, octane number of gasoline and atmosphere conditions could be used. J1349 uses more strict methods, as the engine oil level has to be filled top level (less oil created less internal friction), octane number of fuel used has to be the same as in the manual (there is the whole story of measuring octane numbers, as well: in the USA highest octane number is 95, Europe 98, Japan 105).
The third party person, who signs off the result, makes sure that atmospheric pressure, air temperature and the octane number of fuel are at the right number.
From January 1, 2005 standard J1349 becomes mandatory. Though if the engine family does not change, manufacturer doesn’t have to change the rating based on a new system. Some manufacturers like Acura adopted the system willingly.
J1349 is just a new way of measuring the power. Honda Legend with J35A is still 300 PS, Honda Integra Type R with K20A is still 220PS, unlike RL, RSX type S and Civic SI with identical engines (290hp and 198/201 hp).

As much as I love Nissan Motors, they have a loophole.
Nissan’s famous VQ35 engine is made in Japan. This engine used in Nissan Skyline, Altima, Maxima, Infinities: G35, M35…) rates maximum of 300 hp based on JIS standard (Nissan Skyline/G35 Coupe). Converted to American horsepower from metric horsepower, from JIS to SAE, using lower octane number this number will drop. Only is the Nissan chooses to adopt the system willingly or changes from the VQ35 engine family to adopt SAE J1349 standard of measurement. I dynode 2003 Infinity G35 rwhp at Dynojet at 231.9 hp at 6200 rpm and 222.9 at 4660 rpm and 2003 Nissan 350Z rwhp at Dynojet at 241.0 hp at 6220rpm and 236.5 at 4810 rpm.

On the other hand Acura’s J32A3 is American made. There is no analogoes engine in Honda line up. So it has to conform to SAE standards. I dynode Acura TL fwhp at 219.6 hp on a Dynojet at 6250 rpm (using 98 octane fuel, 19.5 degrees Celsius and 1012 mbar atmospheric pressure) and 198.1 ft-lb at 4990 rpm.

According to Sir Issac Newton Force equals mass times acceleration. With less power Acura apparently has a superior power train if it has 5.9 second 0-60 mph acceleration weighing at 1615 kg (3499 lb) (I cant shift that fast though), while 2004 Nissan 350Z has 5.3 seconds (1515 kg), Nissan G35 sedan – 6.2 sec, coupe –5.5 sec. (1580 kg and 1600kg).

This part of the article expresses my personal opinions, based on educated guesses, but should not be read as facts, as the prior informational part.

So why change the SAE standard. If you read “sensational” article ASIANS OVERSELL HORSEPOWER by Jeff Plungis / Detroit News Washington Bureau, you noticed the absence of German cars and Nissan from the list. Nissan uses JIS standard which does inflate horsepower, as I found out from my Dyno tests of VQ35. German cars use DIN standard. Who rejoices by introducing SAE J1349? You see the answers from that table. Two of the dying Detroit’s big guns need all the help they can get. I love American cars, but by being a mechanic I learned all about the quality of GM’s and Ford’s products. This reminds me of 400 hp!!! “monsters” under the hood of the muscle cars of the 70th, which under current standards of measurements can barely make 200 horses. As an engineer I realize that J1349 is probably a better measure of horsepower, but why change? We all know that SAE is the Society of Automotive Engineers of the UNITED STATES. Draw your own conclusions, but the answer is pretty obvious. If they wanted to measure the “real” horsepower they should measure automobile’s wheel horsepower and not the engine power, which would lower the power, but show the superiority of the Japanese power trains. (I am yet to see a descent American transmission). Detroit tries to overturn the losing battle that goes on for decades, where top three passenger automobiles on the market are: Toyota Camry, Honda Accord, Honda Civiv.

Vassyliy Shevchenko

dooky211

iTrader: (1)

wow.... thats deep, good info!

shevchenko

Thank you.

chill_dog

Definitely the best post regarding the HP change I've read...thanks shevchenko!!

shevchenko

Thanks again. Ask me any questions regarding technical questions about Acuras and I will gladly answer them.

loulinjai

wow that makes so much more sense now! I was just wondering wuts the difference between american, european and japan octane since u said japan gas was rated at 105....

dalieu

nice, sometimes i wonder if i should have gone into mech engineering instead of computer engineer...

trancemission

man I feel sorry for the guy who asks this next time, I think we are all going to quote this..

dan.....k

iTrader: (1)

Good Explanation.

Trelos74

Good job shevchenko, now that's what I call a breakdown...Thanks for the info..

MichaelBenz

iTrader: (2)

Saved in favs list....your right trancemission.....their gonna see it again! Thanks! Great information and very informative. Definate keeper!

Hawhyen51

Shevchenko has provided the best explanation For the SAE HP change. Should sticky that or at least add it to the 3G Garage.

Ron A

I'm working on it. Since most of that is way over my head, I was waiting for enough people to confirm that it is as good as I think it is. With trance and MB and the others speaking up for it, I will probably put it in the 3G Garage soon.

MichaelBenz

iTrader: (2)

^^^definate sticky material or 3G Ron!

Ron A

Welcome to the newest member of the 3G Garage, #A-083

xcelir8TL

Perfect. Sticky this please.

shevchenko

Thank all of you.
To answer the question about octane numbers of gasoline in different countries, it is also based on the way you are measuring and uses same standards Japan: JIS, Europe: ECE and ISO, USA: SAE. Anything with the octane number higher than a 100 in SAE is considered kerosene and ususally used in air industry.

Technically based on my calculus calculations on C++, anything with a compression ratio higher than 11 can theoretically run gasoline 98 octane number and kerosene, without predetonation.

Technically J32A3 and VQ35 with some ECU reprograming (possibly HONDATA adopted module, recalculation of air/fuel mixture, sensor recalibration and rewiring) could run on kerosene, increasing HP up to 10 %. Work in progress...

Since I am new to these forums, what does 3G Garage means?

invincible569

That was great and definitiley opened my eyes to other makers and how they advertise HP. Dont let the Infiniti and Nissan guys read this..

shevchenko

What do you personally think about SAE J1349? Why did they change the standard?

Ron A

Sorry, you'll have to be content with being able to find it in the 3G Garage.

Besides, stickies historically get much less attention than threads in the main stream of the forum, as long as they are still active.

trancemission

SebringSilver

Frankly, any responsible car publication (or any that purports to be socially conscionable) should provide henceforth actual horsepower ratings at the wheel for all their road tested vehicles. Consumers have a right to know the truth.

HiTEC

The 3G Garage is just a collection of FAQ's for the 3rd generation TL. You'll see the sticky to the 3G garage at the top of the threads in the sticky section.

Again... nice write up!

mickey3c

Interesting that with the explanation which makes sense we are a forgetting that tires and the times reported in the mags are not always done in the same place, with the same driver, or at the same time. There is always some room for error. As for the best trannies. I seem to recall the best tranny from years back was the turbohydramatic 400... Which was a GM product. I am sure someone will correct me if I am wrong. But that was then this is now...

I am a big fan of having car manufacturers report WHP. Afterall, efficiency is what we are after. why have something you cannot use....

KilroyR1

I was with you until you editorialized.

You should ask people who bought the Mazda RX-8 about this issue (I was almost one of them). Initial quotes from Mazda reported 250 horsepower. Then when it was released it was 247 horsepower. Then, it was restated to 238 horsepower. Mazda bought back cars from unhappy owners or gave away $500 debit cards AND free maintenance for 50,000 miles. Now, with the new standard, the 2006 cars are rated at 232 horsepower.

This standard is not about helping domestic companies sell cars, it's about truth. The new horsepower standard is more accurate, plain and simple.

So please, spare us the editorial if you are trying to pass off your explanation as factual.

leeherman

Historically, the Chrysler Torqueflite (727 or 904) was probably the best automatic transmission in the industry.

The 727 was heavier and less efficient than the 904, but it was bulletproof. The 727 was used behind small and big-block V8s in cars and trucks.

The 904 was the lighter, more efficient, and less bulletproof version of the Torqueflite which was used behind some small-block V8s and slant-six cars. The 904 is still very popular today in drag racing as it can be built up to be as durable as a 727 while maintaining an advantage in efficiency.

Anyone need a 904? I've got a spare in my garage! It's perfect for that convert the TL to RWD project!!



Excellent explanation about the HP rating change! I've been getting bored with reading all the postings complaining about how the TL is less powerful for 2006, especially from those who own '04s and '05s. It's like my 2004 model is suddenly a slug. NOT!

shevchenko

Well, to me personally this change of standards is kind of ridicoulous. If SAE realy wants to make automakers present true horsepower they should introduce a standard that measures wheel horsepower at the same Dynojet in same conditions. Frictional losses of transmission, driveshaft, differential, excels and tires should be accounted for. That's just my opinion.

SteVTEC

Great post but unfortunately there are some pretty big inaccuracies that I have to point out.

First off, VQ35 engines are built all around the world including the U.S. In the states they're built at the Decherd plant and they crank out 950,000 engines per year including 3.5L 6-cylinders (VQ35DE). Also, if you look on the nissannews.com homepage you'll see that for power quotes they claim SAE J1349 standards for power and torque, not Japanese JIS or other standards. It's just a question of which version of the standard they're using, May 1995 or the newer one. For the 280hp/270tq variant it's still getting the same numbers on the "new" standard, and the VK45DE actually picked up some power. The 298/300hp variants are "suspect" though because they've not proven to be any faster, and are still only quoted on the old J1349 standards. For the Maxima variant they're still holding to the 265hp/255tq numbers on the old standards and put an asterik in that horsepower numbers would drop on new rating system but engine performance will not change. You are right though, Nissan is still attempting to exploit loopholes in language.

Secondly, chassis dyno measurements are ridiculously inconsistent and present all sorts of problems as far as rating them. Now you are dealing with rolling resistance of the tires (dependant on size), inflation pressure, issues with vehicle alignment, the car's alignment on the dyno, internal electronics (some ECUs will sense the excessive wheelspin and retard timing, or richen the mixture thus resulting in unreliable measurements), and especially cooling problems on high performance engines with just a little dinky fan blowing air. On top of that, fixed rolling inertial load dynamometers do not always load the vehicle properly based on its weight or aerodynamic drag. There's even the potential for as much as 5-7% variance in your numbers just based on how the vehicle is strapped to the dyno. Light strapping is a huge safety risk, but if they strap it down extremely tight now you have more rolling resistance and additional "loss" on the dyno. They're just not repeatable enough at this point. I agree that numbers "at the wheels" are useful to consumers, but they can also be extremely misleading as well. On a high powered heavy car with a 3rd or 4th gear run, the dyno may load the vehicle too lightly resulting in much greater acceleration rates than the vehicle would experience on an actual road in 3rd or 4th gear. The result would be lower dyno numbers due to higher intertial acceleration in the drivetrain incurring more losses when in reality the heavier weight of the vehicle and aerodynamic drag (not accounted for on passive rolling drum type inertia dynos like dynojets!) results in a much slower rate of acceleration, lower intertial losses, and much greater actual power being transmitted at the wheels.

I could go on forever, but then there are also different load conditions. How bout going up a steep hill with a full load at near WOT. Your acceleration rate is much lower, intertial losses due to acceleration of the drivetrain much lower, and you could very well see 90-95% of the SAE J1349 rated power of the engine making it to the drive wheels. SAE J1349 rated crank horsepower and torque are still very important. There are lots of issues with chassis dyno measurements that aren't commonly discussed.

As far as the 0-60 quotes, now you are getting into all sorts of things including tire selection, launch traction, suspension dynamics, gearing, and even measurement variability. 5.9 for a TL is damn good, but the G35 sedan (6.2) is actually faster than the coupe (5.5) because it's lighter and has the same exact engine. Individual quotes for 0-60's for whatever car are highly variable and depend very much on the conditions at the time of test, surface traction, and also the driver, etc. That is not a good measure of powertrain efficiency either.


Finally, the statement that the SAE is the Society of Automotive Engineers of the "UNITED STATES" could not be more untrue.

http://www.sae.org/about/

Engineers from all over the world attend SAE conferences, present and publish papers, books, and all sorts of information. I own dozens of these including a lot of Japanese papers on Hondas, Toyotas, and Nissans. Here's one on the Honda J-series V6 engines.

http://www.sae.org/servlets/productD...PROD_CD=970916

Those are not American names, except for Kenneth Lantz of Honda R&D NA.

I'm a member of the SAE and it's by far one of the BEST professional organizations out there.


As for the revised standards, I think that's a very good thing. Obviously from some of the revised figures a lot of manufacturers were playing games with the loose language in the old standards. Like running the engine on the dyno a quart low on oil due to lower internal losses as you stated, or by running higher octane fuel yet only stating that regular is required. Obviously American manufacturers benefit more, because they weren't playing games with the standards like the Japanese were. If you're Chevy and trying to sell a 3.5L V6 Malibu with 200hp, it doesn't look too good compared to a Toyota 3.0L that makes 210hp. But on the new standards the Toyota only makes 190hp, and the 3.3L dropped from 225-230hp all the way down to 210hp. Big difference. Is that really fair? uhh. no. When the language is so loose in the standard that a manufacturer can "tweak" their engines to the tune of 20+ hp differences it effectively becomes a useless standard and claimed horsepower doesn't mean jack. The revised standards bring a lot more credibility to horsepower ratings such that if a manufacturer claims a certain amount of power now you know you're actually getting it and that its definitely more or less power than another competitor on the SAME rating system. The Japanese did get a black eye on that one, but it won't affect them too much because they have too many other things going for them, like product quality and reliability, and brand reputation.


I find the comment about American transmissions to be pretty funny considering this is an Acura forum. GM Hydramatics are exceptional and also highly regarded all around the world. They're so good and have such excellent shift resonsiveness and feel that even BMW used GM 5L40Es in a lot of their Inline-6 powered cars in the late-90's and early 2000's. BMWs are also known to dyno and perform quite well given their horsepower ratings as well, even with those GM 5L40Es in them, so Americans are quite capable of building GOOD transmissions. They do built a lot of garbage ones too though, esp Ford and Dodge. But then again, so does Honda.

SteVTEC

Just wanted to follow up on some personal frustration with this.

My wife and I have a 2002 Toyota Highlander with the 3.0L 1MZ-FE engine. It was rated at 220hp @ 5800rpm, and 222 lb-ft @ 4400 rpm. My question when we bought it was, what kind of power does it make on what kind of fuel? The manual stated that only regular fuel was "required" but for "best performance" use premium fuel. Okay, so does it make 220hp on regular and 230 on premium, or is 220 the premium rating and it actually only makes 210 or something on regular? I looked and looked and looked but just couldn't figure it out.

Anyways, the SUV is a slug on regular so I figured 220hp/222tq had to be premium and that it made something far less on regular, but I couldn't get confirmation until these new standards came out. Unfortunately the variant of the 1MZ-FE in the Highlander (has twin throttle bodies) was out of production by the time the new standards came out, but the twin TB version made 10hp more than the single TB versions on the old ratings. The single TB 1MZ makes a whopping 190hp/197tq on regular fuel on the NEW ratings. So with regular in the tank, our Highlander probably puts out a whole 200hp/197tq, for a 3900 lb AWD vehicle. No wonder it feels like a slug on regular fuel. We put nothing but premium in it because it just isn't reponsive on regular.

If I knew that at the time of purchase we still probably would have gotten the HL (had the best mileage in its class at the time), but we also probably would have given much more serious consideration to other vehicles because that is pretty lame. The new standards level the playing field, don't allow manufacturers to "play games" with their power ratings and force them to tell the truth. That's a good thing, especially in a horsepower driven market no matter what make of car you're considering.

SebringSilver

Great info.

How long will it be before all manufacturers selling cars in North America will be compelled to quote horsepower figures measured using the new standard?

Actuary

um so do we think this new standard really benefits the detroit big 3?

SteVTEC

I believe all new and revised engines must be tested as per the new standards at this point. Going back and recertifying unchanged or carryover powertrains is a voluntary (not mandatory) process though.

IMO the new standards benefit anybody that wasn't fibbing, and they also benefit the consumer who is trying to make intelligent buying decisions. I've seen a lot of people trying to spin these new standards as some weak move that will only help Detroit. But the SAE is an International organization, and I could even make a strong case for the new standards helping the Germans too.

Those 255hp 3.0L Valvetronic I6's that BMW makes suddenly look a bit more attractive now that the cat is out of the bag and the TL only really has 258hp with 200c more displacement. Audi's 3.2L FSI at 255hp (and 243 lb-ft) also would benefit. As would the Mercedes 3.5L V6 rated at 268hp. All of these looked a lot worse before when the TL was rated at 270hp.

A lot of European auto companies have really been struggling and bleeding in red ink lately due to the strong Euro (bad for exporting) and also extremely high labor rates. The Tier1's have been feeling the pinch (BMW, Merc, Audi, etc) and a lot of the Tier2 and belows have been struggling just to stay in business. Saab (GM owned) and Jaguar (Ford owned) have both been doing extremely badly and only stay in business because the parent companies keep feeding them money. Last year Rover (not sold in the US, and different from Land Rover) actually shut down and went out of business. I think SAIG (shanghai automotive internationale group or something) picked up the intellectual property and then a few other companies are fighting over other parts of the company.

The global automotive industry is FIERCELY competitive. You don't want an excellent product to do badly in the market just because a competitor was "cheating" on their power ratings and you weren't. It's bad for business, bad for consumers, and bad for competition also. The playing fields need to be level.

PeteThaPitbull

im still a little confused on this issue, currently i have a 2004 tl with supposedly "270 HP", and looking into buying the new 2007 tl with supposedly "258 HP". basically the standard of measurement has changed to a more accurate measure, so if the 07 model is rated at 258 what would the 04 model be rated at with the new standard of measurement?

ffearless

258

Be-in my TL

you guys just LOVE bouncing threads around don't ya? =p

killahspoz

I wonder how many hourses does the type-s 08 model would have under the new standards. ? ( and this whole time i was braging to my lil brother my 04 TL has more horses then the new one does. )lol. hope he does'nt read this.

levon1830

286 for the TL-S.

black label

For those that don't know, acura has been using the new standard since 2006.