BHP - Asia & Conti rides are different ?

[Contax]

I was reading thru some post and realise that the way Jap's and Kor's calculate their car bhp are different from conti car maker.

 

Japs/Kor = base at crank

conti = base on wheels .

 

Is it true and why the different ?

[Caravan]

Shouldn't be lah. You check out those overseas car websites(fifth gear, edmunds, honestjohn, etc) their specs quite similar to ours(for the same cc). If there is a diff, i'm sure the websites will put. JDM specs sometimes a bit higher cuz maybe they have higher RON fuel there and it's tuned for those fuel?

Anyway at crank and wheel is very big difference. Can't be Jap and Kor so far behind in technology right?

[Silver_blade]

Depend on the source of the info. Like what Caravan said...if you got your source from european media eg. 5th gear, Autocar, etc...then the BHP should be the same. But in s'pore, we do not have a common standard...should there might be difference in how the bhp is calculated like what you have said.

Edited July 3, 2007 by Silver_blade

[Contax]

Sorry , I did not phrase it correctly.

 

I understand that Brake horsepower (bhp) is the measure of an engine's horsepower without the loss in power caused by the gearbox, generator, differential, water pump, and other auxiliary components.

 

Thus the prefix "brake" refers to where the power is measured: at the engine's output shaft, as on an engine dynamometer. The actual horsepower delivered to the driving wheels is less.

 

Therefore , are all Jap's and Kor's measure their car bhp at crank as oppose to conti car which measure their's at wheels ?

[Yeobh]

Depending on the std used. In Japan they maybe using JIS, Germany using DIN and some makers maybe using ISO

[Elfenstar]

No lah. They're all taken at the crank. Just that euro makes tend to be very conservative with their figures. As our other bro said, JDM and export jap cars have different power levels due to the tune being different to suit japanese fuel.

[Ahbengdriver]

The thing to take note is some marques tend to understate their BHP numbers for strategic marketing reasons.

 

BMW is one of them. For example, the 335i is marketed at 306BHP doing 0-100kmh at 5.5 secs. However, I ve read that some tests done independently have clocked 4.8 sec and a much higher BHP.

 

I think there are few reasons:

- to maintain a reasonable gap between 2 models so that people who pay for their more exp model dont feel cheated

- to allow for mid model facelift 'upgrade'

- BHP(at crank) is not a big deal in the end, as many may believe. Its how much BHP ends up at the wheels

[Zcold]

the other day.. i was browsing thru some car mag tink was autocars.... read 1 article....

 

audi (tink was the RS4) had the highest negative difference between quoted and actual HP (tink tested by the mag ppl)...

while mazda MPS has the highest positive difference between quoted and actual.... +7% more in actual....

 

contrary to popular belief...

 

anyone saw the mag? ... i might have misread some fine print...

[BlueSi]

I was reading thru some post and realise that the way Jap's and Kor's calculate their car bhp are different from conti car maker.

 

Japs/Kor = base at crank

conti = base on wheels .

 

Is it true and why the different ?

 

Brake horsepower (bhp) is the measure of an engine's horsepower without the loss in power caused by the gearbox, generator, differential, water pump, and other auxiliary components. Thus the prefix "brake" refers to where the power is measured: at the engine's output shaft, as on an engine dynamometer. The actual horsepower delivered to the driving wheels is less. An engine would have to be retested to obtain a rating in another system. The term "brake" refers to the original use of a band brake to measure torque during the test (which is multiplied by the engine RPM and a scaling constant to give horsepower).

 

hp (SAE)

 

In the United States the term "bhp" fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use hp (SAE) to indicate the net power of the engine, given that particular car's complete engine installation. It measures engine power at the flywheel, not counting drivetrain losses.

 

Starting in 1971 automakers began to quote power in terms of SAE net horsepower (as defined by standard J1349). This reflected the rated power of the engine in as-installed trim, with all accessories and standard intake and exhaust systems. By 1972 U.S. carmakers quoted power exclusively in SAE net hp. The change was meant to 'deflate' power ratings to assuage the auto insurance industry and environmental and safety lobbies, as well as to obfuscate the power losses caused by emissions-control equipment.

 

SAE net ratings, while more accurate than gross ratings, still represent the engine's power at the flywheel. Contrary to some reports, it does not measure power at the drive wheels.

 

Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines show a variance of anywhere from 40 to 150 horsepower. The Chrysler 426 Hemi, for example, in 1971 carried a 425 hp gross rating (often considered to be underrated) and a net rating of 375 hp.

 

SAE-certified horsepower

 

In 2005, the Society of Automotive Engineers introduced a new test procedure for engine horsepower and torque.[6] The procedure eliminates some of the areas of flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as "SAE-certified".

 

Many manufacturers began switching to the new rating immediately, often with surprising results. The rated output of Cadillac's supercharged Northstar V8 jumped from 440 hp (328 kW) to 469 hp (350 kW) under the new tests, while the rating for Toyota's Camry 3.0 L 1MZ-FE V6 fell from 210 hp (157 kW) to 190 hp (142 kW). The first engine certified under the new program was the 7.0 L LS7 used in the 2006 Chevrolet Corvette Z06. Certified power rose slightly from 500 hp (373 kW) to 505 hp (377 kW).

 

Then there's whp or wheel hp. Its measured on a dyno to show you what power is actually put down onto the road. This number will vary due to elevation of test, pressure, temperature and humidity. Calibration of the dyno should be done carefully or it will lead many to believe their civic is just as fast as a RX-7

[Contax]

Thanks all for the reply.

 

I especially like this sentence you make ".......Just that euro makes tend to be very conservative with their figures "

 

In other words , if a asia make declare the car bhp as 130bhp , by the time it goes through all those gear box , shaft etc , the effective bhp at wheel will likely to be 20%(guesstimate) lesser ?

[Rickster]

I read from an article somewhere that the actual horsepower at the flywheel of the current generation civic is actually about 20% lesser than the stated BHP. Just can't believe that it has so much difference . Can anyone verify?

 

If its true, no wonder pple say manual car is more powerful, not just becos you can drag gear, but rather, less power is lost thru the drivetrains.

[Crummytyre]

Take a look at this site. Answer most of your questions.

http://www.rri.se

 

And here are the interesting numbers...

http://www.rri.se/index.php?DN=29

[Watwheels]

Yes it is +/- 20% less.

 

U can always compare Torque fig usually measured at flywheel. This fig is more consistant than HP fig.

[Ahbengdriver]

read that somewhere on internet too.

 

So u see, dont believe all those brochures and SEs. Buy car? Go test drive properly. What the use of having 200 BHP and u are left with say 160 at the wheels

[Watwheels]

Actually the way they put it ie. engine output power = 1000bhp, is not incorrect or inaccurate cos "engine output" mah not at wheels leh.

 

It goes down to how consumers intepret it.

[Watwheels]

All cars are about the same depending on Auto or manual. Of course auto confirm around 20% less cos of the torque converter.

 

But nowadays torque converters are slimmer and have lock-on functions to reduce that power loss. Autoboxes now also have more cogs to maximise the power.

[Zcold]

Ya! use our own BHP best... Butt Horse Power~!

 

use butt sit in car n feel the rawr!

 

aniwaies also muz see torque... power big big torque small small... also no use

[BlueSi]

You mean Butt Dyno? "Dude! I feel 20 more hp with my new exhaust!!!" Haha