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I supported Toymods
Location:
Perth
Registered:
August 2002
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horsepower question
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Tue, 24 September 2002 00:23
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well i was looking at some stats for my car (SV21 3S-FE if you aint seen the pic <---) and its quoted 88KW/171Nm
i was wondering about if this is when the engine was new? taken at the wheels?? cause in this site somewhere is an SV21 with only 55KW or so
ARG CONFUSED
i think i need to go visit my local dyno and wave money in their face
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: horsepower question
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Tue, 24 September 2002 00:25
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That 88kW is most likely at the engine, the 55kW is most likely at the wheels after a few mods. Also, dynos of different types will read different losses too, ie. US dynos tend to read higher.
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Re: horsepower question
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Tue, 24 September 2002 02:56
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A manufacturers output figures are based on two different standards for testing, one is slightly more conservative than the other, however both are a flywheel hp figure.
Both figures are attained with no ancilliaries attached to engine, ie no alternator, aircon, or fans etc.
the engine is fed perfect temperature filtered air from an outside source, coolant is supplied from an infinate reserviour that never heat soaks. they are tested useing hand crafted fuel in an air conditioned room !!!!
It is not a real life figure, all the detrimental variables are removed.
That is why RW dyno figures are not what people expect, and I beleive this is also responsible for the 30% drivetrain losses myth.
rw figures are down 30% from the manufacturers claim, not the real figure.
DOnt use %30 loss as a figure to calculate flywheel hp !
There was also an article in yesterdays telegraph about hyundai overstaing its power figures.
/rant
Matt
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: horsepower question
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Tue, 24 September 2002 09:37
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all manufacturers overstate at least a little
tho I have a feeling the *uz are fairly accurately measured
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Location:
Sydney
Registered:
January 2003
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Re: horsepower question
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Sat, 13 September 2003 13:35
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Ok i got mine dynoed last year with just a 2" cat-back. it had done 120kms and was in good nick. it started with 60Kws at the wheels and after a timing advance and a few more squirts it had 66Kws at the wheels! MAD 10% increase.
Now i have 2" extractors and a straight-through muffler so i'm guessin it has bout 70-80Kws now...
i'm gettin it dynoed again at UniGroup Engineering at 17/17A Amax Avenue, Girraween on the 28th of this month for $45 - $50.
Got to love thoese group prices 
Come if u want 
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Location:
Brisbane
Registered:
November 2002
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Re: horsepower question
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Sat, 13 September 2003 13:57
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There's no way in hell a different muffler and a set of extractors got you an extra 14kW at the wheels.
But yes, back to the topic at hand.. the quoted figures are:
(a) when the car was released new
(b) a flywheel figure
(c) measured with no optional accessories on the engine
(d) optimistic at best
A good example is the new 245kW Holden Caprice - one magazine just dyno'd one, a few weeks old... and got 158kW at the wheels. Which is more like 200kW at the engine... overstated by a massive 45kw (20%!!!!).
Take them with a grain of salt.
In fact, that goes for all power figures. It's all very subjective and many dynos give different readings. Often people can dyno the same car at different places within a day of each other and lose/gain 40kW at the wheels. I have seen it myself, but on a less grand scale...
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