Hi,
I was just reading through my owners manual to my EF Fairmont, and where the specs are that state how much power its got and stuff, it says "Taxable Horsepower"
interesting. So if that's the supposed loss, that would mean that a 185kw AU1 XR8 loses 51kw, to be 134rwkw. And a VCT XR6 that has 172 loses 32, making it 140 rwkw? It must mean something else because even a stock Forte V8 will flog (well, only just beat) a VCT XR6!
interesting. So if that's the supposed loss, that would mean that a 185kw AU1 XR8 loses 51kw, to be 134rwkw. And a VCT XR6 that has 172 loses 32, making it 140 rwkw? It must mean something else because even a stock Forte V8 will flog (well, only just beat) a VCT XR6!
I guess the driveline loss will be dependant on what transmission is behind the engine, a manual will have less power lose than an auto.
In regards to an AU forte V8 beating the VCT it also comes down to weight. The forte being live axle would be lighter than the VCT despite the added weight of the V8.
In terms of power i would hazzard a guess that a VCT XR6 and a V8 forte would put out similar figures at the wheels.
Occasionally, usually when reading overseas vehicle information, I find reference to taxable horsepower. Taxable horsepower is a simple mathematics calculation used to determine the taxes to be paid on the vehicle. It has very little to do with actual horsepower because it doesn't factor in key elements like compression ratios, cylinder head design, and camshaft specifications. To calculate taxable horsepower multiply the cylinder bore x cylinder bore x number of cylinders x 0.4, and don't forget to pay the tax!
actually taxable hp means the power it takes to drive the power steer pump, AC compressor, alternator, water pump etc... so with everything going flat chat (ac on, psteer on full lock, as much load on the alternator as possible etc) on a 185kw motor at full revs you only have 134kw to play with at the flywheel.
obviously the above situation would never occur so you dont have to worry about this loss, you only loose a bit here and there as you drive
so does this mean, if u have the stereo pumping while trying to do a burnout or race someone, it will lose hp because of the alternator??????? or is the alternator fully charged when driving anwyay?? i have no idea
yep its what eb4me said. although the calculation i know is the bore (in inches) squared, times the no. of cylinders, divided by 2.5. but it works out exactly the same.
apparently came up with by the RAC in the early 1900's
thats probably because the 200 has the same alternator and engine fan as the 351....
or EB4ME are you taking the piss? :S
the engine has absolutely nothing to do with it - its the accessories that affect the 'taxable hp'.
yes crowbar, if you are racing (at a drag strip of course) turn off your stereo and AC, remove your p/steer pump belt if you are desperate, this should save a few kw.
if you want to there is actually a way to set your alternator up so it stops charging when your foot is to the floor, combine this with thermo fans and the other 'power saving'meansures and you should actually see a drop in quarter mile times.
*by the way* dont drive around the streets with no p/steering - its crap! its also a good way to possibly stuff your rack as well, and/or crash.
actually taxable hp means the power it takes to drive the power steer pump, AC compressor, alternator, water pump etc... so with everything going flat chat (ac on, psteer on full lock, as much load on the alternator as possible etc) on a 185kw motor at full revs you only have 134kw to play with at the flywheel.
obviously the above situation would never occur so you dont have to worry about this loss, you only loose a bit here and there as you drive
Rollin, this is incorrect. It is as Eb4me said (well copied anyway). It was a figure produced by doing a mathmatical calculation on some of the engine specs to produce a figure. The government then had a price per hp wich was the tax you used to have to pay to run that car...
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