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2003 OBW, 2.5 l, auto, Dyno readings

Using the Auterra software

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I did some testing to measure the chassis power and torque for the wife's 2003 OBW, 2.5 l, auto:

The highest readings i got: Power: 142 hp @ 4300 rpm Torque: 145 ft-lb @ 5100 rpm

From the Subaru specs: Power: 165 @ 5600 Torque: 166 @ 3600

When using the A/C, the chassis power and torque go down to 138 hp and

140 ft-lb.

The tests were performed in second gear, from 2000 to max. rpm, on flat paved road, tire air pressure to specs, fluids to specified level except for fuel which was about 4 gallons in the tank, no loads on the car, air temperature 80F, wheel alignment verified to nominal specs.

I do not want to imagine where the missing power and torque are. ;)

Reply to
AS
Loading thread data ...

Missing? It was never there.... these imaginary specs of 250-300BHP are just that..a dream.... Not ONE of them has a dyno run sheet to PROVE it....

Reply to
Porgy Tirebiter

hmm, that could be right depending on how your results are supposed to be interpreted since Subaru power/torque specs are reported at the flywheel not the road, and you lose about 15% through the drivetrain.

AS wrote:

Reply to
Loren

I would be a little suspect of your software's readings. While I don't have any data in front of me, from memory most manufacturers quoted h/power is at the flywheel and the only way of getting an accurate measurement would be using a 'rolling road' dynomometer.

Secondly most torque is usually developed at a lower RPM than max HP.

Reply to
bugalugs

You might enjoy searching/posting your question at the Proven power forum at

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. many folks there have put their soobs on 4 wheel drive dynos.

Carl

Reply to
Carl 1 Lucky Texan

Carl, great suggestion, thank you.

Thanks to all others for the comments and suggestions.

Alex

Carl 1 Lucky Texan wrote:

Reply to
AS

I'm guessing the tool measures power at the wheels, since that would make physical sense... in that case, your numbers look really damn good. Most people only manage to get low 130's at the wheels, even with a manual transmission.

Reply to
Dmitriy

You are comparing apples and oranges.

You are measuring "chassis" horsepower or "on the ground"; Subaru's measuring it at the crankshaft. The difference is used up in mechanical losses in the transmission, differentials, CV joints, wheel bearings, rolling resistance of the tires etc and etc. Don't forget the alternator and possibly the water pump.

As you already noticed, the AC takes 4 horses to run.

Also be aware that *any* horsepower measuring device is only as good as its calibration. Most folks who deal with either engine dynamometers, chassis dynos and accelerator gauge/software dynos only use them for estimates. Their value is showing how much (and where) the horsepower and torque changes with tuning and modification.

Reply to
nobody >

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