Subaru WRX and WRX STI dyno-ed; E30 comparisons ensue

Hats off to the folks at Road and Track who gave this a try: what happens when you use a dyno to compare the Subaru WRX and STI?  Interesting things. Note: a dyno can be a less than perfect measure of wheel horsepower but manufacturers often test using perfect conditions and the measurement takes place at the crankshaft – before the transmission, differential, and wheels take the steam out of things.

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With that grain of salt supplied, let’s get into the meat of this magazine race: for $35,290 2015 WRX STI comes with more standard equipment and a 2.5 liter, port injected, turbocharged four with a manufacturer-rated 305 horsepower at 6,000 rpm and 290 ft-lbs of torque at 4,000 rpm. For $8,200 less, Subaru makes something with cloth, unheated seats, a manual transmission, slightly slower steering, no fog lights, halogen headlamps, and a 2.0 liter direct injected four cylinder making 37 less horsepower (268 at 5,600 rpm) and 32 less ft-lbs of torque (a peaking on a flat curve between 2,000-5,000 rpm). 

On the dyno, and likely in the seat of the pants, much of this changes. First: the steering, according to Road and Track, the WRX has the same ratio as a 911, so it can’t be all that slow and un-involving. The power and torque are different. The standard WRX puts out 223 horsepower at the wheels at 5,800 rpm while the WRX STI puts out only 24 more at 6,400 rpm. The torque curves are more interesting and reveal the real intentions of the two cars: the WRX puts out 245 ft-lbs of twist at 3,850 rpm while the WRX STI actually offers a peak torque output of 2 ft-lbs less at 5,000 rpm. Translation: one of these is a track car, and the other is more enjoyable on public roads.

As a former E30 owner, I can’t help but make the following, simplistic comparison: in 1987, the BMW E30 M3 cost $34,000; this homologation special of a DTM car came with a fussy little S14B23 four cylinder that put out about 192 horsepower and largely stayed asleep until 5,000 rpm; torque amounted to 177 ft-lbs with a sharp peak at 4,750 rpm. The next-best 325is, admittedly had a less lively chassis, but cost $27,475 and came with a road-ready M20B25 straight-six putting out 168 horsepower at 5,800 rpm and about 160 ft-lbs of torque between 2,000 and 4,600 rpm. Accounting for inflation, these cars cost $70,010.07 and $56,574.31 (a $13435.76 difference). I just thought I’d throw that in there for fun.

-By: Sawyer Sutton

Source: Road and Track