STiMulated 
 
 
 
 

 

"On the road, it all means the APS STi is a more relaxing drive because you’re not constantly hunting back through the six-speed for a ratio that’s actually gonna spool up some herbs. The thing will actually accelerate in sixth now, which is really saying something."

Motor
Magazine 

 

 
 
 

 
 


Motor Magazine Test of the
APS Sprint Spec High Output System


If you’ve just shelled out for a suby STi and find it limp,
APS may be the answer

  



STiMULATED

Peter Luxon is no big fan of the MY02 WRX STi.  And as the bloke who has cranked out plenty of late-model fire-breathers over the years under his APS banner, when Pete says something is arse-about, you tend to listen.

The big drama is, of course, something that we’ve noted here at MOTOR every time we’ve strapped into a current-model STi; that torque black hole below 4000rpm.

See, when you’ve shelled out the $55,000 for an STi, it’s just a teensy bit galling when boofheads in faded V6 Commodores hose you from the lights.

So what’s the prob, Bob…err, Pete?

RIt’s just bad engineering. The diffs are the wrong ratio (4.4:1 would be better than the 3.9:1 it runs) the turbo’s too big and, to get around that, they’ve had to drop the compression ratio to about 8:1 which is just too low,” says the man.

So that’s why it feels like an old –fashioned laggy turbomotor, then?

RYep, and when you look at what the class acts around the world are doing, you tend to find smaller turbos (or twin turbo set-ups) and compression ratios closer to 9:1, so the thing still has some drivability off boast.”

So what’s the fix?

RUltimately – and we’ll get around to it with this car – you’d fit 4.4 diffs, a smaller turbo housing and bump the compression.  That’ll be easy because we’ll be stroking this motor to 2.2 or so. Then it should go properly.”

Um, yep, dare say. But in the meantime, what does an STi owner do to make the car more tractable?

The solution is the basis of APS’ latest kit (the company doesn’t do one-off stuff, allowing it to invest the time and money to engineer the one kit properly).  Stuff like a big-bore exhaust (which is pretty loud under full boost, but okay otherwise) is a cinch, and a free-flow air-cleaner element and a blow-off valve, which is one of the quieter ones I’ve heard, are also part of the package.