Thursday, April 22, 2010

Driving the Mach V STI

I took the Mach V STI home and ran a few errands.  Hauled a big PC to work, took the kid to school.  The car is still its usual self for around-town driving.  The exhaust note might be a tiny bit louder at idle and low speeds, but it's hard to tell.

Full throttle is another story.  When the 20G-XT-equipped STI gets up above 3500 rpm, everything starts to happen really fast, and it sings a baritone Subaru full-throttle song that turns heads -- in a good way if those listening are car fans.  (I got a thumbs-up from a guy in a BMW Z3 M roadster.)  But maybe that noise is not so good if you're trying to keep a low profile on the road.  Not like the car in its current form is subtle -- what with the multi-vented hood, huge wheels, and all that.

The power is pretty fun.  At freeway speeds you can still dip into the gas in sixth gear and get a good dose of passing speed, although there is more lag than there used to be.  Dropping a gear gets the car up into insta-boost range and you'll quickly be at extra-legal speeds.

Which brings me back to the thought of losing my driver's license.  I'm going to have to get the car to the track to see what it's like to drive it really hard at this power level.

Tuesday, April 13, 2010

Blouch 20G-XT on the car

We bolted the new Blouch 20G-XT turbocharger to our STI, and rolled it back onto the dyno for some more pulls.  The turbo delivered as advertised.  Spool was a little slower than the Tomei ARMS turbo we had on the car before, which is understandable given how much larger the turbine outlet is on the 20G-XT.  The car made a lot more horsepower at the same boost levels -- 33 more hp and 30 lb-ft of additional torque to the wheels.  An added benefit that isn't seen on the dyno graphs is that off-boost throttle response is better -- the more wide-open turbo outlet probably is the reason.  The exhaust note is a bit louder now, too!

Most of the time when we put a 20G on a car we've also done a turbo induction hose, TGV deletes, and headers, none of which are on our car.  When we do get those mods done, we'll dyno again.  I'd expect another 10+ hp at that time.

Friday, April 2, 2010

Needs More Turbo

Although the Tomei ARMS turbocharger on our STI made decent power, and spooled very nicely compared to the stock hair dryer, we just can't leave well enough alone.  We asked our friends at Blouch Turbo if they had any suggestions for something with just a little more oomph, and we got a Blouch 20G-XT: A Mitsubishi 20G compressor housing and center section mated to a custom Blouch turbine side that will bolt on to any 2002-07 WRX, and any 2002+ WRX STI.  But wait, there's more.  The compressor wheel is not cast like traditional wheels.  Instead it's CNC milled from a block of billet aluminum.  That means it can be made lighter and more efficient than old-school compressor wheels.  The upshot is supposed to be more power and better spool.  We'll find out next week when we bolt the turbo on and roll the car back on the dyno.

The 20G turbo has always been my "go-to" turbo for 2.5-liter cars.  It spools almost like a stock turbo, but has massively more top-end.  If you have a 2.0-liter car, the 18G is probably a better choice, as the 20G takes a while to get going with only a 2.0 engine blowing on it.  Blouch also has an 18G-XT available.  Watch our web site for more details on purchasing these turbos soon.