The Audi TT 225 comes equipped from the factory with a K04-20
turbocharger and Quattro driveline. While a great combination for making power
and keeping it on the ground, the two leave very little room for a large exhaust
system. The factory 225 downpipe starts out over 3" in diameter, but quickly
reduces and splits into two smaller pipes. These two pipes twist to clear the
driveshaft and meet up with two small catalytic converters. 2.55" exhaust piping
finishes up the remainder of the downpipe. While larger than a stock GTI
downpipe, we certainly wouldn't call the stock 225 downpipe 'performance.' In
fact, the stock K04 is simply begging for a 3" upgrade.
To date, a 225 3" downpipe has been tackled by few. Tight
fitment and custom fabrication costs have kept most from attempting the project.
We certainly understand why! Fitment is beyond tight. From the turbo to the
stock cat-back exhaust there is barely room to spare. Our downpipe slides in
with precision. Every angle of installation has been addressed making this 3"
downpipe upgrade truly worth the effort.
Starting at the turbo discharge our downpipe bolts up with a
CNC machined turbo flange. A tight radius bend at the turbo quickly sends
exhausts gases flowing downward while also steering clear of critical engine bay
components. The first bend has been positioned so that normal hand tools can be
used on all bolts. Next, a flex pipe joins from the bottom. The top flange of
our flex pipe is studded for ease of installation. Both the flex pipe and the
downpipe feature adjustable flanges. These custom flanges allow for precision
adjustment and ensure perfect fitment on every TT. Our cat section bolts up
next, tucking a Magnaflow 3" high flow cat beside the driveshaft and well off
the ground. The cat pipe bends towards the center of the car and bolts up our
2.55" adaptor. This adaptor fits stock exhaust and all aftermarket catbacks.
Our 3" downpipe upgrade has been designed to squeeze all
available power from a street or track driven TT. Horsepower and torque
increases are estimated at 15hp and 15ft/lbs at the wheels. Power increases can
be felt instantly after installation. Midrange and top end power increases
dramatically while almost no low end power loss is felt. Boost builds steadily
without a major spike in pressure.
Our 3" downpipe upgrade is available in two configurations -
street or race. Street series downpipes include a high-flow cat. Race series
downpipes include a test pipe (not yet pictured). Test pipes and cat sections
are available separately for those who wish to change at a later date. Thanks to
our modular flange design the cat can be easily removed on race day and
reinstalled for street use.
Dyno results are in!
Joe Lucchio of Fourtitude/VWVortex put our downpipe to the
test. With his current modifications the dyno showed 9.3 hp and 19.3 ft/ lbs
peak gains at the wheels. Gains were proven throughout the RPM range and
driveability was greatly improved. To read Joe's complete review check out
fourtitude's full feature. To view a full size, un-altered dyno sheet click
here: TT225 dyno
Fourtitude - Project TT Feature