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Discussion Starter · #1 ·
and i say "stock" cause although mine isn't completly OEM anymore, i'm still running the factory turbo, which probably affects exhaust flow the most. so, here's the scenario:

VS0 already in the car (uppipe, unichip, etc..)
if i add the HKS dp, that'll be 3 inches going all the way past the midpipe, eliminating the final 2 cats, but then it'll connect to the 2.5? inch endpipe w/ the stock muffler. anyone wanna tell me how this thing should be expected to run? specifically, i wanna know about what kind of punch this car should be packing 1. off the line, and 2. versus the highway.

thanks!

-Robert
 

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The cat is whats giving you the most restriction, and going to a 3 inch will definitely improve your spool up time, and give you a few more horsepower, and then a few more if you have your unichip properly tuned. If youre concern is the stock muffler and assy, then dont worry, but it would probably sound better with a nice 4-inch tip ...

speed safely,

Joe
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Discussion Starter · #3 ·
thanks, i was a bit worried about how the 3 inch would jive with the narrower stock exhaust.

but specifically i want to get an idea of where in the powerband is affected by the dp. like, from the stoplight, i heard u lose some torque b/c the gases are now flowing through a wider exhaust so there not moving as fast, but that once u get going faster, the wider piping is more helpful so your midrange is improved. thoughts?
 

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The whole "loss of torque at low rpm" thing is a concept thats mostly applied to NA motors, because they need some backpressure to function well at low rpm. But since you have a turbo, which slows your airflow at low rpm anyway (lag), its really no big difference.

speed safely,

Joe
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The muffler pipe is less than 2.5" from the last flange. I talked to Stromung. They could have sold me some exhaust components but recommended leaving the third stock cat in place calling the center section an "excellent piece, don't replace that."

I believed them (sorry, I can't remember the gentleman's name and he deserves credit). So, I have a modified Stromung downpipe and a 2.5" pipe, mandrel bent, all the way to the stock muffler. With the uppipe and the downpipe cats removed, the exhaust sound is quite aggressive. Like the new WRX commercial where the guy turns down the radio to listen to his pipes.

Coupled with the fact that a free flowing muffler is next to negligable in terms of power gains, and is expensive, I like this set up. I know it's not real radical, but it is an effective and practical approach to exhaust performance power gain.

Adding the Stromung downpipe really turns the turbo on. The difference is startling. After that, the muffler, axle back section, needs work.

IMHO

misterx
 
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