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Old 02-21-2013, 06:08 PM   #2240
diss7
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Quote:
Originally Posted by Tansey86 View Post
350rwhp or less 2.5 will be fine
351rwhp and more id suggest 3"

You will see a gain in power and a gain in spool. I've seen a gain of up to 50rwhp in a turbo setup by removing a cat, you dont want any restriction in a turbos exhaust. Thats why high HP cars have about 1 foot of exhaust and exits right off the side of the engine.
Removing a cat is not what we're talking about.
You don't want any restriction for peak power, this is why high HP cars have as little exhaust as possible. But back pressue helps spool turbos. When you're talking high HP, using a smaller exhaust to create back pressure to generate spool sooner will act as a massive restriction on peak power.

This is not the case for this setup.

Edit - Prove to me with dyno graphs showing the same car running the same turbo setup, the only difference being a bigger exhuast, that shows the larger exhaust helps spool. Until then I still call BS.

Is a 2.5" system going to be a significant restriction on this kit? No its not. So, use it, as the smaller piping will create more back pressure to help the turbo spool sooner.
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