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rsx
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Discussion Starter #1
hey i did a quick search but i have to work today.. i have some 2'' piping at my house and i noticed that most guys run 2 1/2'' piping inside to inside..

my question is would switching to 2 1/2'' piping be any more sufficent? or will it not be much of a difference.. i plan to run the stock throttle body and the turbo is a pte entry level 50 trim turbo.. plan on making 300 ish horse power.. maybe 18-20 psi..? thanks fo the help. :bigok:
 

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ej8
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I run 2inch hot side then 2.5 cold. Also on a small t25 around 200hp.
But for 300ish i would say match the intercooler inlet/outlet size. So at lest 2.5 cold, and 2.25 hot for 300ish hp.

Also remember bigger ic pipe is more to fill but small ic pipelimits flow.
 

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rsx
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Discussion Starter #3
thanks.. amd i get the larger diameter helps with the flow of air.. just sucks i have free piping and now i have to buy some lol..
 

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The damn air is pressurized. 2 inches is plenty for your goal

and forget that 18-20 psi crap. PSI does NOT determine power for any turbo
 

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rsx
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Discussion Starter #6
yeah i know its about flow capabilities correct? but i threw the psi out there incase any one asked..
 

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PSI isnt really necessary to mention unless a specific turbo is brought up. then we have a ballpark figure!

A 2inch pipe can flow some serious amounts of air if pressurized enough.

I like to think of the military equipment I get to work on. We have a VERY large V-8 diesel that exhausts to a medium sized turbo on each bank, that directly feeds into a HUGE supercharger. The motor makes over 700 horsepower and creates nearly 1500 lb-ft of torque.

The inlet size on that supercharger is 3 or 3.5 inches

That is a ton of air flowing into there with a 2 cycle 12 liter V8 pushing it.

Now do you really think 2 inches is going to be much of an issue?

Having too large of a diameter pipe can actually HURT power, as the pressurized air is filling the piping before flowing through it.

EDIT for the example above given for a 2 inch hotside and 2.5 inch cold side, REVERSE YOUR THOUGHT. the air is colder and condensed more, so a slightly smaller diameter will help on the cold side.

hotter, expanding, needing a larger pipe
colder, contracting, needing a smaller pipe
 

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Classic Man
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there is a point where trying to move that much air through the pipe will increase air speed until losses happen

cant say for sure when but at a point it will be a restriction
 

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go autoworks probably does it for compatability reasons

the difference isnt going to be sufficient enough to worry.

pressurized air will still make its way to the power punch chamber! lol
 

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another reason for the 2" hotside is its less volume to pressurize.

Less volume = better,quicker spool time.

Especially when u have a large FMIC that needs pressurizing as well. Less volume to pressurize, the quicker the spool.
 

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smaller hot side is in order to get the hot air into the intercooler faster by being a lower volume. Allowing it to flow out into a larger volume allows for better flow I think. but that's only applicable if you have a larger TB and match ported intake.

It might also help by allowing for a slight pressure drop out of the intercooler or less of a pressure increase.
 

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90 CRX
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Let's not leave out the length of the pipes. If you are using a shorter pipe from the turbo to the IC, then not much is to matter. On my setup the Turbo to IC pipe is the shortest so I matched the inlet on the IC that way there is not too many transitions of geometric flow in such a small distance. The main thing to worry about on piping is mandrel bends, and the straightest possible route in the shortest distance possible.

Just my thoughts.

Sent from my SAMSUNG-SGH-I717 using Turbocharged phone.Com Free App
 

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the volume difference betweent he 2" vs 3" hot side piping will take approx .0001 of a second for the turbo to fill.

not even noticeable.
You wouldn't think it would be BUT when I replaced my 2.5" piping with 3" piping, I was able to notice it. This on a 16G baby turbo to boot.
 
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