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is 2 1/4" inner diameter piping too small for the sohc? reason why im asking is because when i took off my generic autozone intake pipe, the inner diameter was like 2.5" and it was a perfect fit for my throttlebody.<p>also is it smart to be using 16 gauge aluminized steel tubing for my IC piping? seems thats the only kind of tubing i can get a hold of at a good price.

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by marshmallow15:
is 2 1/4" inner diameter piping too small for the sohc? reason why im asking is because when i took off my generic autozone intake pipe, the inner diameter was like 2.5" and it was a perfect fit for my throttlebody.<p>also is it smart to be using 16 gauge aluminized steel tubing for my IC piping? seems thats the only kind of tubing i can get a hold of at a good price.<hr></blockquote><p>2.25" is ok for the intercooler piping. You may wanna put 2.5" but 2.25 is ok.<p>Why would aluminized steel tubing be bad for an I/C pipe? It's not gunna get hot enuff to expand too much so it's no problem.

I wondered the same about the steel because steel will hold the heat longer than aluminium.

The intake charge is not high enough to really worry too much about that. I agree that every little bit helps, but that's why you have the intercooler in the first place. Aluminized steel would be fine.

Rule of thub for IC piping sizes:<p>-Under 300HP use between 2"-2.25" IC piping
-Up to 400HP use 2.25" from turbo to IC, then use 2.5" from IC to throttle body
-500+HP use 2.5" IC piping<p>These where stated in the 10/10/01 issue of "Sport Compact Car"<p>Personally I'd use :
-Under 300HP or so 2.25" IC piping
-350HP or so to 500HP 2.25" to IC, then 2.5" to throttle body from IC
-500HP to 600HP or so 2.5" IC piping
-700+ I'd probably go with 3" IC piping cuz that's a Monster turbo Mr.!!!!

i went 2" from turbo to I/C then 2.25" from I/C to Throttle body to help reduce lag and keep a denser charge.

V6 in the 280 HP range:
2.5" from the turbo to the intercooler.
2.25" from the intercooler to the tube before the BOV.
2.75 from the BOV to the TB.<p>I went with the 2.25 on the return from the IC to keep the velocities high since it is such a long run from the passenger-side headlamp to the TB.

Have you tried 2.25 from the turbo to the IC? You have a pretty interesting configuration! I wonder which config would deliver better results? I'm gonna be using 2.25" from the turbo to the IC. Since the air is so hot I'd think it would give it a much higher velocity even all the way up to the throttle body. The only down side being it would pass through the IC faster which would have more negative effect on a bar-n-plate IC than on a tube-n-fin like my APEXi Silvia IC. However by using the larger 2.5" from the IC to the throttle body would be less restrictive (only onder pressures for 300HP & up) allowing less back pressure on the IC core so it could flow faster.<p>Well thats my theory, but I'd LOVE to see some dyno tests on the different setups! Unfortunatly it would be expensive....however it would be a really good thing to test!