I'm going to be putting on a P1SC procharger with a 24x12x4" intercooler. Stock LT1 with mod in sig, 8 psi pulley. I'm building a 355 fully forged motor to go in it in a few months.

My question is piping. I was going to go with 3" intercooler piping but then a friend of mine said he's heard unless you run high boost, you'll lose alot of air volocity.. so he said 2.5" was a very popular choice, and its much easier to get all the pipes into the car. I'm planning on running 15~20 psi on the forged motor.

What do you guys think?

 

Did your buddy give you a reason that you would want higher velocity?

Keep in mind that a supercharger does not in any way affect the velocity of the intake charge, only the density. Velocity is determined by piston speed and displacement. A smaller intake system will have a higher velocity and lose more energy/work due to friction in the system which results in a pressure loss. The best thing to do is not have several abrupt changes in area throughout the system. Most than likely the supercharger will have a 3" outlet and you should maintain at least that to the intercooler and then on to the engine. 2.5" can be successfully run if you Y the 3" to 2 seperate sections and intercoolers of 2.5". 2 2.5" tubes is roughly the same area as a single 3.5", but 2 seperate tubes will have more losses due to connections than a single.

As you're interested in a front mount I suggest doing what's necessary to plumb in the 3".

 

what mark said... never go smaller than the outlet diameter of the compressor.

 

Ok, makes pretty good sence to me. 3" or bigger it is! Poor car is going to have to be chopped up pretty good to get all that stuff in there.. but the more power is going to be worth it!

Thanks for the quick help!

 

I think your friend is an idiot. Would he tell you to get a smaller exhaust too?