what would be ideal for this car?

will have proted stock S4 turbo, w/ 720 secondaries, and walbro fp, 3in turbo back exh, and runing 10-12 psi?

thanks
Bryon

 

2 1/4

 

Corksport makes a kit you should look into.

 

2.5?
3"?

 

hahah corksport? isnt that kit like almost 900??

haah

no im ok, it will be custom, thanks for the suggestion

 

it's way cheaper than my Greddy 3 row was, believe me.

 

Yeah but 2.5 was a little laggy for my liking. I wouldnt go any bigger than 2 1/4 on a stock turbo...

 

you think it was the piping length?

my pipin will be short, would that help with 2.5? or still 2.25 ideal

 

Dang if I was at work still I could run the calcs for you. Mostly likely the stock size or 0.25" higher will work great. There's almost zero restriction in the pipe, even with bends, long runs and what not. Most of the restriction is in the intake filter, the intercooler itself, AFM, etc. And the intake ports easily trump all of those. See, once you shrink to 1/2 size, there is 64 times as much restriction.

If you do a search under my name you might find the calcs for an NA. In your case the airflow and velocity are the same, but the density of the air is a bit higher. So I'd guestimate that you'll get about 50-75% more pressure loss. Even then it'll be an increase from almost nothing to 50-75% more than almost nothing. But increasing the pipe size 0.25" will cut the pressure loss in half, bringing it back down below stock levels.

 

I would recommend 2.0" and maybe 2-1/4" if you think 2.0" is too small.
Smaller pipes will give you better response (with the small, stock turbo).


-Ted

 

well said Ted. everybody is so hung up on girth!