rrounds

I've seen cars with these hoses on supercharged engines(that get 10+ psi, don't know if it will flow 20+ psi) you can get both in 4"
http://intense-racing.com/Merchant2/...3800_Induction
http://shop.zzperformance.com/store/...ke-Tubing.aspx
Kind of pricey.
If your looking for very good hoses then these will take boost but I don't know how much vacuum they will take(and very pricey, good to 600F)
http://www.turbohoses.com/Turbo%20Hose.htm

ROD

icemans2k02

Where I work we sell the 2 ply silicone hose which is great for couplings and radiators were there is pressure. However being as there is going to be suction on it and there is no wire it will collapse under load.

99SH

Those first two links don't have any specifications, I would be very leery ordering from them. And the last link is used for coupling (eg. intercooler pipes) and not for air ducting. We need something flexible and easily routable.

Also, keep in mind that we don't care about positive pressure but negative pressure for the air duct hose. If you're boosting 10 psi, you may only be excreting 4-7 psi of negative pressure on the inlet side of your blower/turbo. It all depends on the pressure ratio.

LandR

I use a 3.5" silicone duct with metal wire coil from my novi 1200. Getting dynoed with and without this cai on Friday and will post side by side.

-Sam

spectacle

That's what she said.