One , what coupler to run to connect a 2.5 pipe to the throttle body? Looks like a 4 inch then squish it. Two, what hose to run for the oil return. I have -10 fittings on the turbo and oil pan so what type of hose. Standard steel braided? Is there a cheaper line to with stand oil. No pressure on it just return so guess it just needs to not swell with oil.

 

a 4" pipe will squish to match the oval throttle body. So an option would be to use a 4" silicone coupler or hump hose, then a short section of 4" pipe and fabricate a transition to a 90* 2.5" pipe. Or you could use a 4" to 3" silicone reducer coupler which I know exist, then step from 2.5" to 3" in your piping near the TB, or maybe even use a 4" to 2.5" reducer if one is available. You'd have to price it out to figure out which would be cheapest.

Personally I would use some sort of reinforced hose to make sure it doesn't kink on the way to the oil pan. If you have a straight shot down and then are using a 90* fitting at the pan, then it might not be that big of a deal.

 

I found a guy on ebay that sells used nascar hose and has a -10 reinforced hose with heat sheilding that is 40 inches for 25 bucks shipped so will get it and shorten it to 24 inches and it has the 90 and 45 degree swivel fittings so a expensive set up for cheap. Was used for a rear end to cooler hose so will be fine. I thought the tb was 4 inch just couldnt find a 4 to 2.5 so with the pipe being alu and my tb is a lingenfelter that has the removeable out side where the hose mounts might take it to some one and have it welded up so it bolts on and off then a rubber coulper after the 90 going back to the intercooler. Either that or might be able to get a muffler shop to strech the end of the pipe up to 3 inch. 2.5 is a lot easier to route over the 3 so went with it. doesnt sound like much until you put the pipe in place and with 2 freinds makeing over 700rwhp with 2.5 will be plenty for what I need with this setup. Thanks again for jumping in Jeremy. You have answered almost every post I put up.