I have a 557 bbc, and a friend is building me a set of 2 1/4 headers, with t6 flanges, the plan is for a couple of 1 to 1 ar 475's. Fwiw streetable may not be the right word because it's in a jet boat, but the point is I want it to be fairly tame(pull the kids on a tube ect.) I know my bud knows his chit, I just want to hear opinions, overkill, maybe 1 turbo, ect. Oh pump gas, 6.5k redline, 8.4 to 1 cr,Alum heads......If you need more info let me know. Edit looks like my post was moved over here, I was just curious what if any advantages there were to twins over a single. Besides spending more $ lol

 

2" tube would be plenty large.
At the point where the exhaust gas hits the turbine wheel it is funneled down to two 360 degree slots about 1/4" wide so there's going to be back pressure anyway. Larger tubes feeding it will serve no purpose. Save some money.

On the single vs twin turbo thing, I think the least amount of hot side piping the better.

 

Thanks Mark, I assume by the least amount of hot side pipe, you mean 2 turbo's would have the least, right? Your heat shields look like the ticket(on the eliminator) I'd love to see a closer shot.

 

2 1/4.....2 1/8.....2.....t6 flange .......x2

 

I am bending up some heat sheilds like what Mike runs as well as having a new splash guard cut for the eliminator. It will go all the way to the bottom of the gunnel and probly 8 inches high, and up to the back seat made from aluminum. With both of those in place it should work just fine and look decent as well!

Travis

 

Yes, twin turbos don't require the 5' of crossover hot pipe.

I didn't take a lot of pictures of the head shields because it's not real trick looking. I came off the front and back of the head with 3/16 alum and that contains both ends of the headers. Between them I bent up some thin aluminum sheet that is the shape that boxes in the headers. I have a vertical piano hinge on one of the end plates and it lets me swing it out of the way to release the center piece and access the plugs.

 

Thanks for the info guys, Travis I kinda like the splash guard/ heat shield idea too. I'm glad I couldn't afford upholstry back there last year for my boat.lol

 

I totally agree with Mark55 he is telling you the best way just go for it.