Manifold tube diameter
 

1) I am going to be building a long runner manifold in SS and was wondering if these would be good from mcmaster-carr- www.mcmaster.com/#43645k315/=24ofga. They are schedule 10 ss with a 1.68 id. Would this be large enough for a streetported motor with a BW s361 looking to make ~400whp? Also should I get them in 304 or 316 (I will only be tacking them)?

2) I am also making a new downpipe/wastegate pipe and am going to ad another muffler to my exhaust. I was wondering if it is possible to use diesel style exhaust flex pipe to connect exhaust components after mounting them. Are there performance/exhaust tone drawbacks?

thanks

I would say 2" schedule 10 316.

Mine is 2" schedule 10 316L tubing

http://img.photobucket.com/albums/v2...m/P1010848.jpg

http://img.photobucket.com/albums/v2...m/P1010845.jpg

http://img.photobucket.com/albums/v2...m/P1010841.jpg

http://img.photobucket.com/albums/v2...m/P1010840.jpg

Why do those a-spec manifolds look so small? I thought I recalled Zero R saying 1.6 or 1.7 a while back.
thanks

The above is a A-Spec Manifold.

viking did they custom make that for you.. I remember you were trying to make your own mani. This is the manifold I saw that made me think I only needed 1.5 schedule 10

Yes, they made my manifold based on my specs.

the spoolup characteristics of the manifold will be noticeably influenced by the size of the runners you use.

So is smaller diameter faster spool? Right now I have 2 inch schedule 40 non stainless pipe which is 2.07'' inside diameter and I am not pleased with spoolup. Can someone just tell me the diameter of pipe on the manifold that comes with one of their gt35 kits?

Anyone? Also does anyone know the answer to question #2?

Yes smaller tubing will help with response. Post a picture of your turbo manifold. Tubing size isn't the only factor that plays a role in performance. The biggest one is the numbers of bends, and how sharp they are.