I'm trying to decide between a .84,a 1.00, or a 1.15 divided hotside for my 60-1 (P-trim). My car has a .96 undivided housing on it right now, and with the manifold i'm using doesn't hit 15psi until about 5000 rpm. At 3000 rpm I could only get about 3-4psi (took a few seconds). My estimate was 335rwhp at 15psi before the engine blew. This will be on stock ports (maybe very mildly cleaned up).

I would like to get closer to 375-400rwhp at 15psi, with say 10psi at 3000 and 15psi at or below 4000rpm. I will be making a fully divided manifold with 13" long runners to complement the new housing.

The other question is what ID should the manifold's runners be? Is the optimal diameter related to the A/R of the housing? I was thinking of using either .065 wall 304 stainless tubing, either 1 3/4 OD or 1 7/8 OD (1.62" ID & 1.745" ID). Does this sound OK keeping the goals in mind?

I'd like this setup to work nicely . Having a good torque curve is more important than all out power, but people seem to have very good boost response (10psi @3k or so IIRC) while attaining ~375rwhp at 15psi. If I could hit that level i'd be happy.

Thanks!,
Manolis

 

Use the 1.15 a/r divided with 2" .065 S/S tubing.
shoot for anywhere between 15~20" primary length.