So I ran into a bit of a problem... I have porting templates for the sec. intake and the exhaust, but don't have a primary template. I need some suggestions on what to do to the primary.

My setup is going to be a BW S360 (.91 AR). I'm shooting for 375-400 without AI, and 450ish with AI early next year. My exhaust template is from pineapple racing with the EP4A insert for a "medium sized turbo"

I stole someone elses picture as a reference. Should I just judge the size increase from the picture, and copy that to the other side using a homemade template?

Any suggestions are greatly appreciated!

 

My ports are quite similar to Ito ports (just earlier port closing).

I port the primary using the 2ndary template, but do not port down at all. Just port the bottom of the primary across to the opening line on the outside with a radius in the corner.

This is to gain the benefits of the streetport early opening and late closing timing without making the primary port volume too large so that intake velocity drops.

If I had a different intake manifold with primary runners as large as the 2ndary runners then I might think about porting down and enlarging the primary port runner as well since there is going to be a loss of velocity upstream of the port anyways.

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If you are keeping your double throttle plates/solenoid intact, you could just leave the stock primary port alone for smoothest idle and snappiest throttle response at the expense of some midrange and top end power.

 

Why not contact Judge Ito and see what he recommends? I will say that the templates are pretty aggressive, and I would go just short of the outside edge where the port closes. If you port all the way to the edge of the template and then finish off sanding everything smooth, its easy to overport and catch a side seal. This applies to many templates, not just these. From the pic it looks similar in size to a Pineapple large street port.