A friend of mine recently picked up an S4 shell and I'm building this engine with parts I have laying around (you know when your an rx7 owner when joke here)

S5 NA housings (w/ turbo inserts)
S5 NA center iron (large pinaepple streetport)
S4 F/R irons
S4 NA rotating assembly

now obviously my NA template from pineapple does not quite correlate on the 4pt irons, and I feel if I made that 6pt F/R port job I wouldn't want to spin it that high to take advantage of it.

I could use a turbo template and leave it be or modify the shape or duration of the port template slightly to benefit the NA characteristic.

BUT

if I was going to that I might as well get a degree wheel and make my own port.

What kind of port timing would I want for a large streetport to benefit the non turbo engine characteristics?

Oh, and this engine is a budget streetport NA build for an ice racing car rx7.

 

Don't go massively huge on the duration. I think that's where my street port didn't fare so well - whoever did it went way late and it raised the RPM range beyond the rest of the engine's ability to breathe.

How does the ported primary ports look on the secondaries?

 

stock port duration is longer. ill take pics of the template in both positions

 

this is the NA large streetport template over the secondary T2 iron


these two show the primary large streetport template over the secondary.



I'm not really keen on porting the large streetport aux to the size of the aux port on the F/R irons. maybe go halfway on it? IE only port to the half the size of the aux port template


or do I just port it to the template as a hole?