Hello everyone,

I was wondering if there is an up-to-date porting template comparison between different manufactures as I only found an old topic.
Questioning if there is much difference between one and another and what the differences are in order to choose one that fits your needs or preferences.

In my case, what the best / smartest one is to combine with a semi-p.p. S5 turbo block for n/a use.

Thanks

kevin

 

If they have a straight closing edge and tight corner pocket they have actually been designed with thought. There is a reason extreme rotaries was first to do a lot of custom parts and cnc stuff.

 

Well I mean port timing comparison for the most part. Can't imaging they're all about the same.

 

I know the Racing Beat street port intake template is almost identical to the port outline spelled out in the FIA Group A 1st gen RX-7 homologation paperwork, because I downloaded it, scaled it correctly, printed it out, and the main window was identical to a set of RB ported Turbo II parts that I had lying around. The homologation was for a bridge port. The drawing for the port eyebrow wasn't to scale relative to the main window but given that the dimensions for the bridge are spelled out, this is easy to make your own template outline.

Given how closely RB and Mazda worked together in racing programs, I wouldn't doubt that RB did the port dimensioning for Mazda, or whoever submitted the homologation. (The Group B homologation was not written/submitted by Mazda but by Mazda Rally Team Europe, a private entity. Interestingly, it used the North American GSL-SE as the homologation vehicle, because that was the only way to get a 13B in 1984. More interestingly, the Group B cars that I've seen were built with 1983 model year shells)

 

I did not know that, but still, how does it compare to other ones at the market in regards to port timing and power delivery. You don't always need or want to go for a port that's based on racing.

 

You can't compare that between different templates, if they are even different, because the shape of the runner is as or even more important than the port window. The different engine components also make a large difference. You couldn't port an early 4 port runner to the size of a Turbo II runner without hitting coolant all around and you probably couldn't port a Turbo II runner to the size of a 13B-RE runner without hitting coolant.

A lot of people don't even use templates. Certainly, the people who make ports day in and day out for different applications don't use a generic template. The inner radius cannot be moved very much, if at all, without damaging the oil control rings. The outer radius is affected by how much you want to support the corner seals and the tips of the side seals (and my experience here is that there is minimal midrange torque gain to be had, while the reliability liabilities are large) and the upper edge can be worked out with a degree wheel and some careful measurement.

My best experiences have been to shape that closing edge for airflow, not shooting for a specific timing. And the side seal tip landing zone MUST be addressed properly for engine life.

 

Here's a 4 part video series of a guy flow testing a bunch of stock and modified ports. The wax molds their cross sections really help illustrate the shape of the runners.