Hey all,

Trying to make the most out of a very simple stock 13B 6 port. For background, it is in my '83, and both the car and rotaries are new to me. The car was once a Pro-7 car and was a no-engine barn find for me. All stock wiring has been removed and exchanged for a basic set up using the stock distributor and a 48 DHLA.

The engine is freshly rebuilt using an Atkins kit; it has no porting. Oil meter is removed and capped and I run pre-mixed pump 92. Carb has been rebuilt with float level set at 15mm/28MM, and fuel pressure is regulated at 2.5 PSI. I noted part numbers from the e-tubes and jets but can't think of them offhand.

After several hours of tuning and breaking in, the car is finally idling pretty smoothly. It revs slow from 1500-4000 and then takes off. From what I've read, that is to be expected with this 6 port setup.

So, I pulled the lower manifold off and discovered the the aux. port inserts are completely gone. Engine was delivered to me with the manifold attached and I didn't think to check for those. There are also no provisions for the insert controls in the manifold.

Trying to figure out now what my best option for those would be. Should I leave them open? Should I replace them with stock inserts and set them to some degree of "open"? Should I replace them with and aftermarket insert - Pineapple and Atkins make some that I have heard of, but don't know if others exist. Will any of these things give it some more grunt below 4000?

Thanks in advance for your feedback and suggestions!

LQ






Here's a recent shot of the engine in my car.

 

Personally, I like functional aux ports, although the question is whether it would be worth the effort to get them working again. I guess it comes down to your personal feelings on the subject. If you do install them, make them fully-functional or fully-open, not partially-open or fully-closed.

That engine will work fine on 87 octane, so you are just wasting your money on 92 octane. Contrary to slick misleading marketing, most brands put the same additive package in all grades of their fuel, not just the premium grade. See Top Tier retailers here: Retailers

 

Good info, Evil Aviator! Thanks.

 

That and you would have to completely change your intake and carb setup to make them work (i believe looking at the pics)

 

Assuming that you have an unmolested 6 port lower intake manifold on there, then theoretically it would just be a matter of reinstalling the port sleeves.

Problem after that is control. The stock system used exhaust backpressure to run a set of actuators. None of that will work in this case.

There are a LOT of methods tossed around do this including a small air pump on a RPM switch, solenoids on an RPM switch, lock actuators. It sort of depends on how far you want to go.

The method I'd suggest is a large solenoid (shaved door kit) mounted somewhere in the engine bay, with bicycle cable connected to pull on the port lever. Then use an RPM switch to open them up at 4000 RPM. Of course the stock system is both RPM and load based, but RPM only is acceptable.

Whether it's worth it depends on how much you want to put into this. The stock manifold actually takes advantage of the port timing to create an inertial supercharging effect. Won't happen with yours but in the same sense decreasing the massive port volume at low RPM will make a large increase in torque.