MARKHBCA

I've been building piston engines for some 25+ years now, and thought I'd try something a little different in my newly acquired Sand Rail. So I got a 1987 13b NA.



Being that I have years of experience with Holley Carbs I ordered the RB Holley Intake from Mazdatrix. While installing my new Intake Manifold I noticed something STRANGE...the AUX Port Sleeves, I'd never seen anything like this before, this is my first Rotary build.



So I called Mazdatrix and inquired about what to do with these things. I was told that I should have bought the $950 kit because it comes with the directions , or to search the forums.



So here I am searching endlessly for weeks now on several forums and still don't know what to do with the Aux Port Sleeves when using an Intake with no provisions for the actuators. My best guess is to just remove them and suffer with the loss of low end but I'm not one who guesses when building engines. Any help would be greatly appreciated.



Mark

j9fd3s

yeah you just pull em out. you loose low end power, but how much depends on the exhaust. if you get the exhaust right, you loose under 2000rpms, and who cares about that?



exhaust needs to be reasonably low restriction, headers, 2.5" piping, straight thru mufflers are better....

ColinRX7

I wouldn't really worry about not using the sleeves. Like Mike says, if you get the other details right, you'll make more power anyways without the sleeves. I liked my FC with no sleeves, different intake, and free exhaust.

j9fd3s

this is an old test, but heres my infoz



car: 84 gsl-se, s4 engine, light flywheel (thats now balanced and told its going to be spinning to 11,500!) working 6 ports, stock ecu/fuel/ignition



1. working 6 ports, RB short header, pre silencer, RB muffler. this is baseline.



2. as #1 but with 6 ports open. power under 4500rpm is GONE, feels like i'm waiting for a giant turbo to spool up



3. installed RB long primary system, working 6 ports. more power under 6000 than #1, #1 has 5-10hp and is peakier.



4. #3 with open 6 ports, much better low end than #2, very comparable to #1, except down slightly @6800-7200rpms, where the short header works better



so with the 6 ports open, low end depended a lot on the exhaust. the long system makes more average power, but its not apples to apples, as it also uses larger piping... they are both theoretically tuned to make peak power around 6500ish

RONIN FC

Yup, pull the sleaves out.



Its gonna be tough getting a steady vac signal with the 6-port motor. You need to fab a plenum under the carb to give that pressure wave a place to go. If you dont, you will get fuel standoff.