I'm just finishing getting everything together for a rebuild (non-turbo six port) and the day is fast approaching. Now, I know what the answer to this would normally be, but here's my situation: Like I'm sure I mention in all of my posts this engine is going into a miata and will be run on a megasquirt w/ a custom wiring harness I built. Nothing is being overlooked; I'm getting a custom long tube header, big ol' street port, serviced red top injectors, lightweight flywheel, yada yada. No corners cut.

Now, I originally planned on running IRTBs from the start, but I dont know if the $:hp ratio is sound enough to justify it. I bought a set of pineapple racing aux port inserts and I was planning on just permanently attaching them to my irons (drill/tap a hole into aux port area, jb weld piece in, add a bolt w/ locktite through hole to secure in place.)

I decided to spend $30 instead of $1000 and got a stock manifold for now, just to get this thing running faster. The stock manifold of course has all these little silly vaccum actuators on it. Being that on a megasquirt you delightfully only need one vaccum line, I would love to throw those guys out. And besides, don't you need an air pump to operate them? (I'm not running one)

So, being that I have never owned (or driven ) an rx7, I have no idea what kind of consequence it yields to have these guys permanently open. Now with the irtbs, I was fine with sacrificing low-end for all-out flow but now that i've got the stock manifold it got me thinking: is it worth it to be able to open and close those ports? will I notice a rewarding gain in low end power and mileage? I mean, megasquirts have a solenoid switch control (like for vtec, for example) so I could (theoretically) wire in some electric servos to operate the aux ports and aux runners at a certain rpm, or be simple and rig it all open. I will be driving this thing on the street, btw, but I laugh at people who whine about 'drivability.' I just might be more inclined to do it if it would significantly affect mileage or something.

What say you? will it matter? should I give a ****? who was phone?

 

I have owned and driven various 6 ports (and turbos) and can tell you that having them permanently open does sacrifice enough low end to make you wish they weren't permanently open.

However with your lightweight flywheel and lightweight car it will at least be tolerable I suppose.

 

I have mine open and the low end does suffer but its not too bad. just expect too do alil more downshifting to jump passed people.

All in all its not really too noticeable and you will soon forget. Which is alot to say considering my daily is a stock s4 with leaky primaries, no emissions, and COI. I probably make 2 hp more than from factory.