Different RB headers have me confused...
 

I hope somebody can help me out soon-I'm planning on placing my RB order in the next few hours...

I found a good deal on a Racing Beat header that's supposed to be for a 13b 4 port, but I'm going to be using it on an SE's 6-port engine. The official RB title is: "Streetable Header/Collector 81-85 RX-7 13B 4PT", and the part # is 16011. Kinda confusing for me, but I'll buy it at the discounted price if it'll work with my 6-port. What's the difference between them, and will this work with a modified 13b from an SE converted to carbs (for the time being-only to get it up and running before I build the turbo'ed engine)? It should, shouldn't it?

Thanks for your help guys-I had been searching for the past hour or so and haven't come up with any answer yet...

Don't quote me on this but the difference should be the little exhaust backpressure tube used to activate the 5th-and-6th-port actuators.

The actual spot where the header bolts up should be the same - same gasket, bolt spacing, etc... But you'll have to wire your 5th and 6th ports open.

Of course if you're converting to carb, you probably have all six ports open all the time anyway, since closing them off is a feature of the stock intake manifold.

So I say go for it.

Jon

Well...all of RB's exhaust components for the SE have the backpressure sensing tube located in the presilencer. I had thought of this, but the RB header for the SE doesn't include it-they locate it in the presilencer. Their SE header is part #16013, and the only difference it mentions in the descriptions are the flange thicknesses-1/2" for the 4-port and 7/16" for the SE's.

My best guess would be something to do with exhaust passages in the rotor housings. I'm going to be searching and asking a lot of questions when I build the turbo'ed engine to find the best way to plug the EGR internal passages in the SE housings, and I'd say that the flange for the 4-port version may cover some passages that aren't in the SE, or only partially cover a passage that's on my SE's housings. Why did Mazda have to make the little details like this so confusing? My brain's starting to hurt...

I have a welder and can fabricate what I'll need to make it work if the problem is some stupid little exhaust passage that the header covers (or doesn't), so if nobody else knows what the difference is I'll just order it and make it work. I'll only use it for a few months or so while the REAL engine is being built anyway...

Thanks for the reply man, I appreciate it. BTW-I am using the aux ports, the actuators will be operational. I'll have a few bugs to work out, but they will work-they had better anyway, as much as I've spent finding parts for 'em and searching for the info I need to get them to work. This header has really got me stumpted though...

Please let me know if anyone of you has any info that may help me! Thanks...

I bet the only difference is the clearance needed for the center iron protrusion on the SE block. Crit just ran into this with an old 13B header he tried to bolt up to his SE block. The center iron has a rectangular protrusion down near the tension bolt. It sticks out a good bit and may be a clearance problem. Crit solved it with a angle grinder and it bolted right up.


-billy

Cool-thanks. I was hoping it'd be something easy like that. After I ordered it I started thinking there may be clearance issues with the aux. port actuators, which may present a problem with my application. The description doesn't give you any real details on it, so I hope it's something like you've suggested Billy.

For what it's worth, I wonder why they even bother making 13B flanges that would interfere with intermediate engine mounts. Why not just clearance the flange and sell the same damn thing across the line. I suppose it hurts the cosmetics a bit for the early and bastard blocks, but it sure would make everyone's life easier down the road. Oh well.

Nope, no issues

I am betting you'll be doing some grinding as mentioned above. The other primary difference is that the 16011 prob does not have a O2 bung in it, any muffler shop can take care of that though.

Cool-this is sounding better and better for me! I've got dual O2 sensor bungs that I'm planning on welding in each of the primaries to aid in tuning, so the missing O2 bung would not be a problem.

84stock-did you mean that there won't be an interference problem with the aux. port actuators? That's my biggest concern at the moment...Thanks for everyone's help and input on this subject!