Gentlemen,

Headers for a GSL-SE have a return pipe that opens the aux ports with back pressure. This fact would seem to contradict the whole purpose of headers; Reduced exhaust backpressure equaling increased horsepower.

What are the benefits of putting headers on a GSL-SE if the backpressure remains consistant with the stock setup to the point that this pressure will still open the aux ports?

I'm interested in possible purchase of headers for our 84 GSL-SE as the easiest bolt on mod but have nagging questions on the benefits to be gained vs just staying stock. Of course the racing beat setup with complete pipe and muffler is not an inexpensive mod so I was wondering what the RX-7 crew has to say on the matter as I decide whether to take the plunge.

Also at heart I'm a closet fan of keeping her stock just because. So the return ought be worth the compromise

What say ye?

 

I installed headers & presilencer on my 84 gsl-se & have noticed an increase in performance.

The inlet pipe for the aux ports is small - maybe 1/4" & i don't think it can create any significant back pressure.

I've been very with that upgrade.

Hope this helps.

 

Which header system did you install?

Did you stay with the orginal muffler then?

Did you notice a significant change in exhaust tone and loudness?

 

i believe some people are wiring the aux ports open when installing a header.

 

there is a little more to the situation than just that.

1. the RB "pressure tube" goes into the pre silencer and then turns to face the engine, so it works more from flow than pressure

2. i've never measured a stock gsl-se, but my stock FC had something like 5psi of backpressure at high rpm stock, lowering it to 3 made a seat of the pants difference. mazda has a backpressure vs power graph in the "rotary engine" book. at 3psi the ports will still open.

 

The "Street Port" system from Racing Beat (with the dual presilencers) is supposed to give an all around improvement, though mainly in the lower revs.

For a while, I had just the headers and dual pipes going to my stock muffler, which in '81-'82 had the pipes still separate until they hit the can. It was loud, high pitched, tinny and obnoxious. I put on a Racing Beat Street Port muffler 3 months later and it's MUCH quieter, and the tone is deeper. I think the reason is because they are joined a little before the muffler and the pulses cancel each other out.

Mazdatrix sells a modified Racing Beat header that has an outlet for auxiliary port activation right on the front exhaust port, but I've been having some trouble getting them working.

 

yeah i should mention going from stock to the RB street port system, is like night and day, more power everywhere

 

This question seems to come up a lot, and I'm still surprised at the # of people that just wire their '6'-ports open (or closed) and leave them that way. Mazda designed the system as a variable bridgeport which allows it to operate like a static port at low RPM (low pressure) and as exhaust pressure builds with power, opens the '6'-ports to adjust intake timing event and air volume. This also has the effect of utilizing high port air flow at just about any RPM range which works with the Dynamic Effect Intake system to give a very flat torque curve.

Wiring them one way or the other kills that effect, and limits the intake and power output entirely.

I'm running the Racing Beat -SE header with O2 sensor bung to the Power Pulse presilencer, stock mid-pipe, and a Power Pulse rear muffler. This setup is docile on the ears, but when you open up the throttle, it has a good sound to it - not too shrill, and not like a lawnmower at the end of a 14ft steel pipe! The Racing Beat headers are same length so the exhaust pulses are timed when they hit the collector to help with extraction. Also, as the other poster mentioned, the '6'-port actuating tube is belled and curved toward the oncoming exhaust flow, helping to build enough pressure to operate the ports. Only 3-6 psi is required to operate the actuators on the intake as long as the gaskets are good, the port actuators move freely (and hold pressure), and the port sleeves are able to turn freely by hand. If anything gets bound up, you'll end up with sticky sleeves which can cause all manner of weird top end power fluctuation at WOT.

If you're running a stock SE right now, you'll be pleased with the sound and performance gain from a set of RB headers. Some guys here think the exhaust note is too tame with a presilencer and PP muffler, but I'm not interested in getting a lot of attention from how my car sounds, as I'm more interested in reliable power and a smooth torque band across the RPM range that you'll see in traffic.

 

i had both RB systems on my gsl-se, and you gain a ton of low end with the street port system, so much so that with the 6 ports tied open on the SP system, it still was better than the shorty setup under 3500 with working 6 ports

working 6 ports with the SP system was the best all around

 

Which RB system would work best on a stock 82 GSL. I"m assuming that their header pre silencer and PP Mufler would do the job? This is my first mod to my car and I'm wanting to make it a good one!

 

The Street Port system (dual presilencers) work best with stock engines.

 

I don't mean to hijack this thread, but I have a question along a the same line. I have a stock base model '83 and I purchased (was told it was RB, but it does not have the RB cutout where it bolts up to the engine block.....it does look like the RB model...it's very thick gauge and has that "sort of" Chrome finish). Anyway I was told it's a direct swap (4 bolt on the block and 2 bolts at the collector).....am I missing something? What is all the talk of a 6th port? Are there other factors in the installation I should be looking at....I'm a newbbie and would rather ask a dumb question than make a dumb mistake.

Thanks in advance.

 

The 6th port thing is only if you have a GSL-SE ('84/'85 cars with fuel injected 13B). The non-turbo 2nd gen cars also have the setup. You don't need to worry about this since you have a 12A.

What the talk here is about is that cars like the GSL-SE have these additional intake ports which open at higher loads. Mazda did this to improve the power band. It allows the low end to remain good and then open these ports when needed for good top end. These ports open based on exhaust backpressure. The original poster was worried that adding the RB system might reduce the exhaust pressure too much. If this was the case, the 5/6 ports would not open. So, the question was whether the increase in power due to having a better exhaust would offset not having the 5/6 ports open. It is not a problem, though, as RBs setup is designed so that the ports will still open.

 

Guys appreciate the feedback on the 5/6th port openning setup on the RB headers. Your feedback cleared up and answered my questions on how the port setup works with the high performance exhaust products.

Now I need some additional advice on the two header options offered from RB. The "street Port" system and the "Stock port" systems. The Racing Beat website states that the "street port" system works on stock as well as ported engines and offers 5% more horsepower. What's the rest of the story on making a decision between these two direct bolt on systems. I don't intend on porting the engine; but do like horsepower!

 

The flow of the exhaust into the inlet to the aux port will cause "pressure" and the ports will open.

Does not particularly mean your exhaust has much backpressure, regardless engines require some backpressure to run well.

My FC with only a cat (Exhaust was stolen) had little to no power till 2.5-3k rpm then it was ***** out, and all the way up to 8k it was massive power, man that was awesome going through that mountain road... the backfires were like claps against the pavement hehe.

Then with the motoria exhaust I got after, there was more low, mid, and high lowered. With the corksport I had there was more mid, and high.