KCGSLSE

Did a search and got conflicting answers. Does the racing beat streetable header have a threaded bung for the o2 sensor? You can't tell from the pic on the rb site. I thought the difference between streetable and road race was no o2 / no airpump provisions.

Do I have to order from mazdatrix if I want a header with a hole for the o2?

Also is the stuff that mazdatrix sells the same as racing beat? All the exhaust components are exactly the same price and look pretty much the same.

I want to do a full exhaust for my 84 gsl-se and I was just going to get the racing beat setup since it seems to be the best option but I wanted to make sure that I would still be able to plug in the o2 and the air tube for the 5/6 port actuators. I saw the twin presilencer system on mazdatrix and was wondering if it is significantly better than the single presilencer setup. Their site says the twin system provides actuation from the front exhaust port and I'm not sure how this works.

ChasRX

They are the same exhaust systems. None of the headers allow for an oxygen sensor.

Siraniko

iTrader: (13)

there is a bung on the collected 13-B header. You have to specifically ask for it. Or just go to a muffler shop and have them install a bung.

LongDuck

To be clear, the header is not the same for EFI/non-EFI systems, as the presilencer has the lead for the '6'-port actuation on a stock motor, and the header has an O2 threaded bung.

Check these pictures from Mazdatrix (where I bought mine, incidentally);

Header with O2 bung;


Presilencer with '6'-port lead (also for use with stock Airpump):


My setup as received from Mazdatrix for the 84SE works with stock airpump up and operational, working '6'-ports fed from presilencer and O2 sensor installed and running. Overall performance and sound impact is amazing. Highly recommended,

steve84GS TII

I added a bung on my 12A header,easy enough and cheap.
The GSL-SE/FC headers should have one already since its needed for proper engine operation.
My collected SE header had one already,not sure about the dual system.

Siraniko

iTrader: (13)

Other than that, it will still bolt-on to any pre-86 13-B (SE or not).

KCGSLSE

I think I am going to end up going with the dual system. Mazdatrix offers it with both the o2 and actuation tube apparently.

"13B 6 PORT (using injection, has 6-port actuation and O2 sensor).. 16-MZTX-4230"

Im getting excited.

If anyone is running the twin pipe system, does it differ that much from the single tube system that forces you to reuse the stock connecting pipe? (which is all welded and jacked on my car)

LongDuck

Well - you might want to check with them on this to be sure that it will still operate your '6'-ports the way they were designed.

The stock SE exhaust system brings both exhaust impulses together right at the exhaust manifold, then routes this through Monolithic Catalyst #1 and #2, then into #3 which is the Catalytic Converter that your AP is pushing air into. Within the Catalytic Converter (the big one), there is an air pressure tube that the AP feeds, but under acceleration, the AP is routing air into the exhaust ports on the engine (via the EGR valve on the LIM), and the backpressure from the cat is allowed to come back up that pressure pipe and into the tube that 'powers' the '6'-ports. These ports only open under hard acceleration above 3800 rpm (stock).

Each port requires approximately 3-6psi of back pressure to operate, which is combined in the backpressure provided by the volume of gas expelled by the engine under acceleration above 3800 rpm. This has the net effect of providing 'variable intake timing' on your 13B-SE engine which opens up alternate intake paths just when you need them. At lower engine speeds, the engine needs high velocity air - at higher engine speeds and heavy acceleration, the engine needs LOTS of air.

If you split the exhaust collection point to behind where the air pressure line feeds the '6'-ports, you will only be sensing 1/2 the air pressure, since you're only connected to one exhaust port. This is guaranteed to NOT provide enough backpressure for your '6'-ports to open when they should - if they ever open at all.

Inop '6'-ports will lead to poor low speed acceleration, reduced low rpm torque (that the SE is known for), and also greatly reduced high rpm torque and power. Wiring them open gives you the top-end advantage, but at the expense of low end torque.

The system that I've been running for years is the Mazdatrix (Racing Beat) header/collector, and presilencer that has the pressure feedback tube installed. This has been proven to correctly operate the '6'-ports at 3800-4000 rpm when it should as long as your '6'-port sleeves and actuators are working correctly.

You'd be amazed how many people have inoperable '6'-ports and don't know it. HTH,

Rm4TWO

How do you tell if they're working or not?

KCGSLSE

This is straight from the mazdatrix website...

"We have also tested the six-port actuators on 84 through 92 6-port engines, and found them to need about 2psi to open. The best opening RPM we have found is right about 3400 to 3600 (relatively stock engine). A single pre-silencer system generates enough back pressure at the pre-silencer to open the actuators, but a dual (side by side) system does not. Our dual systems provide actuation from the front exhaust port, which works excellent. We have tested systems available from other suppliers, and found them to either open too late, or not at all! Also note that the 89 through 92 cars use the air pump to actuate the 6-ports. Our method allows you to either leave the air pump active, or remove it."

They are saying the dual system uses the front exhaust port to open the 5 & 6 ports and "works excellent". Im hoping it will work since I just ordered it today. I told them that I needed the actuation and the o2 sensor so hopefull they will deliver what their website promises.

Can anyone with the dual racing beat system (i.e. streetport) comment on it?