Got my header! (question)
Thread Starter
Environmentally-Hostile
Joined: Sep 2005
Posts: 1,662
Likes: 3
From: Ennis/Arlington Texas
Finally got around to putting her on today. Took me around 5-6 hours total, but nothin really difficult. I was also helping my brother with his 306.
Here is my gratuitous open header video!
http://www.youtube.com/watch?v=Sx_14hpQRMQ
I still don't know if I'm satisfied with the power of it. Still feels like its being held back some. I think a cap and rotor will be next, and I have to refine my six port actuation setup, because I don't think its working at the moment.
edit: before anyone asks, the battery was low which is why it cranked slowly
Here is my gratuitous open header video!
http://www.youtube.com/watch?v=Sx_14hpQRMQ
I still don't know if I'm satisfied with the power of it. Still feels like its being held back some. I think a cap and rotor will be next, and I have to refine my six port actuation setup, because I don't think its working at the moment.
edit: before anyone asks, the battery was low which is why it cranked slowly
Thread Starter
Environmentally-Hostile
Joined: Sep 2005
Posts: 1,662
Likes: 3
From: Ennis/Arlington Texas
Uh what? Its a video, recorded from a crappy digital camera. I can almost promise you an open header 13b will be louder than a 12a. Trust me, this car is deafening to drive, far louder than my old 5.0 mustang with open headers.
Thread Starter
Environmentally-Hostile
Joined: Sep 2005
Posts: 1,662
Likes: 3
From: Ennis/Arlington Texas
Just to update this thread out of posterity, (as I received several PMs about it) I never could get the auxiliary ports to work with the exhaust tap. So if you plan on doing something similar, it is at your own risk.
84SE-EGI helpy-helperton
Joined: Oct 2002
Posts: 3,584
Likes: 542
From: Phoenix, AZ
Wanna know why (over a year later)?
The tap location you used is far too close to your front rotor exhaust port, and additionally, would only 'see' the exhaust pressure from ONE rotor. The stock location for the '6'-port pressure feed is on the main cat, which sees pressure normalized from BOTH rotor exhaust pulses, and is also much further from the high-temperature exhaust coming out of the engine core.
On top of that, the '6'-port actuators use rubber bladders inside to contain this pressure, and routing that hot exhaust gas into the pick-up tube probably toasted your port actuators.
Racing Beat designed their system with these facets in mind, and I've not had any issues with the aftermarket RB stuff as a swap-in system, i.e. PowerPulse muffler, Pre-silencer, and Header using the stock connecting pipe...
The tap location you used is far too close to your front rotor exhaust port, and additionally, would only 'see' the exhaust pressure from ONE rotor. The stock location for the '6'-port pressure feed is on the main cat, which sees pressure normalized from BOTH rotor exhaust pulses, and is also much further from the high-temperature exhaust coming out of the engine core.
On top of that, the '6'-port actuators use rubber bladders inside to contain this pressure, and routing that hot exhaust gas into the pick-up tube probably toasted your port actuators.
Racing Beat designed their system with these facets in mind, and I've not had any issues with the aftermarket RB stuff as a swap-in system, i.e. PowerPulse muffler, Pre-silencer, and Header using the stock connecting pipe...
Thread Starter
Environmentally-Hostile
Joined: Sep 2005
Posts: 1,662
Likes: 3
From: Ennis/Arlington Texas
Wanna know why (over a year later)?
The tap location you used is far too close to your front rotor exhaust port, and additionally, would only 'see' the exhaust pressure from ONE rotor. The stock location for the '6'-port pressure feed is on the main cat, which sees pressure normalized from BOTH rotor exhaust pulses, and is also much further from the high-temperature exhaust coming out of the engine core.
On top of that, the '6'-port actuators use rubber bladders inside to contain this pressure, and routing that hot exhaust gas into the pick-up tube probably toasted your port actuators.
Racing Beat designed their system with these facets in mind, and I've not had any issues with the aftermarket RB stuff as a swap-in system, i.e. PowerPulse muffler, Pre-silencer, and Header using the stock connecting pipe...
The tap location you used is far too close to your front rotor exhaust port, and additionally, would only 'see' the exhaust pressure from ONE rotor. The stock location for the '6'-port pressure feed is on the main cat, which sees pressure normalized from BOTH rotor exhaust pulses, and is also much further from the high-temperature exhaust coming out of the engine core.
On top of that, the '6'-port actuators use rubber bladders inside to contain this pressure, and routing that hot exhaust gas into the pick-up tube probably toasted your port actuators.
Racing Beat designed their system with these facets in mind, and I've not had any issues with the aftermarket RB stuff as a swap-in system, i.e. PowerPulse muffler, Pre-silencer, and Header using the stock connecting pipe...
Racing Beat does sell a Road Race Header with a pressure tap like Starfox's and Mazdatrix sells a header modified the same way. The difference I see is that they put tap it right in front of the exhaust port, so more exhaust flow is channeled directly into it.
84SE-EGI helpy-helperton
Joined: Oct 2002
Posts: 3,584
Likes: 542
From: Phoenix, AZ
Hey, somebody contacted via PM asking to expound on the purpose behind the presilencer, and the PM system only allows 1000 characters (go figure). Reposting it here, and hope the PM guy read it;
The purpose behind the RB presilencer is to combine the exhaust pulses from the collector, cool them, and also provide a pressure source for the feedback tube that 'powers' the '6'-ports (the Aux Ports in the intake). You need about 3-4 PSI of pressure to operate the diaphrams that open the aux intake ports when they're working smoothly, and more than that if they're gritty/gummy. Assuming they're pretty clean, the presilencer has a tube that is bent toward the incoming flow of exhaust gases so it gets a solid pulse of pressure under WOT. In fact, WOT is the only time you'll see 3-4 PSI in your exhaust muffler anyway.
If you go without a presilencer, the exhaust pressure will never be great enough to develop enough pressure to operate the ports because velocity increases as volume/pressure decreases; this is known as the Bernoulli Principle (google it). In other words, if you don't allow the volume to build up early in the system (the presilencer), then velocity remains high and pressure remains low - too low to operate the ports properly.
I've been running the full RB exhaust for many years now, and it's a solid, reliable setup. You can do a lot to get the pressure you need using vacuum ports, routing pressure from a fish tank motor, etc, but it won't be reliable, and will be a lot of stuff to troubleshoot down the road.
You may have already made up your mind, as it's been a couple of weeks, but that's my take on it. Good luck,
The purpose behind the RB presilencer is to combine the exhaust pulses from the collector, cool them, and also provide a pressure source for the feedback tube that 'powers' the '6'-ports (the Aux Ports in the intake). You need about 3-4 PSI of pressure to operate the diaphrams that open the aux intake ports when they're working smoothly, and more than that if they're gritty/gummy. Assuming they're pretty clean, the presilencer has a tube that is bent toward the incoming flow of exhaust gases so it gets a solid pulse of pressure under WOT. In fact, WOT is the only time you'll see 3-4 PSI in your exhaust muffler anyway.
If you go without a presilencer, the exhaust pressure will never be great enough to develop enough pressure to operate the ports because velocity increases as volume/pressure decreases; this is known as the Bernoulli Principle (google it). In other words, if you don't allow the volume to build up early in the system (the presilencer), then velocity remains high and pressure remains low - too low to operate the ports properly.
I've been running the full RB exhaust for many years now, and it's a solid, reliable setup. You can do a lot to get the pressure you need using vacuum ports, routing pressure from a fish tank motor, etc, but it won't be reliable, and will be a lot of stuff to troubleshoot down the road.
You may have already made up your mind, as it's been a couple of weeks, but that's my take on it. Good luck,
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