Alright well i got my RB header and have a few questions: (GSL-SE, racing beat streetable header)

1: Will it fit up to the factory mid pipe/connecting pipe without the pre-silencer, or is it too short?

2: Is there a thread/post somewhere about where and how to drill and tap for the back pressure pickup line?

3: Am I correct in thinking that I have to cut and splice the 02 sensor line? The instructions aren't the clearest thing I've ever read.

 

bump. Somebody has to know at least the answer to question 1

 

I know the backpressure pickup tube is in the presilencer designed for the gsl-se. I do believe you have to get the presilencer for it to fit up.

 

That is what I was afraid of Now I'm gonna have to take it to one of the muffler shops in town so they can hack up my brand new header

 

First of all my impatient friend, you wait 24 hours before bumping up a technical thread.


2nd thing. That's all you had to do was call Racing Beat to get your answers.

 

Or, you could get the pre-silencer...?

 

you most likely will need a presilencer anyways i just spent almost 200 dollars on my exhaust (and already had the header), and now am going back to racingbeat for a presilencer and universal muffler which including the install will be almost nother 250 bucks.... the reasoning behind this, is the exhaust pretty much sucks without getting good stuff. Im guessing you are going with the exhaust you already have though, and just adding the header, i wish you better luck than i have had :-) just saying the presilencer is a good thing to have anyhow!

 

I am probably going to get one of their universal pre-silencers, the one that is only $100. Sorry about the bump...i did get impatient...lol

 

Since you are modding your system you might consider doing something along the lines of what Hyper4mance2k did with his. The difference would be that you are running the RB header and he is running the Rotary Engineering Road Race one.

You might get a more substantial gain by not using the RB silencer. This is something hopefully I will be doing as well this year.

 

So you would recommend straight pipe all the way back to the muffler?

 

Nope. I would take a look again at hyper's thread and see what he is using between the header and the muffler. :-)

 

Ah ok. A dynomax glasspack essentially.

Anyone have any info on what I need to do for the backpressure line?

 

I just put my header on this week. My car was already straight piped. well the cats were deleted. so now its loud!!! I'm about to go to work and I get to **** off all the neighbors lighting her off at 6:30 on a Saturday. I'm also driving her without use of my clutch...

you may want a pre silencer. nerve wrecking to have cops follow you.

 

don't forget to include some kind of backpressure pickup. my friend's car ran like crap without it.

 

Well I don't think I can afford a $240 presilencer so I'm going to just get another SS packed straight through to put after the header, hopefully it will keep it somewhat quiet, at least at partial throttle.

For those wondering about the six port, this is what I'm doing:
https://www.rx7club.com/showpost.php...61&postcount=7
https://www.rx7club.com/showpost.php...21&postcount=2

Took me a while to find a writeup

 

Got some work today done. Went to the hardware store and bought a 1/8 NPT tap and a 90* compression fitting. I was more than a little nervous drilling into my brand new $260 header...but managed just fine:

Used masking tape around the drill area to keep scratches off the finish to keep the rust away (actual drill location was a little different)



Fitting installed:



With copper tubing: (this is for the six port actuation system)



And here is what it looks like now with the DEI header wrap:



Not totally satisfied with the collector area, so I may redo that section.


Can't wait to hear how she sounds!

 

nice..if it were me i would just wire the 6 ports open..im sure your going for that stock look so that's good..

:AA:

 

I just want the car to run as Mazda intended. I have not had working six ports since I bought the car, and I'm tired of either having no top end, or no top end AND no low end torque.

 

THE MUMMY RETURNS!

Seriously, let us know how your pressure tap works. I'm running the RB presilencer designed for the SE with the '6'-port sensor tube installed. It is actually curved inside the main presilencer toward the direction of the incoming exhaust gas flow, and is belled slightly on the incoming end - presumably to catch more of the pressure wave as it flows from the exhaust. Even that has been found to be marginal in terms of operating sticky '6'-ports reliably.

I did a write up many years back on how to clean '6'-ports to free them up which requires removal of the Upper and Lower Intake Manifolds. This is really the only way to fix sticky ports that may or may not open with the Mazda-designed back-pressure diaphragms and sensor tube. It's not easy, but once you get them rotating smoothly, it does make a difference in both low-end and high-end power. Those guys that say 'just-wire-them-open' are trading convenience for performance, and probably haven't played with the car enough with a properly working system to appreciate it's purpose. Mazda went this route to get the benefits of increased port timing and duration without sacrificing idle quality or driveability - it's one of the main reasons why the SE 13b's have such a flat torque curve. The other main reason is the scavenging effect of the RE-EGI box, but I digress.

Suffice it to say that if you don't get the performance you expected, you might need to search for how to clean up your '6'-ports to make sure they're operating with as little pressure as possbile. Operating port pressures were somewhere around 4-6psi IIRC, and that came from the FSM. Plus, you will find that glasspacks won't last long under the heat of the rotary exhaust if you try to use one as a presilencer. Stainless packing with THICK-walled presilencer material is the only way to get that job done quietly, and is why RB parts are expensive. Good luck,

 

Oh I already cleaned up my six port sleeves about 6 months ago...but then I noticed I had no backpressure feed tube anyways so they still wouldn't work. They do spin easily now. Also, if you look, I tried to get a reasonably straight shot into the fitting from the exhaust port, without it being so close that it would burn up because of the heat.

Between regaining my 5th and 6th ports, replacing the clogged-to-hell cats, AND just having a better flowing exhaust in general, I'm expecting gains of around 35-60hp from just the header, that's how pathetic my car is now...

Anyone know what a full exhaust, but otherwise stock SE will run in the 1/4 mile? I probably won't take it, but I'd like it to be around a high 14 or low 15 second car, which is quick enough to be fun.

 

Car And Driver Results, March, 1984;

GSL-SE Acceleration Times;
0-30 - 2.5s
40 - 3.5s
50 - 5.6s
60 - 7.1s
70 - 10.4s
80 - 13.6s
90 - 18.1s
100 - 23.5s

Standing Quarter: 15.9s @ 86mph
Top Speed (quoted): 125 - but I know the car will go faster than that!

Here's some additional interesting info for SE owners from the same article;
Coast Down Measurements (drag and frictional losses)
Road Horsepower at 50mph - 12.5HP
Transmission and Tire losses at 50mph - 7.0HP
Aerodynamic Drag at 50mph - 5.5HP

HTH,

 

15.9 @ 86 is pretty damn good for 138hp! So with a header and full exhaust you think I could get a high 14 then? Its like a 25% gain in power.

 

no. I had 140whp and ran a 14.6 with a perfect 1.9 60ft time. it'll take getting rid of the gsl-se afm to make enough power to run in the 14's. Correct me if I'm wrong, but I haven't seen anyone with the stock AFM make more than 120whp. The GSL-SE had 135 Flywheel HP. which equates to about 108 to the wheels with a 20% drivetrain loss. well you could d it if you put huge gears in it. I remember when Blake (RIP) put 4.88's in his mostly stock SE with just a RB street exhaust and he ran a 14.9

 

Back in the day I ran a 14.8 with a RB header back & 17lb flywheel. I also had installed a nonpower steering box and ditched the smog pump. 5&6 ports wired open.

 

Yea I suppose a 14.9 could be done with just about 130whp when I really think about it, so yea. 14's here you come.