hey everybody (burp)

Here's what's what:

One day the frontmost cat. converter rusted through so the pipe broke and slid out of the flange thingy with the bolts in it. So I had these guys weld it, but of course they didn't want to take it off and weld it, so the top of the pipe has exhaust coming out of it. So I can smell exhaust from the middle of the car, and it's kind of louder than I'd like. Not to mention the exhaust on this car should just be flat out replaced because I need more HP.

Cats are expensive and here (champaign, IL) there is no emissions inspection to worry about. Hopefully it will stay that way, because I'd just like to remove the cats entirely. This is an 86 NA.

My main concern is 6 port and VDI activation or whatever, and also I'm wondering if anyone has any experience doing this to their daily driver. Like is the noise / backfiring a cop magnet? Does the exhaust smell worse? What about low RPM horsepower, doesn't that decrease with the increase of exhaust flow?

Also, anyone have any experience with this product:

RB Complete "Single" Exhaust System

http://www.mazdatrix.com/r-ex86nt.htm

What do you think about it? It's kind of pricey

Or would I be better off getting a shop to custom make the pipes and just buy the mufflers? There's a custom exhaust place right down the road from me. In that case, has anyone had a problem convincing an exhaust shop to bypass the cats on a licensed street legal daily driver? Also, what is a pre silencer and how much louder is it if you don't have one?

I did do search, but I have so many questions it just wasn't working out. I'm sure lots of mod newbs have similar questions about exhaust. Thanks in advance, you exhaust people you.

 

Deathbots, I can answer a couple of your questions. Yes it is gonna make the exhaust smell worse, but its the good old smell of rotarty :-) I haven't had any problems with the cops and the backfires, but then again, could just be me. Also the loss of low RPM hp isn't that big. It isn't anything that is gonna make it hard to drive, just gotta adjust to it.

 

I am currently ripping my cats and am also worried about the 6 port activation......anyone with some experience or knowledge wish to share how they conquered this problem? please?

- D

 

If you go with the RB setup, I think its able to open up the ports. I have the header/presilencer setup with a stock catback and the ports open up just fine.

 

well if it opens up the ports, maybe it's worth the money to me. Thank you all.

 

ok i still am wondering how i can shade tree mechanic the 5th and 6th ports.....After I gut the cats....someone please PM me or poist here a fairly detailed description of what to do and what to buy?

- D

 

NOTE: Only works on S4 (86-88) motors!

Just did this myself...

Tools needed:
Small Pliers
Drill
Knife

After making sure you can move the ports by hand, go to Home Despot (or the home and garden centre of your choice) and buy:

1 Brass Y-Splitter for a garden hose
1 Male brass coupling
1 Female brass coupling
1 brass endcap.
2 1.25" hose clamps

Go to Auto parts place and get about 12"-18" if (I think) 3/8th ID hose, and a suitable barb that with fit. Get some high-temperature sealant. You may already have a short length of hose that will fit, coming from the split-air pipe at the cat into the block.

Step one:
Drill a hole in the brass cap that is just big enough for 1/2 the barb to stick through. You do *not* want the barb to go all the way through. From the threaded side of the cap, insert the barb, seal with silicon and put aside to set.

Step Two:

Remove the air dump hose from the car. The air pump outlet is right between the port actuators. The other end is a silencer. Keep the hose clips. You may want to remove the intake as it give you a little more room to work with.

Step Three:

Cut the elbow out of the air dump hose. This will be replaced by the Y-valve. Don't throw any bits away yet.

Step Four:

Screw the couplings into the appropriate area. The male coupling should be facing the block.

Step Five:

Using the hose clamps, take the smaller straight piece from the air dump hose and clamp it on to the male coupling. Take the longest piece and clamp it to the female coupling. The hoses have a much bigger ID than the coupling, but keep tighting the clamp. It will fit.

Step Six:

Get that brass cap from above and screw it onto the remaining threads.

Step Seven:

I could do a Hayne's Manual and say installation is the reverse of removal, but I'll avoid that for now. You want the bottom of the Y (the straight part) to attach to the block. Re-use the clips to secure the hose to the block and to the silencer.

Step Eight:

Get the length of hose, attach one end to the barb and the other end to the part of the split air hose that goes into the block. Put your intake on. MAKE SURE BOTH VALVES ON THE Y ARE FULLY OPEN!

Step Nine:

Start car and let it warm up. Test operation using the throttle while observing the ports. They should open quickly at about 3500.

Step Ten: Take it for a butt-dyno test. Be careful, the mule kicks a bit now.


(clarity edit)

 

ok thanks so much for the info....now i wonder if there will be any adverse side effects for when I buy a real exhaust that comes with 6th port activation nipple......there i said it nipple.
By chance do you have any pics of this installation?

- D

 

i have my air pump removed and the ports wired open, they were done like this when my exhaust was installed so i don't really know what they feel like coming on. to someone who has had them wired open, and also had them actuated by a mod like the one explained above, what do you think is overall a better way to go? or , would it be best to get those slleves from pineapple racing. ( and once i have those, do the ports need to be actuated)

 

Its definitely best to have the ports work as they were made to do. I am not certain about with a straight pipe whether the ports would open(Ithink they could). But I know that mazdatrix sells a modified header that opens the ports.

 

Right HERE .

The thin hose near the bottom connects to the nipple that you are talking about above.

EDIT: 56k modem users warning - big picture and sorry about the fuzzness. I'll take some better pictures tomorrow after the car is nice and cool and I can take the hood and intake off.

Z

 

Thanks for the pic to see but well........if anyone else has seen the pic it kinda reminds me of a Roshik(sp?) test.....you know the one with a smudged ink blot and they ask you what it looks like and you say something to the effect of "What is that woman doing to that horse?", then the psychiastrist claims insanity in court....or maybe that is just me....

- D

Can't wait to see a clearer image!!!

 

ok no new images or suggestions on this topic? Ok guess I am going to Home Depot or something similar.....

- D

 

I've been daily driving the RX for the last few day and not bacl until it's too dark for pics.

I've got a early shift tomorrow, so I should be able to get some daylight pics.

(getting home at 2am is *not* condusive to good pictures. )

 

hey Zed any luck with the daytime pictures yet?

- D

 

go not cats it was the best thing i ever did to my car it made a huge difference in sound and performance. but with a rb muffler and stock header the sound really isn't too loud and hardly audible at cruise. and gave me enough power to run a 15.2

 

Way to bring back a thread that's over 2 years old.

 

so what..................... bring the dead back!