So I can't really afford the corksport through pipe to replace my cat. I've been worried/annoyed by the sound coming from my damn cat.

My 87 NA has a really nice header coming off and collecting at the cat. Then some what I believe to be stockish mufflers. The car is really quiet except for some hollow rapping at the cat.

So I took the cat off and as far as I can tell it's been hollowed out. There wasn't a god damn thing in it except what looked like a nail and a thick metal grating at the header side.

So I ran to Advanced and bought an 18 inch 2" pipe and hammer the mother F'r all the way through the cat and plan to just bolt this back onto the car. The pipe was a little bigger on one end so that another 2 inch pipe could be put in it. That made it very difficult to get the pipe the entire way in. I cut off the majority of the excess and the other end is about 1/2" from the exit of the cat.

I plan to weld a bead around the section that didn't quite make it to the end, in hopes to keep any exhaust from going back into the cat. The only upside thus far, is the fact this will pass the visual where I get my car inspected.

Anyone see any problems I may run into with this? Will this get rid of the horid hollow noise that came from the cat? I want to put the resonators off of my 86 onto this car since my fiance is driving the 86 (she likes quiet cars).

With the resonators + straight pipe (sorta) will I find some more power vs. the hollowed cat + quiet mufflers???

 

Just save up and buy a real exhaust or just buy the straight pipe later when the money is there.

 

how are you ports going to open without the backpressure? Without wiring them open all the time you will most likely loose power. Do a search on how to wire your ports open.

 

The 5th and 6th ports are actually broken. I'm REALLY not in the mood for taking the lower intake off... I've already taken the upper off a dozen times in the last month. The actuators are stuck solid, and the rear operator (the part that actually turns the port) is broken and does not turn the port.

Oddly enough, the car pulls VERY strongly all the way up to 8k. So maybe they are stuck in the open position? One could only hope...

As for this stupid pipe-n-a-cat, the bolt and nut were shredded on th cat, so now I have to go and try to find a nut that'll fit the new threads I made on it. Add in that it's windy and rainy today, I dunno when the hell I'll get her put back together.

 

I'm not sure how it would exactly hook up to the header, but I got a straight pipe put on to replace my cats for something like $75.

 

The corksport straight pipe would hook up just fine, I just don't have the 75 bucks right now. My extreme boredom was the only thing that allowed me to spend 5 on the pipe to shove into the cat.

 

Damn man, I sold my old RB cat replacement pipe like a week ago, to someone on the forum real cheap.

Wish I would've known you needed it.

Try PBlaster on the actuators to free them up, they're not hard to remove...2 10mm bolts. Take em out, lube em up.

James

 

Any pipe you've bought from Advance is all but guaranteed not to support the heat emitted by a rotary engine. ESPECIALLY one that is encased in something that retains heat very well like a cat does. I'm pretty sure if you run this for any decent amount of time that you'll melt the pipe inside your cat and ruin both.
I've heard of flowmaster mufflers melting due to our engines.

 

I wouldnt worry about a visual inspection. Most of the time they just look under and see what appears to look like a cat and your good to go. Yes you should technically get a very slight horsepower gain from directing your exhaust straight through the cat. Not that you will notice much of a difference though.

 

Haha, well it'll give me a good reason to beg the ol' lady to lemme spend 75 bucks on a straight pipe =)

 

Well, I had that exact same setup for a while. Eventually the weld on the Header side broke apart completely and would fill the cabin with exhaust. Also, you are introducing a huge restriction in the exhaust by using the 2" pipe.

After switching to a full 2.5" open exhaust I noticed a big improvement in power.