Stopped by a local muffler shop looking for some high temp wrap and an o2 bung cap. While I was there I got to talking to the owner for a bit which led me to post this thread.

The owner of the shop asked if I wanted a "custom" catback as I have yet to replace my factory one. I said the obvious...naah I was going to order one online. Trying to get my buisness obviously he asked for the avg. price of a premade and I said that the lower end starts at about $500. He said he could beat that price out the door and probably offer better quality. Mentally knowing that in order to turn a profit he would use the cheapest thing he could find which probably looks pretty and would easily please a ricer.

After walking around the shop for a little bit and noticing all the piping and bending machines and whatnot I got an idea. I asked how much he would charge to do a "custom" exhaust if I were to bring the mufflers and other components myself and simply need piping bent and welded into place. He said that if I were to provide the bits he would do the job for about $150.

Soooooo...for that price its hard to say that it doesnt make sense...that said what would the flying spaghetti monster do? What components would you want and why?

 

Interesting info...I can purchase titanium by the foot fairly cheap from a place in houston...it would require special welding or something tho...I'll call the shop to see if they can shape/weld just out of curiosity...

 

Many of the catback exhausts on the market are stainless steel. The even more higher price ones are titanium. These take special equipment to bend this type of pipe.
What is he quoting a price for, galvanized steel? This won't look very good and you will have to add stainless steel tips to clean it up. What kind of pipe bends does his equipment make? There are a couple of different types. Some put wrinkles in the pipe as it is bent. Some reduce the size and stretch the pipe as it is being bent.
What type of mufflers are he offering? Are they truly low restriction? Can they handle the heat of a rotary engine?
These are some questions you should think about and ask the shop owner before you ask him to do this work for you.

 

They had all sorts of tubing however I was only going to use the stainless 3" stock they had. They have a big machine that according to the owner performs mandrel type bends which I also had to be sure of. The tips I can find via summit or other locations so I am not too worried about that as of yet. The mufflers I am actually shopping around online right now to see what is availible. I am trying to figure out what the average inlet/outlet flow type mufflers that are commonly being used on the catbacks that exist now to do a price comparison.

Glad you asked the questions however I already also mentally had them answered. But at least someone is awake today and paying attention haaa

 

I'd do a 3inch pipe to the Y then run 2 1/2 or 2 1/4 to the mufflers and out.

 

don't bother with titanium, it's very diffuclt to weld and shaep and it's weight savings aren't going to be significant enough unless you are a pro class racer. It is nice to say, "My RX8 has a titanium exhaust!" to impress you friends, but is that worth the extra cost? Even if the shop says they can weld titanium to stainless, I would be highly skeptical. Welding Ti to Stainless Steel is very diffcult.
A full 304 SS 3" system would be hot. You can get some hi-flow mufflers from JEGS or Summit for cheap- look at Magnaflow- they have hi-temp race application mufflers in all different sizes that can handle the heat of the rotary.
Just be sure fitment is right and hot exhaust tips don't touch the plastic shrouds where they exit, or they will melt and be a whole mess. And make sure they secure it right so it doesn't rattle and vibrate and be a nuesance.

Dave

 

So ti is out of the question for the already stated reasons above...no bother...in my scouring for more information I ran into a couple different things.

I can get decent mufflers from summit and the whole rig will run about $400...Not too shabby for "custom" however I still have personal reservations...

In my research I ran into "Spintech" mufflers and I gave them a call. They apparently did a prototype catback for the RX a few years back and they were kind enough to send me pics and information.

And I quotheth...

"I remember the car sounded great, the only difference is our customer had some tips he bought and wanted to use. we have since made our own, 3-1/2" o.d. Stainless.system is 2-1/2" 304 stainless. $659.95 or aluminized steel with stainless tips for $459.95."

The attached pics to be quite honest simply just are not very pretty. I am not sure if the welds are due to its "sample" status or what, but theres also traces of rusting which also worry me. Its very simply not a pretty setup. Perhaps the final product is prettier, I have heard nothing but good things about thier line of product and would love to use it, but it just looks very cheapish and blah. I'm going to be emailing them back for more information so we will have to see.

 

Hey twinkie.... you didn't attach the pics.

 

And I loosely quoth...

"we made it but there doesnt seem to be much of a market so it really never got anywhere..."

I didnt forget to post em...I just had to get them on my server first...






And to be fair, I am hoping that they dont look like this normally...that this is merely the first run sample and a customer unit would be...nicer...

 

What would cause the rust... and what kind of mufflers are those? I never thought High-Temp mufflers would be needed...

 

They are spintech...they are very very unique and are highly desireable in my opinion for the internal design of the muffler. They are VERY effective at keeping noise down and increase in efficiency the higher in rpms you go...they also do this magic while keeping your backpressure low. rotarygod said a while ago that he liked the sound they made, and also liked the design. rotarygod is a pretty well respected exhaust guru so thats what also got me seriously considering them. They are all however handbuilt and everything is handwelded.

I think the pic we have here is the prototype and hence the welds are not pretty. The rusting on the welds could be simply that they had it laying around the shop and its been in water or something. I honestly dont know, but I am going to ask. They are cheap, supposed to be very solid performers and sound great. I am not put off on them yet.

I know youve also been looking for a catback...you interested? Maybe a group buy?

 

what is the size of the intake pipe before the Y.

beers

 

3"

 

sorry,

it is like two step downs... unless the intake to the mufflers are 4" i am not buying the size...

beers

 

I got an email in draft status now...I will reverify...they told me the 3" info over the phone. I am not certain if they said thats what it has or they could provide it. When I called he said that he thought so but to send him an email and he would go see if he could find the sample. So again dunno...list your questions and I'll get em to him...get it all sorted out...

for now...its mainly the welds that keep buggin me haa haa...

 

If anyone else has any questions let me know...I'm going to be sending that email later this evening...

 

Spintech = boat anchor

in this case, boat anchor x 2

and it was already done a long time ago

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/spintech-cat-back-exhaust-info-15737/

don't waste your time/money

 

So I read that entire thread and did not find anything that would scream its a waste. Perhaps I am missing something...care to elaborate a bit?

 

Ever thought of using the new Cherry Bomb mufflers? From the looks of them on their commericails on Spike TV they have one intake and 2 exit ports. I thought that would be a nice way to spit into the dual exhaust instead of the standard Y. Use that for your Y and forget about having to use 2 mufflers. This idea of course would require a little research to see if the new Cherry Bomb muffler can withstand the heat of the rotary but it it pans out it could be a way to reduce a little weight.

 

we used to have spintech muflers on my dads Super Late model race car. we liked them. as for rotary use....... no idea.

and am I the only one here that is anoyed with the Masda on the mufflers?

 

Haa haa...no I was pretty "WTF" w/ the masda...

As far as cherrybombs spintech has a single 3" dual 2.25" or single 3" dual 2.5" muffler that I was looking at. Thats what got me into this mess...I thought about using the "splitcase" muffler and simply get the rest welded up to exit the factory location. But your going down the same path that I was...simplify the whole thing with a single inlet, dual outlet muffler ridding the y-pipe in the process...

 

Cherry bombs cannot stand up to rotary heat, they get destroyed fairly fast.

 

What exactly can happen to a muffler if the exhaust is too hot?

 

Depending on what the muffler is made of (since there are different kinds of mufflers) it can either break apart or melt.

 

it will weigh the same or more than the OE exhaust and not make any more power

the thread I linked to was back in '03 and just to show that it had been done, except back then nobody knew anything about the Renesis engine and what does or doesn't work