I bought a new midpipe and rear muffler for my long primary exhaust.

It was louder than the 20-30 year old rusted out junk, and very sharp. Not quiet and mellow like when I first installed it.

Then, about 1000mi later:



Thin stainless does not work on rotaries!

 

I'm thinking it's a fluke, I've never heard of RB stuff going that bad that quick. Were all the hangers put in the right places? Motor and transmission mounts in good order?

 

It is made out of thin wall stainless, the bends are poor, the hangers cannot be used because of how far off the bends are, (I do have a length of chain at the end of the midpipe because nobody makes 5" long hangers) and a lot of the reason it is so loud is that it is dual all the way back instead of collecting at the axle.

I'm just done with it. Nobody makes quiet exhausts for rotaries anymore. This is NOT the bombproof, quiet, super thick wall mild steel exhausts they used to make, that was like 1/8" thick tubing and 3/16" thick muffler bodies!

 

I'm definitely no expert, but that definitely looks and seems like a stress crack from that connection bearing most of the weight from the muffler.

 

That is what stainless exhausts do... the inner pipe expands faster than the shell because stainless does not transfer heat well, and stainless is a much weaker material. So the inner pipe cracks out the shell.

Note that the crack is in the SHELL, where a tube is closest to the seam, not at the bottom of both tubes on the tubes themselves like it were a support issue. The crack estended up to around the 11:30 position.

 

sucky..... never like the way it looked and sounded from day one

 

Did you let RB know? It might be under warranty so you can get a replacement.

 

I think that muffler should be redesigned to be like the old power pulse and primaflow mufflers that actually worked, that were made in Italy. Dual 1.75" tubes in 14 gauge collecting right above the rearend into a single 2.375" 14 gauge and on into the muffler as a SINGLE pipe and will be less likely to crack. RB does all of this in-house now, so all quality control issues rest on their shoulders. And if anyone is gonna put a muffler to the test, it's peejay. They ought to thank him for breaking one of their mufflers and seek to improve the weak areas.

This dual inlet idea might look kinda cool... I guess? If you don't know how a proper collector is supposed to work. Mazda did the dual inlet muffler as just some short lived 2 year only thing in 1981 and 82 when they first went from thermal reactors into cats. No need to collect before entering the muffler because the exhaust manifold itself did all of the collecting way up at the beginning of the exhaust system.

Also RB obviously needs to get some better materials and correct hanger placements. I'm not a big fan of stainless to begin with and prefer thickwall 11 gauge at the beginning of a system and then 14 gauge after some muffling (presilencing) has already taken place. The Italian made stuff just fits right with proper hanger placement and sounds right too.

Peejay, that crack reminds me to pull my pants up.

 

I was gonna ask: what is the OD of the dual inlet muffler pipes? If they are pretty big, that can be pretty bad for velocity that far back from the engine. Just something to think about.

 

Racing Beat's facebook page says their rotary mufflers are made in house. Hopefully that means this is something they can fix.

 

It's dimensioned the same as the old mufflers, roughly 1 7/8" ID.


I welded the crack back up and re-bent the pipes with application of heat and a pole jack, we will see what comes next.

 

I agree with @peejay . My RB true dual presilencer section for my FC is absolute garbage. It appears to be made out of inferior steel in comparison to the rest of the system (it's the only section of the exhaust that began surface rusting). Given the cost of steel and polished steel at that, they're profit margins can't be great. I'd imagine this or the components are being farmed out now; which isn't necessarily a bad thing, as long as high quality materials are used (seems to not be that way, though).

 

Wait just a second.... are you saying their mufflers should NOT look like this after just one run???


Well I sure hope they fix the build quality, because I want a new street-port system when I put the new motor in.

 

Racingbeat has drastically reduced in quality and viability in the 4 years or so since Jim Mederer died, more than likely it was happening prior to that.

 

Wow! That's terrible, hard to believe their quality has gone to hell. I guess I'll be hunting for a used header this fall.

 

Stop it,mine doesn't look like that after 5 years of use. My car runs right,yours,at that time,not so much. Avatar speaks volumes.

 

seen the headers...havent changed much..think you'll be good....if they made the mufflers like the header it wouldn't be a problem

 

always wondered what they packed in the old italian ones .... anybody kno ?

 

thin stainless can be fine based on type, quality, and temperature, the full race exhaust I built 10 years ago from 20 Ga (0.032”) T321 with T304 end pipes still structurally looks like new. Of course it’s discolored, all it mostly ever sees is wot use.

quality might be an issue if made overseas with reclaimed scrap material that unfortunately may have impurities and/or contamination vs new virgin mill material

the last thing I bought there quite a few years back and was immediately returned (adj endlinks with the same thread type on each end rather than LH/RH threads) struck me as cheapo wuhan poo.

their RX8 header pipes are 14 Ga. T304, so that’s a concrete poop house, never seen one of those crack or break

.

 

I knew you're jump in once I posted that pic.. Even so, the stainless exhaust on my Subaru has 70k on it and looks new. So for more money, I expect a RB exhaust to be on par. The problem with peejay's muffler isn't that it's made of stainless steel. It's inferior build quality at top dollar "pay for the name" pricing.

 

The coloration suggests that there is a baffle plate that poses a severe restriction in the system, high pressure (and therefore heat) before the plate and low pressure after.

 

The coloration in that pic is from heat generated from extremely lean running condition due to carb issues//air leaks.
There may be a baffle restriction in the muffler but it did not cause that coloration.

Put on too many of these systems of both types on carbed and FI cars that ran correctly and had no issues.
Also have repaired cars with serious lean running conditions that ruined previously installed RB systems.
The condition of muffler in that pic has nothing to do with quality of metal it’s made from..

 

Pete, this is very disappointing to read. I'm very happy with my RB exhaust that's in my 80 LS. Its held up very well. It's been on there for 6 years. I would definitely get ahold of RB and express your concerns and ask for a better quality replacement.

 

I agree with Dave, get a hold of RB and see what they have to say. Make sure and post back with the results. We all are very interested in what the answer will be. I hope its, "We will send a new unit at our cost".

I was totally thinking of getting one of these at some point just cause its so shiny and pretty. I'm holding for sure until we know whats up.

 

Here's a complete street system I bought about 15 years ago for my 84 GSL.

About $900 shipped from Racing Beat, complete with seals and block off plate.

I've used it pretty much continuously since then, on two or three different FBs.

Note that the Power Pulse muffler is heavy grade steel and was made in Italy.

I especially like those exhaust tips, still just as shiny 15 years later.

I don't think I'd want one of those stainless steel units, must sound awfully tinny.









Here it is on my LE, taken this morning: