Which muffler is better for a normally aspirated 13B? I've got a RB header and universal type presilencer, but don't have a muffler yet. All I've read about on here are straight through mufflers, with stainless steel mesh, but I haven't heard anything about baffled mufflers. Is there a reason for this? I'm looking at the Magnaflow XL 3-chamber mufflers right now and am wondering if anyone is using a muffler like this. I'd very much prefer a quieter exhaust system over a straight through system at the expense of a few HP. I appreciate any help or experience on this topic. Thanks!

 

Baffled exhaust stays longer in the muffler, runs off the plates and comes out of the outlet in a different pattern to give you a lower tone exhaust, straight through will get your "rasp or bees-nest" effect.

 

Thanks.

I know how they work, I'm more interested in people's opinion and feelings towards baffled mufflers with the 13B... I should have clarified... my mistake.

 

I have the RB system, and love it. It has a very nice sound which is very quiet until you go wide open throttle at high rpms. I really can't imagine a better mix of driveability and performance, but I've never tried anything else either...

 

i second that ^^^^^^^^

i also have the racing beat exhaust, and it sounds and performs awesome.

here's what the inside of one looks like--

https://www.rx7club.com/showthread.p...inside+muffler

 

Thanks guys. I've heard good things about the RB exhaust, but I think it's a bit expensive (or at least it will be by the time it gets to my door step). I'm going to try and make my own custom rearward exhaust section, this is why I'm looking for opinoins on the different types of mufflers.

Approximately how much power do you guys think is going to be lost from a baffled muffler vs a straight through muffler? The car is stock, with no modifications but air pump removal, header, and custom centre exhaust section.

Thanks for the help thus far!

 

I chime in w/racing beat. I began with the header only and used a oem
muffler and could not stand the noise - got the racing beat muffler and
never looked back
power wise you probably loose a few hp's
i hope you like a lot of noise

 

lol if you what to her str8 through give me a call i will start my car lol 828-201-1334

RB header 3inch all the way back

thats my cell name is patrick

 

I'm still a little skeptical as to whether that actually is a RB muffler. Maybe a very old one?

 

If you are concerned about noise and restriction, go with a 3" in offset baffled muffler. increase you pipe size just before the muffler to exhaust velocity up. The offset may give you mounting issues since the in/out pipes are offset, it may not center coming out the rear.

 

Straight through exhausts are loud.

On the other hand, the mufflers don't explode, and baffled mufflers are heinously restrictive for a rotary.

I have a straight through exhaust with two mufflers. It's loud. I quieted it down quite a bit by making a silencer out of a 1 7/8" to 2 1/4"OD adapter, wrapping a piece of steel wool around the smaller diameter, and plugging it into the tailpipe (which is 2.5"OD). It's held in by two hose clamps and a piece of wire. Works ASTOUNDINGLY well. The only downside is that it's still boomy under load between about 2500 and 3800. Fortunately that is below the cruise speed with 4.78's

RB systems are straight-through, but are quiet because they use MegaThick tubing to cut down on ringing noise, and they basically have four or five mufflers - one or two primary mufflers, and the rear muffler is a triple-pass design. All that, and they have decent sized tips on them, big tips = loud and horrible sounding.

 

I've got the RB short header and mini presilencer coupled with standard straight-through bottle silencer to a single in-dual out Magnaflow. My exhaust is loud, but not illegal and has a very decent note with suprising amounts of bass for a rotary. I did have the RB header/presilencer attached to the stock muffler and it sounded like a flock of angry hornets until the muffler baffles were literally blown apart thanks to the strong exhaust pulsations from the header.

In short: straight through is good. Baffled: not so much. Just be prepared to run at least two silencers with the straight through muffler in order to get the noise down to legal limits.

 

Straight through is better no question. On my old streetported 12A there was a huge difference going from a straight through design to a baffled muffler. Rotaries hate restriction.

 

Ok... this is what I've figured out.

1. The stock muffler with a RB header, universal type presilencer, and stock muffler is going to be loud and sound bad.
2. Baffled mufflers are quiet but don't perform well on a rotary.
3. Straight through are the best for performance but are very loud.

So here's the dilemma... I can't stand a loud and annoying car. I know the rotary engine is very "odd" sounding due to its design, so a properly designed exhaust system is a must to prevent having an RX7 that sounds "ricey". But on the other hand, I don't want my exhaust system to restrict the engine, so it has to be as free flowing as possible, which may end up being unbearably loud. There must be a compromise.

Baffled mufflers are restrictive... but what about a larger baffled muffler with smaller diameter piping, let's say one with a 3" inlet and outlet fed by 2.25" piping? The larger piping through the muffler may allow the muffler to flow well enough, while keeping the quieter characteristics of a baffled muffler.

Any comments?

 

Well, all I can say is that I have to verify your #1. I have an RB straight through to the Stock Muffler. It's LOUD and it sounds very 'tinney'. It has a hollow echo and very bees nest sounding. I need a new setup.

the 3" inlet, 2.25" outlets sound like a decent idea. I wonder how that sounds?

 

YA that works, or you can use a packed bottle. Such as...a cherry bomb, my car is actually kinda quiet with its running through the bottle "resonator". The cherrybomb is a performance muffler in the style of a bottle. So it adds rasp but it keeps the car kinda quiet. So if you put a bottle and a flowthrough muffler, it would sound great.

 

what do you mean by bottle?

 

I believe that was my suggestion. I will be less restrictive than a 2-1/2" in/out muffler and give you the benifit of the baffled muffler.

Iirc, a while back some posted a pic of an RB muffler they cut open. It was a baffled muffler with offset internal piping like the pic you posted.

 

A large-diameter baffled muffler will be loud, and it will be an awful kind of loud!!

You'd be better off using a HUUUGE yet small-diameter pipes (say 2") muffler, or Y out to two (1 7/8" or 2") mufflers in parallel.

Use nothing but fully welded mufflers if it's baffled. No crimp-seam crap, it WILL come apart.



Remember there is essentially no such thing as a single, low restriction, quiet muffler! That muffler up there was a 2 1/4" unit and it was LOUD even before it ventilated itself. And it was more restrictive than the stock muffler! Pretty much the WORST of all worlds! Not quiet, not fast, not long-lived!

 

I use a magnaflow 2 1/2 in with dual 2 1/2 out plus RB header/ RB presilencer and an aftermarket presilencer on my S/C GSL SE and it is "loud". I had the RB header, presilencer and muffler on before and it was quieter but it pulls better over 6000 rpm now. If you want queit and economical a friend here used a dynomax muffler on his and it was a good compromise.

 

 

I have a streetported 13b with RB road race headers 2.5" back to a flowmaster. It is not too loud with the ear plugs in.... I sounds great at idle, but is very loud, I can't hear all the other squeaks, and stuff my car makes.


I was wondering if we could start an mp3 section of exhaust sounds. Have some rules (like at idle have the microphone 5 ft behind and 2ft out away from the car). This would allow us to all have a standard on how loud the car is.

 

YA i could that, if i had a microphone...

 

we used that exact muffler on an fc race car (3") as a presilencer.

basically for a race car it muffled just fine, its still gonna be loud for a street car, and then the important part, that muffler isnt built strong enough. it WILL come apart, we got tired of having to rebuild the muffler EVERY race, and just stuck a 3" rb presilencer in there. the rb muffler was quieter still, worked better.

 

How long has that been installed and how is the sound. Has it gotten louder with time?