Jaime Enriquez

Which is exactly why I went with Magnaflow in the middle...supposed stainless packed...blown. Time to try the Borla's in the middle.

rotarygod

iTrader: (1)

Just because it is made out of stainless also doesn't tell you a whole lot. The thickness of the stainless used makes a big difference too. Some manufacturers skimp in this area to save money. Edelbrock makes a stainless muffler that will blow apart when mounted at the back of the car. That's because they use thin crap materials. Rotaries are extremely hard on exhausts as everyone knows.

DriveFast7

iTrader: (1)

Where and how did they blow out? Did it tear a seam apart? Destroy the honeycomb inside?

+ they have a good warrenty but do not pay for LABOR to replace it. which can cost more than the muffler itself.

DriveFast7

iTrader: (1)

I shoved one of those car chemistry inserts into my isuzu amigo's tailpipe when i got busted for noise. it did quiet it down. turned the V6 drone into a hissssss.

It got REAL hot and also pinged when cooling down. for perm. installation definately weld in.

Did numerous comparisons before and after. Same rpm and gear equalled same speed before and after. none of that changed with the insert in.

but the car didn't accelerate as quickly. but it was quieter and my ticket got signed off.

DriftFB

Just yesterday I replicated this exhaust because mine was rotting apart as I was driving, and it was the last smog test my car will ever have to do.

I used 2.5 piping and changed one or two things in the setup, but the car sound great. Barely louder than stock, with a little bit of a burbble noise at idle. Perfect for what I wanted, I don't notice any huge jump in power, but i'm sure it will help once i start upgrading other parts of the car.

Tranquil

iTrader: (1)

You're definitely *not* supposed to place them in the tailpipe. All that'll do will prevent the gasses from exiting your tailpipe and then quieting it down that way.

You're *supposed* to place it 1.5 inches away from the collector of your header or catalytic converter. The spiraling hot and cold air blah blah blah, velocity, blah blah blah, benchflow testing blah blah blah.

vxturboxv

iTrader: (2)

Only problem is when you add RB mini-presilencer, resonator, and muffler It's no longer a straight through exhaust. I'm sure it quieted it down. But your not flowing as much as the loud straight through pipe.

Its impossible to have free flowing quiet exhaust on a rotary! Or on any engine for that matter. What do you think is magically making your exhaust quiet? Restriction to flow. Restriction = quieter exhaust and less flow. YOu can't have one without the other.

rotarygod

iTrader: (1)

You are dead wrong my friend!

Jaime Enriquez

After my driveshaft exploded, the magnaflow was also damaged...to the point where a seam opened up at the end. I looked in...no more packing, just a perforated core.

My friend has a big magnaflow (new) sitting around, I checked it out, and tapped it with a screwdriver. Nice solid thud. Hit the 4" rounds....tink. The packing is GONE!

Labor will cost me about $30....but at least $80+ for the new 4" round.

vxturboxv

iTrader: (2)

Take a general physics class. What do you think is quieting down the exhaust note?

Rx Seven

iTrader: (12)

Are you still using the stock header. Can you give more detail?

Latin270

So I take it Borla is the way to go?

broke7

iTrader: (1)

currently have rb ex i am going to cut the collector off my header and make it like the road race header then two pre sielencers to a flowmaster collector ( two 2"into one 3") to a 3" isc racing rear pipe and undiecided on what muffler but i won't have a coffee can on the back most likely be a hooker muffler the type with baffles instead of packing 84 gsl 13b half bridge port with a dellorto and soon to have a 48 ida and lots of other goodies i have the parts just not the time

DriftFB

The header is the one spot that I haven't gotten to yet, I left the resonator and the presilencer far enough back that when I have to cut it to get the RB header in I won't have to remount anything.

I'll try taking some pics, I don't have access to a lift right now so it might not be the best shot.

rotarygod

iTrader: (1)

I had physics a few years ago when I was going for my Mechanical Engineering degree. Buy or build a flowbench and do some real world testing so you actually know how your classes apply. You don't have to restrict flow. You just have to absorb noise. Yes they are both possible. Now go do your homework.

vxturboxv

iTrader: (2)

Homework is done. You can try and go all star trek on this thread if U want. Im not making any sort of attempt to demean you. But the listed parts in this thread are reducing noise through back pressure, restriction, and destructive interference..

They are not high dollar tuned formula one parts that are designed to reflect the sound waves produced by the engine in such a way that they almost cancel themselves out. Which is possible to a point. Point taken. I was partially wrong. But we aren't talking about tuned race mufflers, which are very application specific and must be tuned for each individual engine.

What we are talking about are these. Have U seen the inside of said items?

RB mini-presilencer
Magnaflow 2 1/4 in/out resonator
Borla offset 2 1/4 in/out 5x9 muffler

They are cheap non tuned exhaust items that crudely resist flow and bounce sound waves all over hell to quiet them down. The destructive interference method works great, but your not going to flow anything like a staight pipe.

Thats all I'm trying to say.

DriveFast7

iTrader: (1)

Does anyone have a picture of this? I'd like to see how the sound and exhast flow bounces around.

rotarygod

iTrader: (1)

LOL You don't need some strange Star Trek technology to make it all work. We don't need to create a static warp shell or modify some phase inducers to quiet the system down. It's easy. You don't even need any physics classes or a degree to figure it out. The first and most important thing you need is common sense to think of a way to do it and then have a way to test it. It's very easy. Establish a max flow rate for the engine. Not too hard to come close to with simple equations. Of course naturally aspirated vs diferent turbo applications will change this but you only need to get it close at first. Getting it perfect is what actual testing is for. Once you know how much flow you need at a set pressure, then you choose product based on flow rate to match what is necessary. If your engine needs 300 cfm of airflow at max rpm and load at your test pressure and you find a muffler that flows that much or more at that pressure, you've got it. Yes it is that easy! What you'll find out is that if you need a 2.25" exhaust pipe, you may in fact need to use a 2.5" pass through in the muffler to get the same flow. It all depends on what you want to use. For some not even this is good enough.

This does hit another factor which is the tuning affects of the larger area in the muffler. Fortunately chambered mufflers appear invisible to an engine so long as they flow enough. When exhaust gasses encounter a larger volume of air, it essentially cuts off the entire system tuning. What you do after that point is essentially irrelevant. Proof of this can be seen in the fact that houses, trees, and cars, etc have no efect on your power as they are in the larger volume of air in the system that is after the tailpipe. You don't need a very large chamber to get this same effect. A straight through muffler will appear to the engine as a longer pipe and can be "seen". If you use a larger diameter in a straight through muffler and it is designed as a part of a tuned system, which is highly unlikely on a street car, you merely adjust the total system length to compensate for the resonance differences.

What if you need a collected system at 22" but it likes to make power with a tailpipe only 10 more inches after the collector? What then? Dump it sraight down as a loud mess? How about installing a large (relatively speaking the size of an average oval muffler) hollow chamber? Test it for desired flow rate as referenced from the header system. Then whatever type of system you do after this box, as long as it is free enough flowing, will have no effect on the total system tuning. Some say it isn't so but I assure you, it is. Any effects you get will be very small and while technically measureable, will not do anything for noticable power.

When you say "you're not going to flow anything like a straight pipe", you are leaving out some very important details. A straight pipe of how large? A muffler with how large of a pass through? A 2" pipe with a chambered mufler with a total pass through area of a 6" pipe (not that you are going to find one)? Where is it stated that you have to use the same pass through area as the main pipe? You don't. You just need a nice smooth transition. Sadly enough, no one seems to realize this.

None of this is difficult for even the most inexperienced to understand. You are trying to absorb sound waves, not restrict flow. Both very possible to do at the same time with simple rudimentary devices without needing a masters degree to design it. I don't care what "said items" are. You originally stated that you can not have a quiet yet free flowing exhaust. You are wrong. It is very possible and it is possible to do it with the desired tuning. That part is the most difficult for the backyard mechanic. At no time did this quantify the argument by saying you can't get it with "said items". I'll agree, probably not. Car chemistry inserts are junk as well as anything else that gets placed inside an exhaust system to "quiet" it. That is a bad way to do it. It's terrible for flow and still not very effective at sound reduction. Vortex generators and spiral mufflers are also terrible. Just as it is possible to kill flow but not do much to sound intensity, it is also possible to kill acoustic energy but not hurt flow. There are no physics violations involved. Yes the absorbed energy has to go somewhere. It's called heat but I'll leave that for another discussion.

Tranquil

iTrader: (1)

2 ˝ “ Straight Pipe 521 CFM

2 ˝” Inlet/Outlet Borla Turbo 373 CFM

That explains your straight pipe and muffler comparison


Anyone can type up a long winded response, but you're basing those accusations off of the mere appearance of the inserts. Do a little research Mr. Benchflow and why not test them yourself?

Tell me how much experience you've had with this product.

"What makes these Inserts so effective? The design seems simple at first. Lets examine what happens to the exhaust pulse as it reaches the Insert. First a portion of the flow moves directly through the center tube, the balance is directed through the first disk. This creates a higher pressure zone in the area outside of the center tube. The result is that the air flow through the center tube is now faster, creating a low pressure zone in the tube. Since the tube is louvered a portion of the air that passes through the first disk is drawn back into the center tube. This helps draw more air through the first disk, thus reducing the back pressure created when the air first encounters this disk. By drawing slower moving, cooler air back into the center tube we reduce sound. Cooler air is “quieter” than hot air. The remaining air that is not drawn into the center tube flows through the next insert, thus slowing the flow and cooling this air even further. Then the difference in pressure between the two air flows pulls additional, “cooler” air back into the center tube. This further reduces the sound of the exhaust gases. If a three disk unit is used the same process is repeated. When the last disk has been passed the remaining air flow exiting the tube, but not drawn into it, mixes with the air flowing out of the center tube further cooling the air. This design not only cools the exhaust gases, to reduce sound, but by mixing the separate air flows multiple times, further reduces the sound emitted."


I can write a lot of ****, too!

candyassmiler

there is a lot more to be said about someone with common sense and a general understanding of the nature of things when compared to someone who jumps on the bandwagon, based on word of mouth and numbers found on the internet.

rotarygod

iTrader: (1)

Had you have read my response instead of just getting upset at what you interpreted as me pissing on your Cherios, you'd have seen perfectly clearly that I stated that it might take a larger pass through in a muffler than the size of the main pipe used to get the same flow rate. I also stated that it was a sad fact that many people can't figure this out as you have so clearly just shown. I was actually typing up a response that could have helped you but instead you closed your mind off to suggestion. Why post a thread in the first place then?


I can guarantee with 100% certainty that you yourself have never tested these. You've probably never even seen a flowbench. Having tested many things on a flowbench and seen how many products behave on the bench, I can say with certainty, these are not doing anything useful for you. Believe ad campaigns though. Just remeber I'm not the one who has anything to be gained by making claims so I don't have much reason to lie now do I? Should you wish to personally send me a set to test I would be more than happy to. The test results wil probably be questioned here though so don't waste my time.

Not your own words! Marketing! Sounds good doesn't it?


Copy and paste does wonders!

What do I know? I only test things. One test result is worth more than a thousand expert opinions. I'm not going to try to teach anyone on this forum anything anymore.

Tranquil

iTrader: (1)

People should try new things. I find it very very very ironic that people are closeminded on a ROTARY forum. We're the oddballs, so why not try oddball things. Obviously the CORE of our cars is the most oddball thing ever to happen to automobiles, and that obviously works. So why wouldn't other oddball ideas work?

DriveFast7

iTrader: (1)

Tranquil

iTrader: (1)

+1 in regards to me

Its just so boring in the Lounge I feel like picking a fight today.

candyassmiler

children. why do this when such enlightenment is provided by someone who knows something we dont?