85rotarypower

That second vid link is no good.

I still don't really think these mufflers will last. I don't know what they are packed with, but if its anything but stainless steel wool then these Borla's can't possibly last for more than a year. I guess time will tell. Untill I see some real results, I'm sticking with Magnaflow.

fcdrifter13

ok hold on Ill get a new link.

fcdrifter13

MAn i cant find the other good link anywhere. When he sighns on Ill try to get it.

mr_ouija

They are SS Wool packed. There are a plethora of FD owners using the Borla as a resonator, and having no troubles after years. Tranquil also researched it and says he found SS Wool packing.

What more proof do you need?

MosesX605

Exactly. So far as the quality goes, Borla and Magnaflow both have all welded stainless construction, ss packing and lifetime warranties. The kicker is that the Borla outflows a similar Magnaflow and is quieter to boot. Now that's a heck of a muffler. Add that to the more pleasing bass note that the Borla produces and you have a clear winner. Borla all the way.

Tranquil

iTrader: (1)

The oval insert doesn't really last on the XR-1, but the ProXS and Turbo mufflers don't have it, IIRC.

The only reason the XR-1 has it is to tune the sound for track legal conditions.

Besides, who would pay for an XR-1 when the ProXS is quieter? These are street cars, not race cars, yo.

ScreaminDemon

This looks like the right thread! Forgive my newbieness. I've heard I can get a reasonable bump in performance on my '82 pure-stock GSL (I'm the original owner--100k miles) by upgrading the exhaust, now that it's past emissions testing req't. I don't want something really loud, but a nice throaty purr would do me. Would the RB "Streetable Header Collector" + Borla ProXS (centered/dual) be a good choice? Anything else, other than connecting pipe? How much performance increase am I likely to see? Thx.

trochoid

iTrader: (6)

Exhaust is the first mod, carb/intake the second. Doing both mods together can yield a 40-50% increase in hp. Now try that on a boinger. The Borla as a pre-silencer, along with 2-1/4" pipe and a Magnaflow/Borla/Dynomax stainless steel outer and stainless steel wool packing should give you a decent sound, a bit louder than the full RB system.

Hyper4mance2k

iTrader: (40)

There is no proof that the Borla out flows a Magnaflow. Just cause you read that supposedly some Corvette guys tested both systems on their cars doesn't mean it's fact. Maybe the Corvette kit uses a offset in out as opposed to a straight through Borla. Then of course it'll out flow it. A straight through Magnaflow will flow just as much as a straight through Borla. From my first hand personal experiances a straight through Magnaflow has allways been quieter than a straight through Borla. My buddie had a borla cat back exhaust on his jeep and thought it was to loud we replaced it with the closest size Magnaflow and it was quieter. Being that they're both straight through I associate the quieter muffler resulting from the bigger rectangular/oval case that Magnaflow uses instead of the Borla oval, which would allow more steel wool packing. Just my .02 though...

p.s. Dynomax are roving fiberglass packed and last about a year. I used one on my first Rx and it sounded like a tin can after a year, and it lost power due to the turbulance caused by the muffler without the packing. I would never use a Dynomax muffler, but the Bullet presilencer is the best damn presilence on the market. Period, I don't put any exhaust togather for myself or my customers without them.

MosesX605

When presented with testimonial evidence vs actual test results, I'll take the test results every time. I don't know why you've chosen to question the CFM tests but what you can't argue with is the dB and dyno tests, as they were conducted by 5.0 Mustang and Super Fords in their Dec 2002 issue. The Borla made slightly more power than the Magnaflow and was significantly quieter.

The Magnaflow isn't a bad muffler. The Borla is just better.

Latin270

Currently running RB header strait pipe to RB muffler. MY brother wants the same set up but I'm going to sell him on a Borla. Any idea if this will be quiet enough for daily driving?

Tranquil

iTrader: (1)

Well my exhaust should be on there as soon as I can locate someone to bend me this one pipe.

It'll be

Rotary Engineering Header
Flowmaster y-pipe
Car Chemistry 3 disk header insert
Apex N1 Metal

I'm getting the Apex N1 muffler for free, and its new and normally $300 so I'm going to try it out. If it isn't quiet enough I'll sell it and buy a borla.
I'll report on how the Car Chemistry header inserts work. I have two of them right now. Depending on what happens I might throw one up on the market for $50 shipped.

Jozay721

yeah i have a full RB set up and its really quiet and restrictive. i dont like it because it makes no noise, but im gonna change it soon

Tranquil

iTrader: (1)

Hey if anyone wants to build a quieter exhaust!

https://www.rx7club.com/showthread.php?t=565366

I'm selling off a spare Insert

OnlyOnThurs

How do those inserts work?!?!? It seem like it would be restrictive?

dantheman

iTrader: (4)

It looks restrictive to me as well.


I put in a magnaflow round muffler as a presilencer. Works great! It is louder at part throttle then at wide open or idle. Very odd. Car is nearly silent when off throttle.

Tranquil

iTrader: (1)

Well I'd have to take pictures of the insides to show you, but how they work is they spiral air from the inside of the tube where its hotter to the outside of the tube where it mixes with cool air through the disks and specifically drilled holes. They were benchflow tested. The spiraling of the air keeps the velocity up so they don't become restrictive.

The majority of the cost is the testing that they did. After all, its $50 for a small one and $90 for a longer one, and all they are are just pieces of metal.

They're less than a pound, and don't take up any excess space. Personally I think mufflers can suck it, just have one of these after a header and a muffler at the end is what I'm doing.

d0 Luck

2.25" is small. might as well have sticked to a stock muffler and stock piping.

Tranquil

iTrader: (1)

pardon?

BigJeff

My eyes may be decieving me, or I've lost my ability to read, but I believe the inserts were 2.5" not 2.25. I also believe the 2.5" borla's showed 200-300% (very rough estimate) flow rate of the stock muffler, and even the magnaflows were about 150-250% (again, rough estimate) the flow of stock, depending on which stock muffler you had.

How is that no better than stock? I didn't think this particular thread was about ricing up your car, I thought it was more the opposite. High performance with as quiet an exhaust as possible.

Maybe I misread the last 7 pages...

d0 Luck

shoot, i apologize then guys. i coulda sworn my eyes saw 2.25" piping somewhere here

but if it's 2.5" then by all means, it should be a marked improvement.

Tranquil

iTrader: (1)

hahahahahah exactly!

Which is why I'm wondering what was going through Monza's mind when they designed their POS exhaust system. 1.8 OD pipes! For the Series 2 at least.

Jaime Enriquez

More input for the record....after a year of driving, my Magnaflow 4" round presilencers are BLOWN! Anyone know how Magnaflow are with warranties? I never sent in the card, but I have my purchase receipt.

Tranquil

iTrader: (1)

They should honor it, but if they don't then you can always try my Car Chemistry silencer. I know of a few other people that have them and they should theoretically work better on a Rotary since the gasses are so hot. It works by cooling the gasses and keeping velocity up. dooooo it!

rotarygod

iTrader: (1)

I think it's funny that people are quoting flow numbers from a magazine test but not a single person knows how to interpret what it all means to a rotary. How much power different mufflers get on a much larger engine are irrelevant. There is one thing that everyone is ignoring. How much flow does the engine require? A larger engine such as a Corvette engine or a Mustang engine have much more flow than a rotary. They need mufflers that flow more than we do. You can't say that because it made less power on those cars that it will on a rotary too. That is undertermined. Those tests were also done at a test pressure of 15" of water when many other tests are done at 28" of water. Higher test pressures over 25" on a flowbench start showing some things that a lower pressure didn't. Logic would tell you that it would all be a fixed ratio at that 28" of water test pressure will always give 1.86 times the flow rate of a test at 15". As a person who owns a flowbench I can absolutely say that is not neccesarily so.

I'm going to just throw out some random numbers to make a point, and please don't try to correlate these to the test numbers from that article as this is nothing more than an example with random numbers I made up. Let's say we are going to compare 2 mufflers. We'll call them A and B. Muffler A flows 280 cfm@28" H2O and Muffler B flows 400 cfm@28" H2O. Let's also compare 2 engines. Engine A will be a larger V8 engine and engine B will be a smaller naturally aspirated 2 rotor. Engine A makes 300 hp with muffler A but makes 320 hp with muffler B. That must mean that muffler B is a better muffler to use. True for engine A but not necessarily for engine B! Why? What if engine A needs 300 cfm of flow at max rpm? Suddenly muffler A is a restriction and muffler B isn't. Now let's throw these 2 mufflers on the much smaller engine B. What if they both get us 200 hp? Which one is better now? Take your pick! This is becasue engine B may only require 250 cfm of airflow at max rpm. Both mufflers can flow the necessary amount of air. You can get quiet mufflers that will flow what the rotary needs.

Again this is just an example I made up so don't try to get on my case about accuracy of numbers. The point is that you shouldn't compare test results done on a much larger engine to a smaller one and don't only look at total flow on a test bench. This is a common mistake that goes back to the flawed way of thinking that more is always better. It isn't. Without knowing how much airflow your engine needs, you are wasting your time and just guessing. If you are just guessing, all that testing was worthless.

I can say from experience that Dynomax superturbo mufflers work quite nice on a rotary and don't burn out after a year. I've never burned out a muffler as long as it was at the back of the car where the stock mufflers are and the engine was tuned properly. Don't use fiberglass up front as a presilencer. You will burn it up there. Remember gasses are cooler the farther back in the exhaust you go.