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  • 3 weeks later...

Cut down L16 Manifold (they had a 1.5" bushing inside) with a 2" pipe the rest of the way. Turbo Muff.


Heres some pics. I'll update later with a video once engine is tuned.






Anybody have any dyno pulls with the assorted mods discussed here?

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From the now defunct overboost.com


Exhaust Theory


We've seen too much misinformation regarding exhaust theory. What kind of misinformation? For starters, there are a lot of people in the "Bigger is Better" camp. We're talking about exhaust pipe diameters. Even the big magazine editors are boldly smattering statements like, "For a turbo car, you can't get an exhaust pipe that's too big." Also, terms like "back pressure" and the statement, "An engine needs back pressure to run properly!" really rub us the wrong way.


Let's start from the beginning. What is an exhaust system? Silly question? Not hardly. Exhaust systems carry out several functions. Among them are: (1) Getting hot, noxious exhaust gasses from your engine to a place away from the engine compartment; (2) Significantly attenuating noise output from the engine; and (3) In the case of modern cars, reduce exhaust emissions.



In order to give you a really good idea of what makes up an exhaust system, let's start with what exhaust gas travels through to get out of your car, as well as some terms and definitions:


After your air/fuel mixture (or nitrous/fuel mixture) burns, you will obviously have some leftovers consisting of a few unburned hydrocarbons (fuel), carbon monoxide, carbon dioxide, nitrogen oxides, sulfur dioxide, phosphorus, and the occasional molecule of a heavy metal, such as lead or molybdenum. These are all in gaseous form, and will be under a lot of pressure as the piston rushes them out of the cylinder and into the exhaust manifold or header. They will also be hotter 'n Hades. (After all, this was the explosion of an air/fuel mixture, right?) An exhaust manifold is usually made of cast iron, and its' primary purpose is to funnel several exhaust ports into one, so you don't need four exhaust pipes sticking out the back of your Civic.


Exhaust manifolds are usually pretty restrictive to the flow of exhaust gas, and thus waste a lot of power because your pistons have to push on the exhaust gasses pretty hard to get them out. So why does virtually every new automobile sold have exhaust manifolds? Because they are cheap to produce, and easy to install. Real cheap. Real easy. Like me.


"Ok," you ask, "so now what?" Ah, good thing you asked. The performance alternative to the exhaust manifold is a header. What's the difference? Where a manifold usually has several holes converging into a common chamber to route all your gasses, a header has precisely formed tubes that curve gently to join your exhaust ports to your exhaust pipe. How does this help? First of all, as with any fluid, exhaust gasses must be treated gently for maximum horsepower production. You don't want to just slam-bang exhaust gas from your engine into the exhaust system. No way, Jo-se'! Just as the body of your '94 Eclipse is beautiful, swoopy, and aerodynamic, so must be the inside of your exhaust system.


Secondly, a header can be "tuned" to slightly alter your engines' characteristics. We'll go in-depth into header tuning a little later.


Nextly, exhaust gasses exit from your manifold or header, travel through a bit of pipe, then end up in the catalytic converter, or "cat". The cat's main job is to help clean up some of the harmful chemicals from your exhaust gas so they don't end up in your lungs. In most cars, they also do a great job of quieting things down and giving any exhaust system a deeper, mellow tone. You'll see a lot of Self-Proclaimed Master Technicians (SPMT's) telling people that removing a cat will get you tons of power. There's room for debate on this, but in our experience, removing a catalytic converter from a new car won't gain you much in the horsepower department. It can also get you a $1500 fine if the EPA finds out! If you drive an OBD-II equipped car, you'll also get that damn annoying CHECK ENGINE light burnin' up your dashboard. (And for all you racers concerned with OBD-II's fabled "limp mode", you can put your fears to rest.)


From the catalytic converter, the exhaust gasses go through a bit more pipe and then into a muffler, or system consisting of several mufflers and/or resonators.

Are you a muff?


Exhaust gases leave the engine under extremely high pressure. If we allowed exhaust gasses escape to the atmosphere directly from the exhaust port, you can well imagine how loud and cop-attracting the noise would be. For the same reason gunshots are loud, engine exhaust is loud. Sure, it might be cool to drive around on the street with that testosterone producing, chest-thumping, 150 decibel roar coming from your car… for about 5.3 seconds. (Not 5.2 or 5.4 seconds… 5.3.) Even the gentleman's gentleman has gotta use a muffler, or system of mufflers, on their exhaust.


Again, you may hear a few SPMT's tell you that "Borla mufflers make horsepower!" Or "An engine needs some backpressure to run properly!" Nonsense. A muffler can no more "make" horsepower than Wile E. Coyote can catch roadrunners. Any technician with any dyno experience will tell you that the best mufflers are no mufflers at all!

Types of Muff


Mufflers can take care of the silencing chores by three major methods: Absorption, Restriction, and Reflection. Mufflers can use one method, or all three, to attenuate sound that is not so pleasing to the ears of the Highway Patrol.


The absorption method is probably the least effective at quelling engine roar, but the benefit is that "absorbers" are also best at letting exhaust gas through. Good examples of absorbers are the mufflers found in GReddy BL-series exhausts, DynoMax UltraFlow, and the good old-fashioned Cherry Bomb glasspack.


Absorption mufflers are also the simplest. All of the above named mufflers utilize a simple construction consisting of a perforated tube that goes through a can filled with a packing material, such as fiberglass or steel wool. This is similar to simply punching holes in your exhaust pipe, then wrapping it up with insulation. Neat, huh?


Another trick absorption mufflers use to kill off noise is, well, tricky. For example, the Hooker Aero Chamber muffler is a straight-through design, with a catch. Instead of a simple, perforated tube, there is a chamber inside the muffler that is much larger than the rest of the exhaust pipe. This design abates sound more efficiently than your standard straight-through because when the exhaust gasses enter this large chamber they slow down dramatically. This gives them more time to dwell in the sound insulation, and thus absorb more noise. The large chamber gently tapers back into the smaller size of your exhaust pipe, and the exhaust gasses are sent on their merry way to the tailpipe.



Doesn't that word just make your skin crawl? It's right up there in the same league with words like "maim" and "rape".


Obviously, a restrictive muffler doesn't require much engineering expertise, and is almost always the least expensive to manufacture. Thus, we find restrictive mufflers on almost all OEM exhaust systems. We won't waste much time on the restrictive muffler except to say that if you got 'em, you might not want to flaunt 'em.



Probably the most sophisticated type of muffler is the reflector. They often utilize absorption principles in conjunction with reflection to make the ultimate high-performance silencer. Remember any of your junior high school math? Specifically, that like numbers cancel each other when on a criss-cross? That's the same principal used by the reflective muffler. Sound is a wave. And when two like waves collide, they will "cancel" each other and leave nothing to call a corpse but a spot of low-grade heat.


There are numerous engineering tricks used in the reflective muffler. Hedman Hedders makes a muffler that looks a lot like a glasspack. In fact, it is a glasspack with a catch. The outer casing is sized just-so, so that high-pitched engine sound (what we deem "noise") is reflected back into the core of the muffler… where those sound waves meet their maker as they slam right into a torrent of more sound waves of like wavelength coming straight from the engine. And, this muffler is packed with a lot of fiberglass to help absorb any straggling noise that might be lagging behind.

The Exhaust Pulse


To gain a more complete understanding of how mufflers and headers do their job, we must be familiar with the dynamics of the exhaust pulse itself. Exhaust gas does not come out of the engine in one continuous stream. Since exhaust valves open and close, exhaust gas will flow, then stop, and then flow again as the exhaust valve opens. The more cylinders you have, the closer together these pulses run.


Keep in mind that for a "pulse" to move, the leading edge must be of a higher pressure than the surrounding atmosphere. The "body" of a pulse is very close to ambient pressure, and the tail end of the pulse is lower than ambient. It is so low, in fact, that it is almost a complete vacuum! The pressure differential is what keeps a pulse moving. A good Mr. Wizard experiment to illustrate this is a coffee can with the metal ends cut out and replaced with the plastic lids. Cut a hole in one of the lids, point it toward a lit candle and thump on the other plastic lid. What happens? The candle flame jumps, then blows out! The "jump" is caused by the high-pressure bow of the pulse we just created, and the candle goes out because the trailing portion of the pulse doesn't have enough oxygen-containing air to support combustion. Neat, huh?


Ok, now that we know that exhaust gas is actually a series of pulses, we can use this knowledge to propagate the forward-motion to the tailpipe. How? Ah, more of the engineering tricks we are so fond of come in to play here.


Just as Paula Abdul will tell you that opposites attract, the low pressure tail end of an exhaust pulse will most definitely attract the high-pressure bow of the following pulse, effectively "sucking" it along. This is what's so cool about a header. The runners on a header are specifically tuned to allow our exhaust pulses to "line up" and "suck" each other along! Whoa, bet you didn't know that! This brings up a few more issues, since engines rev at various speeds, the exhaust pulses don't always exactly line up. Thus, the reason for the Try-Y header, a 4-into-1 header, etc. Most Honda headers are tuned to make the most horsepower in high RPM ranges; usually 4,500 to 6,500 RPM. A good 4-into-1 header, such as the ones sold by Gude, are optimal for that high winding horsepower you've always dreamed of. What are exhaust manifolds and stock exhaust systems good for? Besides a really cheap boat anchor? If you think about it, you'll realize that since stock exhausts are so good at restricting that they'll actually ram the exhaust pulses together and actually make pretty darn good low-end torque! Something to keep in mind, though, is that even though an OEM exhaust may make gobs of low-end torque, they are not the most efficient setup overall, since your engine has to work so hard to expel those exhaust gasses. Also, a header does a pretty good job of additionally "sucking" more exhaust from your combustion chamber, so on the next intake stroke there's lots more fresh air to burn. Think of it this way: At 8,000 RPM, your Integra GS-R is making 280 pulses per second. There's a lot more to be gained by minimizing pumping losses as this busy time than optimizing torque production during the slow season.

General Rules of Thumb with Headers


You will undoubtedly see a variety of headers at your local speed shop. While you won't be able to determine the optimal power range of the headers by eyeballing them, you'll find that in general, the best high-revving horsepower can be had with headers utilizing larger diameter, shorter primary tubes. Headers with smaller, longer primaries will get you

slightly better fuel economy and better street driveability. With four cylinder engines, these are also usually of the Tri-Y design, such as the DC Sports and Lightspeed headers.

Do Mufflers "Make" Horsepower?


The answer, simply, is no. The most efficient mufflers can only employ the same scavenging effect as a header, to help slightly overcome the loss of efficiency introduced into the system as back pressure. But I have yet to see an engine that made more power with a muffler than an open header exhaust. "So," you ask, "what the hell is the best flowing muffler I can buy?"


According to the flowbench, two of the best flowing units you can buy are the Walker Dyno Max and the Cyclone Sonic. They even slightly out flow the straight through designs from HKS and GReddy BL series. Amongst the worst, are the Thrush Turbo and Flow Master mufflers. We'll flow some of the newer mufflers as they become available at our local Chief auto.



On your typical cat-back exhaust system, you'll see a couple of bulges in the piping that are apparently mini-mufflers out to help the big muffler that hangs out back. These are called Helmholtz Resonators and are very similar to glasspacks. The main difference is that firstly, there is no sound-absorbing fiberglass or steel wool in a Resonator. And secondly, their main method of silencing is the reflective principle, not absorption. An easy way to tell the difference between a glasspack and a true Helmholtz Resonator is to "ping" one with your finger. A glasspack will make a dull thud, and a true Resonator will make a clear "ping!" sound.



Another object that might be sitting in your exhaust flow is a turbine from a turbocharger. If that is the case, we envy you.


Not only that, but turbos introduce a bit of backpressure to your exhaust system, thus making it a bit quieter. All of the typical scavenging rules still apply, but with a twist. Mufflers work really well now! Remember, one of the silencing methods is restriction, and a turbine is just that, a restriction.


This is actually where the term "turbo muffler" is coined. Since a turbine does a pretty good job of silencing, OEM turbo mufflers can do a lot less restricting to quiet things down. Of course, aftermarket manufacturers took advantage of this performance image and branded a lot of their products with the "turbo" name in order to drum up more business from the high performance crowd. We're sad to say that the term "turbo" has been bastardized in this respect, and would like that to serve as a warning. A "turbo" muffler is not necessarily a high-performance muffler.

Pipe Sizing


We've seen quiet a few "experienced" racers tell people that a bigger exhaust is a better exhaust. Hahaha… NOT.


As discussed earlier, exhaust gas is hot. And we'd like to keep it hot throughout the exhaust system. Why? The answer is simple. Cold air is dense air, and dense air is heavy air. We don't want our engine to be pushing a heavy mass of exhaust gas out of the tailpipe. An extremely large exhaust pipe will cause a slow exhaust flow, which will in turn give the gas plenty of time to cool off en route. Overlarge piping will also allow our exhaust pulses to achieve a higher level of entropy, which will take all of our header tuning and throw it out the window, as pulses will not have the same tendency to line up as they would in a smaller pipe. Coating the entire exhaust system with an insulative material, such as header wrap or a ceramic thermal barrier coating reduces this effect somewhat, but unless you have lots of cash burning a hole in your pocket, is probably not worth the expense on a street driven car.


Unfortunately, we know of no accurate way to calculate optimal exhaust pipe diameter. This is mainly due to the random nature of an exhaust system -- things like bends or kinks in the piping, temperature fluctuations, differences in muffler design, and the lot, make selecting a pipe diameter little more than a guessing game. For engines making 250 to 350 horsepower, the generally accepted pipe diameter is 3 to 3 � inches. Over that amount, you'd be best off going to 4 inches. If you have an engine making over 400 to 500 horsepower, you'd better be happy capping off the fun with a 4 inch exhaust. Ah, the drawbacks of horsepower. The best alternative here would probably be to just run open


Other Rules


A lot of the time, you'll hear someone talking about how much hotter the exhaust system on a turbo car gets than a naturally aspirated car. Well, if you are catching my drift so far, you'll know that this is a bunch of BS. The temperature of exhaust gas is controlled by air/fuel mixture, spark, and cam timing. Not the turbo hanging off the exhaust manifold.


When designing an exhaust system, turbocharged engines follow the same rules as naturally aspirated engines. About the only difference is that the turbo engine will require quite a bit less silencing.


Another thing to keep in mind is that, even though it would be really super cool to get a 4 inch, mandrel bent exhaust system installed under your car, keep in mind that all of that beautiful art work won't do you a bit of good if the piping is so big that it gets punctured as you drag it over a speed bump! A good example of this is the 3 inch, cat back system sold by Thermal Research and Development for the Talon/Laser/Eclipse cars. The piping is too big to follow the stock routing exactly, and instead of going up over the rear suspension control arms, it hangs down below the mechanicals, right there in reach of large rocks! So when designing your Ultimate Exhaust System, do be careful!


That was a great post, thanks. Shucks i thunk i learned sumting.

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To expand more on what has already been mentioned, I have a few more thoughts and facts. Performance in relation to exhaust has more than just measurable back pressure. Most people will talk about 4" exhaust as having less back pressure, and therefore, more performance. They forget about other factors, such as escape velocity and thermodynamics. If horsepower was only affected by exhaust pipe size, then dragsters would have bigger pipes than engines, the reality is you rarely see a exhaust pipe over 4" on even a 400+hp 4 cylinder drag car.


When exhaust gasses leave your engine, they need to leave quickly and efficiently, the faster the exhaust leaves the engine, the less restriction the next gasses leaving the motor will face, and less parasitic drag on the engine. There is a limit to the gains to be had, and some pipe must exist to move those hot gasses away from the engine to keep temperatures down...and street cars are too loud to blast around open header'ed everywhere. Back pressure is a factor, but what is a bigger factor than just back pressure? Exhaust velocity of course! What is exhaust velocity? Why, that is the speed the exhaust gasses can travel through the piping! There are physics involved, but some of the concepts are easy to understand in the real world. Any time you split or combine the flow of a fluid or gas, it will create some sort of turbulence, and will slow flow. You will also slow exit velocity by going from small pipe to a larger muffler, then back to a small tail pipe. You may not see noticeable back pressure, but you will slow the flow down, and loose potential horsepower.


So what exhaust is right for you? Good question...do you like it loud or quiet? Do you like tone quality or horsepower above all? Do you care how it looks? How much it costs? Do you want to buy it or build it? Do you want a brand name or just a good quality product? Do you like high or low pitched exhaust notes? There is no right answer for every car out there, every car and owner is unique. However, if you know what you want, I can give you some general ideas on sound and performance of various mufflers and pipe sizes and you can most likely make your own judgements from there.



*Exhaust Tubing:



Mandrel Bending: This process uses a mandrel bender and is the best for flow and performance, but costs more.

Crush Bending: Not as good as mandrel bending, but is cheaper and easier to find in exhaust shops.

Crinkle Bending: The worst and cheapest, still not a huge performance killer. Can be recognized by the "crinkles" in the elbow of the bent piece of tube.


Exhaust pipe size: This is key, because too large of pipe, and the gasses cool the same way they would if the pipe is too long, and a huge pipe size can be as bad for performance as a stock exhaust system. The main factors are the size of the motor, if it is forced induction, how high your target RPM range is, and how modified it is. A 1.3 liter turbocharged 300hp motor will require larger pipe than a 2.6 liter 100hp motor, so engine size will only take you so far. A good rule of thumb is most N/A sub 200hp 4 cylinder cars will never need more than 2.25" of exhaust with a free flowing muffler, and it take a BEAST of a 4 cylinder to need full 3+ inch diameter exhaust to see noticeable HP gains.



*Catalytic Converters:


If your car came with one, it most likely will not run well without one, not without a resistor to the secondary O2 sensor. The cat cleans up the leftover unburnt fuel and other emissions, and uses a oxygen sensor behind it to see if the cat is working right. Older fuel injected cars (70s and 80s) did not use a secondary O2 usually, and many cars with a secondary O2 will run just fine with a Cat delete, but sometimes you will get a CEL, or worse case on a few cars, the computer will lean the hell out of the fuel mixture to compensate for the extra fuel it sees, or may even send the car into limp mode. The solution is to be happy with the couple HP loss when using a cat, or run a high flow catalytic converter, or trick the computer into thinking it still has a working cat(enter resistors on the O2 wire or slightly moving the 02 sensor out of the exhaust stream a bit with a spacer).





These are basically a muffler, often a simple glasspack, usually shorter in length, and designed to quiet the car down and get rid of annoying pops,ect. The longer the case, the deeper and lower the tone, the shorter the case, the higher the tone and the less effective at decibel reduction.




There are two main types of mufflers regardless of shape or size...Chambered and Straight-flow(or straight through design). Chambered mufflers use baffles, straight through mufflers use a perforated tubing with packing around the perforated tube. Case types most often seen are turbo-style, glasspacks, sidepipes(or stacks), and "ricer" style.


Turbo mufflers are usually chambered, and use metal baffles to channel the exhaust gasses...these chambers dampen sound well, but without proper engineering, they will not flow nearly as well as straight pipe. Glasspacks are usually straight through(though some are louvered with small protrusions sticking into the exhaust flow...terrible for performance, but reasonably quiet), and they are a perforated pipe wrapped in an acoustic dampening material(like fiberglass or steel wool), then a larger pipe is welded around the packing to hold it all together. Sidepipes are normally glasspacks with a shiny outer casing, made popular on older sports cars like corvettes and Datsun Z's. Ricer style mufflers are usually round glasspacks, but very short(to allow for mounting on compact cars) with large, polished cases for more packing material and better looks.


As far as sound, different baffling chambers, packing materials, size of case, diameter of tubing, size and type of motor will all affect how a muffler will sound on your particular ride. With that said, there are some truths for all cars that I have found so far. I have learned it is hard to make a stock four cylinder sound like a muscle car, and it is almost as hard to make ANY 500+ horsepower motor sound bad(regardless of how many cylinders it has). I also have learned, the longer the pipe, the deeper the tone(due to resonance), and the longer the pipe after the muffler, the louder it gets(thanks again to acoustics and resonance).


What I have found works well to get a deep tone for 4 cylinder cars, is using a VERY long glasspack close to the engine, and a small muffler near the end of the car. A 24"+ long Thrush glasspack with a Borla or short(12ish inches) glasspack at the tailpipe works well. I know some of the non-baffled/louvered ricer mufflers that would normally be too loud and high pitched can be quieted and sound perfect with a long glasspack used as a resonator.



*Favorite brands:


Glasspacks: Thrush (stay away from louvered cores, they are worse than stock mufflers...almost all other glasspacks now have some sort of louvers or chambers and flow worse than the muffler your datsun came with)

Turbo style: Borla(a glasspack with more packing material, great flow and good sound, too bad they are so much $), Flowmaster(lots of R&D, decent flow, and average price with decent quality), and Magnaflow(they sound pretty good on 4 bangers).

The important thing is the warranty, construction, design, flow, welds, material, ect...rather than who makes it...most of the exhaust brand names in the US are owned by the same parent companies anyway.





After all that, I will leave you with an article I found where a few mufflers were tested for flow, noise, and HP.


All mufflers were dyno-tested on a 355-cube SBC with 10.0:1 compression,

Air Flow Research 190 aluminum heads, a CompCams 292 hyd. a Victor Jr. intake,

a Holley 750-cfm double-pumper, and 1 5/8 Headman headers.


Flow: Cubic Feet Per Minute (at 28-in H20)

DynoMax Race Magnum 528.64 cfm

Thrush Magnum Glasspack 507.40 cfm

Summit Fully Welded 343.38 cfm

Flowtech Afterburner 342.20 cfm

DynoMax Super Turbo 333.94 cfm

Hooker Competition 232.46 cfm

Hooker Super Competition 320.96 cfm

Summit Turbo 331.16 cfm

Thrush Boss Turbo 297.36 cfm


Noise: Idle dB and WOT dB

DynoMax Super Turbo 89 123

DynoMax Race Magnum 94 133

Flowtech Afterburner 92 124

Hooker Competion 92 122

Hooker Super Competion 90 125

Summit Turbo 89 124

Summit Fully Welded 92 125

Thrush Boss Turbo 90 123

Thrush Magnum Glasspack 92 128


Power: HP and TORQUE 2,500-6,000rpm Average

Hooker Competition 397.4 381.1 286.8hp/351.9 lb-ft

Thrush Boss Turbo 407.1 384.9 292.1 hp/357.5 lb-ft

DynoMax Race Magnum 409.5 394.3 298.8 hp/366.9 lb-ft

Flowtech Afterburner 409.7 391.2 294.8 hp/361.7 lb-ft

Thrush Glasspack 409.5 389.8 297.7 hp/365.3 lb-ft

Summit Turbo 411.5 386.3 291.5 hp/357.4 lb-ft

DynoMax Super Turbo 412.7 387.2 292.6 hp/358.6 lb-ft

Hooker Super Comp 413.8 387.2 292.8 hp/359.0 lb-ft

Summit Fully Welded 415.4 390.7 295.6 hp/362.4 lb-ft



Well, with all that typing, hope that I helped someone! :)

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  • 4 months later...

hey guys,


Just have a question, more like a clarification request. What do you mean when you say, "turbo muffler"? and who makes turbo mufflers? i read the whole thread hoping to find an answer but did not. Or did I miss it?




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hey guys,

Just have a question, more like a clarification request. What do you mean when you say, "turbo muffler"? and who makes turbo mufflers? i read the whole thread hoping to find an answer but did not. Or did I miss it?



I'm not sure I was told right, but Heard a turbo muffler was run without a baffle before it. I guess that would mean no catalytic converter either.



So its a type of muffler,like a glasspack?




"Not only that, but turbos introduce a bit of backpressure to your exhaust system, thus making it a bit quieter. All of the typical scavenging rules still apply, but with a twist. Mufflers work really well now! Remember, one of the silencing methods is restriction, and a turbine is just that, a restriction.


This is actually where the term "turbo muffler" is coined. Since a turbine does a pretty good job of silencing, OEM turbo mufflers can do a lot less restricting to quiet things down. Of course, aftermarket manufacturers took advantage of this performance image and branded a lot of their products with the "turbo" name in order to drum up more business from the high performance crowd. We're sad to say that the term "turbo" has been bastardized in this respect, and would like that to serve as a warning. A "turbo" muffler is not necessarily a high-performance muffler.

Pipe Sizing"


It's just a name. Could have called them Atomic Mufflers and would work the same.

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L16, peanut head, 260 cam, SU's


header, 2.5 exhaust and a standard magnaflow.





damn that's beefy.


so i got mine done today.


L16, Peanut head, L20 cam, 32/36 weber, 2 in. exhaust, standard magnaflow.

here's a before video of the old stock exhaust.




And video of the new



It sounds pretty good in the cab. wanted something on the quieter side of performance and mellow deep tone. drove around aimlessly for an hour after just to hear it.:)

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  • 2 months later...

What I have found works well to get a deep tone for 4 cylinder cars, is using a VERY long glasspack close to the engine, and a small muffler near the end of the car. A 24"+ long Thrush glasspack with a Borla or short(12ish inches) glasspack at the tailpipe works well. I know some of the non-baffled/louvered ricer mufflers that would normally be too loud and high pitched can be quieted and sound perfect with a long glasspack used as a resonator.


thats exactly what my exhaust is. right under the drivers seat is a glass pack almost 30" long, and at the back i have a fart can. a lot of people seem to like it. my parents dont mind it either, which is hard to do. and it has a pretty deep, mellow tone with none of that annoying raspiness/rattling sound when you let off of the gas. i cringe when i hear that sound on any engine.

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  • 2 weeks later...

I notice most of the posts are for L series motors, when I had my 510 hooked up with dual SU's, headers and 2.25in piping out to an Apexi 3 inch universal muffler it sounded quite nice. It was rather loud, I could barely hold a conversation in the car but it had a deep throaty tone and performance wise I noticed a decrease in bottom end torque because of the decrease in restriction and an increase on the top end, albeit the change was rather subtle and I only noticed it because I daily drove the car.


I currently own a 510 w/ an SR swap, and I recently modified the muffler on that as well. It runs a 3in pipe from the turbo back. I was looking around and researching for turbo mufflers i.e. (Greddy, HKS, Apex, Tanabe) to replace the 4 inch magnaflow muffler that was on it. I went down to a local high performance shop to get some suggestions and they turned me onto a company I've never heard of before then. They recommended a company called "Burns Stainless" aka (Coastfab, who makes the mufflers that Burns restamps as theirs).


I looked into it and they supply ultralight stainless steel racing mufflers for custom applications. I decided to go with a 12in length, 5.5in OD w/ 4in inlet/outlet packed with their stainless steel scrubble for use with modded applications and for longevity as opposed to their bottom line fiberglass pack. (They also supply a stainless steel mesh for extreme racing applications). It ran me about 350.00 for the muffler and when I received it the quality of craftmanship and material is second to none these guys do great work, and their based out of Huntington Beach, CA. Each muffler is custom made and it really is a unique look as opposed to running something like an HKS etc. I recently installed it and as opposed to the magnaflow muffler that was previously on the car, it has a deep crisp sound. Surprisingly quite for a race muffler at idle (mostly due to the turbo) but on anything other than idle it gets loud very fast. The way the muffler is designed it comes as close to a straight pipe as you can get.


I haven't noticed a difference in performance, which I wasn't really expecting, I just really didn't like the sound of the magnaflow and I was looking for something more raw sounding. I will post pictures as soon as I can figure it out as well as a video if anyone is interested in this application for their exhaust system.












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i just want to hear it. lol


I will work on getting a video of the sound up. I have to find the time and place, I can't really do it in my driveway because it may ruin my friendly relationship with my neighbors (if you know what I mean). They already thought my last 510 was loud enough haha.

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  • 1 month later...

I'm not sure where some of this quoted info originates from~ but a "turbo muffler" did not originate from turbine design. THE original turbo muffler was the premier performance muffler for over a decade, and was the only option for true performance. Along came the imitators by the drove, but nothing really changed in muffler design til an acquaintance of mine down in Santa Rosa started in his garage what is now known as FLOWMASTER~ but that's another story. So where did this mystery "turbo muffler" come from? The GM parts counter of course! Application~? The 1965-66 180hp turbocharged Corvair Corsa... And in all but the most robust of performance applications~ it's still my first choice!



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