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so after looking around and not finding anything, i have decided to start this thread to discuss a very important but sometimes overlooked part of our powertrain, EXHAUST. Any discussion on pressure sciences, bending techniques, etc. I have had my exhaust done 3 times by a local shop and its worse than it has ever been! it sucks having the skills and know how to build a nice exhaust but not having the tools and equipment to do so. Also lets talk about mufflers, any opinions, construction etc. So far i have learned that anything but mandrel bent tubing sucks!!!!! rednecks with mig welders suck!!! and glasspacks and cheap mufflers sound like shit and really do hurt performance. my truck ran better, burned less fuel, and had more power when i had nothing but a straight manifold! it was loud as shit but it turned heads for sure!!!! as for now im thinking of running my own 2.5 inch exhaust from the manifold to under the cab then straight out the sides. feel free to POST PICTURES of your exhaust no matter how shitty it looks.

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I think 2inch to a turbo 2/3 chamber type muffler would be good.not so loud.


if you want 2.5 that will be up to use but think its overkill. Thats if you think a Turbo muffler is restrictive

If I remeber correctly didnt you have a turbo on here before and had a vid. it sounded good to me.


I think straight exhausts are for kids.I gave Datto510(Eric) a CherryBomb 2 turbo muffler. he had a resonator on his 510wagon. I gave him the turbo as its the smallest one they make and fits perfect in the 510 spot. he says its just perfect on long hauls. So he has the resonator and the Turbo muffler.

See if he chimes in if there was a power loss.

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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!

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My wagon has a stainless Magnaflow in the stock location, 2 inch pipe from there back to a Stinger pipe. Nice tone & not loud, sounds good on the freeway.

My 720 has a 1 3/4 straight pipe w/ a Ansa tip on the end. Loud on the freeway & not bad around town.

My 620 had 1 3/4 pipe manifold manifold to roll pan. 40 Series Flowmaster in stock location & a blown out dual chrome tip on the end. Louder than the 720 @ all speeds & at idle.

Heres the 620 @ idle...



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i had 2 inch pipe that was crush bent into a thrush turbo muffler, sounded ok but it was a little loud out on the highway, that was fine for my old tired l20 with hitachi carb. now i have another 2 inch crush bent exhaust thats all fucked up hanging down and ugly, it has several bends in it and i know the actual pipe diameter at the bends is 1.25 inches or less!!! i tried the turbo muffler on this setup and it sounded like shit so i ran a cherry bomb glasspack, its worse than before and it really really choked my motor up, i have threatened cutting it all off but im afraid the exhaust shop wont help me out. mine looks like ballsack and sound sliek shit, you may not beleive me but i swear i lost 10+ horsepower especially at high rpms my thrush turbo and glass pack will be available for sale soon if anyone wants em. if i have to go crush bent im going to bump up to the 2.5 diameter pipe, also both times i have requested 2 inch pipe it has been od not id 2 inch so it was 1 7/8 inch id to begine with. i loved the sound of the straight manifold but it was dangerous and potentially harmful to the engine. the only thing i didnt like abotu the open manifold was the roaring sound of exhaust gases, the actual frequency of the note was good but the expulsion of the gases sounded like a huge ass continuous fart.

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oh yeah and both times i had my exhaust done the guys didnt even weld the pipe all the way around, they fucking suck ass, and if they dont give me a refund or redo this shit atleast half asses the right way im gonna flip. i mean hell half ass doing it the right way is bad but damn half ass doing it the wrong way is just plain shady, if you guys hear about arson on an exhaust shop in ky you will have know wether or not they fixed me up

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I filed a complaint with the bbb today after i tried one last time to get my local shop to fixx my exhaust they screwed up on, bastards, and to think that the owner is a magistrate!!! part of our local government!!!

Filed on : November 8 2010


Filed by :

Braden Bowman

233 Summit Pointe Dr.

Somerset KY 42503


Filed against :

D&M Muffler

110 Super Service Dr.

Somerset KY 42501


Complaint Description:

In the Summer of 2008 I took my 2004 Chevrolet Silverado to D&M Muffler for an exhaust leak repair. They did not have the part needed so I purchased it and returned and they installed it. Afterwards I had them install an aftermarket Muffler. The muffler did NOT meet my expectations but it was sufficient. Total Cost Of labor and Muffler 70$ After my first experience I Decided to give D&M another try. On November 23, 2009 I returned to D&M driving my 1977 Datsun Pickup. The trucks exhaust was damaged and it was removed, therefore I needed a complete exhaust from th emanifold back. I supplied the muffler, and they supplied the pipe and labor. Total cost was approx 65$ the pipe was crush bent thus making the pipes effective diameter in the bends less than 1.5 inches. I had requested 2 inch exhaust pipe but they fitted my truck with 1 7/8" pipe. Upon further inspection I found some of the welded joints to be incomplete, the top of the pipe wasnt even welded completely! I did not complain because this exhaust was only temporary and was suffucient for the time being. August 6, 2010 I returned to D&M Muffler to give them one last chance at properly fixing an exhaust on my Datsun Pickup. I had removed all of the previous exhaust and left only the muffler and tailpipe section under the truck. I needed to get my exahust red-done to accompany a brand new engine i had just built that was larger in displacement than my previous engine. Although My engine was still fitted with the same exhaust manifold as before. This time I built a custom 1/4" thick steel Exhaust Flange so that they could olt it to my Manifold and weld new pipe from there back to my old Muffler. I test fitted the custom flange before taking it to D&m to ensure a proper fit. I also supplied a new gasket for the flange. I picked up the truck later that day and pulled out of the parking lot only to find that the new exhaust was rattling against my drivers side torsion bar. Also where the new exhaust pipe met the new it came to a downward point below the cab and was rubbing the ground in some places.TOTAL COST $95.40. I paid with a Check #1069. On My invoice it states they used 4 ft of pipe, although i already had my old pipe under the truck. I returned to D&M a few days later to have the issues addresed, after all they told me if I had any problems whatsoever to come back and they would take care of me. They put my truck on the lift and looked around at the exhaust for a moment. they decided they would take a torch, heat the pipe up, and bend it inwards with a crowbar in order to push it away from the torsion bar. Upon doing so they heated my torsion bar cherry red taking some of the spring out of it (torsion bars hold the truck up using a bar as a spring with tension on it). Also when they pushed on the exhaust with the crowbar they punctured a hole in it, they proceded to weld up the hole leaving a protrusion of metal inside my exhaust pipe. While i was there I had them weld on a different muffler (Which I Supplied), they cahrged me another $10. I left the shop and the pipe still hit the now damaged torsion bar. I returned a few days later and the only employee there told me I would have to return when the owner was there. I asked him for a partial refund so that I could Have my exhaust fixed elsewhere, they denied. In the meantime I inspected my exhaust to find that once again ther were incomplete welds letting my exhaust leak, and make unwanted noise. I returned today today speak with the owner, Mike Strunk. He exclaimed he wished he had never worked on my truck and he wasnt going to help me at all. I did however convinve them to finish welding the pipe to fix the leak. I am now out over 100$ and have a noisy, clunking, down-hanging, improperly welded and installed exhaust. THANKS D&M!!!!! Poor workmanship, poor attitude, poor service. negative 10 Stars for D&M Muffler, 110 Super Service Dr. Somerset Ky. 42501.


Your Desired Resolution:

I demand a full refund, or atleast a new exhaust that doesnt rattle, is welded properly, and the pipe is the correct diamter for my engine displacement. 2.5" for crush bent pipe, or 2" for mandrel bent pipe. They say its impossible to keep it from rattling against my torsion bar, the factory did it 35 years ago. With todays technology why cant they do it now? All I ask is that they fix their mistakes. They Half-Assed my exhaust wrong, the least they could do is Half-Assed do my exhaust right. Beware of D&M and Mike Strunk!

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  • 2 weeks later...

Good luck with that complaint. Let us know what they end up doing. I had a similar experience with a local exhaust shop and when I threatened to go file a complaint the owner personally re-did my exhaust from the header back and threw in a new muffler for the trouble. I have since found out that there was already two complaints on file for that shop and he basically did it to shut me up, but anyways I got it fixed. Hope everything works out in your favor.



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be honest they dont charge that much.


PS I run 1.75 in pipe

hainz, they gave me 2 inch od pipe, which actually is 1.875 od pipe, only reason i say 2.5 is because of how much they crushed the pipe!!! the literally rduced the diameter of the pipe by 60% or more, they didnt follow the old exhaust route, they brough it down and up and down and up and all around crooked and shit.bigger pipe isnt always better, i understand there is a complex and in depth science about exhaust gases and the pulses the cylinders emit yada yada yada, although when i first installed my engine and ran it for a few days it was fun, i went and had this shitty exhaust put on and its like i switched from a fresh l20b with cam and dual carbs to an old ford tractor in need of a tune up!!! well maybe not that much of a difference but i know for a fact that this shitty bent exhaust really choked this thing down. on the top end i cant get it to wind up as fast, from 4 to 6000 rpm its much slower in winding up. when i had no exhaust it would wind up like a dog with his ass on fire and it would put your ear out doing it!!! i can really tell a difference with this exhaust and i threw a cherry bomb on it in an effort to offset the crushed pipe and i hate the soudn of it now, i need a good borla muffler or a high quality magna flow, i have tried the cherry bomb, and the thrush turbo and both of them sound awful, the turbo is alot better than the glasspack though. im gonna check on the status of the complaint today.

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I have a 69 510 with the stock L16...completely stock. I talked to my exhaust guy that I have known for 20 years here and with the future plans of dropping a V6 into it, he recommended 2 1/4 from the downpipe back. It is a straight pipe, no resonator, and using the stainless steel Magnaflow muffler in the back in the stock location. we had talked about 2 1/2 as well, just kinda threw it out there to see what he said for the V6 and he said "yeah...a bit big for the stock motor..but perfect for the V6." He is a cool guy and knowing that the exhaust will be changed at some point, He made the exhaust from the crossmember back at 2 1/2, and so is the muffler, and then out the tail so only the easy mostly straight stuff in the front will be replaced but I won't have to replace the muffler. I do know this...it's a hell of a lot better then the original, what is it, 1" to 1 1/4 pipe that was on there?!?! noticeable gain, but I wouldn't say it was drastic by any means.


Verdict? It's perfect! :D It's quiet while cruising, but when you get on it, you know it's there. It's got a ballsy sound to it but it's not annoying like most honduhs are. ;) (most..not all...lol!?) I will try to get some video up of it so maybe you can get an idea...

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i had a 3" ID built by the PO.

when i went into the shop we agreed that 2.5" would be better suited.

turbo muffler only.



butt dyno was significant and the mileage went up almost 5MPG



now im ready to swap the stock ex mani for a SS 4-2-1 header ive been looking at my reflection in :w00t:

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I think its hard to get your money back

But yes they should have put and tuck up the pipe if that what you tell them.

Some shops around here will only put on mufflers they sell.

Some only will put on mufflers you give them. as soem people dont like the sound of them.

Kids like Noise

Old men like quieter


I have to admit Datto510 rolled up in his wagon he has a L20 with 40mm webers and he runs a blue streak resonator and Cherry bomb Turbo 2 muffler and its nice and just a slightly deep tone but you can drive w/o yelling or dont get tone deaf on the Hiway.


If I have mine ever redone Im going to upsize to 2in and Turbo muffler 87701 pn(smallest they make) I bought 3 of them from JC Whitney years ago and gave Datto 510 one. they were 19$ at the time now they 43$The Thrush clone is 17702 same size.maybe cheaper elsewhere.

cant swear if they last long other wise the Dynomax Super Turbo or the Dynomax Ultra Flow turbo (stright thru design in a turbo) are better quality but maybe louder




cant believe you didnt like the Thrush Turbo

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i beleive 2 inch would be sufficient but you have to take into account the joints these guys make instead if slipping the pipe together to promote flow they slip the pipe together opposite of what it should be creating a lip inside the pipe itself, this cant be good for flow! i think the pipe should either be butt welded or a coupling used to prevent the sharp inside edges and promote a better flow

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the thrush turbo was ok. a tad too quiet for me, im about the only one who rides in my truck so a little extra loud doesnt bother me! i dont liek teh glasspack at all. i had read somewhere that someone did flow bench testing and the turbo had better flow characteristics than the glasspack. i wish i had kept the turbo as the glasspack was 25$ and 10$ to weld it on!!!

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  • 2 months later...

Here's my Datsun exhaust


tone: loud

looks: great


It's ,tubular headers for that metallic sound, a 2.5" inch tubing to keep it loud, a 5.0 Mustang turbo muffler to tame the four-banger pulses, and a stainless glass pack at the end to keep it raspy


Since it's only 1.4 liter engine it's only 100HP. A 2" exhaust would probably give me a few more HP.

But in the end it looks and sounds good, so it's a win.



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  • 1 month later...

hey guys, im not sure if this is the right place for this or not,

but i do have an exhaust related question.


i just ka swapped my 72 510, and the exhaust flange on the stock manifold contacts the steering gears rear bolt, and the o2 sensor cant be installed since its in the way. i read a thread about relocating the o2 sensor bung, but have anyone seen this problem before and how have you overcame it without spending a ton of money?


im running stock mounts on a reversed crossmember. is there different mounts i should be running? they're definitely a little tweaked and i'm just not sure what the solution might be.


thanks in advance

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im a mechanic of about 12 yrs and an exhaust tech for about 6 now. i have a 77 629 kc i have found 2.25 is best with minor mods.



Im hoping to get a good deep sound from my naps z24, was thinking a magnaflow muffler with resonator... thoughts?

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