Dynomax vs Flow40's

[Matt 4.3 TBI]

Rather than hijack the current thread, I'll just start another-

I'm giving a lot of thought to ditching my Flowmaster 40 for a Dynomax muffler since I've heard such good things about them. Does anyone have a sound clip of one on a 4.3? I like the Flow40's sound (especially at idle!), but the interior resonance is starting to get to me after 2 years (I think it got to the wife about 2 months after I installed it :D )

I'm looking to pick up some more mpg on the highway since the highway mileage dropped after the build. I'm also going to put a 2.5 tailpipe back on and ditch the 2.25. I'm still trying to find out just how much cfm a 4.3 actually needs so I can pick the right muffler. I've heard 2.2 cfm per estimated horsepower, but that doesn't sound very accurate.

What kind of flow numbers do the other Dynomax mufflers have? The flow40 I have is only about 249cfm, and I've seen the Super Turbo's rated at 278 cfm. Trying to get all the data I can find to actually get it right this time!

[Sparky2263]

My Flowmasters are starting to get a personality complex. They're really getting worried........;)

[Supercharged-ZQ8]

The Ultra Flow Dynomax is in the upper 300s or lower 400s, if my memory serves me correctly.

Sound clips? OK, try this:

http://www.geocities.com/akhilleus_187/Truck2.wav
http://www.geocities.com/akhilleus_187/Truck3.wav

If those don't work, then try http://www.geocities.com/akhilleus_187/page2.html and go to the middle of the page.

[Supercharged-ZQ8]

http://www.sicgmtrucks.com/forum/showthread.php?t=735

The Ultra Flow listed there is the "bullet" style -- close to a straight pipe. The cannister type is about 100 CFM less than that, so around 400 CFM or so.

[Sparky2263]

I'm really not that partial to my Flowmasters. I'm just curious if the addl. cfm is even needed for our V-6's? Say I dump the Flowmasters for a set of Ultra-Flow's, will I really see a performance increase?

[Supercharged-ZQ8]

Here is another link, but I think the CFM figure for the UF is WAY over-inflated:

http://www.dynomax.com/ultrafloweld.stm

[Supercharged-ZQ8]

Performance increase: going from a SuperTurbo (around 270-280 CFM) to an UltraFlow (??? CFM), I saw an 8 rwhp increase with NO other mods.

[Sparky2263]

Performance increase: going from a SuperTurbo (around 270-280 CFM) to an UltraFlow (??? CFM), I saw an 8 rwhp increase with NO other mods.

All figures corrected? 8 horse ain't nothin to sneeze at and I carry the rpm's to use it.

[JROD©™®]

wow...i'm glad i have my flows...i did not like that sound clip...

[ZR1-S10]

I think the 4.3L's natural sound is great! My muffler rusted off so I'm just dumping out the cat (great sound and performance). I'm going to put a new exhaust on that goes all the way back to help keep interior resonance low, however I still won't run a muffler. I'll have sounds clips of the cat dump soon.

[bvr775]

If you like the flowmaster muscle car sound of the Original 40s(i do not like the deltaflows) you won't like the dynamax sound. I have a dynamax 3" inlet camero stlye mufler in my garage. I yanked it because I didn't like the tinny sound and put on a flowmaster 2 chamber. it gained .03 in the 1/4. That's nothing, but It proves dynas' claim arn't on the mark like they say. That dosn't mean I'm saying flowmaster claims are completly on the level either.

hear's the simple facts of the matter when you get your engine to the point when you no longer need to scavenge to excite the charge in the cumbustion chamber...umm......simply put... In outher words when your a/f is perfect and you can instantly burn everything in a cold cylender and a hot cylender equaly as efficent a mufller is just a problem to eliminate, but you have a stock engine so exhaust tunning will play as important a role in the performance of the engine as tuning. do you have the money for dyno time and several differnt muflers for a 1/2 hp gain or lose. this means you need to know what you engine is capible of flowing out and what you total exhaust system is flowing.



Idealy you want a tuneable muffler for stock engines, a mufler with removeble packing or baffels, but most people arn't going to spend 150-300 bux on a mufler

[Matt 4.3 TBI]

As far as cfm, I'm thinking the ideal cfm is somewhere in the high 200, mid 300 range. This would rule out 3" exhaust, as it would lose too much velocity from the oversized pipes. I don't believe my problem currently is too much (or even enough) flow, but since I don't have an exhaust pressure gauge or an airflow meter, I can only speculate. From all the volumetric-efficiency formulas I can find, I will need 287-322 cfm through the exhaust, depending on if I tune it for 3750 rpm (my torque peak) or 4200 rpm (my horsepower peak). However, the engine analyzer JJ used to run the #'s put out a 86% VE through that range, which would bring the numbers down to 246-276.

I do appreciate the tone the Flow40's have, and the aggressive muscle-car rumble, but it just seems like form over function at this point. What's another good option with: low-interior resonance, good overall tone, better flow? I've heard the Magnaflows (I believe that's what they were, I'll have to ask the guy again) in person on a 4.3, and they sound damned impressive, but as they were overall louder than the Flow40, I doubt they will help with interior noise.

[Matt 4.3 TBI]

One more gripe about the flows I forgot to mention, though it will probably hold true for any muffler: it almost seems louder at 2000 rpm than it is at WOT. At least at WOT the engine is drowning it out :D I don't care how loud it is at the peaks, cause when I'm mashing it I'm not concerned about the noise, it just wish it wasn't so damn loud RIGHT AT my cruising rpm. Right about that speed it creates a resonance through the system that has a bad echo inside, especially in the backseat. This probably isn't anywhere near as noticeable on pickups. The only other mufflers I've used were a Thrush glasspack, the stocker and this flow40.

[joker2040]

I have a 40 series blowmaster and I like it. The only real reason for buying it was the price. It gets the job done though and sounds decent.

[Sparky2263]

I think I'm gonna try an H-pipe first. Been wanting to do that anyway.

[Minitrucker]

Any one have accurate flow numbers for the Ultra? I cant believe the 1000 cfm plus on the box.

[03 Rado]

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.

Hardware

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.


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.

Restriction

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.

Reflection

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. 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. 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.


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.

Resonators

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.

Turbos

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 2 1/4 to 3 inches. Over that amount, you'd be best off going to 3 1/2 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
exhaust!

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!

[ZR1-S10]

A 2.5" Dynomax is about 512cfm.

[03 Rado]

You have to take this with a grain of salt, but all the mufflers here under the Dynomax are competitors so Dynomax maybe lieing to sell there own stuff, but the point is made again and I wouldnt think they put the Flowmaster on the bottom unless it really did deserve it.


What's The Dynomax Difference? It's In The (Flow) Numbers


Brand Combines Aggressive Sound, Dyno-Proven Flow Advantages for Enhanced Performance

Las Vegas, Nev., November 8, 2004 - When it comes to enhancing engine performance through the installation of an advanced exhaust system or muffler, knowledgeable vehicle owners understand that product acoustics take a backseat to flow characteristics. Perhaps not surprisingly, flow is the key differentiator that has helped DynoMax become one of the most successful brands in the exhaust aftermarket.

“We combine an aggressive, application-tuned sound with a variety of innovative design approaches that significantly enhance exhaust flow,” said Nick Macaluso, chief engineer for the DynoMax product line. “Flow is the characteristic that determines whether or not you will achieve increased engine efficiency, horsepower and torque, and it’s where we spend most of our time.”

Enhancing exhaust flow helps reduce power-robbing system backpressure. The backpressure encountered in a restrictive exhaust system forces the engine to work harder to expel gases from the cylinders. In some cases, these gases can dilute incoming air/fuel mixtures, further reducing engine efficiency and performance.

DynoMax offers a variety of exclusive muffler designs engineered to provide exceptional flow and appealing sound on a full range of popular performance applications. The brand’s leading muffler designs are the DynoMax Ultra Flo™ muffler, featuring straight-through single-tube routing and continuous-roving fiberglass; and the DynoMax Super Turbo™ muffler, which contains patented flow directors to channel exhaust flow for enhanced power.

The DynoMax brand’s dynamometer-proven performance advantage can be seen in recent side-by-side testing of Ultra Flo (No. 17263), Borla (No. 40600), Edelbrock (No. 5511), and Flowmaster (No. 42540) mufflers. The DynoMax Ultra Flo muffler delivered 1,000 cubic-feet-per-minute flow, compared to 846 CFM for the Borla, 579 CFM for the Edelbrock, and 352 CFM for the Flowmaster units, respectively.1

In addition to ultra-high-flow muffler designs, DynoMax offers complete cat-back exhaust systems engineered to reduce system backpressure. Each cat-back system features all-mandrel-bent tubing that delivers a consistent inside diameter to eliminate unwanted turbulence, particularly at bends.

For more information on DynoMax performance exhaust systems and components, please contact your performance exhaust specialist or visit www.dynomax.com.

Tenneco Automotive is a $3.8 billion manufacturing company with headquarters in Lake Forest, Illinois and approximately 19,200 employees worldwide. Tenneco Automotive is one of the world's largest designers, manufacturers and marketers of emission control and ride control products and systems for the automotive original equipment market and the aftermarket. Tenneco Automotive markets its products principally under the Monroe®, Walker®, Gillet® and Clevite® Elastomer brand names. Among its products are Sensa-Trac® and Monroe Reflex® shocks and struts, Rancho® shock absorbers, Walker® Quiet-Flow® mufflers, Dynomax® performance exhaust products, and Clevite® Elastomer noise, vibration and harshness control components.

11 Flow rate measured at 20.3 inches H20. Tested mufflers were short-body, 2.5-inch side/center configuration units. Tests utilized side connection as inlet.

Contact:
Drew Shippy, Pinnacle Communication Group, Inc.
(330) 688-3500
drew@pinnmedia.com.

[Sparky2263]

Excellent articles guys. My Flowmasters are losing their luster by the minute.........

[Supercharged-ZQ8]

wow...i'm glad i have my flows...i did not like that sound clip...
You didn't?! Wow. . . Not bragging at all (everyone should know I'm not the type), but your the first that hasn't liked it. . . Of course, in person it's a little deeper and rumbly -- the little 1/2" computer microphone just doesn't do it justice. . .

[Matt 4.3 TBI]

I think I've got it narrowed down to a few brands right now...Spintech, and Dynomax are leading the pack, but I haven'r ruled out Borla and Magnaflow because I haven't researched them as much. Spintech looks very nice, and I keep hearing good things about them from the SSF guys, but I haven't found any flow #'s yet. They have a lot more variety in the design and volume of their mufflers as well. By the way, the other muffler I was thinking of was a FlowTech. Loud as hell, but it sounded very good. Sounded a lot better than my Flow40.

[03 Rado]

You want to talk about something sounding TINNY and makes a god awful whire sound in upper rpms, SPINTECH!

[bvr775]

hooker makes a good muffler. sound, performance, and durabilty for 50bux

[Maximus]

M-A-G-N-A-F-L-O-W, ya can't go wrong.Sounds great flows awesome and you can get stainless.

[JROD©™®]

You didn't?! Wow. . . Not bragging at all (everyone should know I'm not the type), but your the first that hasn't liked it. . . Of course, in person it's a little deeper and rumbly -- the little 1/2" computer microphone just doesn't do it justice. . .

that was your truck...hmmmm...well for you my friend i will listen again...louder volume...better speakers..with a $150 Harmon/Kardon Woofer...first time i heard was on yamaha low volume at work. i'm at home now...so it'll rip...


well ok...its not bad....the more you nailed the gas the more i like. and not to brag either but i prefer the idle of my flows better. you can hear that wuhwuhwuhwuhwuhwuhwuhwuhwuhwuh. i think all clips would sound better being drive bys rather than idle revs. the only cars that sound great will in park and revving are the big blocks...

have you heard maximus's exhaust...that fool don't have cat...his kicks ass...

[<-~Jo~->]

i like more flows .. but hooker those some nice mufflers too i mean they sound well but flows are in advance .. yeah flowmaster 2 chamber exhaust or get some cut-outs straight pipe on a switch that will be the best sound youll get

[Minitrucker]

Will the great debate ever end!!!!
Sound vs Flow

[Maximus]

The new Super 40's gives ya the best of both worlds.And thanks for the compliment JROD.Im tellin ya though most of the sound on mine is from having no cat.It makes a VERY dramatic difference with out the cat.

[JROD©™®]

i wish i could nix my cat...i love that sound...thats really one of my favorite things about my truck is hearing the exhaust...i ride with the bucket seat down on the passenger side and the windows down just so i can hear it...

[Maximus]

You know what I find funny a good friend of mine from my Fbody board lives in DC.He has a 1999 SS Camaro 6 speed with some decent amount of work done to it.I don't know what exact exhaust he uses but I do know that he runs catless.He gutted through the cats and used a straight pipe to make it look like they are still there working fine.And he passes emissions testing no problem.Don't know how but he does.He even posted the proof to a few nonbelievers on the board.Just thought that info would be interesting.

[csledge]

I'll ressurect this thread :D Anyone know how bad the Ultra Flows are inside the cab? I want something that sounds good, flows good, but quiet as possible in the cab - i'll roll the windows down when I wanna hear it :) I've been told the Dynomax Super Turbos are good for that, but just wondering how much the extra flow of the Ultra Flows would help performance and/or hurt interior sound

[MikDee]

The Dynomax ST are way too quiet, the Ultraflows have a deeper sound, still little to no resonance in the cab.

[04silveradomykk]

My DST is plenty loud, might have something to do with the short side exit.

but FM Super 40's do sound pretty damn good

[gmcjimmy96]

ok so how about instead of just telling everyone that interior noise isnt to bad, does somebody have a sound clip? ive looked everywhere, because im looking at puting a dynomax ultraflow on my 96 jimmy, and interior noise is a major concern. so if anyone has a interior sound clip (or can make one) please post it ...thanks!

[Sparky2263]

If interior noise is a concern, shoot 'em out the back and don't install those goofy ricer looking big-assed tips.

I can shoot straight pipes out the back and hear very little. Now, the guy behind me, that's another story. He's hatin' life when I get on it.

[rkmdogs]

Last year I needed to replace a muffler on my LT-1 Caprice.
I did a lot of research. Went with Flowmaster RV series 50's. Sound good with no droning.
A friend then sent me this chart from the Corvette C3 forum. The figures are the flow rate in CFM for each muffler.

OEM............................................... ........................................225
Gibson SuperFlow 788200............................................ ...311
TTS Bullet Cat
Converter......................................... ..........324
Flowmaster 40 series 42540...........................................35 2
Flowmaster 50
Series............................................ ............362
Flowmaster 40 series 43040...........................................39 2
Dynomax Super
Turbo............................................. ..........410
Flowmaster
62631............................................. ................435
Carsound Cat Converter......................................... ..........436
FLP Cat
Converter......................................... .....................440
Edelbrock Victor
5535.............................................. .........562
Flowmaster 40 series 435409........................................576
Edelbrock RPM series 5511............................................57 9
Flowmaster Delta Force Racing 54040-10...................634
Edelbrock 304 series 5560.............................................. 640
Edelbrock Gen App 5505.............................................. ....708
Dynomax Race Magnum Welded 17216.......................711
Borla XR-1
40600............................................. ..................836
Borla XR-1
40615............................................. ..................854
Dynomax UltraFlow SS 17263.......................................1000
Dynomax Race Magnum Welded 17218.....................1000
Borla XR-1
40575............................................. ................1100
Dynomax
UltraFlow......................................... .................1133
Edelbrock Victor
5537.............................................. ........1400
Borla XR-1
40450............................................. ................1400
Borla XR-1
40741............................................. ................1450
Dynomax UltraFlow SS 17296, 17268.........................2200
Dynomax Race Magnum Welded 17220, 17224.......2200
Dynomax Race Magnum Welded 17225.....................2600

The formula for required exhaust flow is: horsepower times 2.2. Pretty
simple eh? So if your car makes 400 hp, you will need a total of 880 cfm
muffler capacity for an unrestrictive exhaust system. So for dual exhaust,
you would need mufflers that flow 440 cfm. For reference, a 2.5 inch
diameter pipe flows ~500 cfm. Adding non-mandrel bends will lessen that
amount.

I hope that this helps.

[rkmdogs]

You know what I find funny a good friend of mine from my Fbody board lives in DC.He has a 1999 SS Camaro 6 speed with some decent amount of work done to it.I don't know what exact exhaust he uses but I do know that he runs catless.He gutted through the cats and used a straight pipe to make it look like they are still there working fine.And he passes emissions testing no problem.Don't know how but he does.He even posted the proof to a few nonbelievers on the board.Just thought that info would be interesting.

You have to mess with the timing, on a temporary basis to get thru the
inspection. But you can't leave it that way to really run.
I know, did that on a Malibu in TN when they had emission testing.
Changed it back next day!
Of course everything has to be in top shape to pass when you tweak the settings.

[Hammer Head]

For those too lazy to do the math here's a chart... S=single D=dual (I did this per the equasion)

1.75" pipe flows ~ 350 cfm S 160 hp D 320 hp
2.00" pipe flows ~ 400 cfm S 180 hp D 360 hp
2.25" pipe flows ~ 450 cfm S 205 hp D 410 hp
2.50" pipe flows ~ 500 cfm S 225 hp D 455 hp
3.00" pipe flows ~ 600 cfm S 275 hp D 545 hp
3.50" pipe flows ~ 700 cfm S 320 hp D 635 hp
4.00" pipe flows ~ 800 cfm S 365 hp D 725 hp

[87wildside]

For those too lazy to do the math here's a chart...

1.75" pipe flows ~ 350 cfm
2.00" pipe flows ~ 400 cfm
2.25" pipe flows ~ 450 cfm
2.50" pipe flows ~ 500 cfm
3.00" pipe flows ~ 600 cfm
3.50" pipe flows ~ 700 cfm
4.00" pipe flows ~ 800 cfm
....like me!
good info, thanks.

[Sparky2263]

My flowmaster 40's out the side;

http://www.s10planet.com/forum/SPARKYS/MVI_0103.AVI

[Everfalling]

wow this is a long thread....hehe don't want to raise any ghosts or anything but I have a flowmaster hushpower II on my 2.2 and it sounds alright...it sticks out the side and I like it well enough....especially going through construction where I can bounce the noise back into my truck...lol ...I own a Muffler Brothers automotive repair shop and here are some interesting things I've found for all you people who do NOT worry about .001 of a second on a race track...

just about any equasion for CFM is way beyond me as I"m not a math major but for my money I would simply understand that if you are not worried too much about times in th 1/4 mile and just want some extra HP and maybe even a little more miles till ya fill up your fuel tank any and I do mean just about ANY aftermarket muffler will be fine for you. If you are a casual drive your truck to work kind of guy (or girl) worry more about sound. Yes a straight through muffler is going to be better than a chambered muffler as far as HP and MPG. however chambered aftermarket mufflers are much better than your OEM muffler anyways.... so buy your muffler based on what kind of tone you want to hear. unless you really do race your truck or a tenth of a second means something to you....personally I put my flowmaster on and got around 50 more miles per tank.....maybe a little more. now I can drive my truck like I stold it and still get around 22-24 mpg... I am not rich enough to worry so much about HP gains at the moment....gas is like....3.50 a gallon here...and I don't like filling up. I might be rambling now.....hehe it's kinda late and I have to get up early for work... I think I'll quit typing now.

PS. if you have a 4 cyl. you will probably NEVER get a GREAT rumble from it......although the hushpower is kick ass.

pps just cuz I said a bunch about flowmaster's doesn't mean I think they are the best.... I work on exhaust every day of my life....and to me....Magnaflow has a killer sound...deep like a flowmaster but a lot smoother.

ppps if ya have any exhaust questions I'd be happy to answer as long as you don't worry too much about CFM and stuff like that...cuz I don't drag race....I try to get ok or even slightly better than average gas mileage.