Flowmaster FAQ

What makes Flowmaster mufflers different?

Flowmaster's patented ''chambered'' design is what sets it apart from any other muffler. The theory behind the design is based on basic principles of physics. By stifling the exhaust stream (exhaust pulses and sound energy) and then recombining them in another chamber, the collision of energy cancels the sound waves, which creates a low pressure area in its place. This resulting low pressure area then helps scavenge/ accelerate the following pulses into the muffler and out the tailpipe resulting in a more efficient and cleaner burn, which means more power.

How does Flowmaster compare to straight through mufflers?

Straight through mufflers consist of a perforated flow tube, and rely on packing materials such as steel wool or fiberglass to simply absorb sound. While these mufflers may improve performance by using larger internal flow tubes, the packing materials will burn or blow out over time which results in an increase of sound until it eventually becomes ineffective. The Flowmaster design uses no packing, and therefore will maintain its sound control over the life of the product.

How do Flowmaster mufflers rate on a flowbench (CFM)?

Many muffler manufacturers advertise, test and rate the performance of their mufflers with me use of a flowbench. The problem with this methodology is that a flowbench produces a steady, low temperature stream of air and lacks the acoustical and thermal dynamics that are produced by an internal combustion engine. Flowmaster designs, tests and proves its products under real world conditions in the dyno cell, at the track and on the road. After all, when was the last time you raced a flowbench?

What does a Flowmaster sound like?

The Flowmaster sound is unique to itself and is very different from that of glass packs or other packed stye mufflers. The Flowmaster sound can best be described as a deep smooth sound, and has proven to be the preferred and most recognized sound of most automotive enthusiasts. Flowmaster offers many different levels of sound from mild, to moderate, to aggressive. In general, the 60 Series, 70 Series and Super 50 Series mufflers are milder with reduced interior sound. The 50 Series Delta Rows are moderate, and the 40 Series have a more aggressive tone.

What is the difference between a 40 Series and a 50 Series muffler?

The 50 Series (moderate to mild) incorporates an internal tuning chamber that helps reduce interior sound level in the cab area of your vehicle, and provides a slightly milder exterior tone than the 40 Series. The 40 Series (aggressive) will generally resonate or ''drone'' inside the vehicle, around 1800-2000 rpm and again around 2400-2600 rpm. The performance characteristics of the 40 and 50 Series are the same, so it's simply ''a sound decision.''

How do I select the correct Flowmaster?

The sound of your exhaust is much like music; we all have different preferences so it's important that the system be ''tuned'' to what you like. With the Flowmaster family of products you can accomplish this by answering the questions below. The approach will allow you to choose the best product to suite your needs and expectations.
  1. What is the vehicle year, make, model?
  2. Which engine do you have or how much horsepower does it produce?
  3. What is the vehicle used for? ie: daily driver, race, towing, etc.
  4. Preferred sound levels (interior and exterior?)
  5. What are the space requirements?
  6. Would you like a complete exhaust system or universal pipe kit if available? Single or dual outlet?

Will I lose power going from a 40 Series to a 50 Series, or to a 70 Series?

No. Flowmaster engineers have designed each series of mufflers with maximum efficiency in mind. The differences between the various muffler series are in the varying sound levels produced both inside and outside your vehicle This is why it is so important to take the time to carefully choose the right product that will suit your individual needs and sound preference.

What is ''Delta Flow'' technology?

This patented new technology is an improvement over the original Flowmaster design that provides improved scavenging and additional reduction of resonance inside the vehicle. This advancement was born out of Flowmaster's extensive involvement in racing and its commitment to Research and Development. This new design incorporates additional delta deflectors placed at precise angles and spacing within .004-inch tolerance. The result is improved performance while maintaining a pleasant tone, both inside and outside the vehicle.

What is a Laminar Flow Technology Muffler?

Laminar Flow Technology mufflers are the latest generation in the Flowmaster family of performance products featuring innovative, patented technology. Flowmaster Laminar Flow Technology mufflers actually accelerate the exhaust flow as it passes through the tapered core and expands into the large volume outlet core area in multiple layers. This all adds up to a design that delivers distinct torque and horsepower improvements over straight through designs, along with a deep mellow exhaust tone.

What kind of performance gains can I expect when installing a Flowmaster system on my vehicle?

Performance gains will vary dependent upon your application. The more power the vehicle makes, the bigger the gains will be. Generally, in full size vehicle applications, a 5-7% gain of power is fairly typical, while 1-2 mpg can be achieved. That is if you can keep your foot out of the gas to hear that Flowmaster sound.

How can I be sure that I'm buying a Flowmaster muffler?

The Flowmaster name is embossed in every muffler case that Flowmaster builds. If it doesn't say Flowmaster on the case, it's not a real Flowmaster muffler. Buyer beware; Flowmaster knock-offs may look similar, but may not perform or sound the same, and often have a high defect return rate.

What size exhaust tubing should I use for my street application?

The size of tubing used in an exhaust system is as important as selecting the right muffler. Your tubing diameter choice will affect the sound level and performance characteristics of the muffler, but keep in mind that bigger is not always better. Using tubing that is too large can actually hinder exhaust scavenging by slowing the velocity of exhaust pulses in tubing. As a rule, most stock street applications (dual exhaust) use a 2.00'' through 2.25'' tubing, and modified street applications will generally use 2.25'' or 2.50'' tubing. Very rarely will 3.00'' tubing be used for street applications. In general, the following guidelines should be applied for street applications.

Do I need to install an ''H'' pipe in my dual exhaust system?

Flowmaster strongly recommends using a crossover tube, otherwise known as an ''H'' pipe or balance pipe on all true dual exhaust systems. The crossover pipe equalizes the exhaust pulses and allows the sounds waves to communicate between both banks of the engine. Not only does this usually improve torque in the low to mid rpm range, it also creates a deeper mellower tone both inside and outside of the vehicle and helps eliminate ''back-rap'' on deceleration.

Is an ''X'' pipe better than an ''H'' pipe?

Flowmaster has performed extensive testing and determined that the ''H'' and ''X'' pipes deliver no significant difference in performance, but do affect tone, the ''X'' pipe giving off a higher pitched tone. Flowmaster Scavenger ''X'' pipes however do increase torque through use of their patented D-Port technology and retain the deep Flowmaster muffler tone desired by most performance enthusiasts.

Will my late model vehicle run better if I replace the single inlet muffler with a true dual exhaust system?

Flowmaster does not recommend replacing factory single inlet exhaust systems with a ''true dual'' system on computer controlled vehicles. The computers in most late model vehicles may not be able to compensate with the fuel needed when increasing the exhaust flow, and may void your factory warranty and emission compliance. Flowmaster's dual outlet kits will give you the look of a ''true dual'' system, while optimizing the vehicle's performance.

Do I need to run tailpipes after the mufflers?

Yes. Flowmaster highly recommends running a minimum of 12'' tailpipe after the muffler. This will not only greatly help in sound control; it will also provide an increase in exhaust efficiency (more power). Running tailpipes out from under the car in street applications will also direct the potentially harmful exhaust fumes away from the vehicle, as well as minimize the sound transmitted into the cab area of the vehicle.

What is Flowmaster's warranty?

All Flowmaster stainless steel products are covered by the lifetime warranty to the original purchaser. The Flowmaster aluminized products have a 3-year limned warranty against defective materials and workmanship (excluding race products). All warranty related returns must be processed through original retail outlet with original sales receipt.

What materials are used to build Flowmaster mufflers?

All Flowmaster chambered products are fully MIG welded and built from either 16-gauge aluminized steel or 409S stainless steel tor durability and value. Select part numbers of the 40 and 50 Series are offered in 409S stainless steel. The internal construction of all Laminar flow mufflers is 409S stainless steel and the dBX line of mufflers utilizes a 304 stainless steel outer casing that can be polished to a high luster. The HP2 mufflers are also available with this material and final appearance.

Is stainless steel a better material for manufacturing exhaust products than aluminized steel?

Not necessarily... and it can heavily depend on where you live and on your vehicle application. Through years of field testing under street and racing conditions Flowmaster has found in many applications aluminized steel is just as durable as stainless steel at a slightly reduced cost. If you live where road salt can come in contact with your vehicle on a regular basis, a stainless steel muffler is the right choice. For most racing and high performance application where daily driver chores are not commonplace, aluminized mufflers are a great thing to consider.

Will installing a Flowmaster Cat-back exhaust system void my vehicle's factory warranty?

There are some modifications that have the potential to void a vehicle's factory warranty, but modifying the exhaust system after the catalytic converter is not one of them. All Flowmaster exhaust systems are designed vehicle specific and do not violate manufacturers factory warranty. If you're having problems regarding this issue, please contact www.sema.org for more information regarding consumer's rights on performance aftermarket parts.

Are Flowmaster Performance Cat-back exhaust systems and mufflers street legal?

Flowmaster has fifteen different styles of performance mufflers allowing customers the opportunity to choose a Flowmaster signature sound ranging from mild to moderate or aggressive to accommodate the customer's local and state laws.

Please note:
Using FLOWMASTER performance exhaust in conjunction with other performance modifications, i.e. high flow air filters, air boxes, headers etc., can cause an increase in exhaust dB's that could exceed allowable local limits. For additional information regarding exhaust laws please go to www.sema.org.