Q1. 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 splitting the exhaust stream (exhaust pulses & 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.

Q2. 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.

Q3. 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 style 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 Flows are moderate, and the 40 Series have a more aggressive tone.

Q4. 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.

Q5. 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 we can help accomplish this by answering the questions below. This approach will allow you to choose the best product to suite your needs and expectations.

1. What is the vehicle year, make, and model?
2. Which engine do you have or how much horsepower does it produce?
3. What is the vehicle used for? i.e.: daily driver, race, towing etc.
4. Preferred sound levels (interior and exterior?)
5. How are the space requirements?
6. Would you like a complete exhaust system or universal pipe kit if available? Single or dual outlet?

Q6. 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.

Q7. 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 & 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.

Q8. 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 outer 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. See page 7 of the Flowmaster Catalog for more information.

Q9. 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 mz can be achieved. That is if you can keep your foot out of the gas to hear that Flowmaster® sound.

Q10. 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 the tubing. As a rule, most stock street applications (dual exhaust) use 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.

Q11. 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.

Q12. 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 retains the deep Flowmaster muffler tone desired by most performance enthusiasts.

Q13. 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 vehicles performance.

Q14. 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.

Q15. What is Flowmaster’s warranty?

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

Q16. 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 for durability and value. Select part numbers of the 40 and 50 series are offered in 409S stainless steel (check with the tech line for updates). 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 hat can be polished to a high luster. The HP2 mufflers are also available with this material and final appearance.

Q17. 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 your vehicle application. Through years of field testing under street and racing conditions, we’ve 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 applications where daily driver chores are not commonplace aluminized mufflers are a great thing to consider.