Although all three manufactures have similarities, each manufactures system has it's own 'personality'.
Flowmaster comes in both Aluminized and Stainless Steel,'H'-Pipe , 'X'-Pipe, or Cat-Back, and comes in 2.25", 2.5", or 3" diameters. They also offer Headers for Mustangs and Chevrolet models. As far as muffler sound levels, the 70 and 60 Series are Milder, the 50 Series is Moderate, and the 40 Series is Aggressive. The general rule of thumb is that the lower the series number, the more sound you're going to get. Flowmaster also offers a GM A-Body system with no mufflers, so you can chose the sound you'd prefer. Flowmaster offers a wide range of mufflers to suit most peoples taste, so below is a list of their mufflers in order from aggressive to mild:
Aggressive- (Sound level decreases from left to right)
Super 10, 40 Series, Super 44, Super 40, Delta 40, & 80 Series Crossflow (GM F/X-Body, Aggresssive-Moderate)
Moderate/Mild- (Sound levels decrease from left to right)
Delta 50, 60 series (available in 2.25" only), Super 50, & 70 Series Big Block.
You will find the following Flowmaster videos very informative:
MagnaFlow systems are made of 409 Stainless, and all systems are 2.5" or 3" 'X'-Pipe configuration. They also offer Downpipes for several GM, Mopar, and Ford models. All of their systems feature free-flowing, straight-through perforated stainless steel core mufflers with a very throaty but mellow exterior sound, and a minimal interior drone.
Here's a great video by MagnaFlow about exhaust theory, engineering, and application-https://www.youtube.com/watch?v=RWTARjxiqlo
Pypes systems are made of 409 or Polished 304 Stainless Steel. Their systems come in 2.5" or 3", 'True Dual', 'H' or 'X-Pipe', Cat/Crossmember -Back, and 'X-Change' which allows you to install Electric cut-outs for that 'open header' sound. They are also offer a system if you have a GM F-Body with a DSE Quadra-Link rear suspension. They also offer Downpipes for most models, plus original style Exhaust Tips in 304 Polished Stainless Steel. Pypes offers 3 styles of mufflers: Race Pro, Street Pro, and Violator. Race Pro's are the best flowing and the quietest of the three mufflers. Street Pro's offer the necessary back-pressure needed for stock to mildly modified engines but offer an aggressive sound. Violators flow extremely well and offer a moderate idle and cruise sound, but get very aggressive when the throttle is opened. Pypes also allows you to buy their systems without mufflers, allowing you to install the muffler of your choice.
NOTE: Unibody Convertibles (GM F-Body, Mustang, Cougar, Mopar E-Body etc.) WILL require modifications to either the exhaust system or factory cross-bracing to fit!
NOTE: Each of these systems were designed for cars that have not been altered. Items like aftermarket transmission crossmembers and fuel tanks, rear tubs or coil-overs etc. can greatly affect fitment of these exhaust systems!
All of the systems sound different from each other, and all sound different on different engines. A stock Small Block will sound different than a highly modified Big Block with a big cam and high compression with the same system, and 3" will sound different, and louder, than 2.5".
Dynomax mufflers come in two styles, 'Ultra Flo', and 'Super Turbo'. Ultra Flo's are a straight-thru design and can flow up to 1000 SCFM and handle up to 2000 HP for the 3" versions. Super Turbo mufflers are an excellent street muffler and come in 3 case lengths- 14,16,& 20". The longer the length, the quieter the muffler. Dynomax has provided a list of their mufflers showing the SCFM and 'Loss Free HP' ratings. The Loss Free HP rating is the HP level at which there is no loss of power with the muffler installed. Example- Super Turbo #17749 is rated at 386 Loss Free HP. It is not until the engine is making more than 386 HP that the muffler will start restricting flow.
You can find the information from Dynomax here-https://www.dynomax.com/downloads/product-catalog/2015_dynomax_techsection_secure.pdf
Proper exhaust pipe size is a function of both engine output and displacement. The higher the engine’s output, the larger the pipes should be. Likewise, larger engine displacements call for bigger pipes. But you don’t want to become a victim of “More’s Law” either: While up to a point reducing exhaust restriction generally helps both power and gas mileage, going too large can over-scavenge an engine and actually decrease an engine's output as well as fuel efficiency. A stock horsepower car with 3" exhaust can lose noticeable low end torque and affect performance. Also, 3" pipe usually requires increased installation precision because of limited clearance issues. As a general rule, cars with less than 500-550hp should use 2.5" mandrel bent exhaust. Cars in the 600hp range could potentially benefit by a 3" system but unless you are trying to shave 1/10ths in the quarter mile, 2.5" mandrel bent pipes are still dramatically better than 3" shop bent systems.
My manifolds have outlets smaller than 2.5", can I use 2.5" exhaust?
Yes! In all cases that we have 2.5" downpipes, they are engineered to bolt up directly to your existing smaller manifolds without modification.
Who makes 2.5" manifold downpipes for my car?
Chevrolet- Pypes, Flowmaster, MagnaFlow
Pontiac- Pypes, Flowmaster, MagnaFlow
Mopar- MagnaFlow (B-Body)
Ford- Pypes, Flowmaster, MagnaFlow
It seems as though 3" exhaust is the popular choice these days. Are there any disadvantages?
Yes- A stock horsepower car with 3" exhaust can lose noticeable low end torque and affect performance. Also, 3" pipe usually requires increased installation precision because of limited clearance issues. As a general rule, cars with less than 550hp should use 2.5" mandrel bent exhaust.
Can I install my new exhaust system myself or should I take it to a local service center?
If you have never installed an exhaust before, it just takes patience. You may need to cut pipes to length on some systems. Having a lift makes the process much easier but lots of people install our exhausts on a car with jack-stands every day. Welding is a great way to seal the components of your system together but it's not necessary. Clamps are provided with all of the complete systems. Also be sure to follow the manufactures instructions when installing components.
What are the advantages of Stainless Steel Systems?
Stainless Steel is primarily a metal alloy that contains chromium. It this chromium content that give the metal it's corrosion resistance. It's name is meant to imply that it will "stain less" then other alloys, and not that it is "stain free". There are currently have two grades of Stainless Steel exhaust components available:
409 Stainless: The price is comparable to most aluminized systems on the market. This material is used on most of the newer cars produced today. While 409 Stainless will turn a reddish-brown color and may get a hint of surface rust, it will not rust through, allowing it to have exceptional corrosion resistance.
304 Polished Stainless: Highly polished with a nice show-quality finish. This material has excellent corrosion resistance. It may turn a bluish-gold color at the hottest points.
Do I lose a lot of clearance after installing a 2½" or 3" X-pipe system?
Clearance is no different than a non-crossover system of the same size, and properly installed X-pipes DO NOT interfere with transmissions!
I was always under the impression that open headers provide the maximum HP. Is this always true?
We were under the same impression. But in recent tests, we saw noticeable HP increase by adding an open X-pipe to the headers. That is why the Pypes 'X-Change' electric cutouts are located after the X-Pipe.
California Proposition 65 Compliance Notice and Warning
To Our Valued Customers,
Effective August 30, 2018, All products manufactured in Stainless Steel will include a California Proposition 65 warning label.
The California Safe Drinking Water and Toxic Enforcement Act, better known as Proposition 65, lists more than 800 chemicals believed (By the state of California) to cause cancer and / or birth defects or reproductive harm.
Proposition 65 requires manufacturers to provide a clear and reasonable warning before knowingly and intentionally exposing anyone to a listed chemical.
Hexavalent Chromium is listed on the label on Stainless Steel. It is used in the production of Stainless Steel and in welding.
The following risk information was published in a California EPA Fact Sheet.
At what level could health effects occur?
The Office of Environmental Health Hazard Assessment (OEHHA) has calculated a cancer risk associated with exposure to Cr6 if that exposure continues for an entire lifetime. Continual exposure to 0.045 nanograms per cubic meter (ng/m3) of Cr6 from all sources combined for 30 years could increase cancer risk to 25 in a million. Exposure over shorter periods of time would be associated with much lower cancer risks.
The Office of Environmental Health Hazard Assessment (OEHHA) has also developed a chronic Reference Exposure Level (REL) for Cr6. A chronic REL is a health-based benchmark that is set at a level at or below which adverse non-cancer health effects are unlikely to occur in the general human population when exposed continuously over a lifetime. Levels above the REL do not indicate the health effects will occur, but rather, that the chances of these health effects occurring increase at levels above the REL. Non-cancer health effects associated with Cr6 include nasal, throat, or respiratory irritation or allergies. The chronic REL for Cr6 is 200 ng/m3 in air (0.2 μg/m3).
Find the complete document at: https://oehha.ca.gov/air/health-effects-hexavalent-chromium