Systems 101: Designing a Custom Exhaust System for Your Truck

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Old 07-08-2014, 06:29 PM
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Systems 101: Designing a Custom Exhaust System for Your Truck

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Header Collector Ball Flange Kits:

The Flowmaster Ball Flange Kit takes the place of messy three bolt flange type connections and allows for a leak free and gasket free ball flange type connection. All kits are 16ga aluminized tubing and are sold in pairs.

Pipe Size:

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 running dual exhaust use 2.00” through 2.25” tubing, and modified street applications (dual exhaust) will generally use 2.25” or 2.50” tubing. Very rarely will 3.00” tubing be used in dual exhaust street applications.

In general, the following guidelines should be applied for street applications:

Single Pipe Diameter / Horsepower

2.50" / 150-200
3.00" / 200-250
3.50" / 250-350
4.00" / 350-425
4.50" / 425-500
5.00" / 500 and up

Dual Pipe Diameter / Horsepower

2.50" / up to 400
3.00" / up to 500
3.50" / up to 700
4.00" / up to 850
4.50" / up to 1,000


Balance Pipe(H-pipes and X-pipes):

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.

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.

Muffler Selection:

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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 suit 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?

System Hangers:

Adequate hangers should be used to properly support the system. Flowmaster uses OE style hangers in all systems.

Resonators:

Resonators are designed to be used in conjunction with your mufflers for improved sound reduction. Resonators will help to eliminate interior resonance.

Stainless Tips/ Exit Location:

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.
Flowmaster's line of Stainless Steel Exhaust Tips are a great way to let people know that you have Flowmasters under your ride! They come in a variety of styles from brushed to polished and will greatly enhance the look of your vehicle!

If you have further questions regarding any of our products, please call (707) 544-4761 or visit our website.
 

Last edited by Matt@Flowmaster; 07-08-2014 at 06:50 PM.
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Old 07-08-2014, 07:08 PM
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I designed a new exhaust for my 08 5.4L f350. I am eliminating the y pipe and going with a h pipe and dual super 44s. Just waiting for the shop to finalize numbers and I will be getting it done. It will be lightning style.

 
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Old 07-09-2014, 06:13 PM
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Originally Posted by nojoke327
I designed a new exhaust for my 08 5.4L f350. I am eliminating the y pipe and going with a h pipe and dual super 44s. Just waiting for the shop to finalize numbers and I will be getting it done. It will be lightning style.
I applaud your creativity, but I would not recommend running a "true" dual exhaust system on your truck. Your vehicle's engine management system is setup for a single exhaust configuration. Putting a dual exhaust system on the truck may result in power loss. I would suggest a single in, dual out configuration for your application if you would like to have two tailpipes.
 
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Old 07-09-2014, 06:55 PM
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I agree the setup may not he 100% optimal now but the truck will be getting 4.88 gears and a custom dyno tune some time this year. That should help with the power. I have a setup like you mentioned and I love it but after I heard the system I designed in another truck my current exhaust can't come off fast enough

 
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Old 07-10-2014, 09:40 AM
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Originally Posted by nojoke327
I agree the setup may not he 100% optimal now but the truck will be getting 4.88 gears and a custom dyno tune some time this year. That should help with the power. I have a setup like you mentioned and I love it but after I heard the system I designed in another truck my current exhaust can't come off fast enough
It is your truck, so if you enjoy the sound of the exhaust system that you designed, that is all that matters. I wish you the best of luck!
 
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Old 07-23-2014, 03:15 PM
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Which piece(s) to replace?

I currently have a 2003 F-250 4x4 SCSB with the 5.4/Manual Trans that has a completely stock exhaust. I would like to replace some portions of the exhaust system to gain more HP/TQ for occasional towing. If you could select only one of the following items to replace to improve exhaust flow, which would it be?

1. Exhaust Manifolds - Replaced with headers
2. Factory y pipe - replace with SPD Y pipe
3. Catalytic Converter - Replace with higher flowing Cat
4. Muffler

If you were going to replace two, which two? I am looking to keep basically stock noise levels and not break the bank, but I am willing to spend a reasonable amount of money for substantial gains.
 
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Old 07-24-2014, 11:01 AM
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I would first swap out the muffler with either a Flowmaster 70 Series or Super 50 Series. Both of these mufflers are designed for high performance and sound great without being too loud, which makes them suitable for daily driving and towing. Your muffler is the last thing that exhaust gasses pass through when leaving your truck. In order to increase power and run more efficiently, your motor will need to "inhale" more air. Changing out the muffler will allow your truck to "exhale" more efficiently than the stock unit.

My next recommendation would be to replace the stock Y-Collector section of your exhaust system with Flowmaster part number Y250300. This collector is a proven design that is capable of producing just as much horsepower as our muffler!

I suggest that you leave your catalytic converter alone. Your cat is already a high flow unit from the factory. By switching out your catalytic converter the only thing that you will increase is the sound level of your truck.

Headers would be a good idea down the road, but I would install a high performance cold air intake system or a high performance filter replacement before making that purchase.
 

Last edited by Matt@Flowmaster; 07-24-2014 at 11:03 AM.
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Old 07-24-2014, 11:52 AM
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Matt,
Thanks for the opinions. I appreciate the response.
 
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Old 07-26-2014, 05:56 PM
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Don't bother with the Y pipe if the headers you're thinking about have a Y included like Heddman or Thorley.
 
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Old 07-30-2014, 01:41 PM
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Originally Posted by Super Duty DJ
Matt,
Thanks for the opinions. I appreciate the response.
No problem at all. Good luck with your system!
 
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Old 08-01-2014, 10:55 AM
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Custom Exhaust

Matt: I am thinking about replacing my stock exhaust system with a custom system. I am wondering what your thoughts are about the exhaust diagram
and notes below. Do you see any potential problems or issues with it? Thanks

 
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Old 08-02-2014, 03:08 PM
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Originally Posted by makthenif
Matt: I am thinking about replacing my stock exhaust system with a custom system. I am wondering what your thoughts are about the exhaust diagram
and notes below. Do you see any potential problems or issues with it? Thanks

You do realize your asking a flowmaster guy about a magnaflow muffler right. Not being an *** here but what sort of answer do you expect to get?
 
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Old 08-02-2014, 11:56 PM
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Flowmaster,

1979 F150
400- bumped compression, lopey idle cam, headers, intake, MSD, exc..
Daily driver for less than 20 miles a day
Interior noise- Mild drone is okay
Exterior noise- Aggressive. I would like it to complement the cam lope
Space restricions- I would like the muffler not to be seen when standing next to the truck or sitting in traffic.

The current setup is true duals after the fender well headers exiting at the bumper. 2.5" pipe without a crossover section. I am looking to replace everything from the header to the axle back section. One of the inlet pipes from the existing mufflers has broken free and has caused a rattle and exhaust leak.

What muffler would work well for me, and is there a practical way to install an H pipe without it being seen? I was thinking a Super 10 and possibly a resonator to help calm down the interior drone.
 
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Old 08-04-2014, 09:51 AM
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Originally Posted by makthenif
Matt: I am thinking about replacing my stock exhaust system with a custom system. I am wondering what your thoughts are about the exhaust diagram
and notes below. Do you see any potential problems or issues with it? Thanks
You may want to direct your question to a representative of the brand of muffler that you are planning to run. They should be able to give you a better idea of how to set your system up in relation to their products. Good luck!
 
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Old 08-04-2014, 10:34 AM
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Originally Posted by 61steven
Flowmaster,

1979 F150
400- bumped compression, lopey idle cam, headers, intake, MSD, exc..
Daily driver for less than 20 miles a day
Interior noise- Mild drone is okay
Exterior noise- Aggressive. I would like it to complement the cam lope
Space restricions- I would like the muffler not to be seen when standing next to the truck or sitting in traffic.

The current setup is true duals after the fender well headers exiting at the bumper. 2.5" pipe without a crossover section. I am looking to replace everything from the header to the axle back section. One of the inlet pipes from the existing mufflers has broken free and has caused a rattle and exhaust leak.

What muffler would work well for me, and is there a practical way to install an H pipe without it being seen? I was thinking a Super 10 and possibly a resonator to help calm down the interior drone.
I would definitely suggest that you build a new 2.50" exhaust system using an H-pipe. As far as a way to install it without being seen, that is something that you or your muffler shop will have to work out. Because of the custom nature of what you are describing it is difficult for me to recommend a way to do this without getting under your truck and figuring out a mounting method or a way to run your tubing. You should be able to accomplish this without too much of an issue. For mufflers, go with a pair of Flowmaster Super 44's and then build 3.00" tailpipes , or dumps, after the mufflers. By using 3.00" tailpipes, you will achieve a deeper tone.
 


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