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Old 07-08-2012, 11:04 AM   #1
Hussain-Vtec
 
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***How to Choose an Exhaust System***

Hi There ALL,

Lets talk about Exhaust Systems.




How to Choose an Exhaust System

One of the most popular performance upgrades is an aftermarket exhaust system. We'll show you what makes an aftermarket exhaust system such a popular upgrade and provide tips on how to choose the system that's best for your vehicle.


VS
Exhaust Construction: Crush Bends vs. Mandrel Bends
So what makes aftermarket exhaust systems one of the most popular performance upgrades among hot rodders? Like aftermarket headers, performance exhaust systems are built differently than their stock counterparts to reduce power-robbing restriction, promote exhaust scavenging, and ultimately free up more horsepower.

The first difference between a stock and aftermarket exhaust is the diameter of the pipes. The diameter ranges available on aftermarket exhaust systems vary depending on the application. However, these systems typically come with larger diameter options to flow larger volumes of air. Again, the proper diameter size will depend on variables such as engine size, rpm, application—a Summit Racing sales rep can help you choose the right size for your specific vehicle.

The second major difference between stock and aftermarket exhaust systems is the pipe bends. Stock exhaust pipe is typically formed using a technique called crush bending. Although crush bending is a quick, easy technique, it also causes performance-robbing restrictions at the pipe bends. To eliminate these restrictions, aftermarket exhaust manufacturers use a process called mandrel bending. This process utilizes a flexible rod, which is inserted in the exhaust pipe. As the pipe is bent, this flexible rod prevents the pipe walls from collapsing or kinking. The result is consistent pipe diameter with no restrictive kinks in the bends.

&

Exhaust Types: Cat-Back, Axle-Back, and More
The three main types of exhaust systems are header-back, cat-back, and axle-back. Depending on what type of system you choose, aftermarket systems will come with some combination of header or intermediate pipes, crossover pipe, catalytic converter, mufflers, and tailpipes.

Header-back exhaust systems replace everything from the header collector to the tailpipes. By replacing all exhaust system components, header-back systems allow you to enlarge the diameter of your entire exhaust system to flow a greater exhaust gas volume. However, these systems tend to be more expensive and tougher to install than comparable cat-back or axle-back exhaust systems because you are replacing nearly the entire exhaust system.

Cat-back exhaust systems replace exhaust components from the catalytic converter back. These systems typically include a muffler and tailpipe, but depending on the make and model, they can also come with a mid-pipe, X-pipe, H-pipe or a Y-pipe. Cat-back systems are among the most popular exhaust upgrades for several reasons.

A cat-back exhaust system is a relatively simple modification that will free up your exhaust gas flow. The result is good “bang-for-your-buck” power gains, although the exact amount of horsepower depends on the remaining stock exhaust components and design of the catalytic converters. The freer exhaust flow can also help your engine operate more efficiently, leading to improved fuel economy. Cat-back systems also produce a more aggressive exhaust note and are typically emissions-legal because they retain the use of the stock catalytic converters.

An axle-back exhaust system includes all the components from the rear axle to exhaust tip. Although cat-back and header-back systems can deliver more power gains, there are many benefits to opting for an axle-back system. A well designed axle-back exhaust system will provide power gains over the stock exhaust but is often less expensive than comparable cat-back or header-back systems. Axle-back exhausts are easier to install and can deliver the performance exhaust sound you want.


Single.jpg or Dual Exhaust.jpg
Exhaust Configuration: Single vs. Dual Exhaust Systems
Another important consideration in picking an exhaust system is configuration. Common setups include single, dual, dual crossover, and dual exit.

The single exhaust system is the most common setup. This design features a single set of exhaust components, including a muffler with exhaust tip that typically exits behind the axle of the vehicle. Aftermarket single exhaust systems will provide a significant performance upgrade over stock thanks to larger pipe diameters and less restrictive mandrel bends. Plus, they’re usually less expensive and lighter weight than true dual-rear exhaust systems.

Dual exit exhaust systems are basically a twist on single exhausts. These systems utilize the same configuration as a single exhaust system—one headpipe, converter, and muffler—but have two exhaust tips exiting from the muffler. There is no real performance advantage to this design, but some hot rodder prefer the added performance styling of the dual tips.

True dual exhaust systems are arguably the most popular exhaust systems in the hot rodding world. This design features two separate pipes that run from the headers all the way back to the exhaust tips, along with two catalytic converters (depending on the application and system) and two mufflers with their own exhaust tips. Many performance enthusiasts prefer this design because of its sporty look, the distinctive growl of the dual mufflers, and the high flow capabilities of two separate exhaust passages for each bank of engine cylinders.

The one main disadvantage of a dual exhaust system is potential pressure imbalance between the two sets of exhaust components. Uneven backpressure can cause one bank of engine cylinders to back up and make less horsepower than the other bank. Dual crossover systems incorporate a special “crossover” to eliminate this problem. This crossover pipe allows exhaust gases to flow freely between the two sets of pipe, balancing out the exhaust flow and eliminating excess backpressure on one side. The dual crossover exhaust system is generally regarded as the best performing exhaust but, in many cases, requires some extra modifications for proper fit.

Depending on the manufacturer, there are other less common exhaust configurations available, including single muffler dual-rear exhausts and side exit exhausts. For more information on what is offered by each manufacturer, check out our complete line of exhaust systems.

Mid steel.jpg VS Stanless.jpg

Exhaust Material: Mild Steel vs. Stainless Steel
Aftermarket exhaust systems can be made from a variety of materials; Summit Racing offers systems made with mild steel or stainless steel. The biggest advantage to a mild steel exhaust system is cost. While these systems will save you some cash, they will eventually rust or corrode. Stainless steel resists corrosion, making it the ideal exhaust system material for rainy or snowy climates.


You can choose a universal exhaust system (usually requires fabrication) or use our Make/Model or Make/Engine searches at the top of our site to select a system designed for your vehicle.

How To Calculate Muffler Size and Exhaust Pipe Diameter

If you’re a math wiz and/or an engineer, you’re probably going to like this article and the resources we’ve linked to. However, if you find yourself getting stuck (or bored) with the info below, here are the key take-aways:

1. The factory exhaust pipe diameter is usually a good choice for most vehicles.

2. The muffler manufacturers are doing all the math for us – no need to reinvent the wheel. If they say it will work for your vehicle, it will probably work for your vehicle.

3. We’ve got an easy-to-read exhaust system size table that is good for quick calculations.

Breaking Down The Problem

While we’re not going to go through and list out all the formulas and calculations you need to figure this exactly, we will break down the problem, explain how you would go about figuring things out scientifically, and then leave you with some good quick-and-dirty exhaust system math as well as some interesting links.

The science goes like this…

1) Mass of air that the engine breathes in + mass of fuel = mass of exhaust gases
Conservation of mass, right?

2) To calculate the volume of air the engine takes in, we multiply the displacement of the engine by the engine RPM and then divide by two (it takes two full revolutions for the engine to exhaust it’s entire air volume). We then convert that to volume to mass.

3) To make the calculations easy, you want to assume that combustion is perfect, i.e. there aren’t any byproducts, any unburned fuel, etc. It’s easier to assume perfect combustion and then “back in” to the actual numbers using an estimate after the fact.

4) Since you’re assuming perfect combustion, it’s easy to figure out how much fuel mass is added to the exhaust.

5) Once you know the mass of the exhaust gas, you just figure out how much volume that mass would occupy. Of course, you have to adjust for expansion due to the high exhaust gas temperature.

That’s it! Of course, when you sit down to figure it, you’ll find that getting a good scientific estimate takes a lot of work (which is why we don’t bother with it here).

Quick and Dirty Exhaust System Math

Easy Way To Estimate: Your intake system needs to flow 1.5 CFM per engine horsepower, and your exhaust system needs to flow 2.2 CFM per engine horsepower.

Good Way To Estimate: Take engine RPM x engine displacement, then divide by two. This is the intake volume. Use this same volume of air for the exhaust system, but then correct for thermal expansion (you need to know exhaust temps to figure things out).

Exhaust Pipe Size Estimate: A good section of straight pipe will flow about 115 CFM per square inch of area. Here’s a quick table that shows how many CFM each common pipe size will flow, as well as the estimated max horsepower for each pipe size:



PHP Code:
Pipe Diameter     Pipe Area       Total CFM      Max HP         Max HP For 
   
(inches)         (in2)          (est.)        Per Pipe     Dual Pipe System
     1 1
/2           1.48           171             78               155
     1 5
/8           1.77           203             92               185
     1 3
/4           2.07           239            108               217
       2             2.76           318            144               289
     2 1
/4           3.55           408            185               371
     2 1
/2           4.43           509            232               463
     2 3
/4           5.41           622            283               566
       3             6.49           747            339               679
     3 1
/4           7.67           882            401               802
     3 1
/2           8.95          1029            468               935 
NOTE: These numbers are just estimates. All pipes are assumed to be 16 gauge steel.

The table above is probably over-estimating pipe size, but you can see that a 400 hp vehicle with a dual exhaust system only needs 2 1/4 – 2 1/2 inch pipes. Anything larger is overkill.


PIPE DIAMETER AND PERFORMANCE
Use the guide below when calculating pipe size for custom exhaust work.
Keep in mind that the goal is to improve exhaust flow.
In most cases, just changing the restrictive OEM muffler and replacing it with the same size straight-through, Wide Open Performance MagnaFlow muffler will do this job.

To reduce additional backpressure, the OEM exhaust tubing can be replaced with madrel-bent tubing of the same size or one size up from the OEM.

As a general rule, you can enlarge the pipe diameter of your OEM exhaust system by 1/4- to 1/2-inch to increase your horsepower.

However, any additional increase in pipe diameter is likely to decrease your performance; specifically, low end torque.

Bigger is not always better.



PHP Code:
                                                Muffler Inlet     /    Outlet Size 
Engine Size              Horsepower             Single Exhaust         DualExhaust
150
-200 CID               100 to 150             2" to 2-1/4"              2"
200-250 CID               100 to 200            2-1/4" 
to 2-1/2"      2" to 2-1/4"
250-300 CID               150 to 250             2-1/2" 
to 3"         2" to 2-1/2"
300-350 CID               200 to 350             2-1/2" 
to 3"       2-1/4" to 2-1/2"
350-400 CID               250 to 550               3" 
to 4"           2-1/2" to 3
Use as a general guide for engine size and performance.

Link
http://www.magnaflow.com/wideopen/performdata.asp








CATALYTIC CONVERTER BASICS
DESCRIPTION & OPERATION
The catalytic converter is a passive after-treatment device designed to reduce engine-out emission levels to meet an acceptable standard. Together with the Oxygen Sensors and other Engine Management components, this Emissions System works to reduce harmful emissions at the tail pipe. The catalytic converter contains two or more ceramic substrates, coated with
a combination of Platinum, Palladium and Rhodium and a Ceria based wash coat, packed into a stainless steel housing. When placed in the right environment of heat (400°C) and proper air/fuel mixture the catalyst forces
a chemical reaction reducing toxic gasses to less harmful ones.



Toyota NZ engine
The Toyota NZ engine family is a straight-4 piston engine series. The 1NZ series uses aluminum engine blocks and DOHC cylinder heads. It also uses SFI fuel injection, and has 4 valves per cylinder with VVT-i.

We should No Every thing about our Engines in order to Do Modified parts in
That case we no that which is Good To Go for!



1NZ-FXE
The 1NZ-FXE is the earliest 1.5 L (1497 cc) version built in Japan. Bore is 75 mm and stroke is 84.7 mm. It features forged steel connecting rods and an aluminum intake manifold. The engine has a high physical compression ratio of 13.0:1, but the closing of the inlet valve is delayed. The net result is that the engine has a greater effective expansion than compression—making it simulated Atkinson cycle, rather than the conventional Otto cycle.
The reduction in cylinder charge means reduced torque and power output, but efficiency is increased. This combination makes the 1NZ-FXE suitable for use with the Hybrid Synergy Drive, where peak torque and power are of less importance. Output is 57 kW (76 hp) at 5000 rpm with 115 Nm (85 lb·ft) of torque at 4000 rpm.




1NZ-FE
The 1NZ-FE is a 1.5 L (1497 cc) conventional Otto cycle variant of the 1NZ-FXE. It has the same bore and stroke, but the compression ratio is lowered to 10.5:1, and it features VVT-i. Output is 80 kW (107 hp) at 6000 rpm with 141 Nm (103 lb·ft) of torque at 4200 rpm.




2NZ-FE 1.3 L
The 2NZ-FE is a 1.3 L (1298 cc) version built in Japan. Bore is 75 mm and stroke is 73.5 mm, with a compression ratio of 10.5:1. Output is 63 kW (84 hp) at 6000 rpm with 121 Nm (89 lb·ft) of torque at 4400 rpm.
The Toyota 2NZ-FE 1.3 L engine was designed in 1999 with Otowa Yamaha as the head engineer of the project. Toyota introduced the VVT-i system on the 2NZ-FE to improve fuel efficiency and emissions. VVT-i is now a feature of all current Toyota engines.

Original Link
http://en.wikipedia.org/wiki/Toyota_NZ_engine

Last edited by Hussain-Vtec; 07-08-2012 at 12:27 PM. Reason: Toyota NZ engines
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Old 07-08-2012, 11:09 AM   #2
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I thank you, kind sir!
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Old 07-08-2012, 11:13 AM   #3
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Quote:
Originally Posted by G-Ammo View Post
I thank you, kind sir!
Your Welcome Sir that's just as a starter it will be updated Soon.
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Old 07-08-2012, 12:32 PM   #4
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Don Updating Guys Feel Free to read.

I am @ Work and i am going home for now.
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Old 10-25-2012, 05:10 AM   #5
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This just answered my question. Thank youuu sooooo muchhhh
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Old 03-15-2014, 01:17 PM   #6
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"Cat-back systems also produce a more aggressive exhaust note ."

"Axle-back exhausts are easier to install and can deliver the performance exhaust sound you want."


Great informative thread. However, all I want is a stainless system this summer to replace my 2010 HB OEM system. I don't want more sound or looking for performance enhancements...just stainless. When I search the web, all I see are systems that "give you that growl you are looking for" and the like. Has anyone purchased an axle-back or cat-back stainless system like the one I am looking to find?
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Old 03-15-2014, 02:00 PM   #7
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Quote:
Originally Posted by bairjo View Post
"Cat-back systems also produce a more aggressive exhaust note ."

"Axle-back exhausts are easier to install and can deliver the performance exhaust sound you want."


Great informative thread. However, all I want is a stainless system this summer to replace my 2010 HB OEM system. I don't want more sound or looking for performance enhancements...just stainless. When I search the web, all I see are systems that "give you that growl you are looking for" and the like. Has anyone purchased an axle-back or cat-back stainless system like the one I am looking to find?
Are you only concerned with the bling factor of stainless? You are looking for T304?
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Old 03-15-2014, 02:06 PM   #8
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I just want a longer lasting replacement.
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Old 03-15-2014, 02:38 PM   #9
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Quote:
Originally Posted by bairjo View Post
I just want a longer lasting replacement.
My preference is T409 rather than T304. When I was at Miami Muffler back in 2011 they showed me the difference between the two after a few years and the T409 tends to have less likelihood of cracking due to the way they form the piping. T304 is supposedly the highest grade however they also showed me that for the most part this is a marketing thing. It costs more therefore they want you to buy it over T409 most times. T304 is less tolerant to heat from what they shared. I went with T409 and my piping looks like it did when it was installed in June 2011 and that is with running boost and living in Northern Maine. Just my 2 cents. I would also go with a mandrel bent custom setup and just be done with it. It was also cheaper for me that that. Who knows...I may actually have to ditch the one that I have since I will be running so much boost and hp. I had never thought that I would need bigger than 2.5". I may have been mistaken.
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Old 03-15-2014, 08:07 PM   #10
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So is that a draw back to stainless...cracking? It doesn't rust but cracks? I ask this due to what you said along with my experience with my stainless gas grill burners. I use the grill all year, cold weather and hot, and they always crack and fail in a year. Yes, they are not the best grade of stainless, but amplify things on an exhaust system and now im starting to have second thoughts.
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Old 03-15-2014, 08:35 PM   #11
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Stainless has bad thermal conductivity, and it has bad thermal expansion characteristics comparison to mild steel. The reason it cracks can be due to many things, but mostly because of a product design problem. Since steel expands slightly when heated, if that isn't taken into account when designing the product, it will fatigue and fail.
You'll notice alot of aftermarket headers do this as well Miatas specifically, and it almost always happens at where the metal is joined together, and thats specifically because the weld is more brittle compared the surrounding metal making them less ductile. So to get around this you can use thicker material, that can handle more stress compared to a thinner material.
If you want a fun experiment watch a truck climb up a steep grade at night, you'll see a glow underneath the car because the header is probably 900-1600 degrees, and thats the typical heat range a header is expected to operate in, whereas further down the exhaust stream you may only be seeing 200 degrees.

So in essense what I'm getting at is, nothing else out there is going to be as durable as the stock exhaust. Its made of 409ss and double walled, its sufficiently thick and has been properly designed to without the stresses of driving.
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Old 03-15-2014, 09:11 PM   #12
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Thank you xnamerxx. Sounds like you know metalurgy. But when you are saying the stock exhaust, are you saying the Yaris exhaust is already stainless? You have to understand...I'm not very bright.
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Old 03-15-2014, 09:58 PM   #13
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Stock exhaust is stainless for sure. It's made of out 409ss, its not quite as corrosion resistant, and will develop surface rust. Hence why its that brown color.

Since OEMs have to warranty their exhaust for 10 years of weather and salt, they need to use a material that's capable of withstanding that with a semi low rate of failure. So that means they can't use any grades of carbon steel, so low grades of stainless steel are cheap enough while offering enough weather resistance to last through the warranty period.
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Old 03-15-2014, 10:43 PM   #14
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Thank you for clarifying that...guess I'll hold of on any exhaust upgrade for now. Thanks again. You got to love Yarisworld...ask the question and you will get an answer from someone that knows his shit..er exhaust.
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Old 03-16-2014, 12:40 AM   #15
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As xnamerxx has said the stock exhaust is 409....that is also what I had the shop use to create my custom system. It has held up very very well and actually hasn't discolored either for the most part.
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Old 03-16-2014, 03:28 AM   #16
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I have the Trd axle back on my sedan. I love it , and when I had it installed the mechanic said the quality of the stainless was top notch. I also noticed a little bit more top end with it.
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Old 03-16-2014, 08:02 AM   #17
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409 also is less brittle then 304 stainless. We do 80% of our custom exhausts in 409 with basically no failure rate.
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