Well after seeing yet another exhaust question I decided to try make a thread that can be made sticky and people can look here before posting. I know that people tend to just click 'new thread' instead of 'search', and well we all have at one stage.


Performance exhausts on N/A Ford I6 motors.

Some brands to take into consideration are:

Lukey
Redback
Pacemakers

There are also some brands that people dont touch:

X-flow (which can be found at your nearest midas car care center)

The standard for for i6 from EA-AU is 1.75" (some one please check this).

Upgrading to a performance exhaust is one way to make your car sound and perform better.

Before we start talking sizes we must know what parts of the exhaust there is.
These can be broken down to 3 parts.

Part 1 - The Headers. These are responsible for converting all 6 exhaust ports into one pipe.

People go for Pacemakers (Pacies), Redback and Lukey extractors. Extraactors are a must for power gain and future upgrades. You dont want bottle necks do you?
There is some debate about the Lukey extractors with people saying they are not as good as Redback or Pacemakers. But when it comes to the crunch Extractors are better then stock headers and lukey rob you of 1 or 2 horsepower when you start getting into the high horse's.

Expect to pay around $200-550 for a set of extractors. It also depends if you group buy, second hand or brand new.


(Extractors on a i6)


(thanks to tickford666 for that one)

Part 2 - The Catalytic Converter

One word...EPA. Basically our cars put out gases such as nitrogen oxide, water vapor and carbon dioxide and monoxide. The cat converter is a 'catalyst' to these gases and help convert them to things that are less harmful to the o-zone layer. They have a mesh in they with ceramic and other elements that are teh catalyst.
So because there can be alot of restriction in these we tend to get high-flow and ultra-flow cat converters. Depending on the useage on the car, for a ford i6 N/A most people go 2.5". This is a pretty good size in the way of flow and back pressure. If we go bigger we can loose back pressure. If we go smaller then stock then things get tight and dont work the way they should.

Here its always good to stick to a brand that you have heard before. Dont go buy a cat from some dodgy itallian looking guy in the back streets because it probably wont work the way it should.

Expect to pay $90-320 for a cat converter. As i said before it all depends where u get them from. Trade, cost, group buy, or retail.


(high flow cat)


Part 3 - Center and rear pipes.


(No front resonator version - Suits all 6 cyl Falcons from EA to AU live axel)

Here is the last part of the exhaust.
This is commonly called the 'catback' exhaust. Hence its from the cat conveter and back.
The best thing to use here is mandrel bent pipes. This is when they get things called mandrels and put them inside the pipe while they bend it. The Mandrel is basically a steel ball. Having a mandrel bent exhaust over a standard bent one is that the pipe is nice, even and doesnt have any kinks in it. This improves the flow rate of the exhaust gases.

As i said before the best size to use is 2.5". This is for N/A i6 ford motors. Some people with jap cars that have the 4 or 6 cylinder with big turbos go for 3" or 3.5". This is not practicle for ford motors.

Some people like their exhaust to be noisy and sound sweet as. Some poeple like them quiet as stock. Its all up to you.

Since the catback is devided into two parts, the center pipe and the rear pipe i will talk about them separately.

The center pipe usually has one or two mufflers. What you get is all up to you. IMO the best to go with is two lukey center mufflers. Some people like one small one. Changing the size and amount changes the note of the exhaust.


(center muffler)

The rear pipe. MOST people like to have a straight through pipe here. Simply for the nice sound. If you find your exhaust to be too loud or crap sounding you can have a 'hotdog' muffler installed. be careful as this can be clasified as 'rice'. If you get a hotdog and you want to stay at this forum without being flammed then hide the hotdog with the bumper.

Lastly you can have a standard resinator installed to it. This will make is quieter then before.

Be careful when it comes to this as the loudest you can have an exhaust is 96db. Any louder and you can get defected.

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Not a bad idea for a thread (ill add it to the FAQ sticky as well).

quick comments though...


redback dont make extractors, just exhausts.

The two most common headers people get are the pacemaker 4480 and 4499 - you might want to talk about them. There are also other brands such as genie and advanced.

Might be worth adding some info about picking the style of extractors you want. Thinks like the design (6-3-1 like the 4480's or 6-2-1 like most others), pipe size (big = lots of flow, small = higher velocity and better scavenging), primary and secondary pipe length. If you know the general rules of thumb you can just look at a set of pipes and have a good idea about how it will suit your engine.

Also what would be very useful is a collection of good pics of the different extractors for I6's.

It was ok for someone thats doesnt know much about exhausts.

Well i think that you can grab whats there and touch it up. We then get a mod to post and stick it.

It was ok for someone thats doesnt know much about exhausts.

Well i think that you can grab whats there and touch it up. We then get a mod to post and stick it.

So what determines the noise output of an exhaust system?

Everything within the exhaust system will make a change in the note. It depends what you want. For me i have a 2.5" catback with no rear resinator. That gives a nice note.

But over all the mufflers and the resinators make the biggest difference.

If want your exhaust to sound different and louder then cut out your rear resinator which is the muffler basically in the bumperbar.

I don't want my car loud but I do want a nice rumble, not the annoying drone associated with riced up 4 cylinders, a deeper, smoother noise.

[self-deleted]

Last edited by blackjack_original on Sat Jun 07, 2014 12:18 am, edited 1 time in total.

Thats what mine has. Its not a commodore whine and its not a ricer f**k splutter but its like a long wet f@rt haha

yea but u still need some backpressure

maybe i got it wrong..... I was saying if you make the exhaust tooo big and not enough mufflers then it can result is poor back pressure.

Now do you have something important to add to this or are you just going to flame other people about their work???

You have no idea about what your talking about.
You want the smallest amount of backpressure for best power/torque.
This is an old argument.

sorry dude but you are wrong.... You need some backpressure for power... its not about having not enoughf and too much, its about getting it just right, a balance.... iv run my I6 at the drags with it coming straight out the extractors, straight out the cat, and normal street exhaust setup. i am almost 98% sure i lost low down power when running it straight from the headers... seemed to be able to get the power range moving alot better with more backpressure.... it also depends on the car, maybe if you have a totally hotted up monster that pulls 10/11s it might make a difference with less back pressure, but with the I6 it gives you nothing but a cool loud noise

I have a mate that is right into drag racing and he fabricates his own exhausts. His recommonation (for drag racing) is get a piece of pipe the same diameter as your collector and as long as possible, Weld a flange on to so it bolts to your collector, after you have staged the car paint a line down the length of pipe. Do your run and kill the engine right on the finish line.Look at the line of paint and mark where it has burnt off to then cut the pipe at that mark. Make support brackets to hold it up.Theres your tuned length drag pipe. This has been proven on the dyno to work BUT is only good for drag racing.

Thanks south

Like i said if your exhaust is too big and there isnt enough mufflers then you will loose the back pressure.

I think out of everyone on this thread, south will be the one to listen to for the above reasons. Me and him may only be 16 and 17 but least we just dont go blurting out things that we think is true..... we actually find out first. Mainly (for me) i dont want to sound like a f**k wit when i get it wrong. Like my boss says to me. He likes it when someone else f**k up. That way he wont punish, he laughs because aslong as it wast him he doesnt care.