Gday
Im just after opinions on what sort of mufflers i should get for a full 3" exhaust for a NA6. I don't want it stupidly loud either. I was thinking a decent Magnaflow muffler and also a Varex muffler so i can open and close the valve when i need too.

Cheers

If you've got an N/A 6 I wouldnt go for a 3" exhaust, 2.5" is a better bet.

Gab

The 2.5" is currently restricting it a fair bit mid-top end power.

whats done to the car? i see in your sig you have a fair bit of power so if youve got a s**t load of mods you probably would benefit a 3 inch,but how good is the 2.5 inch, mandrel bent or press bent?

WOW nice result - did you just gain 30+ rwkw by changing to manual?

its had alot work done to head from CVE, the 2.5" i have is pretty average it has mandrel bent tail pipe an slight press bends in the middle.

http://www.boostedfalcon.net/viewtopic.php?f=16&t=21494

nice work

try hitting up justin from tuffcarparts for a rage 3" system, while they drone a bit, they do have a nice deep sound, and some crackle on overrun, and are priced well too

thanks mate, there prices are pretty good. I'm hoping i can keep the noise down abit though, i just tested my current one and its 108db

Without being forced induction a 3" system is just over kill. I've had major head work done to my 95DT head by Gilbert's P & A Cylinder Head Services, these guys really know the EA-AU 3.9/4.0. I've tried like every off shelf system made for EL 4.0, it's taken me years to make a system that flows very well but also sounds good. I running 4480 pacemaker headers 2.5" redback high flow cat, 2.5" mandrel bent pipe into hotdog just before diff then 2.5" mandrel bent tail pipe with a mercury 2.5" high flow muffler cut in. This system sounds nothing like an off shelf sports system, it has no drone at all it is actually pretty quiet highway driving. Has a real nice lumpy growl not that horrid droning bark sound most falcons with sports exhaust have, sounds really good echoing off buildings even turns heads

Can you come up with one good reason why 3inch is overkill?

its not overkill, I will show the next dyno sheet when a 3" system is on it.

Back to your original question, I think you'll just have to squeeze and as many mufflers under it as you can.

Can you come up with one good reason why 3inch is overkill?[/quote]

Um well first where talking about a NA Ford 4.0 I6 not some high performance turbo engine.

I'm not just some kid with no knowledge giving my opinion, i'm talking from years of research training and experience i've only been a fully qualified mechanic for 7yrs but have a lot of knowledge from working with guys that have 30+ years in the trade. I don't care what your dyno read out says, dyno's do not measure real world performance! They measure the amount of maximum power your engine makes at the rear wheels. So because a 3" inch system might make a little more power at max revs does not mean anything, do you constantly drive at max revs, is this a race or drag car or just your daily drive? If it is for a daily drive it is overkill and not to mention will sound terrible

Where did you hear that your 2.5" system is too restrictive? If anything it would be your mufflers causing a restriction not pipe diameter, a good section of straight pipe will flow around 115 CFM per inch of diameter.

Exhaust gas is hot and it's best to keep it hot throughout the exhaust system. Why? Cold air is dense air, and dense air is heavy air. An extremely large exhaust pipe will cause a slow exhaust flow because the gas cools and becomes heavier

Mass of air that the engine breathes in + mass of fuel = mass of exhaust gases. A 2.5" diameter is well suited to a 3984 cc engine that revs to only 6000rpm. Turbo or supercharged engine is total different story

The problem is exhaust shops are just fitters most do not know much at all and they will tell you fitting 3" system will improve performance.

That doesn't make sense at all. Why fit 3" exhaust if your going to fit more mufflers to quieten it? It's actually mufflers that cause a restriction

Um well first where talking about a NA Ford 4.0 I6 not some high performance turbo engine.

I'm not just some kid with no knowledge giving my opinion, i'm talking from years of research training and experience i've only been a fully qualified mechanic for 7yrs but have a lot of knowledge from working with guys that have 30+ years in the trade. I don't care what your dyno read out says, dyno's do not measure real world performance! They measure the amount of maximum power your engine makes at the rear wheels. So because a 3" inch system might make a little more power at max revs does not mean anything, do you constantly drive at max revs, is this a race or drag car or just your daily drive? If it is for a daily drive it is overkill and not to mention will sound terrible

Where did you hear that your 2.5" system is too restrictive? If anything it would be your mufflers causing a restriction not pipe diameter, a good section of straight pipe will flow around 115 CFM per inch of diameter.

Exhaust gas is hot and it's best to keep it hot throughout the exhaust system. Why? Cold air is dense air, and dense air is heavy air. An extremely large exhaust pipe will cause a slow exhaust flow because the gas cools and becomes heavier

Mass of air that the engine breathes in + mass of fuel = mass of exhaust gases. A 2.5" diameter is well suited to a 3984 cc engine that revs to only 6000rpm. Turbo or supercharged engine is total different story

The problem is exhaust shops are just fitters most do not know much at all and they will tell you fitting 3" system will improve performance.[/quote]


^^^^^^^^ hit it right on