Exhaust Configuration

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Exhaust Configuration

Postby Santa'sBoostinSleigh » Wed Mar 12, 2008 2:29 pm

im in the process of doing a couple of exhausts at the moment, one a 20v AE101 FXGT road car - Carpet Burn wants to retain the duel exhaust goodness, so we've got a couple of tips, a reso and a couple of mufflers
we've decided to go with 2" as she doesnt want it stupid loud, just a nicer sound. ran into a problem with the fact that the mufflers are too long, so was thinking of installing the reso, then the muffler, then a length of pipe, a Y piece, then the 2 rear pipes with tips attached - is this going to cause any issues with noise, performance etc?


also on my 20v AE92 FXGT racecar, im in the process of redoing the exhaust. for the life of me i cant remember if its 2.5" or 2.25".
ive got one resonator and a fairly small muffler - in the old setup i had the muffler in the stock position, but theres not a huge amount of room where it exits.

question: does it make any difference if the exhaust is in any of the following configurations:

MOTOR----resonator--muffler------------------------------

MOTOR----muffler--resonator------------------------------

MOTOR---{small muf or reso}-----------{rear muffler}-- (stock setup)



does it make any difference with the lengths of pipe between the muff and reso and/or the length of pipe from the exhaust exit point back to the rear muff/reso




im also contemplating doing a side exit on the racecar, but obviously i want to keep everything tucked up as tight as possible so i dont wipe it out on ripple strips and bumps etc on hillclimbs, this is going to prove to be a mega mission however as the car sits low and the sills stick down a fair amount!

any ideas or opinions appreciated!
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Postby postfach » Wed Mar 12, 2008 3:08 pm

Just a theory of mine after thinking about this quickly, but I would imagine that the more pipe you have between the muffler and where the exhaust ends, the louder or more annoying sounding it will be, because there is more muffler-free pipe for the sound to bounce around in. There must be a good reason most factory exhausts (all of the ones i've seen?) all have the muffler right at the end. Unless its just a space thing, since there's usually a bit of a cavity at the back of the car where nothing exists so it makes a good place to put a muffler?

Side exit - I made one for fun on my car when we made the dump pipe for it, no mufflers or anything and it was so loud I thought my ears were going to start bleeding, are you doing anything to cut the sound or are you just going to put up with it/go deaf?

Bit of a hijack but does anyone know if a resonator actually has any muffling effect or if they just cut out raspiness?
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Re: Exhaust Configuration

Postby barryogen » Wed Mar 12, 2008 4:31 pm

Santa'sBoostinSleigh wrote:im also contemplating doing a side exit on the racecar, but obviously i want to keep everything tucked up as tight as possible so i dont wipe it out on ripple strips and bumps etc on hillclimbs, this is going to prove to be a mega mission however as the car sits low and the sills stick down a fair amount!

any ideas or opinions appreciated!


I had a thought about this, if you were to use a 1 or 1.5"(to keep the height nice and tight to bottom of car) pipe split down the middle with two flat sections to make the pipe an oval, it should still give plenty of flow, although there would be more friction caused by the increased surface area.

postfach wrote:Bit of a hijack but does anyone know if a resonator actually has any muffling effect or if they just cut out raspiness?


I added two resonators to my 2zz and it did muffle it a bit... took it from deafening to just above too loud... made it sound nicer though.

Adding a large oval muffler made it quiet.
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Postby strx7 » Wed Mar 12, 2008 4:48 pm

Yip I pretty much have the same theory on exhuast noise, the more length after the muffler the more drone & resonance you get, my surf and my mates commodore both have a muffler in the middle of the car but nothing at the back and they resonate alot.
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Postby Santa'sBoostinSleigh » Wed Mar 12, 2008 5:02 pm

side exit would go:

MOTOR
|
|
RESO
|
MUFF
|
|________>exit


rather than:

MOTOR
|
|
RESO
|
|
|________
...............|
...............) .... loop over rear xmember
...............|
...............MUFF
...............|
...............V

dots are just space fillers
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Postby Mr Revhead » Wed Mar 12, 2008 10:02 pm

20vs are 2.25 stock... im not so sure going down in size is a good idea

the stock system is very good, other than the piece over the cross member
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Postby d1 mule » Sat Mar 15, 2008 2:39 am

no i think he means get a small daimeter pipe, cut in half, weld in 1 or 2 inch "spacer plates" so the exhaust is now an oval like (=====) ish

it was done on that super extreme 70s rally celica resto thing, the one with like 100000 pages and photos
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Postby Mr Revhead » Sat Mar 15, 2008 3:43 pm

ok didnt see that bit
i was referring to santas original post where he mentions using 2' pipe
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