Exhaust basics???
Exhaust basics???
Can someone please enlighten me on some exhaust system basics. Basically my exhaust is WAY WAY too loud and i need to make it quieter without re-ducing performance. I have a decent mufler and i have been told i can;t go a quiter one there. And my system currently has a resignator and no hotdog.
Im just wanting to know...
What does a Resignator do?
What does a Hotdog do?
Dave
Im just wanting to know...
What does a Resignator do?
What does a Hotdog do?
Dave
EJ conversion wiring harness cut downs available. Please PM or email (davem2000@hotmail.com) for details.
- sven '2'
- General Member
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a resinator is best described as a small muffler - ie has baffles that slow the exhaust gases by creating turbulance in one way or another.
A Hotdog (hmmmm...hotdog) does a similar job but is packed with fibreglass to absorb the sound - is straight thru (ie no baffles) when looking thru them.
I have used them on Turbos / NA, and on non-subarus over the years and have always been happy
For your application, go a couple of 'dogs. When if set up right will = quiet exhaust round town or cruising at highway speeds - hate cars that drone - and a good note on WOT, without affecting peformance
sven
A Hotdog (hmmmm...hotdog) does a similar job but is packed with fibreglass to absorb the sound - is straight thru (ie no baffles) when looking thru them.
I have used them on Turbos / NA, and on non-subarus over the years and have always been happy
For your application, go a couple of 'dogs. When if set up right will = quiet exhaust round town or cruising at highway speeds - hate cars that drone - and a good note on WOT, without affecting peformance
sven
73 Yamaha DT3 250
08 Ford BF wagon - LPG FTMFW
14 Toyota Kluger - goodness!
08 Ford BF wagon - LPG FTMFW
14 Toyota Kluger - goodness!
- discopotato03
- Senior Member
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- Location: Sydney
Every solid thing known to us has a natural frequency or vibration period .
Often what people think is a noisy exhaust is a rigid exhaust transmitting that low hum/vibration to our mobile boom box (cabin space) .
Firstly does your car have a "soft spot" in its exhaust ie one of those two bolt sprung carbon ring joints or the stainless bellows flex joint with the braided wire outer cover ?
Big diametre exhausts make great "engine steady bars" but you don't have the NVH (noise vibration harshness) qualities of an engine mount if the exhaust is rigid .
Lastly even turbo exhausts don't have to be HUGE . There is a rough rule of thumb with exhaust diametre and horse power , if you can find out how much you have and equate it to the exhaust size used on a NA engine of similar output its a start . If its an EA82 I wouldn't go over 2.25" maximum . The reason being that the std header is so woeful and the std turbine housing outlet so small that theres little if ANYTHING to gain .
Often what people think is a noisy exhaust is a rigid exhaust transmitting that low hum/vibration to our mobile boom box (cabin space) .
Firstly does your car have a "soft spot" in its exhaust ie one of those two bolt sprung carbon ring joints or the stainless bellows flex joint with the braided wire outer cover ?
Big diametre exhausts make great "engine steady bars" but you don't have the NVH (noise vibration harshness) qualities of an engine mount if the exhaust is rigid .
Lastly even turbo exhausts don't have to be HUGE . There is a rough rule of thumb with exhaust diametre and horse power , if you can find out how much you have and equate it to the exhaust size used on a NA engine of similar output its a start . If its an EA82 I wouldn't go over 2.25" maximum . The reason being that the std header is so woeful and the std turbine housing outlet so small that theres little if ANYTHING to gain .
- vincentvega
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- Suby Wan Kenobi
- General Member
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- Joined: Tue Oct 04, 2005 10:00 am
- Location: Sunny Godwin Beach Qld
I get a good note a pretty good performance out of a 2in exhaust with a turbo type muffler with 2in and out the noise is good and the ride inside not deafening. With the EJ22 you could probably go a tad larger if you wanted to but i have not ever noticed a gain in power with a bigger exhaust. (seat of pants observation in the drivers seat).
The best setup i have driven had the standard headers cut to form a "Y" and then an aftermarket cat added in behind it then 2in all the way to the single muffler in the usual L series spot.
The best setup i have driven had the standard headers cut to form a "Y" and then an aftermarket cat added in behind it then 2in all the way to the single muffler in the usual L series spot.
[SIGPIC][/SIGPIC]
The long road ahead
The long road ahead
id call a resonator the same thing as a hotdog(torpedo resonator)
its perhaps more the traditional oval shape, but would be straight through and have dimensions of say-5"by 3" by 16" long for eg.---sounds to me like you have a fully unbaffled system(straight through) and would benefit from a baffled muffler(larger oval of course--normally offset-centre inlets)to get the noise down. this wont effect the power output, may just slighlt alter the peak torque range.
my car has a small 2"cannon and 2 resonators jammed underneath(all straight through) also a catalytic converter of course so its throaty but not annoying.
with bigger pipes---------
wagons always drone in your ear,,,,no catalytic..is always more noisy,,,,,
only turbos need more than 2"(generally-4cyl..)
its perhaps more the traditional oval shape, but would be straight through and have dimensions of say-5"by 3" by 16" long for eg.---sounds to me like you have a fully unbaffled system(straight through) and would benefit from a baffled muffler(larger oval of course--normally offset-centre inlets)to get the noise down. this wont effect the power output, may just slighlt alter the peak torque range.
my car has a small 2"cannon and 2 resonators jammed underneath(all straight through) also a catalytic converter of course so its throaty but not annoying.
with bigger pipes---------
wagons always drone in your ear,,,,no catalytic..is always more noisy,,,,,
only turbos need more than 2"(generally-4cyl..)
94 gen2 lib wagon tt converted(when missus lets me)
92 Lserious 4wd wagon(about to eat left over ej)
92 Lserious 4wd wagon(about to eat left over ej)
Hotdogs ftw. I run 2x hotdogs on the STI to reduce the rumble/scream on noise and still have great performance and a great engine note.
I have one placed just after the dump pipe and one before the rear muffler.
I have one placed just after the dump pipe and one before the rear muffler.
[SIGPIC][/SIGPIC]
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Excelent... thanks for the info guys... i currently have a resenator but it has taken a hit. A hot dog style shape makes more sence for offroad. Exhaust guy recons i have a pretty quiet mufler already which made me laugh. So time to add some hot dogs im thinking.
It was just bearable before i added the Supercharger but that has made it sound much much louder. I like being able to have conversations in the car at freeway speeds.
Dave
It was just bearable before i added the Supercharger but that has made it sound much much louder. I like being able to have conversations in the car at freeway speeds.
Dave
EJ conversion wiring harness cut downs available. Please PM or email (davem2000@hotmail.com) for details.
- Suby Wan Kenobi
- General Member
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- Location: Sunny Godwin Beach Qld
If you buy a reasonably priced hotdog they come with a very thick outer wall which is perfect for offroad knocks. I brought one about 10 years ago for my L touring wagon and took it off cause it made the noise out the pipe have datto cackle. Anyway i used it on a later project but had to shorten it and it had a side wall of about 2mm
[SIGPIC][/SIGPIC]
The long road ahead
The long road ahead