Exhaust tip change volume??

SuBaRiNo · Post by **SuBaRiNo** » Thu May 22, 2008 10:36 pm

Im wrestling with my hatch at the moment... the exhaust is just way too loud... just spent $160 on getting 2 Hot Dogs added which did not much. I don't have a lot of options with this because of the size of the car.

The mufler is one of the only ones that will fit. I have been told that if i change it for anything else it will effect performance. There is absolutey no straight pipe left to add any more hot dogs or anything else.

Simple question i need answered... would changing the exhaust tip make it any quieter? I have a rather large tip on it at the moment.

Dave

Post by **Alex** » Thu May 22, 2008 10:41 pm

i noticed a very very very very slight change in note when i had a big tip put on my liberty. But nothing to go woo-haa about. Wont do much IMHO.

alex

Matatak · Post by **Matatak** » Thu May 22, 2008 11:29 pm

if it was changed to a restrictive tip then yes...but you really wouldnt want that.

so may aswell leave it as is.

did it quieten down at all with the 2 new hotdogs?

i wuld have to think the problem lies in the Muffler u got. look at everyone else running around with 2.5inch system, Hotdog, and one muffler (or in some cases a cannon)
nowhere near as loud as what i remember yours to be on full song (even more so with that Charger there)

ChPLAT · Post by **ChPLAT** » Fri May 23, 2008 7:49 am

Would having it 'Y' split into dual exhausts right near the end do much? Just a thought.

Or Get one of those fancy cannons where you can use a remote control to change the volume i.e. flow rate. Then when you want it to have some balls just hit a pre-set button....

SuBaRiNo · Post by **SuBaRiNo** » Fri May 23, 2008 3:27 pm

The idea about changing it to a "Y" peice is exactly what i had in mind... figured this would make the most difference if any and not effect the flow.

Anyone had experiences in that?

Dave

YouTube · Post by **El_Freddo** » Fri May 23, 2008 4:57 pm

apparently this is what subaru has done with the latest models - basically they loose their thumpy beat due to the exhaust gases "meshing" in like a set of gears rather than running into eachother to create the thump.

I have no experience in this, its just something i've heard from a mate who's dad owns and operates an exhaust joint. He tells me that doing this will loose the note but gain a lil performance.

How about making an exhaust that comes upright to the roof line? Hatchie would really be ready for water then

Cheers

Bennie

Subafury · Post by **Subafury** » Fri May 23, 2008 7:35 pm

exhaust tip wont to crap all for volume. unless you limit flow lots like the resonator piece in a rice boy cannon.

discopotato03 · Post by **discopotato03** » Sat May 24, 2008 1:31 pm

I gather you have an EJ22 NA in an MY Hatch ?

Firstly , what sized exhaust tube is the current exhaust ?
If its 2.5" or up then I'm not surprised .

People want to argue about exhaust size and often go larger than they really need to . There is a relationship between the mass (weight) flow of exhaust gas and its velocity . Quite simply if the tube size is too large the exhaust gas velocity will be too slow , when it's too slow it has little or no momentum so the engine suffers reversion and can't scavenge properly in the cams overlap period .
Once you get passed the "tuned" section of the exhaust like your header pipes velocity is not so much of an issue unless its too fast (too restricted) .

Also importantly , you MUST take every opportunity to isolate the exhaust from the body otherwise it transmits its vibration frequency to the body shell and no amount of muffling will stop it .
Also it's advantageous to have "soft points" in the exhaust to help isolate the engine from the exhaust . Turbo RX's have these where the down pipe meets the exhaust behind the gearbox . These are important because they allow the exhaust system to not be a totally rigid effectively engine steady bar .
So if you can isolate the vibration at the soft point and compliant exhaust hangings the agro factor starts to fall .

Out of time , cheers A .

Gannon · Post by **Gannon** » Sat May 24, 2008 1:44 pm

El_Freddo wrote:apparently this is what subaru has done with the latest models - basically they loose their thumpy beat due to the exhaust gases "meshing" in like a set of gears rather than running into eachother to create the thump.

Yep, its a "Tuned Header" or "Extractors"

Each pipe from a cylinder is the same length as each other and they have a diameter that is designed to be non restrictive but keep exhaust velocity high to help scavenging like Disco said.

On an EJ22, any exhaust over 2.5" is unnecessary.

To reduce noise, try mounting your last muffler about a foot before the exhaust tip.

discopotato03 · Post by **discopotato03** » Sat May 24, 2008 8:46 pm

IMO 2.25" is as large as I would go with a production NA engine of that size in its std state of tune .
If it had 300 degree race cams and was intended to run to 8000 it would be a different story but it isn't .
The situation is not like it was 25 years ago when most engines had pretty agricultural heads and manifolds let alone carburetion or fuel injection .
These days you are hardly likely to pick up 20% more torque with a set of off the shelf "headers" and a drain pipe exhaust .
These days the manufacturers are rupturing themselves to get every foot pound of torque they can within the manditory noise and exhaust emission regulations because thats what feels good to drive and also generally shows up as reasonable fuel consumption figures .

I kid you not , it wouldn't be the fist time people have tossed production exhausts for the Viagra kit only to be driven insane by noise/cops/low performance/poor fuel consumption figures .
You could do worse than to look at exhausts from the same/samish model car with a bigger engine option ie NA EJ25 and use that exhaust on your car . Factory fit and quality and appearance and noise emissions .

Out of time again , cheers A .

SuBaRiNo · Post by **SuBaRiNo** » Sat May 24, 2008 11:20 pm

Getting off the topic a bit here guys. Was asking about the tips not the entire exhaust system. I realise a smaller diameter exhaust or stock system would make it quieter... was trying to get a cheaper solution since it just cost me another $160 and im not about to change the entire system.

It's not exactly NA... i have a SuperCharger bolted to it and will be getting an aftermarket ECU with a tune very soon.

Dave

YouTube · Post by **El_Freddo** » Sun May 25, 2008 8:42 pm

discopotato03 wrote:I gather you have an EJ22 NA in an MY Hatch ?

Firstly , what sized exhaust tube is the current exhaust ?
If its 2.5" or up then I'm not surprised .

You should hear this thing disco... crazy! The problem subarino has is that the exhaust is in the hatch which has every nook and cranny packed with stuff, there's not a lot of room in there for the exhaust as it is.

Lengthing the tip and keeping it under the car would be a difficult task in the hatch.

Dave: It's already cost you $160 - noise fine i'm guessing? Hope they haven't "marked" your car, its not hard to find it at the busiest of times...

Hope you get it resolved quickly.

Bennie

discopotato03 · Post by **discopotato03** » Tue May 27, 2008 8:21 am

All I can suggest you do is post some pictures of what you have otherwise we are all guessing .
I went back to the beginning of this thread to try to fathom what you are actually asking . Is the question do I need a set length of tube after the last muffler to make it achieve anything .

Generally with mufflers the silencing value is in the volume of the can and its packing material . The size of the holes or perforations also is supposed to make a difference .
I try to use mufflers with straight through tubes rather than repeated runs inside the can . Getting OT I know .

If it is costing noise fines then you have to do something about it , usually the occupants won't tolerate the aural torture at that stage so no fun driving it .

A .

SuBaRiNo · Post by **SuBaRiNo** » Tue May 27, 2008 8:45 pm

I am putting a step down tip on the back which will reduce the flow but also make it tons quieter. It may effect performance it may not.... but it MUST be done. So i will be welding a step down from 2.5 inch to 2 inch coming straight out of the mufler.

I guess it's hard for people that have not set eyes on the car to work out my predicament... i think i have my answer now anyways... seams like... you can't really change the noise without effecting flow.

Dave

YouTube · Post by **El_Freddo** » Wed May 28, 2008 10:50 am

SuBaRiNo wrote:i think i have my answer now anyways... seams like... you can't really change the noise without effecting flow.

Unless you have more pipe lenght to play with... which unfortunately for you dave, you don't have this luxuaray...

Let us know how you go with it.

Cheers

Bennie

sven '2' · Post by **sven '2'** » Fri May 30, 2008 11:29 pm

Dave,

My experience is with the the tips only on a NA EA82 - had a lot of problems with drone at hwy speed, as opposed to the actual note as such. The tip was very much the cause - a crome rolled item over to look nice, but sounded awful.

My exhaust guy identified it straight away, cut a piece of pipe to replace it, drone gone. Apparently the length of the rear protrusion also matters.

Hope this helps.

sven

TW83 · Post by **TW83** » Tue Jul 08, 2008 10:29 pm

I had a similar problem.

Was running the ej22 with a 2.5inch system with only a straight through. So unbearably loud.

Anyway we welded in an 18inch hot dog and it is a huge improvement, cut out almost all the drone. Im amazed that two didnt make a difference in yours.

Im guessing your blower makes it louder though.

Subafury · Post by **Subafury** » Wed Jul 09, 2008 12:17 am

blower doesnt make much difference at all i reckon.
hatchie has always been loud and proud

discopotato03 · Post by **discopotato03** » Wed Jul 09, 2008 3:43 pm

A thing to remember also is that you really only need huge pipes if you want to rev the thing high .
Forced induction tries to make a small engine into a larger one so the exhaust flow ends up being more like a larger one .

You MUST have some soft or flex type things in big exhausts otherwise the "tubular engine steady bar" (much more rigid now its diameter has increased) leans hard into the body mounts and transmitts lots of vibration (sound is vibration) into the cabin area . Everything (inc engines and the exhaust system itself) has a frequency which makes them give off the dreaded drone . The flex sections attempt to isolate the pipe from the engine and propper exhaust "hangers" , the exhaust pipe from the body which is a perfect acustic boom box at times .
Trust me you can have a muffler the full length of the car but if the engine and exhaust are rigid it won't make much difference . The drone is a low frequency vibration not necessarily exhaust noise .

Out of time again , cheers A .

SuBaRiNo · Post by **SuBaRiNo** » Wed Jul 09, 2008 7:54 pm

Im going to choose not to repeat myself and not respond to that post.

Dave