Incorrect Silencer size can cause engine problems

[adammet04]

Hi all,

as most of you know (or guessed) i have finally got the skunk2 exhaust installed

without silencers the car is loud and i love it, however the boys in blue probably dont (or the epa) , as such i fitted the silencers (supplied with exhaust)..

I want to discuss what the ramifications are of doing this, i have heard/been told the silencer will cause the following : carbon buildup in the engine and eventually engine failure..

I found this site as well which seems to confirm this.
http://www.eiwilliams.com/steel/index.php?p=EngineSilencers

There are some equations on the above site so i might see if i need to do something about it.

This seems like an important topic and hence why i raised it, so many people with exhaust etc around (not a lot with silencers mind you). just seems like a valid thing to discuss (what with police and EPA crack downs on everyone with a modified car ATM)...

my questions for discussion

a) if the silencers that come with the engine arent the right size and my car engine dies, that might be the fault of the manufacturer of the exhaust for not supplying proper silencer?? ANSWERED

b) I know i can fit an extra resonator to the exhaust for sound reduction too. but maybe a corect size silencer might be better... thoughts??

c) I had a c question but forgot it..

[bungsai]

few good questions there i cant answer any but suggest a few..

a silencer will generally reduce flow whilst a good resonator will not.

A silencer will also alter tone, whilst resonators tend to alter volume and not affect tone as much.

[adammet04]

Thats good information mate

thanks

that maybe a reason to go for resonator as opposed to better silencer

[sivic]

as for the first post:

a) there is no way you'd be able to hold the manufacturer of the exhaust responsible for any damage. I would imagine there are disclaimers etc.. plus you'd have a hard time proving beyond a doubt that it was the silencer which did the damage

as for damage to the engine - unless the silencer created more restriction than the stock exhaust i don't think you'd have anything to worry about

[JasonGilholme]

I doubt it will causeyou any trouble unless the silenver didn't have an exit and just totally block the exhaust up.

[adammet04]

a) fair enough :) just wondering about the ramifications there.. updated first post to say answered..

b) ok so as long as the silencer has same or less restriction than the stockie , you think ill be ok..hmm what about the fact that the skunk2 is a larger diameter than the stockie, larger diameter, more air out, silencier = stock, then that more air cant get out as quick?

The silencer is not just a plug :)

[JasonGilholme]

I know the sliencer is not just a plug.

The silencer will not restrict the flow as much as stock but it will reduce the flow a large degree.

Think about it tho. Other people have been using silencers on there cars for years and they haven't had any engine probs.

You'll be fine.

[adammet04]

I know the sliencer is not just a plug.

The silencer will not restrict the flow as much as stock but it will reduce the flow a large degree.

Think about it tho. Other people have been using silencers on there cars for years and they haven't had any engine probs.

You'll be fine.

I know you know its not a plug..my post wasnt too articulate, i meant that the silencer i have isn't a plug shape, eg no output :) my bad ! :)

exactly my thoughts about the silencer, surely this would have appeared along the way and im sure skunk2 wouldnt produce a shitty silencer for their systems ...

but two people have said to me, get a resonator as silencer will cause issues at over 3000rpm with car..

maybe they were referencing in regards to track work, etc,

idrive my car hard, but not track work hard ..

[JasonGilholme]

I think you'll be fine. i know people that use them all the time.

I use one on my other car and have had them on cars previously and its cool.

Think about it though, why would the carbon build up happen in the chamber when theres all this force pushing the gasses towards the end of the exhaust system. you'd have a have a really big blockage (ie. a totally blocked muffler) to make the exhaust gasses go back into the chamber.

[aaronng]

I don't think the problem comes from the carbon build up, rather from the exhaust gas pulses being forcefully stopped by the ring of metal which makes the exit hole of the muffler smaller. If the hole is much smaller than your exhaust piping diameter, it can causes the exhaust pulses to be messed up.

[vti_ek9]

hurmmz....interesting.....does this apply to turbo cars aswell?
i've been driving around for about 2 years with silencer on....i feel it does restrict air flow but not so sure about damaging the engine?

[honest muz]

Guys,
When i was riding a motorcycle on the road I think I went through some of Adammet04's questions, so let's see.

a) Any after-market pipe is probably illegal and probably doesn't meet the Australian Design Rules for your car. Quite separately, it wasn't part of the manufacturer's design or build so if anything breaks, it's certainly not the car manufacturers' fault. It may be the pipe retailer's fault, under the trade practices act, but not the manufacturer of the pipe (unless you bought directly from them.

It's likely illegal because it likely emits more noise & unconverted gases than standard. In motorcycle land everyone wants the same as you, a louder engine sound. You can add another pipe legally (in NSW) but it's got to have a Statutory sticker that shows that an acredited tester has measured the noise (@ 1 metre?) at the right engine speed for your car. The right engine speed is the one that the RTA says produces the most noise for your car. For my old pride and joy, that was 3,500rpm and the test showed it made only 90.9dB(a) of noise. Because the ADRs for bikes says it can't go over 94dB(a) then the combination of the after-market pipe and the Stautory sticker meant that the pipe was legal. Typically any pipe bender will be able to certify your pipe if you sumit it to test. Try Carline or similar.

Sivic is correct. It's not enough to have a burnt valve and claim it's the pipe's fault. YOU HAVE TO PROVE IT. Nearly impossible.

b) Exhaust design, gas flow, scavenging of unburnt gases is, ultimately, trial and error. Yep apply bernouli's equations or any other relevant modelling and you'll get close, but testing gets results. You'll need to check dyno tests (and interpret at the wheel, at the crank). To gain max. power / torque it's not simply a matter of having the most free-flowing pipe. Aarong got it Right, the pulses, standing waves, moving waves all contribute it good extraction. Any Honda from the EFI age is likely to have the best possible performance pipe installed at the factory......for the factory engine tune. But if you wanna make some noise........rock on.

[Non Vtec]

1 thing you should check is if your on a dyno try running the car with and with-out the silencer.. I personally gained almost 3wkw from start to 9000 from putting the silencer into the RWorks N1 exhaust on my B18CR..

[Andrew21]

I think the size of the silencer diameter and also your exhaust piping diameter plays a big role. For Example - I had a 5" cannon on my old R33 Skylne, with the usual 3" turbo back, i noticed my cannon had a silencer which reduced the hole to about 2" .. Once i removed the silencer the car definately breathed alot better and went harder with quick pickup.. The db level did not increase that much also, mayb couple db a the most ?

[TypeG]

if u are so worry about it, you shouldnt get this kind of exhuast in the first place since I believe it is N1 style muffler. I believe a resonator wont help THAT much on noise compare to a silencer but it just looks stupid putting silencer in.

[silver_screen]

adam.. ur car will be fine :) your engine wont break.

Never heard/seen of it... EVER and i been doing this since i was 16yo :)

[adammet04]

cool thanks for info impressions suggestions guys !

typeG why do you say an extra resonator (or possibly one before each cannon), will not help? im not understanding why this wouldn't help. can you explain to me?



aarongg you said something about the pulses..removing the silencer would help ?

cheers

[EuroAccord13]

Exhaust air travels in pulses, you want it to be as smooth as possible with no change in pipe size to distort the pulses that interupts the scavenging of the exhaust gases..

With the silencers, imagine your exhaust pulses travelling at 2 1/2 inch at XXX intervals having to squeeze through a hole half the size..

It's like you you trying to take a huge dump from a small arse heeheeheehee...

Put a resy after the bend from the cat :D

[SiReal]

It's like you you trying to take a huge dump from a small arse heeheeheehee...


HAHAHAH! sorry couldnt help myself.

OR

trying to piss with a rubber band around your *ahem*

[TypeG]

cool thanks for info impressions suggestions guys !

typeG why do you say an extra resonator (or possibly one before each cannon), will not help? im not understanding why this wouldn't help. can you explain to me?



aarongg you said something about the pulses..removing the silencer would help ?

cheers

i am saying compare to a silencer, silencer maybe a better go if u are o concern about the noise level and cost nothing

[aaronng]

aarongg you said something about the pulses..removing the silencer would help ?

cheers
Removing the silencers will allow the pulses to flow properly and not encounter a barrier that can cause disruption. I agree that it would be better to add a resonator rather than to rely on the silencers to reduce the booming sound.

[aaronng]

if u are so worry about it, you shouldnt get this kind of exhuast in the first place since I believe it is N1 style muffler. I believe a resonator wont help THAT much on noise compare to a silencer but it just looks stupid putting silencer in.

Nah, the Skunk2 is not supposed to be an N1 style exhaust. It's still a street legal one (at least in the USA).

[adammet04]

ok well i pulled out the silencers last night,

will loook into it when i get back

thanks for the great discussion in this thread !!

[Zdster]

As others have said, I would be more inclined to look into a resonator rather than a silencer. All I know is that when the first exhaust shop I went to messed up my exhaust it was VERY loud. Took it somewhere else with the intention of replacing the muffler, but instead was convinced to try a resonator and that fixed it right up.

[adammet04]

..From skunk2 product support!!

Thank you for your interest in our products. They are like 115dbs they are not street legal. Should you need any further assistance, please feel free to contact me. I'm always here to help. Thank you for being a customer and Happy New Year.

Silencers are going back in!!!

Bring on the extra resonators :)

[SiReal]

wowow... so did u make the Fast n fusrious entrance into threadbo like the other time? Drop it into neutral, vroom vroom, bit of nos out the side, pssch psscch.

[TypeG]

Nah, the Skunk2 is not supposed to be an N1 style exhaust. It's still a street legal one (at least in the USA).

i thought it is N1 style from the shape of it
http://www.tsxparts.com/product_info.php?cPath=22_35&products_id=121

[TypeG]

why i dun suggest to have silencer it u cant back back when u need it as I think adding resonator do restrict some power. so if you are on track or drag, u can simply just remove it.

[SiReal]

well you can also think of it this way as well. SKunk2 wouldva done their R&D on silncer vs no-silencer. this exhaust is made JUST for the EURO, hence all factors, including exhust piping diameters, back pressure etc shouldve been taking into account for when producing the solencer for this system.

imo, if they provide it commercially on a large scale basis, then it is ok to use. Skunk2 wouldnt be making parts which'll open them to gazillions of lawsuits from euro drivers whove engines have blown up.

[aaronng]

LOL, Team YCD should invest in a sound level meter from Jaycar. :)

[aaronng]

wowow... so did u make the Fast n fusrious entrance into threadbo like the other time? Drop it into neutral, vroom vroom, bit of nos out the side, pssch psscch.
That was his windscreen washer spray. :p

[adammet04]

why i dun suggest to have silencer it u cant back back when u need it as I think adding resonator do restrict some power. so if you are on track or drag, u can simply just remove it.

fair call,

however my intention for the car is street not track or drag, so im happy to drop *a little* power, for no yellow pieces of paper stuck to my car... but its a fair enough comment,

after putting them back in i do notice the drop in power, but the sound is much less, surely very close to 95db's so i shall see how we go..

the great resonator search has commenced !!

lolz

[EuroAccord13]

The great hotdog search has begun??

Is there even a decent mechanic in the mountains or you have to drive down to the nearest town to find one?

[adammet04]

yeah apparently there are some good shops up here, because of the volume of work that happens in the winter months

ill research it this weekend...

I will start new thread

[tinkerbell]

I personally gained almost 3wkw from start to 9000 from putting the silencer into the RWorks N1 exhaust on my B18CR..

you gained HP by running with a silencer?

[honest muz]

[QUOTE=adammet04;1050355]..From skunk2 product support!!

Thank you for your interest in our products. They are like 115dbs they are not street legal. Should you need any further assistance, please feel free to contact me. I'm always here to help. Thank you for being a customer and Happy New Year.
QUOTE]

115dB !!!
Man that is freakin' LOUD.

In the USA their laws seem to be geared towards low gas emissions (and for bikes, non emission of sparks). In Australia, I'm thinking that our upper limit is...94dBa? For every 3 dB you are doubling the "percieved" noise. So 115dB sounds 6 x times louder than legal.

THE CHICKS AND COPPERS WILL DIG IT!

[aaronng]

Depends on their test methods. 115dB at what RPM?

Australian specs is 90dB now for cars manufactured after Jan 2005, so new cars have it more strict.

[Chris_F]

115db is crazy... would be heaps louder than my exhaust :O

damn I'm lucky i scrapped in with an 04 lol