Exhaust bung

[Lucky]

I need to quieten the car down a bit for when I am at work and I have a bung that came with the exhaust. Question is, by using the bung, is it safe with the map?. I know it sounds a funny question but I dont want to put the bung in, reduce the flow and then have a problem. Any answers much appreciated.

Steve

[Anger]

Ive used bungs with quite a few exhausts and never had any problems with maps

[C. J.]

Yes it will f it up as it's a restriction
Send simon a pm

[Anger]

Funny as Simon has always told me its ok lol

Even mapped a car with the bung in as we didnt want to make that much noise with a Nur spec

[C. J.]

Ask Charlie about the difference on the rollers when I had the 2.5 and a md321t .
Simon was there ,cut 70 bhp of the figures and the mapp was not happy or simon.
Bung out and all Happy .
As above pm simon If he says it's fine go with it .

Had a bung with my afterburner vortex and when in use it did make a noticable difference in performance(on the road, never had it rolling roaded to see) So I would guess that it would have some effect on the way the car performs, via its map.

If you have the option, safest way IMO would be to have a map for in and out to be safe although, so long as the car is not driven hard with the bung in place, I would guess it should be fine This is what I was told when I purchased my bung....

Wasn't long before our bung was just left out, so would suggest changing to an exhaust that more suits your all round needs than going for a bung

[Lucky]

Originally Posted by thepieman

Had a bung with my afterburner vortex and when in use it did make a noticable difference in performance(on the road, never had it rolling roaded to see) So I would guess that it would have some effect on the way the car performs, via its map.

If you have the option, safest way IMO would be to have a map for in and out to be safe although, so long as the car is not driven hard with the bung in place, I would guess it should be fine This is what I was told when I purchased my bung....

Wasn't long before our bung was just left out, so would suggest changing to an exhaust that more suits your all round needs than going for a bung

And there lies the problem!. I love the sound of it without the bung and have been driving it around without the bung for 3 years, just thought I may start using it to quieten it down a bit in the week, but looking at this thread so far, its staying out and I will just continue to be noisey!!. I will pm Simon as he mapped it to see what he thinks.

[Scott.T]

IMHO the bung is so far down the exhaust that it will have no detremental effect, only a slight reduction in power.
Lucky's car is only 350BHP (ish) so the % loss will be neglegible.

If the restriction was in the header or up-pipe that may be a different matter because the exhaust gasses will struggle to escape at high rpm / high boost and may cause detonation.

The exhaust gasses are well on their way out of the exhaust by the time they have reached the bung and would of also disperssed, cooled and reduced in density at this point.

[Anger]

The bungs with Afterburners is alot smaller exit than with a Nurspec bung.... So i suppose the bung would be a factor aswell

[Jolly Green Monster]

basically if the car is mapped with bung in, then it needs to be driven off boost with bung out and visa versa.. I have seen a big drop in power with bung inserted and the back pressure makes a huge difference to exhaust gas removal from the cylinder and therefore how clean the charge is etc.. which influences how much ignition advance is possible to run and therefore the detonation level point and the boost is altered.

I have seen car mapped without bung totally safe with the bung fitted as it drops the boost at the same time due to the increase back pressure but I wouldnt like to assume that would be the same with every car. When I map a car if I know there isa bung for the exhaust I tend to map it in the configuration the owner drives the car in most of the time and double check it is safe in the other configuration.. generally they will make more power with the bung out.. with varying amount of alteration to the power depending on the power output of the car. ie. if it is a 280bhp car once mapped then the bung is going to lose very little power.. if it is 600bhp then expect a big drop in power with the bung.

Thanks
Simon

[Jolly Green Monster]

Lucky,

If you fit a bung just drive it gentle etc..

Simon

[Jolly Green Monster]

Originally Posted by SilverSurfer

IMHO the bung is so far down the exhaust that it will have no detremental effect, only a slight reduction in power.
Lucky's car is only 350BHP (ish) so the % loss will be neglegible.

If the restriction was in the header or up-pipe that may be a different matter because the exhaust gasses will struggle to escape at high rpm / high boost and may cause detonation.

The exhaust gasses are well on their way out of the exhaust by the time they have reached the bung and would of also disperssed, cooled and reduced in density at this point.

I dont agree with YHO, sorry.

treat the exhaust as a hose.. and the cylinder as a tank the hose is draining.. it makes no different if you restrict the hose flow at the end of the hose or halfway down it.. it just restricts the flow.. less flow, the more back pressure, the more dirty gas in the cylinder for next stoke etc...

The only exhaust I have found to flow well and be quiet enough to no annoy and attract attention is the revolution 3inch exhaust.
But I find it great for a month or so and then two quiet so I swap about

Simon

[Scott.T]

Originally Posted by Jolly Green Monster

I dont agree with YHO, sorry.

treat the exhaust as a hose.. and the cylinder as a tank the hose is draining.. it makes no different if you restrict the hose flow at the end of the hose or halfway down it.. it just restricts the flow.. less flow, the more back pressure, the more dirty gas in the cylinder for next stoke etc...

The only exhaust I have found to flow well and be quiet enough to no annoy and attract attention is the revolution 3inch exhaust.
But I find it great for a month or so and then two quiet so I swap about

Simon

I agree about the flow and your analogy to a hose, but was thinking more about the heat and density being far greater at the header end compared to the tailpipe end. The tailpipe bung when fitted to luckys probabley has a centre bore of around 2.5 Inches in a 5 inch tailpipe, which is no smaller then the rest of the system. He also still has both cats in place which are going to be far far more restrictive then a 2.5 Inch straight through bung.

It's a fairly standard car so not maxing the extraction capabilies of the exhaust system.

Lucky, best thing would pop over and i'll strap all my bits on and double check it. if I can detect det or any major change you can then decide whether to live with the noise or go see Simon for a tweak.

[AndyWRX]

My car hates having a bung, with the bung out its nice and smooth etc but with the bung in its lumpy, restrictive etc, thought it was all in my head so i ran the with the bung out, pulled over and put it in and went for a drive, didnt like it at all so took it at and straight away it went back to normal

[Scott.T]

Originally Posted by AndyWRX

My car hates having a bung, with the bung out its nice and smooth etc but with the bung in its lumpy, restrictive etc, thought it was all in my head so i ran the with the bung out, pulled over and put it in and went for a drive, didnt like it at all so took it at and straight away it went back to normal

Whats the bore of the bung ?

[Lucky]

Thanks guys. When the bung is in, it will be for toodling around town at 20/30mph for work so wont be near any boost, so I guess it will be ok.

[Jolly Green Monster]

It will be fine then steve

[Jolly Green Monster]

Your ecu will take the racerom kit so it is possible to do a bung map (that sounds like a crime) and a nonbung map, alone with launch control, throttle blip and flat throttle shift

Simon

[Jolly Green Monster]

Originally Posted by AndyWRX

My car hates having a bung, with the bung out its nice and smooth etc but with the bung in its lumpy, restrictive etc, thought it was all in my head so i ran the with the bung out, pulled over and put it in and went for a drive, didnt like it at all so took it at and straight away it went back to normal

Usually find the bung has the tube about 10inches long with a plate at the end so the exhaust gases pressure to the plate etc and its worse than the diameter of the tube

Simon

[Anger]

As i have a RCM back box and a Team ice.... Will there be that much difference between these two do you think Simon

Not sure if it would fit but for loads of dosh(compared to normal bung) you could buy the Apexi ATS (active tail silencer) linky here

Does give you the option to boot it if needed with a bung in, without the worry your doing any damage?

[Lucky]

Originally Posted by thepieman

Not sure if it would fit but for loads of dosh(compared to normal bung) you could buy the Apexi ATS (active tail silencer) linky here

Does give you the option to boot it if needed with a bung in, without the worry your doing any damage?

Nice!, and nice price lol.

[Lucky]

Originally Posted by Jolly Green Monster

Your ecu will take the racerom kit so it is possible to do a bung map (that sounds like a crime) and a nonbung map, alone with launch control, throttle blip and flat throttle shift

Simon

mmmm.. now that sounds like a plan!

[C. J.]

So I was wrong then !

[Jolly Green Monster]

Originally Posted by Anger

As i have a RCM back box and a Team ice.... Will there be that much difference between these two do you think Simon

Would be best to check

[bigemp]

or just sell me your exhaust steve and buy a quieter one or put my cobra one on which is deffo quieter than the afterburner(im not gonna order a new one untill monday morning(in case one pops up on a forum over the weekend)so let us know if you wanna do a deal !!!!

[jura11]

Similar system have Hyperflow AES,which work in similar way as Apexi http://www.hyperflow.com.au/index.ph...ust-system-aes


Jura