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-   -   Restrictive bung or quieter backbox (https://www.scoobynet.com/general-technical-10/850415-restrictive-bung-or-quieter-backbox.html)

PJF 09 September 2010 10:31 PM

Restrictive bung or quieter backbox
 
Hi people, this is prob a stupid question however i shall ask any way, ive got a full decat and afterburner vortex backbox on the car at the mo so its pritty loud and im on track this weekend so obviously it needs to be quieter to pass the sound test, my question is would the bung that i use in the vortex be much more restrictive than a quieter/bigger box powerflow backbox which i have spare?
I assume the powerflow backbox would be better to put on than the bung but am hoping people are gonna say bung due to my laziness :D
thanks in advance for any comments

P4UL 09 September 2010 10:49 PM

Bung will sap power, I had one on my HKS super dragger on my evo, spat it out at full pelt indicating how restricitve it was.
I would opt for a quieter box that has a decent flow!!!

ginger321 09 September 2010 11:33 PM

spat it out:eek:

I was thinking of getting a bung for my HKS Hi power, do they get secured with screws?

P4UL 09 September 2010 11:49 PM

yeah it was but, screw worked its self loose with the vibration. Least it missed the car behind me at the time:lol1:

chris84 10 September 2010 01:43 AM


Originally Posted by PJF (Post 9592189)
Hi people, this is prob a stupid question however i shall ask any way, ive got a full decat and afterburner vortex backbox on the car at the mo so its pritty loud and im on track this weekend so obviously it needs to be quieter to pass the sound test, my question is would the bung that i use in the vortex be much more restrictive than a quieter/bigger box powerflow backbox which i have spare?
I assume the powerflow backbox would be better to put on than the bung but am hoping people are gonna say bung due to my laziness :D
thanks in advance for any comments

i've just had the full decat done with afterburner vortex. scoobyworld said the backbox has changed recently so the stock bung won't fit mine properly, would need a custom.

need to run half boost with bung, restricts airflow and you dont want the pressure building up too much. i'll be buying the racebox backbox before i track mine next year. easy enough to swap it on for tracks then swap back after.

midnight 10 September 2010 07:38 AM

If you have a spare backbox put it on imho,the bung will sap power and definetley increase back pressure in your system - one thing you dont need if your going to be 'ragging' it around a track.

'I assume the powerflow backbox would be better to put on than the bung but am hoping people are gonna say bung due to my laziness'

I cant really see any problem :wonder:, the back box will take you 15 mins to get off ,even if your a complete novice:2x 16mm bolts and a liberal spraying of wd40 on the rubbers and job done,or failing that take it to your local exhaust outlet ,give them a £10.00 and let them do it. I changed my ninja 2 for an afterburner vortex last week and never even bothered jacking the car up.:thumb:

ScoobyNoobie 10 September 2010 08:11 AM

As everyone has said, if you have a another back box use it!
I have a full 3' decat but have it matted to a 2.5 inch pro drive back box as i couldn't put up with the noise of the 3' back box i had. Can't actually remember the make of it, but it wasnt hks or a well known one.

Car still going really well, and much quieter!

RS74 10 September 2010 09:25 AM

do what i do ... put your bung in . let them do the sound check , you normally get a sticker in your windscreen saying it's passed .... then after a couple of laps , take bung out ... sorted:thumb:

53 10 September 2010 09:30 AM


Originally Posted by RS74 (Post 9592519)
do what i do ... put your bung in . let them do the sound check , you normally get a sticker in your windscreen saying it's passed .... then after a couple of laps , take bung out ... sorted:thumb:

And then you get black flagged for drive by noise :nono:

FWIW Raceboxes aren't that quiet for track, STi/PD boxes or original scoobysports (H&S) are the best option for bolt on 2.5" bore.:)

PJF 10 September 2010 07:07 PM

Thanks for the info guys i have swapped to the powerflow backbox abit to quiet for my likeing but as you all say bung restricts it to much, and last time i was on track saw the scooby next to me black flagged on second lap for noise, definatly dont want that.
this is for chris84, the bung i got didnt fit the vortex had to grind it down, and now its a perfect fit although need a pair of pliers to get it out.
Thanks for all your info guys it was a big help.


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