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pop and crackle de cat

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Old 01 February 2004, 02:35 AM
  #1  
zakesm
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just got my downpipe de catted, and i had the centre section done already. can i expect pops and crackles on gear changes coz i aint gettin any. (UK my99 turbo). will a VTA dump valve ensure it? also, just after the centre cat, there is another small booster thing on the exhaust. what is that. i did a diy centre de cat so i didnt remove this little tube thing. thanks 4 any help.
Old 01 February 2004, 03:04 PM
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zakesm
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this is a pic of the resonator/booster on the exhaust that i am unsure about. the one painted silver in the pic

http://scoobyboy0.tripod.com/DSCN9751.jpg

anybody?
zak
Old 01 February 2004, 03:30 PM
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greasemonkey
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That image isn't coming up. As for the pops and crackles, a VTA valve won't "ensure" them, no. Why do you want your car to make unnecessary noises?
Old 01 February 2004, 03:45 PM
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zhastaph
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Now now Greasemonkey, nothing wrong with a few bangs from your exhaust

I decatted mine. And for the first few weeks no pops and bangs at all. But now she bangs sometimes although it's quite unpredicatable, but never pops. I think you need to wait for the downpipe to coak up so that it's got something to ignite the fuel with.

BTW, I've got a standard recirc dumpvalve. And I've got a resonator, though I didn't originally. There was no difference at all when I fitted the resonated centre pipe.

The VTA will help, but I think generally speaking they're not recomended round these parts as they can cause massive overfueling when you close the throttle which results in premature wear of your piston bores.
Old 01 February 2004, 04:46 PM
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tmo
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mine pops and bang, thats with a TSL group N back box, De-cat centre.
Old 01 February 2004, 04:59 PM
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BlackScoobyWRX
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Mine pops and bangs a bit
(99 STi5 - full decat, HKS **** off exhaust!!)
Old 01 February 2004, 05:05 PM
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scoobyverysoon
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mine pops and bangs only when very hot though my00 with magnex dentre decat and blitz back box + also VTA dumpvalve

its funny to see people look round when you gear down pop pop pop pop

regards

JUD

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Old 01 February 2004, 05:10 PM
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SiDHEaD
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Mine pops and bangs with just decat center and a custom backbox. Does it a lot more on NUL.

Andy
Old 01 February 2004, 05:22 PM
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SUBTYPER
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Mines bangs MY98 STi Type R with full decat exhaust and downpipe. VTA dump VAlve and K&N panel filter. It only pops and bangs when the exhaust has warmed up and it does it around 3000 rpm when coming off the throttle. Also it doesnt do it in Neutral only in gear. Strange or what. Or does the Ecu recognise you have sleected a gear
Old 01 February 2004, 05:25 PM
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andypugh2000
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pops and bangs something stupid in hot weather, in this weather only get them whilst giving it hell and also bouncing off the limiter.
Old 01 February 2004, 05:59 PM
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greasemonkey
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Also it doesnt do it in Neutral only in gear. Strange or what. Or does the Ecu recognise you have sleected a gear
It recognises that there's no load on the engine, and so there'll be no boost, much less fuel, and hence nothing to go bang down the pipe.
Old 01 February 2004, 10:31 PM
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SUBTYPER
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Oh right but how does it do this if you got the car in gear and the clutch depressed. In my line of thought surely the car isnt under load and also the car is stationary. Like I said I aint a techie just wondering id the car knows when its in gear
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