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Pops and Bangs from the exhaust

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Old 22 December 2005, 01:54 PM
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James Neill
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Default Pops and Bangs from the exhaust

I have a UK MY98 with a De-cat downpipe. That's the only mod. Sometimes I get some great pops and bangs from the exhaust when I lift off and the revs drop. Is this normal for a car like mine (ie, relatively tame)?
Old 22 December 2005, 01:58 PM
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Abdabz
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Aye my almost standard wrx bugeye makes some splendid poppy bang bangs Sounds tip top! With HKS exhaust.
Old 22 December 2005, 02:10 PM
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alloy
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with the decat it will pop and bang, enjoy it
Old 22 December 2005, 02:44 PM
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cookstar
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I get plenty of pops but no loud bangs

How do i make it bang more


02WRX Full decat.
Old 22 December 2005, 02:48 PM
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Duck_Pond
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Mine bangs and pops with a H&S centre section and backbox only. Classic UK turbo, std.

I find that by driving slowly in a higher gear, then changing down to a more appropriate gear usually gets a decent bang... which can be concerning when trying to roll past horse-riders

Sometimes bangs when flat out too, but that's hit and miss.
Old 22 December 2005, 02:50 PM
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impreza22b_WRC
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Originally Posted by cookstar
I get plenty of pops but no loud bangs

How do i make it bang more


02WRX Full decat.
Easy, just fit a Gems or Autronics ECU and get it mapped correctly.
Old 22 December 2005, 02:56 PM
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When my WRX was still speed restricted to 110mph (or 112mph, which ever it is) i used to let it hit the limiter for a few seconds then gently lift off. Sometimes got a huge BANG with lots of flames (enough to light up a dark, unused runway/private road)
Old 22 December 2005, 07:05 PM
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EddScott
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I have an MY00, full decat with H&S back box and TEK mapping. Only time I get a pop is if I blip the throttle to 3K when ****ing down. Without the atmos DV to allow overfueling it wont even pop.

Thought the 4" H&S angled exit BB would reward me with some decent noises but not as many as others.
Old 22 December 2005, 07:42 PM
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Ah so lack of VTA could be stopping the pops
Old 22 December 2005, 08:01 PM
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si97
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Eddscott..

i hope i dont meet you when you are '****ing' down at 3k, probably need to use the screen wash whether you blip the throttle or not
Old 26 December 2005, 01:05 PM
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rgv_stu
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Originally Posted by Duck_Pond
I find that by driving slowly in a higher gear, then changing down to a more appropriate gear usually gets a decent bang... which can be concerning when trying to roll past horse-riders
hehe had the same issues with horses myself , although i feel that they shouldnt even be on the road !!

mines notoriously poppy downhills when held in lowish gears and when on light throttle after a good blast
Old 26 December 2005, 02:22 PM
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oh, mine pops and bangs everytime I lift off the gas quickly, If I gentley lift ioff it doesn't bang but lift it off fast when going some and all hell is let loose.

I've a Uk99 with FMIC,VF28, 3" 5Zigen exhuast, VTA and a TEK3
Old 26 December 2005, 02:24 PM
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It must be the VTA that causes this.


VTA next for me then
Old 26 December 2005, 02:33 PM
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Mr_Wid
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Vta mine, tek3 not mapped for the new turbo yet, get pops and bangs after usuing light turbo pressure and then taking foot off throttle, after a long run i can even see flames reflecting on the rear spoiler!
Old 26 December 2005, 03:25 PM
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For the car to pop and bang means there is unburned fuel in the exhaust. ie the car is way to rich at some part of its operating perameter. This means there is the possibility to improve things, extract more power or dramatically improve mpg.
Also check for exhaust gasket leak.
If you think the pops and bangs are cool then please ignore this info.
For big bangs you can switch the ignition of while driving and then back on. On some cars this will result in fantastic bangs. Not good for the car though and it could give pedestians brown skid marks.
BTW Moley : Running onto the rev limiter is best avoided unless you are happy to knack your engine.
Old 26 December 2005, 05:11 PM
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my00 uk ,headers,H+S downpipe,blitz nur spec r,baileys vta.
never bangs or pops but then again it has been mapped properly
Old 26 December 2005, 07:45 PM
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Mine never used to pop and bang until I changed the exhaust from a magnex 2.5" to the 3" 5Zigen, interesting what you say about the gasket, I'll have to have a look see on a cold morning.

oh and mine was properly remapped only last month!!!!
Old 26 December 2005, 08:51 PM
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rgv_stu
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harvey
all mine has is a STI 2.5" exhaust and it pops a fair bit.
any suggestions as to what i can do to improve the matter ??
i dont mind the pops but if its only doing it due to overfueling then can i get some benifit from some fiddling ie resonator box removal or similar??
Old 26 December 2005, 11:32 PM
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Start by looking to see if air could be sucked in somewhere on the exhaust system. If that leads to nothing check under the bonnet to see if any of the vacuum pipes are perished, split or whatever. If none of that serves a purpose consider resetting the ECU.
When was the last time you changed your plugs and are your coil packs OK ?
Next step is to get a Wide Band up the exhaust and check your AFRs. Not difficult if you find somebody that has the right gear
Old 26 December 2005, 11:39 PM
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im getting pops and flames using a Blitz NUR Spec R and a bit of over fuelling in the map.Apparently it flames quite a lot.My guess is to get your mapper to make it run a bit rich in the over run and when u lift off u get a pop and perhaps a bang (chance would be a fine thing)
Old 27 December 2005, 12:55 AM
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Originally Posted by cookstar
It must be the VTA that causes this.


VTA next for me then
if only you can get the pops and bangs with a VTA but without the PSSSSH that would be sweet. (I think the PSSSH is a bit to much Boy Racer for me)
Old 27 December 2005, 10:30 AM
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cheers harvey
everything exhaust wise / vacumn hose wise seemed fine when i was under the car about 2 weeks ago.
the exhaust is a sti uprated item from japan, no centre cat
i could probably do to take the hoses / boost solenoid out and clean them as i get fuel cut in 5th if i plant it at 3k
looking at the service history plugs were changed about 28k ago so i presume they need changing now aswell. whats the recommended items ??
Old 27 December 2005, 11:51 AM
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NGK PFR 6B are O/E recommendation and work well.
PFR7B if you have gone beyond mild tuning. These work OK at 500 bhp from experience.
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