Backfiring!?
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This is a discussion on Backfiring!? within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Originally Posted by speedracer420 I've been noticing with my 04 wrx that every so often that I hear this poping ...

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    ClubWRX.net Vendor JSCspeed's Avatar
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    Quote Originally Posted by speedracer420 View Post
    I've been noticing with my 04 wrx that every so often that I hear this poping sound, i guess its backfiring. I have an uppipe and a prodrive exhaust but no midpipe. Just wanted to know if any1 knows what this could be from and if its common with these cars. Sometimes its really loud just want to make sure that nothing serious is wrong with the car.
    Are those the only mods on the car?

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    I smell the release of PSI to atmosphere

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    Registered User Micah's Avatar
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    afterfire is not the same as backfire
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    Registered User pweizman's Avatar
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    Could be fairly normal if it is just a small popping...

    That would signal you are running rich...it usually occurs in off throttle situations...I am guessing.

    Are you tuned?

    My '03 with UP, shorty DP, stock mid pipe, cat back and tuned will pop a bit off throttle....

    I think it is fairly normal.

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    Registered User Micah's Avatar
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    the joys of being catless

    I get a bit of afterfire when I shift while at full boost, I don't think it happens every time. I've had plenty of people tell me they see it when I'm getting on it, but when cops are around, I stay out of boost and I've had plenty of cops behind me yet none have pulled me over.

    Oh, and FWIW - if you aren't catless, afterfire is really bad for your cats, risk of fire being one of the worse things, tripping a cel for unsafe EGT being one of the lesser things. Probably other things that can happen as well.
    Torch Red 2002 Chevrolet Corvette Z06 46k mi.
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    "Six stars gleaming, five speeds breaking, four tires chirping, three differentials working, two liters screaming, one turbo boosting... it's what makes a Subaru all-wheel-drive, all we'll drive."
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    Registered User Knome's Avatar
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    I thought it was normal on these cars? mine always does it, when i go tuned it did it. It happens ever time i rev to redline in neutral and step off the gas. I've heard tons of other subies do the same.

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    yea mine pops insanely loud when i continuously get on and and rev high, and ive heard flames shoot out as well....... i love it haha
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    Registered User guatemalanboi's Avatar
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    thats true i think these cars just do that depending on your mods because even i get the popping and all have is my catback its nice at times but yes my friends have popping to but theirs is louder then mine

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    Registered User SubyPsycho's Avatar
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    Most turbo cars pop when off throttle to an extent, especially between shifts when boosting as Micah has already said. If you think about what's happening when it's on boost, more air is being forced into the engine which means more fuel is needed. When you back off the throttle and the pop-off valve releases the excess air pressure, there is going to be a small amount of fuel left over that didn't burn because there suddenly isn't enough air (O2) left to complete combustion. That excess fuel gets pushed out of the combustion chamber on the piston's exhaust stroke, and it goes into the exhaust system. Once it contacts the hot exhaust pipes, you'll get some pops and rumbles.

    If it ever starts sounding like gunshots, you've got a problem. Timing, incorrectly functioning or poorly matched bov, etc. If it's just pops, it's normal.

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    Registered User powder's Avatar
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    I love my rice krispy's sounding exhaust.
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    Registered User Destros's Avatar
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    my car pops somtimes too...it sounds like its coming from the intake???

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    Registered User disaster646's Avatar
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    mine does it all the time.. even when i stay in gear and let go off the gas pedal..(downshifting) if i barely tap it.. it pops, sometimes really loud.. i love it..i dont do it next to cops tho.. its so loud.. especially if u have a catless downpipe, i need some tunning cuz im running rich tho..

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    Quote Originally Posted by disaster646 View Post
    mine does it all the time.. even when i stay in gear and let go off the gas pedal..(downshifting) if i barely tap it.. it pops, sometimes really loud.. i love it..i dont do it next to cops tho.. its so loud.. especially if u have a catless downpipe, i need some tunning cuz im running rich tho..
    Are u running a Blow Off Valve?

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    Registered User Destros's Avatar
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    I have UP, DP, and SPT intake. Stock recirc valve. I was thinking that valve might be sticking some, or not opening enough and the fresh air is hitting the remnants of compressed air.? Compressor surge?....?? Is the Perrin recirc or APS recirc decent upgrades to the stock valve..if I'm accelerating and let off the gas the car slams forward as though you were jumping on the brakes...
    ...I have know idea.

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