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Discussion Starter · #1 ·
so i've got a 5spd is300 with
srt intake / obx headers / stock y / custom 2.5 inch straight b pipe / HKS ti limited axle back

after i got the custom bpipe, when i
have my foot on the gas (at crusing speed) then let go (without shifting), let it drop to around 2000rpm then step on the gas a little bit, theres popping sounds from my exhaust, almost like spit fire or something.

obviously i cant tell what it is since im in the car and it does sound kinda cool to be honest but i wanna make sure its not killing my car

what is this popping sound and what is causing it?

thanks :)
 

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I've noticed the exact same thing with my exhaust. At first I thought it might be a bit of backfire but I guess the change in pressure may be causing it.

And I also have a very similar setup: SRT intake / Mazzuri V2 header / Mazzuri V2 y-pipe w/ Magnaflow cat / Apex-i GT-Spec b-pipe / HKS TI-Limited
 

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i have the same exhaust setup as you guys and then stage 2 cams and a tuned emanage ultimate and when my car makes this sound its acutally spitting fire :) i have seen it when someone else drove my car and i was behind it
 

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so i've got a 5spd is300 with
srt intake / obx headers / stock y / custom 2.5 inch straight b pipe / HKS ti limited axle back

after i got the custom bpipe, when i
have my foot on the gas (at crusing speed) then let go (without shifting), let it drop to around 2000rpm then step on the gas a little bit, theres popping sounds from my exhaust, almost like spit fire or something.

obviously i cant tell what it is since im in the car and it does sound kinda cool to be honest but i wanna make sure its not killing my car

what is this popping sound and what is causing it?

thanks :)
An exhaust pop happens when unspent fuel ignites in your exhaust manifold. This generally means you are running rich. It sounds cool, but your engine is capable of using those unspent gasses in a more productive fashion, like toying with A/F to a more ideal level. This typically happens when people bolt on things to their cars and do not get it tuned by a shop. The continued burning and sudden pressure increases from the exhaust popping may reduce the exhausts structural integrity over time in a quicker fashion than a properly tuned beast.

That being said, there are many things that could cause your exhaust to pop, such as high exhaust manifold temps as well as running rich.

Reset your ECU and then see if the popping happens, if it doesnt, then your computer has adjusted to run richly, necessitating a tune or SAFC or something of the sort to maintain a constant stoichiometric equilibrium of 13-1 A/F. Your unspent exhaust gasses would be better off spent.
 

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An exhaust pop happens when unspent fuel ignites in your exhaust manifold. This generally means you are running rich. It sounds cool, but your engine is capable of using those unspent gasses in a more productive fashion, like toying with A/F to a more ideal level. This typically happens when people bolt on things to their cars and do not get it tuned by a shop. The continued burning and sudden pressure increases from the exhaust popping may reduce the exhausts structural integrity over time in a quicker fashion than a properly tuned beast.

That being said, there are many things that could cause your exhaust to pop, such as high exhaust manifold temps as well as running rich.

Reset your ECU and then see if the popping happens, if it doesnt, then your computer has adjusted to run richly, necessitating a tune or SAFC or something of the sort to maintain a constant stoichiometric equilibrium of 13-1 A/F. Your unspent exhaust gasses would be better off spent.

What he said lol.
 

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all i have is a 3 inch catback and it pops like crazy.
 

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Forgive me, proper stoichiometric equilibrium for most petrol cars is 14.7 to 1(Hmmm 1 Bar.), and I said equilibrium is 13 to 1. Stoichiometric ratio is what I meant.
just brain sharted a little bit
 

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Mine was doing that with just a Ypipe and the Hiper, now with all the cats removed when I hear a louder bang I know it pops a small flame, at least what I was told by a friend driving behind me.

The IS runs way too rich with the stock tune that's why

It's cool I guess but not exactly good
 

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I get the popping sound with the factory headers, xerd Y, and n1 catback.... I'm looking into a piggyback for a more refined air/fuel
 
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