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Discussion Starter #1
Exhaust popping!? My MBRP exhaust is popping a little bit more then it did when it was first put on about 2 weeks ago. Is this normal? It does not pop during acceleration, just when I'm off the throttle and it's still in gear or when holding it steady around 2800rpms. My sport bike (Honda CBR 600RR) had a similar sound when off the throttle but higher in pitch.

So anyone else out there with an MBRP exhaust having the same popping when off the throttle or while just reving the engine?
 

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yes it happens i didnt like it at first but now i kinda do makes it feel like i have a v-8 lol but then i hit the gas and remember its a focus but yes it pops when u rev high and normally when i shift
 

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DTF
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my magnaflow spits and pops alot, i notice it more in 3rd and 4th gear if i hit the gas hard and then let of and leave it in gear.
 

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mine does the same thing all the time.....i love it!!!
 

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this is a result of the catalytic convertor not being able to properly consume the hydrocarbons. the reduced backpressure cuases this
 

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my borla does it when i rev high its cool sounding lol.
 

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Discussion Starter #8
Thanks guys that is a real load off! I was worried for a while there. I to like the sound it is more athentic I believe. I here a lot of ricers around my area with Cherry bombs on the back that don't pop at all. Just a high piched whine.
 

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The Mailman 666 said:
Thanks guys that is a real load off! I was worried for a while there. I to like the sound it is more athentic I believe. I here a lot of ricers around my area with Cherry bombs on the back that don't pop at all. Just a high piched whine.
i have noticed that it seems most domestic cars will do this. my buddies cavailer did it alot too.
 

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wickedgreyzx3 said:
this is a result of the catalytic convertor not being able to properly consume the hydrocarbons. the reduced backpressure cuases this
i dont know anything about all that, i dont have a cat on my car but i dont see how the hydrocarbons would have anything to do with the car popping. reduced backpressure i can kinda understand.
 

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not specifically HC, but fuel saturated vapors that ignite in the exhaust.

a decat pipe (or removal of the catalytic convertor), and a muffler that has many baffles increases this effect.
 

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Foci_Fosho said:
not specifically HC, but fuel saturated vapors that ignite in the exhaust.

a decat pipe (or removal of the catalytic convertor), and a muffler that has many baffles increases this effect.
which would lead me to believe that this is going to be more promentent in a car which is running rich.

however i know that flames from the exhaust is usually an indication of a lean condition (somehow).

so idk
 

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I belive my car is running rich, even on my stock exhaust the tip had about a 1/4 inch black ring on the OUT SIDE, now this one is doing it a little too.
 

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i'm fairly positive my car is running really rich because my tip is covered in a very thick black layer which takes some strong chemicals to get off, yet i was told that flames could be seen in my exhaust. i really need a wideband and a laptop to datalog so i can get my tune right!
 

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Discussion Starter #15
focusin said:
I belive my car is running rich, even on my stock exhaust the tip had about a 1/4 inch black ring on the OUT SIDE, now this one is doing it a little too.
so black on the tail pipe means your car is running rich? How do you fix this? My stock exhaust was black inside too. Does running rich waist fuel?
 

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No, black is normal but excessive black like where its getting on you rear bumper or getting on the outside on the tip might be running rich. If its not doing either of those you should be fine.

My stock exhaust had a ring on the outside of the tip, it was about 1/4 inch all the way around.
 

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gump1114 said:
i'm fairly positive my car is running really rich because my tip is covered in a very thick black layer which takes some strong chemicals to get off, yet i was told that flames could be seen in my exhaust. i really need a wideband and a laptop to datalog so i can get my tune right!
The flames could have been the unburnt fuel igniting at your tailpipe, not because you are too lean or too rich. If you are truly running rich, you will smell fuel and it will be strong at start up. If you are too lean, the inside of your tail pipe would be very lightly discolored, and you would most likely hear knock under load at WOT unless your knock sensor has not been modifed to retard spark as much as it does stock.
 

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Mine is kinda poppy especially when not in gear and not under load when losing revs.

My car smells of petrol, but I feel that has a bit more to do with my lack of cats. I'm running a focussport tune for 91 octane, and right now I think it is doing just about right. I'll get a wide band and we will know for sure thuogh.
 

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Ever since I put my RT Hi-flow cat on, I could smell slight fuel, especially after going WOT.

When it smells strong and you see dark smoke coming out of your tailpipe you are most likely running way to rich.

If your tailpipe is dark brownish colored, almost black, you are running a pretty good A/F, but you can't really judge the tailpipe color because the color won't change when you go open loop then change back when you go closed loop, doesn't work that way.
 

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just because your tip is black means nothing there are millions of stock crs out there with black tips. hell my friends new GT has black tips and its only got a thousand miles on it its normal exhuast is black
 
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