Exhaust back pressure

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Oliverjohn

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Hi all I have removed the front cat on my 07 fz1 and fit a akrapovic exhaust but I have been told to leave the baffle in because the bike need back pressure is this correct :thinking:
 
Back pressure is another of those common automotive myths or thinking that was applicable 50 years ago. A quick Google search will explain how and why

Like loosenut says, try it out and see what you notice. A small baffle isn't going to make a colossal difference anyhow
 
The only reason you might "need" the backpressure is to keep it from popping on decel if you don't remove the AIS stuff... Once that is removed/blocked off, it hardly ever pops anymore.
 
Oliverjohn said:
Hi all I have removed the front cat on my 07 fz1 and fit a akrapovic exhaust but I have been told to leave the baffle in because the bike need back pressure is this correct :thinking:
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Take the baffle out & leave it out, you are just robbing yourself of the gains of an aftermarket exhaust leaving the baffle in. Ride the bike and if you dont like the popping open up the airboax and block off the snorkel with a plug, marble, screw, silicone or anything that will do the job and no more popping.
 
KNEEDOWN69 said:
Take the baffle out & leave it out, you are just robbing yourself of the gains of an aftermarket exhaust leaving the baffle in. Ride the bike and if you dont like the popping open up the airboax and block off the snorkel with a plug, marble, screw, silicone or anything that will do the job and no more popping.
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+1

And like Dustin said, "Back pressure" is a misleading misnomer and misunderstood. Whether they know it or not, what most people are referring to is "exhaust velocity".
 
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Once you get the AFRs fairly well dialed in, some of the popping may return, even with the AIS plugged. The underlying issue is that the AE and DE in the stock ECU gets a little hosed without the valve in the exhaust and the flies up top. The PC5 simply does not have enough adjustment capabilities for the transitions.

Beast
 
whittlebeast said:
Once you get the AFRs fairly well dialed in, some of the popping may return, even with the AIS plugged. The underlying issue is that the AE and DE in the stock ECU gets a little hosed without the valve in the exhaust and the flies up top. The PC5 simply does not have enough adjustment capabilities for the transitions.

Beast
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Leaning out the zero column fixed about 90% of the popping on mine. With my cam swap I use -4% at idle. That give me a 13.5:1 FR at idle. I lean anywhere between 5-12% from 1K-7K. A little bit at the time until the popping is almost gone.

Worked for me...:yes:
 
My bike is all MAP based tuning until the front tire starts getting light. Most if not all of the popping I am referring to is in the transitions.

Beast
 
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