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hi i jut ordered a two brothers used exhaust ( i am poor :( ) do i need a power commander or can i run the bike with out it??? thanks for your help i will load pics when i am done
 

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its more of a nice to have rather than a need to have, but ive just ordered one, suppose to feel much better with power delivery etc, so its gotta be good...fingers crossed!
 

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you don't need it. PC is just another performance enhancer. you will be fine without it. wait till you have the dough and upgrade when you can if you want to. you aren't going to hurt your bike.
 

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duper said:
you don't need it. PC is just another performance enhancer. you will be fine without it. wait till you have the dough and upgrade when you can if you want to. you aren't going to hurt your bike.
You can't guarantee that.

No one can tell you how that 2B's pipe will effect YOUR bikes fuel map. You may or may not need one. Most likely you will with a 2B's. Certian pipes will change the fuel mapping dramatically enough to cause problems. My Leo Vince needed a PCIII to correct the lean conditions in the higher RPM range and the rich conditions down low. The PCIII is WELL worth the money. It's a tool to allow you to get the most Hp out of your bike.

If your bike starts running rough at idle, backfires on decelleration, or lags at higher RPM's, get it on the dyno to see what the A/F ratio is doing. Don't simply adjust the idle screw up to cover up for a bad fuel map.
 
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NewRedRider said:
If your bike starts running rough at idle, backfires on decelleration, or lags at higher RPM's, get it on the dyno to see what the A/F ratio is doing. Don't simply adjust the idle screw up to cover up for a bad fuel map.
If by backfires on decelleration you mean exhaust popping on decelleration, then it's not a case of an improper map, but rather because of unburned fuel exploding in the ehaust pipe because of the SMOG equipment (Air Injection). it helps, but not to the point of remedy.

these bikes simply do not back fire. not in stock form anyway. if it did, you'd have an airbox explosion, and fire coming out of the ram air nostrils like a dragon. neet idea!

oh hell.
 

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Knightslugger said:
If by backfires on decelleration you mean exhaust popping on decelleration, then it's not a case of an improper map, but rather because of unburned fuel exploding in the ehaust pipe because of the SMOG equipment (Air Injection). it helps, but not to the point of remedy.

these bikes simply do not back fire. not in stock form anyway. if it did, you'd have an airbox explosion, and fire coming out of the ram air nostrils like a dragon. neet idea!

oh hell.
That's my point. The unburned fuel is extreme because of the fuel mapping being too rich. Disabling the PAIR valve is not the cure but only treats the symptoms. If the mapping is corrected you shouldn't get backfiring.
 
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NewRedRider said:
You're splitting hairs.
not at all. A back fire suggests a reverse ignition that travels BACK to the fuel source. Since the ignition is in the exhaust manifold and is POST IGNITION, then it's traveling in it's initial intended path out the tail pipe. A Back Fire and an Exhaust Pop are 100% inverse of each other.
 

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Knightslugger said:
not at all. A back fire suggests a reverse ignition that travels BACK to the fuel source. Since the ignition is in the exhaust manifold and is POST IGNITION, then it's traveling in it's initial intended path out the tail pipe. A Back Fire and an Exhaust Pop are 100% inverse of each other.
This is 100% correct but common termonolgy says 99.9% of people call it backfiring when the exhaust pops, right or wrong. That's why I'm saying your splitting hairs with me. The debate is about the PCIII and not the terms of the words used. Blame my redneck upbringing for the termonolgy if you want. The cause and effect are the same when the fuel mapping is off.
 

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Harp said:
A slip-on won't change the exhaust characteristics enough to require a PC.
Too broad of a paint brush for that statement. You don't actually NEED tires to drive your car either. You can run on the rims but it'd be a lot better with tires.
 
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...Except even with a tuned PCIII you're still going to have the 'Popping' BECAUSE of the Pulse Secondary Air Injection Check Valve (PAIR Valve, aka smog reduction system). The reason the unburned fuel explodes in the ehxuast pipe is because air (or rather the oxygen in the air) is being introduced into an environment that is devoid of oxygen (Burned exhaust gasses cositing mostly of CO2 and water, as well as some sulfates). The fuel cannot burn unless there is oxygen present. The PAIR valve facilitates this introduction and without it, the unburned hydrocarbons would travel down the pipe cooling itself and eventuall out into the cool atmosphere where it can be consumed by other things that require air.

The PCIII helps, but to get rid of the 'Popping' you MUST remove the Pulse Secondary Air Injection Check Valve. the popping happens all the time even without a louder S/O, you just never hear it. i've had many a discussion with other experianced engine tinkerers and the collective answer to the issue is oxygen. fuel cannot burn without oxygen.
 

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Knightslugger said:
...Except even with a tuned PCIII you're still going to have the 'Popping' BECAUSE of the Pulse Secondary Air Injection Check Valve (PAIR Valve, aka smog reduction system). The reason the unburned fuel explodes in the ehxuast pipe is because air (or rather the oxygen in the air) is being introduced into an environment that is devoid of oxygen (Burned exhaust gasses cositing mostly of CO2 and water, as well as some sulfates). The fuel cannot burn unless there is oxygen present. The PAIR valve facilitates this introduction and without it, the unburned hydrocarbons would travel down the pipe cooling itself and eventuall out into the cool atmosphere where it can be consumed by other things that require air.

The PCIII helps, but to get rid of the 'Popping' you MUST remove the Pulse Secondary Air Injection Check Valve. the popping happens all the time even without a louder S/O, you just never hear it. i've had many a discussion with other experianced engine tinkerers and the collective answer to the issue is oxygen. fuel cannot burn without oxygen.
If that theory is correct then stock bikes would leave the showroom floor popping. I've never heard a stock bike pop unless it had a problem with the mapping/EFI.

Mine has a PC, Leo Vince S/O, and still has a fully functional PAIR valve. I have never had any popping nor have I heard a properly tuned bike pop. If the fuel mapping is correct you should not get popping. Unless you have an exhaust leak.
 

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can you guys shut the hell up and do this in a pm? question was if he needed a pcIII....stick to that
 
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I think the original question warranted a broad brush. No damage will be done to the bike if a PC is not used with a slip-on. The bike may not run optimally, but it will be fine.
This CAN be true, but isn't firmly true, so i agree with NNR about it. if it burns up plugs because it's running too lean then that's damage to the engine plain and simple. It's happened on a few S/O installs around here.

NNR: It is the PAIR Valve injecting O2 into the chamber that causes the unburned and extraordinarily hot fuel to combust post stroke in the headers. It doesn't surprise me that you don't hear it in a stock exhaust because the resonator (exhaust canister) baffles it completely as does the catalytic converter. if you remove the catalyst that converts the gasoline into CO2 and water (Oxygen), it will either combine with another element/molecule or out the tailpipe. Like i said, the mapping helps reduce fuel overload, but with air injection installed it can still happen.

I hope i am not the only one who feels this is a relevant discussion to any problems (be they mechanical or aesthetic in nature) a motorcycle may have when a Slip-on exhaust is installed without the aid of a PCIII. if i am alone on this, i will gladly shut up. :)
 

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...if it burns up plugs because it's running too lean then that's damage to the engine plain and simple. It's happened on a few S/O installs around here....
Plugs are a wear item, they aren't the engine. Regardless, show me some proof that a slip-on changes the A/F ratio enough to cause the plugs to burn up...then I'll gladly shut-up. :)
 
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