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I need a little education here. I see there are many exhaust systems for the vrod in the aftermarket. Most of these require some type of re-mapping device to set fuel curves to optimize the exhaust. Some are only pipes that replace the stock mufflers or replace two mufflers with one. I have read on many posts that failure to re-map the fuel after adding a new exhaust may burn down the engine due to an overly lean condition. Why would this be so? Don't the existing O2 sensors optimize the fuel/air ratio for best combustion/least emissions? Granted there are going to be better maps than H-D uses stock but I don't believe there is any danger of "Burning Down" an engine due to lean conditions by using aftermarket exhausts as long as the O2 sensors are in the circuit.
Tell me why I'm wrong.
Thanks, Wes
 

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I need a little education here. I see there are many exhaust systems for the vrod in the aftermarket. Most of these require some type of re-mapping device to set fuel curves to optimize the exhaust. Some are only pipes that replace the stock mufflers or replace two mufflers with one. I have read on many posts that failure to re-map the fuel after adding a new exhaust may burn down the engine due to an overly lean condition. Why would this be so? Don't the existing O2 sensors optimize the fuel/air ratio for best combustion/least emissions? Granted there are going to be better maps than H-D uses stock but I don't believe there is any danger of "Burning Down" an engine due to lean conditions by using aftermarket exhausts as long as the O2 sensors are in the circuit.
Tell me why I'm wrong.
Thanks, Wes
Without knowing all the details, the stock O2 sensor only adjust in a limited range not for a full blown intake/exhaust modification.
If you change intake/exhaust it's best to get a dyno tune to make sure you are not burning up your engine.
The engines comes from the factory very lean to satisfy EPA pollution requirements and an exhaust change will make it run even leaner.
 

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Why would this be so? Don't the existing O2 sensors optimize the fuel/air ratio for best combustion/least emissions? Granted there are going to be better maps than H-D uses stock but I don't believe there is any danger of "Burning Down" an engine due to lean conditions by using aftermarket exhausts as long as the O2 sensors are in the circuit.
Tell me why I'm wrong.
Thanks, Wes
Believe it or not,the narrow band O2 system and programming Harley uses is antique as hell,and has very limited capability's of making any adaptive adjustments at all.They went as far as they had to to pass the epa rules,nothing more.Even if they would have given us a system as simple as a Toyota Corolla,the lean surge complaints on all late model Harleys at 2900 rpm's would not exist.

There are some companys that offer a self learn ecm,but I do not have a very high regard for these.They have the capability of what Chrysler offered back in 88 with the logic modules that didn't communicate very well with the engine controllers.If you surf over in the other threads in this forum,you will see that most people that use these things have nothing but problems with them.

So,with all that shit out of my way,if you change the exhaust on a V-Rod,it must be tuned accordingly,because the base mapp that comes from the factory is tweaked very lean to pass epa rules.
The best way I have found to tune a V-Rod ecm is by reprogramming the ecm with the SERT,and the Mastertuner on a dyno.
There are systems offered,like the power commander,but that is a "box" that can be programmed to interupt signals.The PC's theory worked fine on my 03,when it worked! The reliability of the box sucked.

It's a damned shame that Harley has such piss poor management skills.They are going broke from the lack of profit making skills and cannot afford to give us a true wide band system that actually works like a late model automobile does.They cannot afford to fix the fuel sender problem in the late model V-Rods since 2007.
Maybe the new Buffet-Davidson company will have some foresight and give the public what they are paying for.
 
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