^ true but for the record the PC3 & PC5 do not allow for lowering of the idle like apparently the super tuner does.

 

What change in air flow?

The engine is a simple air pump....increasing the capacity to evacute air from the engine doesn't allow more air to enter it (which is what a tuner is all about....increasing the amount of fuel delivered to correct the A/F ratio) unless you can prove to me that the exhaust is more restrictive then the stock intake. There might be dyno's out there to prove this. Which even if it is....is probably only marginally which the ECM can adjust.

Maybe you are making the assumption that the OP has a high flow intake like a stage 1 or Arlen Ness super sucker where I am thinking he just stated that he removed the baffles from his muffler and my assumption is he is otherwise stock.

We both could be wrong depending on his set-up. If he does have a high flow intake and running screamin eagle slip-on's then I agree. However, he should have had a tuner or remap on it already in that case or he is running very lean!

There are numerous people out there who buy their performance exhaust before the intake because they can't afford to buy the exhaust, high flow intake and fuel mgt system all at once. So the default answer is to buy the exhaust first, fuel mgt system second or with the high flow intake but to never put the exhaust and intake on w/o a air/fuel mgt system. I have yet to hear from any issues running this way since I got my EFI sporty in 07'.

 

It looked like the check engine light was on in the video.

 

I have done nothing other than remove the baffles, in doing so the entire inside of the muffler is removed which opens it completely to the large diameter of the muffler. After doing so the idle speed increased significantly in the range of 200 RPM.

 

You don't understand fully what an exhaust pipe does. It establishes pressure waves that alter the amount of air allowed out of the pipe. Those waves both push and pull on the air at the exhaust, and a simple change in pipe does not necessarily indicate that more air will flow. It isn't that he put a low restriction pipe on - that pipe if poorly designed may not match it's intended purpose, or it may, in either case the pressure wave will not be identical to that of the stock pipe. Just changing the baffle is enough to alter the pressure wave, and therefore the exhaust and intake capacity. If it is scavenging more air from the intake chamber, then the air:fuel mixture will definitely be off, regardless of how much air is being allowed in (stage 1 air cleaner). So, yes changing just the baffle can have an affect on the a:f ratio despite no corresponding change in the intake.

Your recommended recipe of buying exhaust first, fueler next, then the a/c is typically sufficient - but not necessarily so. The OP might just find everything runs fine at other than idle - remember we're talking idle here at the moment. The idle system is a bit different in that there is an iac valve that steps open and closed to allow idle air in, (in fact there is a separate map for idle).

However - all this aside (both mine and yours), something changed in order to affect the idle. You posited that there isn't enough change in exhaust alone, if true - then what affected his idle? BTW, the OP never mentioned changing the intake - and I didn't factor it into my comments.

 

Right - and this makes sense to me, the mixture is leaner and the ecm is doing something to try to compensate. Exactly what, I don't know. Too many different maps in use for idle control, I'm not that good at this.

 

Open Loop - The ECM monitors sensors positioned on the intake side of the engine and does not monitor the end result of internal combustion at the exhaust.


That is the part that makes me wonder. My bike has O2 sensors and if they are not mentioned or used, why is it there?

 

That part you quoted refers to sensors on the intake side - they could be ambient air temp, manifold absolute pressure, or some other type - but it wouldn't be useful to measure air:fuel on intake on an injected engine since the fuel is added just prior to the intake chamber, not mixed earlier like in a carb'd engine. The O2 sensor on the exhaust side - as in our present Delphi systems produces a voltage that the ecm reads based on the amount of residual oxygen - an indicator of the combustion efficiency and therefore an indicator of air:fuel ratio. Our bikes want to be at 14:1 from the factory (if I recall correctly), most of the tuners we use on our bikes target a 12:1. The ECM has a slight ability to make adjustments based on the reading it gets from the O2 sensor, but only over a very narrow band of performance.

Many of the piggyback tuners commonly used on our bikes actually disconnect the O2 sensors because what they do is fake the reading going to the ecm so that it thinks the bike needs more fuel. For example, they might tell the factory ecm that the engine is cold (adds fuel), or that it is running lean (adds fuel).

I'm not an expert at this, but I read a lot!

 

Hello and thanks for the info, however, I am still at a loss as I have been told by many that just changing to a straight through exhaust will not require a remap for any reason. There are no other changes other than the removal of the entire baffle on the Screamin Eagle mufflers. I am aware of the factory throttle blade stop screw and may make an adjustment to this to see the effects. I have searched for a factory setting dimension for the throttle blade open amount and am sure someone knows this. I would like to know what the setting dimension range is from the blade to the throttle bore at idle position, anyone out there know? It's hard to believe it would cost an arm and a leg to have an adjustment made to change idle speed. I thought we are supposed to be moving forward with new technology but it seems like the technology is a way to scavenge money. Thanks for any info you guys can give me.

 

i would try putting the baffels back in and see if it changes. pipes alone shouldnt change idle i dont think