I found this post on another forum. He discusses modifying the exhuast system of '07 and later Sportsters. I just thought it was interesting ...
Saw this at the IED site:
Do I need to remap my ECM when installing exhaust and air cleaner upgrades to my 07 and later Harley?
NO, you do not have to do anything. You can put the mufflers/air cleaner upgrades and ride the bike without having to worry about the engine
The simple truth is the 07 and later HD's will run just fine with exhaust/air cleaner upgrades and you do not have to do anything to the ECM at all. Closed loop EFI operation uses feedback from the O2 sensor to maintain a constant AFR, even if changes are made to the exhaust and air cleaner.
The amount of information about what has to be done '07 and later Harley when installing exhaust/air cleaner upgrades has been the subject of FUD (Fear, Uncertainty and Doubt). Riders, Dealerships, Parts Suppliers and Aftermarket Shops have presented old-wives tales, bad technical information, mis-information and in some cases, just plain flat lied about the capabilities of the Delphi closed loop ECMs on these bikes.
Most people hold on to their old ideas about what was required for the early EFI ECM's. Shops and Dealerships never bothered to learn new the new technology. Marketing information did nothing to dispel the differences between the old and new bikes. Sales staff did not know the difference or mis-represented what was required on the new bikes.
There is more independent proof that you do not need to remap the HD EFI when installing mufflers. The March 2009 (page 66) CycleWorld dyno tested a set of slip-on mufflers on an '09 FLH, getting 5% more HP and 9% more torque on a "bone-stock, including EFI mapping" bike. Cycle World is not known as a big Harley cheerleader, so it would be a reasonable assumption that they are not going to do any special favors for MOCO.
Th CW information is right in line with what HD published in the Fall 2006 Enthusiast Magazine showing a 3% HP and 7% torque increase with slightly more restrictive mufflers and air cleaner kit. American Iron Magazine has also published similar articles about "no remap" upgrades involving exhaust/air cleaner changes.
How much information has to be presented to Harley Riders that remapping of the ECM is not required for exhaust/air cleaner upgrades for closed loop bikes? When it can be shown that much of the "gain" in power for bikes remapped with expensive tuning software and piggyback controllers would have occurred without spending $400-$1000, riders need to start thinking about what they are really trying to accomplish on their bikes rather than blindly following the "you must remap just to add exhaust/ac" advice that has been discredited.
The Dealer told me my engine will run too lean unless I get the Stage 1 download. Is this true?
What the Dealer told you is not quite accurate. The HD Stage 1 download will not richen closed loop ECM operation. EPA and CARB emissions regulations will not allow Harley or the Dealership to make the fuel mixture richer than it currently is right now.
What are the differences between the various IED's?
The primary difference is the effective AFR (fuel mixture)
Which IED is best for my bike?
You can use any IED on any bike, but here are the primary recommendations:
06 Dyna's Dyn OiED
Sportsters X14iED
XR1200 XiED
07/08 FLH XiED
09 FLH NO IED UPGRADE APPROVED
07>later Dyna XiED
07>later Softail XiED
I have a Vance and Hines Fuel Pak on my bike. Can I use an XIED? Do I need an XIED?
Fuel Pak and IED's have proven to be a very effective combination. Because Fuel Pak is primarily an open loop device and the XiED's a closed loop device, they actually compliment each other. Multiple fuel controllers always has the potential for problems because they can fight for control of the fuel mixture. We always recommend you try to work with your original fuel controller before adding an IED, but the Fuel Pak/XiED combination has proven to be one that is well behaved.
I have a PowerCommander on my bike. Can I use an XIED? Do I need an XIED?
Multiple fuel controllers always has the potential for problems because they can fight for control of the fuel mixture. We always recommend you try to work with your original fuel controller before adding an IED. Because the PCIII actually turns off closed loop mode, you have to take off the PCIII supplied O2 eliminators and install the IED's. This does negate the tuning map in the PCIII.
For this reason, with PCIII, we highly recommend working with your engine tuner to resolve engine performance issues by altering your current PCIII maps.
I have SERT, SEST or TTS for my bike. Can I use an XIED? Do I need an XIED?
Multiple fuel controllers always has the potential for problems because they can fight for control of the fuel mixture. Because these software tuning programs can alter the O2 Bias Tables, we do not recommend using IED's with them. Our first recommendation to riders with these programs is to alter your bias tables to values in the 700-750 range, which accomplish the same thing as the IED's.
For bikes that have SERT/SEST/TTS installed with a canned fuel map downloaded by the Dealer or aftermarket shop, some riders have used IED's to further reduce engine heat. But because you have no idea what map might have been loaded or how it might have been altered, the impact of the IED's can not be predicted.
For this reason, with SERT/SEST/TTS, we highly recommend working with your engine tuner to resolve engine performance issues by altering your current maps.
What causes decel popping?
For the record, decel backfiring is not a 'lean' issue. It has to do with fresh air mixing with unburnt fuel coming out of the engine under off throttle situations. As you noted, it started when you installed the new slip-on mufflers. Because these are a free flowing muffler, they allowed fresh air to get into the exhaust system and mix with the unburn fuel at the header pipe under off throttle situations resulting in the little "bangs" you hear. I'm sure the Dealer tried to convince you your bike is too lean, but the closed loop O2 system kept the AFR exactly the same with the new exhaust as the OEM. That is what closed loop does.
Installing the stock exhaust would eliminate the popping, but also eliminate some of the fun of having your HD. Usually the IED's do put enough extra fuel into the off throttle mixture to reduce the decel popping. But rider style (not quite letting off the throttle, even by 1-2%), a slight throttle mis-adjustment (too tight) or a mis-adjusted TPS sensor can cause the same result of increased decel popping.
