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How capable is the ecm?

2K views 12 replies 11 participants last post by  yzernie 
#1 ·
Just picked up a de-catted head pipe and freedom performance american outlaw megaphones. My question is can the ecm handle the exhaust change or should I just put the mufflers on and wait till I get a tuner to install the head pipe? I'm leaving for Sturgis on the 4th and it's going to be 3,000 mile + trip.
 
#4 ·
I agree. Don't make any major changes like a complete new exhaust before a long trip like that without a tuner. As you know, you're probably going to be sitting in stop & go traffic in Sturgis and elsewhere, and that's really not a good place to test new components, without having a tuner. Trust me, you don't want to be that guy whose bike breaks down on main street Sturgis in the middle of the traffic.

Lil Chief
 
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#5 ·
If it were me, I would've waiting until you go to Sturgis.....only because it's the LARGEST bike rally in the country. Ton's of vendors are going to be there with their products, you probably could've gotten an insane deal on a full exhaust with free install while you are out there and most places will even ship your old exhaust back to your house for free! It's just like that in Daytona for Bike Week, so I'd leave everything alone and just throw the mufflers on for the trip, wait till you get a tuner before you change out everything.
 
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#6 ·
Everything said here is 100% correct.

Harley's are tuned to run lean from the factory. Making this change will cause the bike to run more lean. This causes additional heat to the motor and you will be riding long distances in heat and sitting in traffic. Leave it stock for this trip.

Best bet is to do as previous poster said and have it done in Sturgis as there will be a lot of vendors there and you should be able to get a good deal.
 
#8 ·
Yep Sturgis, great place to have your bike tuned . bubba takes your cash and you never see him again. But you will save money at first. good luck with that one.
The system you are installing is going to flow very free. That is not a good thing for performance but it may sound bad ass.
ECM can handle reasonable exhaust changes and losing the cat. But going to extremes pushes the limits of what HD can allow it to do.
 
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#13 ·
Yep Sturgis, great place to have your bike tuned . bubba takes your cash and you never see him again. But you will save money at first. good luck with that one.
Some of the biggest names in the industry go to events like Sturgis. I don't think anyone would go to Bubba for a tune when there are highly respected vendors at Sturgis.
 
#10 ·
I've spent the last two decades working in IT, designing, building, and maintaining (mission critical) business networks. And the one - only foolishly breakable - transcendent law-of-Murphy is that there is easily an 85% chance of getting 50/50 odds wrong. So... regardless of what is supposed to be possible, always (always...) err on the side of caution.
Computers can always be trusted to do exactly what they are told - Therein lying the problem ... Because, what they were told to do isn't exactly always what you meant to want them to do.


So anytime what something should do and what that something will do conflict ... Refer to the Murphy's law statement above.:wink:
 
#11 ·
Everything I've read from most of the builders and tuners, as well as from HD says that the stock ECM can certainly handle almost any change you make on the exhaust side with out the need for a tuner. it's only when you change the airflow on the intake side that things get dicey. Think about it, if you have the same intake you are going to be restricted to the amount of air that makes it to the cylinder to get mixed with the fuel (A/F ratio) regardless of how much you open the exhaust. The stock ecu is designed to operate in all possible altitudes and deliver the pre-programmed A/F ratio to the cylinders to be burned. That said though, regardless of whether the ECM can handle the changes, Mr.Murphy just make an appearance due to the change over of parts especially on a 3k plus trip. If it were me, I'd wait until I got back to do my own changes, but would probably drop the coin for a new intake, exhaust, and tuner in sturgis. I'd just do it either at Black Hills HD's vendor show by a reputable shop that offers warranty and support after the show or at a factory rep site with the same support. IN WRITING!!!!
 
#12 ·
Don't worry about it!
The ECM will make all the adjustment necessary to make the bike run right.
Just as long as you don't make any modifications to the intake and just stick with the exhaust modification the bike will be OK, you don't need a tuner until you do more performance mods.
 
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