Hello everyone,

After days of reading it seems there there are as many opinions about efi tuning as there are options. It's a bit overwhelming.

Just in case anyone is interested i found the following conversation and thought i would post it. The gentleman answering is a 30+ year harley tech and i found his explanation intersesting. Any opinions or comments are welcome.


Customer Question

I have a 2011 FLHTK with the HD stage 1 setup from the dealer - including: V/H mufflers, Screaming Eagle Stage 1 aircleander, and a HD stage 1 download. I am planning on changing out my stock headpipes with an aftermarket cat-less headpipe from Fullsac Performance.*If I change out the stock headpipes, will I need to re-tune the bike or will the HD stage 1 download still work ok?I have read and heard a lot of different information regarding this topic, and value your input.*

Welcome. Thank you for choosing Just Answer.*your 2011 utilizes wide band O2 sensors.they will work with your ECM to automatically adjust your air/fuel ratio after changing the head pipes.*I would not advise making this modification if you live in California. if you do, save the OE pipe for re-installation, should you need to for emissions testing. it's only a matter of time.*let me know if you need more help.Steve

Steve, thanks for your response.I'm familiar with the O2 sensers, and what they do. The ECM automatically adjusts the air/fuel based on the parameters defined in the HD stage 1 MAP downloaded by the dealer.My question is whether the parameters in the HD stage 1 download will still work with the new headpipe, or would I be better off with a custom tune or custom MAP downloaded using TTS Mastertune?

Steve: from what you have posted I am not sure you fully understand the system operation.*the fuel and ignition maps in the ECM are defined by the stage 1 download and are dependent upon head temperature, inlet air temperature, altitude, manifold vacuum and throttle position. these maps are continually revised by the feedback from the O2 sensors to optimize the air/fuel ratio.*this was an issue with the*older open loop systems*because they had no O2 feedback to correct for modifications.once the system is operated closed loop with feedback, the need to re-map after all but extreme modifications was eliminated.*the "mastertune" is redundant and unnecessary for your bike with the changes you propose to make.let me know if you need more help.SteveC.

You're right about me not completely understanding the system. That's why I am asking these questions. I (incorrectly?) thought the HD stage download changed the values in the stock ECM / re-mapped the ECM, and the feedback from the O2 sensors allowed adjustment within the parameters of the stage 1 MAP; didn't know the maps are continually revised based off the O2 feedback.*You stated that once the system is operated closed loop with feedback, the need to re-map after all but extreme modifications was eliminated.If this is the case, why has every HD service center that I've talked to said that the ECM needs to be remapped whenever a stock bike is modified with higher flowing mufflers and air-cleaner so that it doesn't run lean? I don't think mufflers and air-cleaner modifications are extreme. Sounds like the HD download that I paid for may have never been necessary?*I am going to install the 'cat-less' head pipes, which will definitely open the exhaust up even further. I want to avoid running too lean / hot, and hurting my motor. I simply need solid confirmation that the stage 1 download will either work or not work with the new headpipe. The information provided will help me determine if I need to spend the $5 - 8 hundred for a tuner, fuel management system, or custom dyno tune.

Steve: the stage 1 download is a good option. it changes some mapping parameters but also raises the rev limiter to 6200. this is recommended after initial break-in, even if you choose not to modify anything.*dealers make money off of re-mapping and dyno tuning bikes. the salesman that sells you these things gets a commission. they were not always necessary since 1996 and hardly ever necessary since 2010.*make your pipe change and ride the bike. the sure signs of a lean air/fuel ratio are a much higher oil temperature and a persistent "cough" from the intake.if you experience neither, you are good to go.*after any modification, it is always a good idea to check your air/fuel ratios on a dyno with an exhaust gas analyzer (EGA). this not only verifies your A/F ratios are correct but also ensures all system controls are operating normally.it's fairly cheap assurance, all things considered.*realistically, I would be surprised if you experienced any issues.

Steve
Experience:*30+YRs,MMI,HD tech,HD early,engine rebuild/perf,bike builder,kit bike program manager, cci 2001-2004

 

Interesting first post, I & a lot of others don't agree with Steve the"EXPERT". The O2 sensors on our bikes are narrow band & actually provide feedback in very limited running conditions, they keep the EPA happy, but still let the bike run extremely lean in most conditions. He also recommends running on a dyno to check AF ratios, yet if all you have is a download you can't do anything about it anyway, basically a waste of $$. Get some kind of tuner or at least some way to richen the AF ratio & preferably a dyno tune by someone who knows what he's doing.

 

Thanks for posting the tech response, it confirms what I thought all along......by the way, welcome to the forum from Arizona.

 

I have to agree. The "expert" is the first and only person I've EVER heard describe the O2 sensors on a late model Harley as wide band. I've pretty sure they are narrow band.

 

30+ years experience? Doing what? Certainly not working as a HD tech. He's a phony from the word go.

 

 

It amazes me how much discussion there is on this subject with absolutely no clarity. I have been reading a lot to decide what to do on mine and I still don't know.

 

I stopped reading as soon as that tool said wide band O2 sensors were stock.

 

http://www.justanswer.com/car/expert-motorcycle-steve/
this link gets you more of his nswers. He does not seem to be aware of or support DIY tuners. the post the OP included was from 782 days ago. It is but another opinion based on that persons experience.

any topic on these forums will have opinions from both ends, you have to learn to read between the lines to get the correct answers.

 

Thanks for the responses guys. I just thought I would throw it out there. Again, there are a lot of opinions on the subject. I have a 2012 103 and the most I am going to do is the AC and free flowing exhaust with no cat. I'm on a limited budget and am trying to find an economical way to accomplish my goals. My parts list includes SE Ventilator AC, Jackpot head pipe, Rinehart 3.5 slip ons (because they are already on the bike) and ViED's.
I still can't find a solid answer on if I need to do a HD stage 1 download with the ViED's or if I can get away with just the ViED's.

Thanks again for the input!