EFI tuner question...
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Banned
Joined: Nov 2009
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From: Joliet, IL
EFI tuner question...
ok so I have read that if i change my exhaust & a/c i should get a EFI tuner... but how many of you are running a full exhaust and a/c with no tuner? I have V&H short shots with the stock a/c but want to change the a/c to something smaller. I'm not trying to squeeze every bit of hp out of my harley, just wondering if it can be done without going so lean i do engine damage...
BTW PLEASE DON'T REPLY IF YOU AREN'T ACTUALLY RUNNING THIS SET UP!!!
i don't want read about what people have heard, just people that have tried running an after market exhaust and a/c without a tuner because i know there are a few that have tried it...
BTW PLEASE DON'T REPLY IF YOU AREN'T ACTUALLY RUNNING THIS SET UP!!!
i don't want read about what people have heard, just people that have tried running an after market exhaust and a/c without a tuner because i know there are a few that have tried it...
Elite HDF Member
Joined: Sep 2008
Posts: 4,440
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From: Northwest
( BTW I used to run V&H StraightShots, Stg.1 a/c, and MoCo stg.1 download.... pretty damn close to the setup your talking about).
If your pissed 'cause I responded, and I was not/am not, running that exact setup.... I'll delete my text...
Thread Starter
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Banned
Joined: Nov 2009
Posts: 908
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From: Joliet, IL
nuggets of info from people telling me not to do it even though they never tried it? yes i'd like to totaly skip that advice...
Road Captain
Joined: Jun 2008
Posts: 735
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From: Lagoa - VNF
yeah, got my FXDC exactly like that (short shots and OEM AC). bike ran rough and hot as hell, but I bet it was the same with the stock pipes either. OEM calibrations suck, IMO the SEST is a must have even if your bike is bone stock. night and day difference.
Road Warrior
Joined: Jun 2009
Posts: 1,333
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From: Jefferson, Oregon
Did it, yup...it'll run. Hot. Can you do it? Yup. Should you? I wouldn't. If you are trying to save some cash, do the XIED's or whatever they voltage foolers are called to get some fuel and cool that engine down. Cheap and you might even get someone with some sitting on a shelf to sell you a set for even less than the $100 or so they are new.
.02
.02
Elite HDF Member
Joined: Sep 2008
Posts: 4,440
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From: Northwest
The ECM will attempt to maintain the programmed AFR, based on it's current VE mapping. If you change intake and exhaust, you have modified the engine's volumetric efficiency.
I won't tell you one way or the other, what you should do. I will give you a 'nugget'.
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Tourer
Joined: Dec 2010
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From: Where Uncle Sam tells me to live!
+1 on that! once it is re-tuned it will run cooler and SOOOO much smoother. not to mention you have stock pistons (casted pistons) increasing the heat increases your chances of burning a hole through one. and thats bad juju, dude. you bike should be fine the way it is because i hear about guys running a setup just like that all the time with NO problems. personally, i never did it because im rough on my bike enough as it is. keep in mind my goal here isnt to say what you should do either way... just trying to pass good info.
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Road Captain
Joined: Oct 2010
Posts: 683
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From: Florida
ok so I have read that if i change my exhaust & a/c i should get a EFI tuner... but how many of you are running a full exhaust and a/c with no tuner? I have V&H short shots with the stock a/c but want to change the a/c to something smaller. I'm not trying to squeeze every bit of hp out of my harley, just wondering if it can be done without going so lean i do engine damage...
Anyhow I am running V&H Big Shots and the SE A/C (which came with my bike). I presently do not have an actual tuner, but according the records in the saddlebags when I bought the bike used it does have the old 2007 SE dealer map download which is not as advanced at controlling the mix as todays tuners, but it is a compensator for the pipes. However I "do" want to get a Tuner (TTS MasterTune) but just don't have the funds yet.
My bike does run hot. All Harleys run a hotter due to Emission requirements of a "functional" lean mixture, which won't damage your engine, short term unless you do parades, very long traffic lights or traffic jams without turning your engine off. However the functional hot is not the "add pipes hot" you are referring to.
BUT changing from stock pipes to the free flow V&H will cause your engine to run "more" lean and hot "IF" you don't do something to compensate for it, that is a definite yes on that. That is proven physics. Years ago when I was in High School everything had carbuerators (no ECM's or EFI) and when we put straight pipes on our bikes we would unscrew the brass jets from out of the float bowl and drill them out very slightly with a drill press, reinstall them and check the color of our plugs until we got them drilled out enough to make the lean (whitish grayed ash color) go away.
If you don't do something to correct "over leaness" (not meaning the Factory lean mix which is the limit of the envelope) then over time it will burn your valves. You can verify that with any mechanic auto or bike.
Your larger A/C helps but the ECM that controls the EFI mix is complex and it needs new data to go along wth flow changes.
Hope this info helps you.
Last edited by R_W_B; Dec 26, 2010 at 08:23 PM.
Elite HDF Member
Joined: Sep 2008
Posts: 4,440
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From: Northwest
Just to add a real-world experience... when I installed the intake that I built on the bike, (up from a Stg.1)... I went out and put a couple hundred miles on it. When I fueled up and checked the mileage, I was getting 56mpg.... pretty nice... but I knew I was burning way lean. Pulled the plugs when I got home and sure enough they were pretty white. Went ahead and retuned with my TTS... all is good now.