Stage 1 and Fuel management question
Road Warrior
Joined: Aug 2015
Posts: 1,712
Likes: 410
From: Puyallup, WA
Open loop is a system that has an oxygen sensor in the intake; and it adjusts fuel accordingly to intake readings. Closed loop has oxygen sensors in the exhaust, checking for complete combustion; an emmisisons thing.
Your original post says, an SE A/C and new pipes. New pipes as in head pipes, or just slip on mufflers? My understanding is the newer bikes run decently with a bigger A/C and just slip-ons; system can adjust somewhat. If you have new head pipes then you will need different fuel management. Any Harley will benefit (run better, cooler, etc...) with a non-stock fuel management.
Your original post says, an SE A/C and new pipes. New pipes as in head pipes, or just slip on mufflers? My understanding is the newer bikes run decently with a bigger A/C and just slip-ons; system can adjust somewhat. If you have new head pipes then you will need different fuel management. Any Harley will benefit (run better, cooler, etc...) with a non-stock fuel management.
Stellar HDF Member
Joined: Apr 2012
Posts: 3,117
Likes: 1,193
From: Maryland
This is exactly what I was wondering about from start. Yes it is only AC and SE slip on do I really need to spend 500$ for these gizmos? Not sure what is close loop but I heard that there is some kind of learning with stock module. It will make me really happy to keep my $ in my pocket and put it out for tuner when I go to next stage but I heard concerns about leaning lean already AF ratio which might result in overheating which is not good thing
I haven't seen the tune files for the stock '14 big twins... But they likely run lean (and all that comes with that) to keep the EPA happy. They'll likely have it running closed loop control for as wide of a range in the operating band as they can get away with. Since it's closed loop control with narrow band O2 sensors, that means the AFR's are going to be in the 14's. On my '09 Nightster, with older tune strategy, that meant almost the entire AFR table (except the extremes - idle/decl, WOT, above 5000 rpm) set to 14.6. On newer strategies (believe starting on '14) they increased the range of AFR for close loop/narrow bands from 14.2 to 15.0. So the richest it's going to get in closed loop is 14.2.
If you are alright with all that, it's possible (I would guess probably likely) that closed loop control and adaptive learning will compensate for the changes (additional error injected into the VE tables) caused by your SE additions. However, decel pop might become audible with the SE slip-ons.
Anyway... that would be my guess... I'm not a pro and don't tune bikes for a living. Take it for what it's worth.
Last edited by T^2; Oct 20, 2017 at 11:57 AM.
Road Warrior
Joined: Aug 2015
Posts: 1,712
Likes: 410
From: Puyallup, WA
I don't know this for sure, but have heard from pretty reliable sources, that the stock air cleaner on newer bikes is very free flowing as compared to old stock A/C's; and adding an SE A/C won't make motor run much leaner if at all. You might be fine and richer by just leaving the stock air filter in place.
Stellar HDF Member
Joined: Apr 2012
Posts: 3,117
Likes: 1,193
From: Maryland
No. That's not the difference between the two.
Road Warrior
Joined: Aug 2015
Posts: 1,712
Likes: 410
From: Puyallup, WA
Maybe I should have said closed loop has sensors both in the intake and exhaust. Very simplified, but essentially correct I believe.
Grand HDF Member
Joined: Nov 2012
Posts: 3,515
Likes: 887
From: Upstate New York
Just get the PowerVision with a preloaded map for what you have. Flash it and then you`re all set until you go to stage 2.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Times Harley-Davidson Chucked Tradition Out the Window
Verdad Gallardo
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
Road Master
Joined: Nov 2014
Posts: 1,072
Likes: 212
From: Alabama
The Thundermax is expensive but isn't married to the bike. There's a lot of crossover in the various models as well. It's expensive because it completely replaces the ECU. So, you save the cost of a Dyno and you can box the ECU. A replacement ECU ain't cheap so you do end up with a spare.
If I had it to do over again, I'd just bite the bullet.
If I had it to do over again, I'd just bite the bullet.