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He has a 2014 Fatbob and he states in the video that the "closed loop" system on the newer bikes allows the addition of the Intake and Exhaust without the need for retuning. And he also gains approx 10% hp which is impresive
My question is this right? Meaning would it not cause issues running an intake and exhaust without a tuner or fuel management? Watching the video i noticed his AFR is in the 15.5-15.6 range. Is this acceptable? From what i can remember (been a long time) but i think and most likely am wrong but isnt stoich AFR is 14.7:1.
doing some quick googleing i found the below chart
12.2 AFR - Safe Best Power at Wide Open Throttle
13.3 AFR - Lean Best Torque
14.6 AFR - Stoichiometric AFR (Stoich)
15.5 AFR - Lean Cruise
16.5 AFR - Usual Best Economy
This leads me to believe that 15.5-15.6:1 would be safe or "should"
The closed loop system can compensate a little while it is in the closed loop range ~ basically cruise power settings, but how about when you are outside of that are like accelerating and decelerating? Now with more airflow you will running leaner than stock loaded AFRs, not optimal in my books. If you noticed he was very smooth accelerating and decelerating on the dyno, my bet is if he chopped the throttle it would sound horrible - decel pop like crazy. Even HD has a Stage 1 AFR map they recommended after doing these mods, not that I recommend it, I had it on my initial Stage 1 and it was bad.
Anybody interested in Stage 1 mods and above should invest in a nice fuel tuner.
On my 14 Fat Bob, I am running V&H 3" slip-ons, a DK Customs 587 High Flow AC and Night Riders FL-Vied's for fuel management. I had my bike dynoed this past sat and the number were pretty good.74.5 HP 94 Ft/lb Torque and the AFR in the cruise range (2k -4.7k) rpm was on average 13.65. After anything past 4.7k the system is in open loop mode. I am happy with the results for the cost. Once the bike is out of warranty, I will have different cams installed.
While at the Laughlin Run last week I had visited the S&S trailer booth, got tapered slip-ons, Stealth a/c and the S&S/Vigilante tuner - which they highly recommend since I don't plan on doing any other engine mods. Bike runs amazing, no pops burbels or hick-ups. I find it hard to believe that a tuner isn't a necessity on these bikes but who knows, I haven't ran it without the tuner. I got a great deal on my parts and everything was installed right there for free, they are even shipping my stock parts back at no charge. I couldn't be happier with the results or the S&S customer service I received.
The closed loop system can compensate a little while it is in the closed loop range ~ basically cruise power settings, but how about when you are outside of that are like accelerating and decelerating?
The Stage 1 in the S&S video resulted in about a 10% airflow change, similar to what one can get with just temperature and altitude changes, which the stock engine control system handles fine.
Automatic adjustments in closed loop are used to automatically tweak open loop settings, so that's pretty much handled too.
Last edited by Warp Factor; Apr 29, 2015 at 07:54 PM.
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fuel management question
