Decel popping on 2012 Fatboy with Rush Slip ons
fatboy lo
#52
11-08-2013 | 12:11 PM
Road Master
Joined: Jun 2012
Posts: 1,119
Likes: 7
From: USA
What isn't clearly stated is that once HD started including O2 sensors, some autotune (WITHIN EPA SPEC) will occur in a stock configuration.
The 'disinformation' is partly due to the differences between models and configurations, not necessarily due to lack of knowledge.
Some exhaust systems work better when the AFR, sometimes coupled with changes in timing are delivering results (emissions) outside of EPA regulations. They will require remapping to get them to perform to their maximum potential in many cases.
Popping on decel is due to a lean condition (you can't even get everyone to agree on this fact). Emissions have to be increased beyond EPA regs (which any HD dealer following the law will not do) and so tuning and/or an ECM replacement by non-dealer parties is required.
The 'disinformation' is partly due to the differences between models and configurations, not necessarily due to lack of knowledge.
Some exhaust systems work better when the AFR, sometimes coupled with changes in timing are delivering results (emissions) outside of EPA regulations. They will require remapping to get them to perform to their maximum potential in many cases.
Popping on decel is due to a lean condition (you can't even get everyone to agree on this fact). Emissions have to be increased beyond EPA regs (which any HD dealer following the law will not do) and so tuning and/or an ECM replacement by non-dealer parties is required.
#53
11-09-2013 | 07:30 AM
Stellar HDF Member
Joined: Mar 2006
Posts: 2,395
Likes: 152
From: Utah
Actually real decel pooping isn't necessarily a symptom of an overly lean condition. What causes decel popping is unburned fuel exiting past the exhaust valves. This unburned fuel ignites in the pipes due to the additional O2 that is sucked into the pipes on decel. The combination of unburned fuel, addition O2, and heat in the pipes causes the decel popping.
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#54
11-09-2013 | 08:39 AM
#55
11-09-2013 | 09:23 AM
Supporter
Joined: Jun 2012
Posts: 2,912
Likes: 72
From: Pittsburgh, PA
I have the same pipes, and my decel pop vanished after adding ViED's...
#56
11-09-2013 | 01:46 PM
Decel pop is normal for a bike with open exhaust and open A/C.
Decel popping does Not damage your engine...it is simply unburnt fuel that is burning in the exhaust tract after exiting the engine.
Decel popping occurs when one of two things are present.
1. The bike is so lean the exhaust is superheated and is burning the unburnt fuel that is in the pipes (there is always some unburnt fuel in the pipes no matter how lean). This is very rare.
2. The AFR IN THE pipes is just right to burn the unburnt fuel. This is quite a common occurrence when free flowing pipes are installed (whether or not a free flow A/C is installed). It can also occur if there is an exhaust leak that is introducing extra air into the exhaust tract.
Check for leaks...if there are none, then move on.
One way to change the AFR IN THE Pipes is to install Thunder Torque Inserts.
We have had hundreds use the TTI's to reduce/eliminate it. Extra benefit is a nice bump in low and mid range power.
Another way to change the AFR is to use an XiED product. More details HERE
Extra benefit is smoother acceleration and a cooler running engine.
Decel popping does Not damage your engine...it is simply unburnt fuel that is burning in the exhaust tract after exiting the engine.
Decel popping occurs when one of two things are present.
1. The bike is so lean the exhaust is superheated and is burning the unburnt fuel that is in the pipes (there is always some unburnt fuel in the pipes no matter how lean). This is very rare.
2. The AFR IN THE pipes is just right to burn the unburnt fuel. This is quite a common occurrence when free flowing pipes are installed (whether or not a free flow A/C is installed). It can also occur if there is an exhaust leak that is introducing extra air into the exhaust tract.
Check for leaks...if there are none, then move on.
One way to change the AFR IN THE Pipes is to install Thunder Torque Inserts.
We have had hundreds use the TTI's to reduce/eliminate it. Extra benefit is a nice bump in low and mid range power.
Another way to change the AFR is to use an XiED product. More details HERE
Extra benefit is smoother acceleration and a cooler running engine.
#57
12-01-2013 | 02:59 PM
Hi guys, I have a similar issue. I have the Rush short style on my 13 FXDWG. Popping and rumble on decel as well. I'd say I got rid of about 90% of it this weekend, when I added The Power Vision (from Fuel Moto) they put a map on for my pipes. That and a couple auto tune runs and it's pretty clear. I would like to get about 100% of random pops gone, if possible.
MY QUESTION is, how will richening/adding fuel to decel help eliminate it? If the pop/backfires are due to being too lean, then how will more fuel help? Is it a flooding more fuel in the AFR simply making it more fuel than air and thus "smothering" the reaction?
MY QUESTION is, how will richening/adding fuel to decel help eliminate it? If the pop/backfires are due to being too lean, then how will more fuel help? Is it a flooding more fuel in the AFR simply making it more fuel than air and thus "smothering" the reaction?
#58
12-01-2013 | 04:36 PM
Supporter
Joined: Jun 2012
Posts: 2,912
Likes: 72
From: Pittsburgh, PA
http://sales.nightrider.com/fl-vied-10.html
You're not making it "more fuel than air".
The ratio of fuel to air is quite high.
The stock AFR is around 14.6:1 (that's 14.6 parts air to 1 part fuel) - the XiED's (or ViED's) can drop that to around 13.9:1.
And just to not be confusing, you're not lessening the amount of air, you're increasing the amount of fuel)
By adding more fuel, the bike will run cooler, and it follows that so will the pipes...
Last edited by jam436; 12-01-2013 at 04:40 PM.
#59
12-01-2013 | 04:45 PM
Road Master
Joined: May 2009
Posts: 983
Likes: 4
From: Fredericksburg, Va
Phochief...IMHO decel pop sucks and stay away from the FuelPak as its does nothing (dyno proven locally). Getting rid of decel pop is a task that your local dyno shop can handle and ask them which module they are more comfortable with and buy that one. If no dyno shop is around, call fuelmoto who is also a site sponsor and they will set you straight
#60
12-01-2013 | 05:00 PM
Outstanding HDF Member
Joined: Aug 2012
Posts: 3,217
Likes: 88
From: Detroit
Pretty much. By adding fuel, you're taking the fuel/air ratio (in the pipes) out of the "correct" range where it is most easily ignited, so it passes on through without burning. You can do the same thing by going way too lean, or shutting off the injectors completely on decel, but there's some cooling benefit from vaporizing more fuel. Any time you vaporize a liquid, there is a cooling effect as the liquid changes state to a vapor (latent heat of vaporization).
Last edited by Warp Factor; 12-01-2013 at 05:05 PM.