EFI and AFR Checked by a Gas Analyzer

[Coasty]

Sporty EFI Pipe and AC



Well, conventional wisdom on some but not all and it is thinning out.  Many think you do not need to modify the fuel management when either changing the AC or pipes. Well this is a big bull stinky I have been installing Nightrider IED flavors and fuel management systems on many of the 07 and newer EFI sportys.  About 95% of the people have had issues when changing out the pipes or ac.  The bikes run bad and just about all ended up with a lean ping worse than stock.  Changing both the AC and pipes (typical stage I) does require an IED flavor or fuel management.  In addition to changing cams will require a complete engine management system so the timing can also be tweaked. EFI bikes prior to 07 (non sportys) seem to be more tolerable to an AC or pipe change with any other modifications.

From what I have been able to determine all bikes 07 and later have had to meet newer EPA clean air standards with an AFR 14.7:1.  The bikes are tuned very tight and there is no slop so to speak as there was in the pre 07 EFI bikes.  I have recently purchased a exhaust gas analyzer.  It has been very helpful for clues and patterns of exhaust readings to figure out if we have a problem in the ARF and combustion itself.  The dealer reflash to compensate for a Stage I is bull "Potty mouth".  They can only slightly adjust the AFR and what they do not tell you they cannot violate the EPA AFR and set-up.  You still will end up with a lean ping especially when the bike gets hot and you piss away yout $$.

Good combustion is simply put this way: HC + O2 + N2 = H2O + CO2 + N2. HC,
Hydrocarbons
CO, Carbon Monoxide
CO2, Carbon Dioxide
O2, Oxygen
NOx, Oxides of Nitrogen

I leave out the numbers which show proportions ideal mixture of 14.7 AFR if you really want to get down in the weeds go to the GAO link
http://tinyurl.com/cl6sdh

From the use of a 4 gas analyzer my 07 EFI bike with the XIEDs installed has an AFR of 13.9:1 warm throughout the entire throttle range and cold at start-up the AFR is 12.4:1.

Generally the AFR of 13.5:1 provides the best for power, and AFR of 14.7:1 for economy, and AFR of 12.8:1 removal of all pinging which produces the worst gas mileage.

A fuel management system can be tweaked to different AFR at a wider range of RPM.  That said the AFR still ranged from 13.5:1 to AFR 0f 14.0:1 during normal operating temperatures depending how you want to set it up.  The differences are minimal and for general riding a stage 1 mod the IED flavors do their job without a hurt in the wallet.

I was able to check my 03 carbureted sporty and found at higher RPMs the AFR was 14.2:1.  I changed the high speed jet from the 170 to a 175 then to 180 and it dropped the AFR to 13.9:1.  I am running a #44 slow speed jet with an AFR of 13.8:1.

Ok is the cost of an exhaust gas analyzer worth it? I would have spent that on fuel management systems on two bikes anyway.  Plus now there is no guess work on what the bikes are actually doing when it comes to combustion.  I have used combustion analyzers for many years tuning boilers and gas turbine engines.  It just makes sense to use them to tune your bike.

Coasty

[Don D]

What unit do you use? Is this mobile or for dyno use?

[Coasty]

What unit do you use? Is this mobile or for dyno use?

It is a GS1000a purchased a factory refurbashied unit for $1500 new around $3000.  It is portable and has an internal printer that uses heat sensitive printing rolled paper.  It has the software to be used with my laptop but I have never used for long data recording.