Hey guys help me out,I removed the 2-1 stock header off my 2010 Streetglide and replaced it with a 2010 2-1-2 stock header and removed the cat.I also added the max performance 2 slip ons from B&E and it ran cooler,better,but still a little sluggish.I had also purchased a SEAC that I planned install later after I ordered a PC-V and Jackpot muffs.Well I installed the SE A/C just to see if there was a differance in performance and the bike ran way smoother,with better acceleration.I didnt notice any pinging or knocking,I ran the bike for 160 miles. My question is why would it run better with the SEAC? Does removing the cat increase flow by the O2 sensors and enrich the AFR? Does ambient temp ( 75 degrees here in Texas) have effect on the O2 sensors?

 

your 02 sensors will compensate for most exhaust changes and air cleaner changes to a point. the reason your bike runs better with the screamin eagle air cleaner is because if you look at the backing plate of the stock air cleaner, there's about the same size opening as a snickers bar on its side. not the wide side but the thin side of the candy bar. that's all the surface area that's open for breathing on the intake side of your motor. with the screamin eagle backplate and using your stock football or aftermarket cover, there is a lot more surface area of the filter exposed which improves breathing.

 

when your operating in the closed loop portion of the stock fuel map the computer should be able to compensate for the changes. Most will tell you that you have to have some kind of programer and I can't dispute that but in the automotive perfromance world you can get away with a lot before you have to do any reflashing of the stock computer. Would love to see a dyno with the AFR on your bike the way it is now. good luck getting it figured out I'm sure u will get plenty of feed back here.
Me Im waiting for the SupperChips programer that comes out latter this year.

 

If it does compensate for these changes,will it adjust back to its set AFR? I'm probably running lean but how lean is too lean,didnt feel much heat differance with or without SEAC.

 

if your bike isn't popping on deceleration, then yes, your ecm did use the information provided by your 02 sensors properly and adjusted it back to the correct settings. there's a lot of hype about if you use slip on mufflers and a screamin eagle air cleaner that you need to use a power commander or some other fuel/ignition product. i don't buy into that hype. if you don't have between 4 and 5 thousand miles on your bike, then it will tend to run hotter than after you get to that mile range. they loosen up at about that mileage and seem to get better fuel mileage, run smoother, cooler, and with more power. the rings seat pretty quick, but at the aforementioned mileage they seem to just work better altogether. i remember back when the twin cam motors came out and everyone was complaining about how hot they ran. that's a misconception and the reason is that the twin cam motor is so much more efficient at radiating heat from the cylinders and heads that it appears to the non informed that they're running extremely hot. they aren't, the twin cams are just so much more efficient at radiating heat than the evo that preceeded it, is all. to answer your question, your afr should be just fine.

 

No popping on decel but I did notice that my fuel mileage did decrease i bit after removing the cat( from 40 to 34 mpg),not sure if its because lack of back pressure from cat or better throttle response.But after I installed the SEAC I thought I saw a bit of increased in mileage,I'll be doing some riding tomorrow to see.