I have a 2007 Ultra with Screamin Eagle slip-ons. It has the O2 sensor on the exhaust.

1. Can I increase my air intake without having to retune? Someone told me that because I have the O2 sensor, the engine should automatically tune to the higher air intake.

2. I thought I would need a different air cleaner for more intake, but someone told me that I could just change the filter to a K&N filter and get more intake. Is that true?

I would love to get a PC or fuelpak but right now I don't want to spend that much.

 

Remember a engine is a process. More air in needs more fuel, all other things being the same(AFR for one). Thats a fact.

Now--The engine management, which by the way is basicily the same on almost every auto made also, can adjust intelf in a small range, up or down. The O2 sensors can take into consideration about 5% up or down. Give or take a little.
The system keeps on trying to see 14.6 AFR but only in "closed loop". Closed Loop is basicly crusing areas of the program.

The late models, 07 and up, cover a lot of the map with Closed Loop but some areas, particullar wide open, is not covered. A calulated AFR is used, but the ECM doesn't know--- things have changed.

If you increase the air flow of the engine ---just a little---, OK in crusing, but you will be lean in preformance areas.

A few seconds won"t hurt. Always run the higest Octane you can and I like Name brands.

If you "ping" maybe get a range or two colder spark plugs. People used to do this all the time. Don't hear about colder plugs much today, but this works perfectly well.

 

Modern engines all run with very lean air/fuel mixtures, to meet emission laws. Happens the world over and affects all vehicles. Mess even a little with that fine balance and you risk causing serious damage.

It is possible you have already used up your free lunch with the SE slip-ons! I wouldn't trust a further change at all. Leave it as it is until you can afford to modify it properly. The times when we could mess about with motors and get away with it are behind us, but the improvements we can gain using modern tuning cleverly are considerable. Be patient!

 

Well a tuner like TTS Mastertuner or even SERT or SEST or even some others and a computer are really the tiny screwdrivers and wrenches we used to use, and of course many do today.

I tell you how I look at things.

My Granddad was born before auto or airplanes or electricity.
My Dad put the first wires in their house. Learned from Boys Life the Boyscout Magazine. Wern't a lot of electricians running around in 1922. Small southern town.
Did all kinds of things mostly brand new just invented.
Had a hot rod model T with Ricardo Bronze High Compression Heads. Used to haul Sugar and Copper tubing down some bad roads to some bad dudes, at 14 years old. Sherrif didn't keep an eye on kids then.
Had a flat head HD then a Kuncklehead. Got married had kids away went the Harley.

I figure if my Dad and Granddad could make things work that was not even invented hardly when they were coming up---

I can tune on a late model Harley. All the same.

 

Thanks, I decided to get a Screaming Eagle stage 1 kit and have the H-D dealer install it and recalibrate the ECM. I pick it up in the morning - hope it was worth it!