Just purchased a set of V&H round double slash cut slip on mufflers. I've read several post on Fuel Pack versus other mapping-tuning devices. My question is it necessary to map if all I'm doing is adding slip ons, or adding the slip ons is going to cause me to also chnge the air filter and then remap?

 

In my own opinion... yes you need to 'map' the bike. Changing any part of the exhaust will allow more air to pull thru the engine.. The Stock AC will readily allow more air to be pulled thru, too. The Stock AC has quite a bit of reserve in it.

We have found that the exhaust is the 'choke' point on our bikes when stock. ANy little improvement of the exhaust will readily allow more air to be pulled thru, Stock AC or not.

More air, without new 'mapping' to gain more fuel along with it, will make a bike that is already quite lean, to be even more lean. Lean meaning for every pound of air, there will be a corresponding amount of fuel. And... that amount of fuel is really not enough for a good running engine.

For example and teaching... lets say our bikes run at 14.6 AFR at a certain engine speed. Now with the exhaust changed to allow more air, the amount of air changes that AFR ratio and we have 16.0 AFR after the pipe change.

Being lean, in and of itself is not a bad thing overall. Like the 16.1 in our example, But... we all ride bikes that are aircooled with aluminum and steel pieces. Race cars, our personal cages, even most bikes have water cooling systems that allow for the removal of built up heat..... actually limit the production of excessive heat to begin with.

Our bikes do NOT have this, so excessive heat is not really good for our engines. We should all really try to at a minimum keep that 14.6 AFR and ideally up that a teenie bit to say 14.4 AFR. That example of 14.4 will not get rid of heat. More fuel doesn't really cool much off. Instead what it does is slow down the production of heat to begin with.

It used to be thought, until quite recently, that an owner could EITHER do a bigger AC or a free flowing exhaust and as long as one did not do the other part of the stage1... everything would be ok.

That thinking has been proven false by too many tests. Even the exhaust manufacturers are starting to come around and say a 2013 bike will need tuning but the same pipe on an 11 bike will not. HAHAH!!! THAT is just so all the guys that got sucked in by the pipe builders wouldn't scream bloody murder!!! And sue or some such.

Hope that helps you a bit, Sir! Yes, you should investigate the various methods to make the bike slightly richer to compensate for the extra air the pipes will allow the engine to use.

And... every bike owner has to confront this issue one way or another. We ALL wish to ditch those crap sounding pipes for sure! So... we come to the TRUE HIDDEN HARLEY TAX.... I usually say that tax is the cost of a tuner and a dyno tune. But in reality it IS the cost of whatever it is you do to compensate for the extra air being used.

Some will do a Stage 1 or a Stgae 2, and buy a full blown tuner and have the bike Dyno Tuner by a competent tuner. This is the top flight way to go. Could be the most expensive too. All the way down to spending a few bucks and buying some XIEDs for their bike and use those. And... there surely is a TON of choices in between those two examples I have given.

Good Luck and have a fun and safe summer my friend!

 

I appreciate the info. With your spot on knowledge, I will pick your brain on any first hand knowledge/experience with a Power Commander v?

 

Not that I can add anything to "wurk truk" post, mapping won't hurt but can only help it, to me. But so any here are split on whether or not slip ons needing any addition work on the engine.

Again, GREAT post truk!

 

One problem with mapping is the quality of the map. I had Stage 1 air and 4" Rinehart true duals put on a 2013 Street Glide along with the SEPRT and all that was installed was the "generic" map on the tuner for that type setup. From what I gather from reading, all pipes and or full exhaust along with air changes are NOT created equal and thus the should not be mapped or tuned as an equal either. So when doing these type of changes you should definitely get a true Dyno tune so throttle and RPM positions can be dialed in to the fullest.

 

I'm only on page 55 of the "SEPro/SEStreet Tuner Information Thread" but I would say smart tune it.