To put it in simple terms, think of your engine as noting but a big 'air pump'....

Air is pumped in, mixed with fuel, ignited, and then the exhaust exits through the pipes.

From the factory the 'computer' tables on EFI bikes are set assuming that a fixed amount of air will be entering the engine, and a fixed amount of fuel is added to that air to provide a 'semi accurate' air/fuel mixture.

When you add a 'high flowing' air intake system more air is pumped into the engine, and when mixed with the fixed amount of fuel the mixture will be too lean. This fixed amount of fuel is determined by either the jets in a carb or the current 'fuel map' in the computer of EFI systems.

That is why it is more critical to verify that you have the correct air/fuel mixture after adding a high flowing intake. It will probably be too lean, meaning you will need to rejet the carb or 'remap' the computer on EFI bikes.

Not as critical on the exhaust side as pipes aren't actually impacting the air/fuel mixture being pumped into the engine.

 

No, it's a little more to it than that. The VCI is the "box" it doesn't stay attached to the bike. To make a recording you have to hook it up to a computer or laptop, and the bike, via the small connector below the maxifuse under the battery cover, and set it up to record, then disconnect from the computer. Then you can press the button and make a recording, but you have to press it again to stop it before you turn off the bike or lose the recording. I put the box in my jacket pocket and ride around that way. After you've acquired a bunch of recordings based on the tune you loaded in the bike, (if you selected it as a "smart tune" load) you can use all of these recordings and the smart tune function will compile them and make the necessary changes to your map. Save it, reload it, and tuning is done, no box stays on the bike. That's why I eventually went for it, nothing under there to fail, or fight for space. You can use it to record while running hard, regular riding, the manual has detailed instructions on how to make recordings for the best recordings. I saw a significant change to the map I loaded that came with it. One thing, you lose the stock map. My only gripe with the setup.

But...the VCI does store a copy of the map you load to the ECM on it, so if you are ever on the road and need it, like at a shop, you've got it if you have it on you.

 

So, if I was to restrict the air flow in some way, I would be fine until which time I could install a PC5? I could cover the filter with something that restricts airflow but for an opening the same size as what is on the stock air cover.

 

I'd just run the stock airfilter/intake setup until you can manage the AFR.

 

Already got the AC and all other take-off parts listed on ebay. Not a big deal though, can't ride much here in Wyoming this time of year anyway. I will get the PC5 and tune it, then take it to the stealer and have them fine tune it. I already emailed Power Commander and asked them what the best map is for my set up. So, I can buy the PC in a few weeks and install it, and go from there.

 

I looked on the PC site and they don't have a part number listed for a unit for my bike. Only 2008 Dynas. Would this be the one I need?

 

Come on now OFG, you know better than that. Removing a restrictive exhaust for a free flowing one, affects the overall rate of air moving thru the engine. The faster it can exit the more it can take in.

 

now I am confused. I searched a little harder on the PC site and they list a 15-013 for my bike as "under developement". I checked ebay and there is one for 289.00. Is this BS or is the PC site behind?

 

Call me crazy, but wouldn't just pulling a spark plug and checking it's color, indicate how the bikes running?

 

HI Guys, I am now understnding how the things work and why I need one thanks for all your imput. I am still leaning towards the ThunderMax though just because of ease of use and the bit where it auto tunes itself. But like I say if there is somthing better in 6 months time, let me know
cheers Derek