Here is a dumb question that hopefully some of you EFI guys/gals can answer.

I've owned and worked on Harley's since back in the early 1970's, but they have all been 'carb'd models.

Decided to go with EFI on the Fatboy I just purchased, as I don't plan on yanking the engine apart for performance improvements. I ride year round, and just want the Fatboy to be a good performing, long range cruiser that you just 'start and go' in all weather conditions.

Question that I have is how picky is the 'puter' when it comes to changing out the exhaust?

I talked with the previous owner, and a Stage 1 has been done on the Fatboy, and it was optimized for the bike which is running the stock pipes with the baffles/restrictors removed.

I would assume that doing nothing more than changing out pipes for something else wouldn't require doing anything with the EFI system, but I just wanted to check and make sure..

(Where I live we have no acoustical limits on sound, aren't even required to run mufflers, no emission checks, no smog checks, and no equipment checks, so it's pretty much anything goes on bikes, cars, or trucks)...

Thanks in advance...

 

There is no tuning to the HD stock download or the Stage I. You just have to bolt you pipes on and hope for the best. Most bikes run ok to pretty darn good just doing that. However, they usually will run better with a FI tuner, like a simple DFO, on top of the download. There's really only one thing to do....Put on the pipes you want, see how she runs, and monitor the plug color till you are satisfied that it's not running too lean.

 

If you just have the download, go ahead and change pipes. I never heard of a computer "flash" optimized for no baffles, reguardless, you are going to lose power with the stage 1 and no baffles.

 

The Stage 1 download is a generic program for upgraded air/pipes. It hasn't been too effective per all the reports both here on the forum and other places. You usually will wind up with your pipes popping and backfiring because the motor is running leaner than normal. The best fix/easiest is put a controller like a Power Commander III with the proper map download for your air cleaner/pipes combo between the computer and the FI and then you can control it without messing with the stock computer.

 

I noticed the other day that the Vance & Hines website lists different programs for their FuelPak with different slip-ons and stock headers. That would lead me to believe that you would want to re-map the computer for any changes that you make to the exhaust.

On the other hand, my dealer told me that if all I did was change to different slip-on mufflers from stock that I wouldn't need to re-map. I'm leaning towards believing Vance & Hines over my dealer...

 

The dealer is right. This is true, if your just added slip-ons, you don't need to re-map. If you change your air intake you will need to re-map. I didn't re-map for my SE II's, and the bike ran very well, later I had the arlen ness big sucker added and the download. The re-map is generic and you should only get popping on decell, which won't hurt anything. If you get the PCIII, you can eliminate the popping, but I would recommend getting it dyno-tuned if you go with the PCIII, as I would rather run lean with the re-map than run too rich with an untuned PCIII.

 

The V&H Fuelpak is like the PCIII in that it is put between the bike's computer and the FI system. It operates in the same way only exclusively set up for V&H pipes. It works very well and they have their own maps. To actually mess with the bike's computer you would need the Screaming Eagle Race Tuner (SERT). That in itself is quite a bit to work with and you need a lot more info on your bike and knowledge since it is set up for race bikes that "tune" between runs for optimum performance.
For ease of use go with either a SE download cartridge or PCIII. A dyno run on the initial set-up does wonders to your tuning.

 

Check out V&H's site to make sure they make a map for the Fuelpak for your bike and the pipes you want. They didn't have one last I checked for my FLSTSCI and the fishtails, post hd Stage 1 d/l.