FI, pipes and re-mapping

Hey Vatos

My knowledge of engines comes from HS physics in the early 70's. That is where it stops too.

So, I would like to put a custom set of pipes on Hidalgo. With my Bandit, being carburated, I was told that if I did that I would need to rejet [whatever that means]

Hidalgo being fuel injected, will I need to do something if I put on a new set of pipes (like the the FI remapped or something?)

Muchas Gracias

If you put a full exhaust system on Hidalgo, you will definitely have to have the fuel injection remapped. You can buy a Dynojet Power Commander that will allow you to change the FI map on your Mean Streak. If you get slip-ons you could probably get away with leaving the stock fuel map in place but I'd recommend you look at getting it remapped. You can download maps directly from Dynojet once you have the Power Commander, by the way.

http://www.powercommander.com/205-211.shtml

Thanks for the info

What I wonder bout is if a powercommander is worth the cost if you only remap once after you change the pipes or if a dealership would remap it fo ryou for a lot less

JadeRider said:

Thanks for the info

What I wonder bout is if a powercommander is worth the cost if you only remap once after you change the pipes or if a dealership would remap it fo ryou for a lot less

Click to expand...

I would contact your dealer to see how much they'd charge to do this.

Most FI systems can compensate for the changes made by simply installing a different pipe, unless the airflow characteristics are seriosuly changed. However, while the FI map may cover the range of conditions caused by a new pipe, it will be doing it outside the optimum settings of the FI system. So the bike will run, it just won't be perfect Enter goodies like the Power Commander...

What the PC's do is insert themselves between the sensors and the FI system. You use a map on the PC and it sends fake data to the FI system to trick it basically. For some bikes, with specific modificatins, you can download maps from the PC website or other places. However, even an identical bike to yours with the same mods is not really an exact match, but often the maps are good enough that it won't matter.

If you really want things done right ($$), then you take the bike to a shop with a dyno. BEFORE you have the pipe installed, you have them run a baseline dyno run to see what the stock perfomance numbers are for your bike. Then you install the pipe, air filter, or whatever and run another dyno run to tweak the air fuel ratio at different thottle positions and loads. This yields a custom map for the PC that is then used to feed data into the map of the FI systems. Ideally, you will then have an optimum air/fuel mixture for all possible conditions. This is confirmed during the dyno tuning by the use of a gas analyzer stuck in the exhaust of the engine while you are doing the dyno runs. It's really quite fun...

The result of the time and expense is maybe a few more HP and Ft-Lbs of Torque and a smoother running bike.

On carbed bikes, there are little dohickies in the carbs that control the amount of fuel that sprays into the air moving through the carb. These are called "jets". Rejetting a carb means adjusting the jets to accomodate a change in the airflow characteristics of the engine, as might be caused by a new pipe, air filter or other mods. It's easier and cheaper to do than remapping an FI system, but it is also not as controllable or precise. It is more of a black art...

Adios,

I now feel wiser

Thanks