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sv-flyer
January 22nd, 2005, 12:26 AM
Iam looking at the "maps" for my CBR and some of the values are negative , like -8. Does this mean a negative 8% reduction of mixture from stock ? I have added a YOSHI RS-5 , so wouldnt I want to increase
all values over stock ? Like maybe 5% across the entire RPM spectrum ? Should I start with a "zero" map and increase the mixture across the board ?

HELP, Iam confused !!!!!

NathanH
January 22nd, 2005, 09:54 AM
You wouldn't want to increase fuel into the mixture in all cases. Bikes come with some pretty screwy maps from the factory in order to meet emissions regulations. Basically, the manufacturers are told at what rpms the various emissions tests will be conducted. So, if they know that they have to be putting out no more than X amount of unburned particles at Y rpm with Z throttle opening, they often will have some spike or dip in the map right at that point to compensate.

The goal of an aftermarket fuel map modifier (PowerCommander, Techlusion, ECU flash like Yosh offers, etc.) is to smooth that out for maximum performance over the entire rev range and at all throttle openings. Smoothing out the power characteristics may involve all sorts of increases or decreases in fuel delivery depending on where in the rev range you are. Been true since well before fuel injection. In carbed bikes, many people talk about jet kits. People assume that bigger jets equal more fuel equals more performance, but that just isn't the case. At some throttle openings you would want more fuel, but at others you wouldn't. Thus, "jet kits" often involve other changes to needle height etc. and may not necessarily require a larger main jet.

Your best bet for maximum performance and/or smoothness is to have your bike custom dyno tuned by someone who REALLY knows what they are doing. They can observe what your bike is doing both through power output graphs and exhaust gas analysis, and at various throttle openings, to map for maximum performance. The second best alternative if you don't want to pay for custom tuning, is to simply download the map that is closest to your individual setup. Often there will be maps available for, "slip-on", "full-system", "full-system with high flow air filter", etc., or even for specific brands of aftermarket exhausts. Just pick the one that is most specific to the changes you've made and load it. It may have fuel increases, it may have fuel decreases. But, when you get it from the dynojet website, someone who knows what they are doing has mapped it. It may not be absolutely perfect for your bike, but it's bound to be an improvement over stock since it will undo all of the "to meet emissions regulations only" dips that the manufacturers have to build in.

[ January 22, 2005, 10:16: Message edited by: Nathan ]

Sunshine Cowboy
January 22nd, 2005, 11:44 AM
Nathan is right about the custom dyno tune. If you are handy with a laptop you can do it yourself if you are mechanically inclined. Vijay and myself custom tuned my PC3 in my garage on my F4I. When I ran it on the dyno the guy said we did it perfectly. Just my .2 cents. smile.gif