BoonDocker YAMAHA: Nytro Turbo User Manual
Page 11
BoonDocker – 1585 Hollipark Dr. Idaho Falls, ID 83401 – 208-542-4411 / 877-522-7805
www.boondockers.com – email:
– fax: 208-524-7381
Revised 2-13-08
Copyright © 2004-2008 by Boondocker
Page 11 of 20
Tuning Instruments:
Air/Fuel gauge:
A good wideband O2 gauge is highly recommended as an effective tuning tool. The sensor will have a limited
lifespan due to exposure to pre-mix oil and leaded racegas, but in many cases it can last for a season and it is a very
valuable tuning tool. If desired, after initial tuning is completed the probe may be removed to prolong its life.
Be aware that too rich a mixture can cause the gauge to read lean due to unburned fuel not being read by the gauge
(the oxygen will produce a lean reading). Whenever the engine is decelerating, your A/F numbers will be lean - these
readings can be ignored. However, whenever the throttle is being applied, pay attention to the readings!
Higher numbers are leaner (less fuel), lower numbers are richer (more fuel). A 14.7:1 ratio means all the available
oxygen has combined with all the available fuel. Numbers from 11:1 to 13:1 generally produce the best power (extra
fuel helps cooling and can help prevent detonation). A lower A/F ratio (10.8 to 11.2:1) is considered safer on a turbo
since the extra fuel prevents heat build-up and helps prevent detonation. We recommend you find the lowest ratio
where the sled still runs without being too rich.
EGTs:
Exhaust Gas Temperature gauges can also be an effective tuning tool, but they are not a substitute for reading spark
plugs and piston wash and for a general feeling of how the engine runs. Use EGTs only as a backup to verify what
you see. They can be misleading under certain conditions and safe readings can vary greatly from engine to engine
depending on such things as probe placement, fuel, timing, pipe design, porting, etc. For this turbo, typical EGT
temps seem to be around 1300 – 1325degF after a long pull.
Plug and Pipe Color:
Color will develop inside the pipe and on the plug after running a while which can be used to determine fuel mixture.
A tan/cardboard brown color is desired. Light-gray is too lean, and dark brown is rich.
Tuning tips:
Important: Find the settings where your motor runs rich before you decide to go lean!
1. Tune with the engine and pipe at operating temperature. The sled’s ECU will make adjustments as the engine
warms up – you might think the engine needs leaner settings then later realize you are too lean once the engine
warms up.
2. Use the Load/Save Map feature to quickly change and compare fuel settings when testing. This can also be
useful for riding under different conditions. For example, changing elevations or temperatures may require
different adjustments if the stock ECU does not compensate properly for your modifications. For drag racing,
you might want to run richer settings for longer distances than you would for short distances.
3. One method for finding out where a fuel adjustment setting is effective, greatly increase only that setting. Run the
engine to find out when it suddenly becomes too rich – this is where that setting is effective. Be careful – you can
easily flood the motor, especially with LO load or low rpm settings. If this happens, to restart the engine you may
have to pull several times with the throttle held wide open.
4. The Stats Capture feature can be used to determine RPM, and if the load setting is LO, MD, or HI. The nitrous
button can be configured to capture these stats (see nitrous configuration section below). From the Main Menu,
select N2O, set Btn to CAP. Whenever the button is pressed, the Stats: Capture screen will be displayed. The
current stats will be captured when the button is released.
N2O Menu in “Capture” mode:
Fuel TPS RPM Btn
040 OFF OFF
Æ
CAP