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I am wondering about injector timing.


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This is the first time I have installed an ECU that allows me to change the injector timing, and I am having trouble.

My 4A-G 16v is designed for 296° 10.5mm 288° 10.3mm compression ratio 12.7 rev limit 9000rpm, but I have no information on how to set the injector timing in Japan.
Is there any information that I can refer to?

 Thank you very much for your help.

DSC_0395 (800x450).jpg

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At idle sometimes you can find the best injector timing by watching lambda as you move the injector timing, the most efficient injection point will give you the richest lambda.  The difference is more noticeable with larger injectors, and generally with many mild engines once you are above about 30% injector duty cycle it is difficult to see the difference - even on the dyno.  Most commonly for engines with the injector close to the intake valve they will usually be around 400BTDC at idle/low speeds, but since your injectors have been moved further away from the valve the best timing may be a little earlier (larger number).

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It may vary depending on the specification of the engine, but for a naturally aspirated engine, how does it change from idling to high RPM?

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As I mentioned above, in most road engines with small injectors it will have no effect at high RPM because injector duty cycle is too high.  If you have say 80% duty cycle that means your injector is open for 580 degrees of the 720deg cycle.  So changing the time it closes makes no difference since it is open nearly the whole time.  

On high end engines we use multiple injectors per cylinder so even at WOT we keep duty cycle down at ~35%.  In this case your injector timing will get earlier as RPM increases.  It also gets earlier as you move the injector further away from the chamber.  

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