Injector Firing Angle
07-23-2011, 10:50 PM
#4
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this is a megasquirt?
the inj timing table is set up so that your valves are opening just after TDCC/360deg.
you'll probably have numbers in the mid to high 300s.
the inj timing table is set up so that your valves are opening just after TDCC/360deg.
you'll probably have numbers in the mid to high 300s.
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07-24-2011, 10:11 AM
#6
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that is true. intake mass flow increases with rpm and/or MAP.
you can start by making some educated guesses on the angle to finish the injection and then when you are next on a dyno do some back to back runs and measure AFR and power as you change injection timing (do no not use O2 corrections--keep pulsewidth fixed).
Here's brainy's take on it:
http://www.msextra.com/forums/viewto...timing#p266854
you can start by making some educated guesses on the angle to finish the injection and then when you are next on a dyno do some back to back runs and measure AFR and power as you change injection timing (do no not use O2 corrections--keep pulsewidth fixed).
Here's brainy's take on it:
http://www.msextra.com/forums/viewto...timing#p266854
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07-24-2011, 12:22 PM
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I'm not familiar with your Haltech but the same basic principles should apply. Basically you can change the injector timing then take a datalog and if it shows you can pull fuel while still hitting your target AFR, you have made an improvement. If you have to add fuel, you changed injector timing in the wrong direction. This is easy with the autotuning funtion in tunerstudio because you can see where it wants to add or pull fuel in real time, but you can accomplish the same thing with datalogs.
I have been thinking about injector timing mostly in terms of fuel efficiency as opposed to power output. But I would think that as long as you're maintaining the same target AFR then your power would remain the same. (?)
I started with Braineysack's map then dropped the timing so it was a tad less advanced, and was able to pull a few % of pulse width. I believe Brain set his up based on theory or prevailing wisdom, but my testing suggests it is a tad too advanced. The changes are not dramatic so it takes a good bit of logging to have high confidence in the results. Mine is mostly different in the sub-4000 rpm range and up to 100 kPa (still n/a). It is an improvement but still a work in (slow) progress. Timing is set for end-of-squirt. Maps for a 1.6 should be similar to a 1.8 since the injectors are in a similar position relative to the valves. If you know how your cams differ from stock then this could give you an idea of where to start.
I have been thinking about injector timing mostly in terms of fuel efficiency as opposed to power output. But I would think that as long as you're maintaining the same target AFR then your power would remain the same. (?)
I started with Braineysack's map then dropped the timing so it was a tad less advanced, and was able to pull a few % of pulse width. I believe Brain set his up based on theory or prevailing wisdom, but my testing suggests it is a tad too advanced. The changes are not dramatic so it takes a good bit of logging to have high confidence in the results. Mine is mostly different in the sub-4000 rpm range and up to 100 kPa (still n/a). It is an improvement but still a work in (slow) progress. Timing is set for end-of-squirt. Maps for a 1.6 should be similar to a 1.8 since the injectors are in a similar position relative to the valves. If you know how your cams differ from stock then this could give you an idea of where to start.
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