Inj Firing angle ... again

User avatar
HaltechMatthew
Haltech Staff
Posts: 2722
Joined: Tue Feb 07, 2012 12:45 pm
Location: Sydney, Australia
Contact:

Re: Inj Firing angle ... again

Postby HaltechMatthew » Wed Jul 12, 2017 2:36 pm

Pretty much, yes.

So long as you are ballpark, and our default tables in the later Elite firmware versions are exactly that for most direct port (spraying onto the valve) injected setups, you would just tune the engine first, then try shifting the timing maybe +/- 30 degrees or so to find the sweet spot.

Generally it wont make power. It might improve economy and emissions, and maybe run a fraction smoother if you get it perfectly optimum. It is kind of like tyre pressures. There is a wide window where it just works, and a narrow point where it is absolutely perfect for that condition and application, but the difference is splitting hairs in the real world.

squeue
Posts: 11
Joined: Tue Jun 05, 2018 2:30 pm

Re: Inj Firing angle ... again

Postby squeue » Thu Jun 07, 2018 8:18 am

but can you confirm that the start angle

User avatar
Drwaffles
Posts: 111
Joined: Sat Jul 28, 2018 11:51 pm

Re: Inj Firing angle ... again

Postby Drwaffles » Sun Feb 24, 2019 8:43 am

Just a quick question on this topic.
The Axis on the standard table is MAP and RPM (Both seem like good factors to scale the inj timing against)

But if you've got variable intake timing, wouldn't it be beneficial to link it to the intake cam angle? That way the inj phase/position stays the same relative to what the valves doing? Especially given you can introduce some good overlap.

The next question would be, would that be a better axis than either RPM or MAP.. Could you combine RPM and MAP into an axis say normalized load, or calculated air mass.. Or even just replace one of them, which is more of a factor? (MAP less important I'd assume)

Could be wrong, but I could see a situation of you're using AFR 'leanness' to determine cam timing that you may get skewed results because of unburnt fuel blowing through (if it's still injecting while overlap occurs)
Granted, if you've dialed in the cam timing and the injection table it would achieve similar result.


Return to “Tuning Discussions”

Who is online

Users browsing this forum: No registered users and 2 guests