DIYEFI.org Forum

hey guys. if you are using a system, with say 35 teeth, in the camshaft. i get that :
if you count teeth, and each teeth is 10degrees from the other, you can know, that 16 teeth you are at 160 degrees.
my question is this:
Does, the injection time of Each injector, ALWAYS start at the same degree BTDC?? say, cylinder 1, will start to be injected always at 10degrees, and depending on engine load, it will get injected more or less time?

or is it a metter of engine taste??

Taste, and theory and hand optimised/tuned values. It's not critical at all.

cool! writting the code,to start the injection on fixed degrees, at least fot the begining, seems easier

Fred wrote:It's not critical at all.

Why do I sense irony here?

I don't know, FreeEMS has had tunable timed injection for half a decade (that's 5 years). No one's tuned it yet. It ceases to matter completely @ 100% duty. At low duty and depending on the quality of your injectors it can matter a fair bit (for idle), but you could never call it critical. Unless you were a complete idiot, that is.

Various users over at the evil empire have indicated notable improvement in idle, cruise, part-throttle, and tip-in performance using sequential / timed injection. As Fred notes, this goes away quite quickly as the throttle opens and the duty cycle picks up. Dialing this in is a non-trivial experience, taking lots of road time, and the 'sweet spot' can change quickly back and forth, depending the configuration and timing of valves, airbox, runners, etc.

i think i will go with something like
"inject X degrees before each cylinder's ilnet valve open"
move that X earlier, for every Y rpm. ( i will be using sequintal anyway)

then i will try to measure the best X and Y , by observing the o2 outpout... (although i will need wideband for that, and building a controller for it is hard on its own )

settra wrote:(although i will need wideband for that, and building a controller for it is hard on its own )

Don't bother - seriously. Get a Spartan from Alan To at 14Point7.com for $105; that's an integrated sensor and controller. It's tiny (entirely in the connector!), and you only have 4 wires to hook up.

You'll spend more on parts and labour just to develop the controller, even before you include the sensor ...

1) i leave in greece
2) no way dude. it seems way expensive for my taste. i bet i can make something like that, with the only cost, being that of the actuall sensor... of course it will not be as good, but the whole consept of the project, is to be as DIY as possible ... :/

While I agree with buying the WBO2 controller (the sensor alone would be $50 anyway), here is a link which might help - http://www.waltech.com/site/index.php/o ... -projects/

I hope you are going to use a DIY microcontroller from silicon and copper?