foreigneRS

i guess that there are some of you out there running both anti-lag and coil pack (or other form of wasted spark)

are there any issues with the ignition timing firing the wrong cylinder of the pair and backfiring through the inlet?

i guess not as although you want the ignition event after TDC on one cylinder of the pair, the other cylinder has not yet had the fuel injected as it's sequential? is that right?

Mike Rainbird

iTrader: (3)

I have no issues and am running P8 with coil-pack .

foreigneRS

thanks mike, i guessed that you would be

any idea why you have no issues, how the timing and injection events work?

Mike Rainbird

iTrader: (3)

Absolutely none what-so-ever . I would only be assuming for the same reason as you, but I don't know for sure.

GARETH T

what cylinders are pairs on the coilpack? and what stroke would the other cylinder be on?

foreigneRS

any chance of speaking to your contacts and asking?

markk

iTrader: (2)

i have no issues what so ever

foreigneRS

GARETH T

cylinders 1 + 4, and 2 + 3 are paired.

when you fire cylinder 1 after TDC after the end of what would have been the compression stroke, cylinder 4 will be on it's way down on the induction stroke. in that case, the inlet valve will be open and the fuel / air mixture will be going in, at which point it would be not a good idea to spark up

or am i wrong?

GARETH T

i just sat down and thought about it aswell,, and your right not as simple as i first thought,,,

but i also know it works with no back-fires

DaveEscos

ditto

foreigneRS

got to get off 'net now and go home for tea.

thanks to anyone who replies tonight, and i'll have a look in the morning.

markk

iTrader: (2)

the firing doesnt actually change the ignition is retarded that far ( system dependant ) after tdc that the stroke is still the same, the cylinder firing is still the same, but the time frame the spark is delivered is moved far enough to prevent an actual power stroke being developed

foreigneRS

markk can you elaborate please, i don't understand what you're getting at

Stu @ M Developments

iTrader: (12)

Firing order of a YB is 1,3,4,2

When cylinder 1 fires, cylinder 4 is not on an induction stroke its on an exhaustive stroke.

Edited to say i now see what your getting at, having not thought the question through properly. What Mark is saying is correct, and when you ally this to the fact that the mixture is very un volatile without compression means you have no issues.

foreigneRS

thanks for the clarification stu. i couldn't quite get what mark was getting at, talking about firing, when he's saying that the firing order doesn't change. well, i know that, it's just retarded until after tdc when the exhaust valve is open.

but as far as i can imagine, that means that the inlet valve is open on the other paired cylinder which i thought might mean that the incoming charge could be lit causing a backfire through the inlet system.

but what you're saying is that at that point in the cycle, bearing in mind we have sequential injection and can maybe start the injection a little later as we're not needing to fuel enough for a full power stroke, there isn't enough fuel / air mixture to combust (and the fact that it has not been compressed means that it is also not likely to combust).

is my understanding now correct?

if so, the window to run anti-lag gets smaller with higher rpm if you don't want the injection time to coincide with the 'wasted' spark. so is there a maximum allowable rpm with anti-lag? i'd imagine that over 4000rpm you don't need it anyway, but have no idea as i have never driven a car with it.

GARETH T

im sad and went too bed thinking about this

your thinking about it a little too much! it doesnt do anything clever like that!
heres an als igntion map


here you can see that the angle of igntion is very small,,, so there is very little a/f int he chember, there is no comrpession (well of cuase there is boost) so the mixture simple dont burn!

foreigneRS

thanks Gareth. so you don't change the injection timing at all, only retard the ignition?

on your y-axis, how does that throttle angle relate to actual throttle position? is 50° open or closed?

and what does the ignition angle ° mean? is that degrees after TDC, and is there any other offset?

GARETH T

throttle is % open,,, and the number is degrees

foreigneRS

thanks mate. so it only works on less than half open throttle

GARETH T

yas mate

markk

iTrader: (2)

the map that gareth has given you there is just spot on, but the main ign table may look a little differant to a normal map due to the way its used in conjuction with the als map, the retard figures can be taken from the main table and worked out like that.

as for the rpm doesnt really make much differance in operation, ita more with throttle position. i can close my throttle at 6000rpm and the als will work fine. its all really in the map. there is no real timing changes to the fuelling, just ign.

i may not have explained myself there at the top to what i was thinking made sence to me tho, but i know how it works, but recently ive have the pleasure of looking at some really crap ALS maps from another company's managment. very complicated for what it does ( or didnt do )

foreigneRS

thanks very much to mark, gareth and stu for their input. i now understand things a little more