for track car as im going emerald i can use batch fire method what difference and pros and cons of it

 

Ask Dave Walker!!! Read his book to.

 

Both work...

Sequential is better for emissions mainly but does help a little with the other things too.

 

Swings and roundabouts from what I can tell (and depending who you listen to) - BUT, on a car that already had sequential fuel injection why would you want to go 'backwards' technology wise?

I seriously doubt any experienced Cossie tuner would go to batch fired injection over sequential....

 

ask your mate tabetha, he'll tell you to go batch fired as you will be able to get twice as much power from a set of injectors than sequential

 

Oh dear that old topic again

Paul

 

To answer your question, there aren't really any pro's in it.

 

one pro is that it is theoretically easier to map as you don't then have to spend time optimising when in the cycle to start injecting on each cylinder as you could do with sequential

 

i might be a complete div but can someone explain the term batch firing and sequential??

 

sequential is when you inject fuel into each cylinder in turn on their intake stroke which is basically when it needs it, and batch is when you inject all cylinders at once (some of which will have closed inlet valves etc)

 

But that is IF you decide to fine-tune the maps to that level of detail, which I doubt anyone does outside of OEM's and works race teams to squeeze the tiniest extra out of it.

 

that's why i said theoretically, as almost nobody will. especially as most tuners will not be using equipment to measure emissions and fuel consumption that would be needed to optimise it

 

as you may have guesses im no top engine builder, but the idea of firing fuel into a closed valve doesnt sound like a great idea??

 

Almost nick...

Sequential - as you say - each injector delivered all of the required fuel in one hit during the induction stroke.

batch - injectors fire in sets (eg 2 pairs on a 4 cyl engine) - each time the injectors fire, they deliver 50% of the fuel required. As they are firing once per revoultion (so opening once on induction and again on the power stroke) they deliver the same amount of fuel - but in 2 hits rather than one.

Alex

 

Its fine - the fuel will hit the back of the closed valve and vapourise. This not only cools and cleans the valves but also means that when it is sucked in to the cylinder it will mix with the air and burn well.

Alex

 

Actually batch-fire is all injectors at the same time, semi-sequential is like 2on, 2 off as you describe Alex.. Unfortunately the Megasquirt goons call it the wrong thing

 

All the injectors at the same time I would call continious injection.

This might be a case of symantics! lol

 

Listen to Tabs and prove to everyone that you can get 700bhp out of light blues by batch firing .

https://passionford.com/forum/general-car-related-discussion/203154-power-wise.html

https://passionford.com/forum/showth...ght=batch+fire

 

if you get high fuel consumption as your fuel just to cool and clean the valves, if you run a top ecu is there no way of fuel it sequentially, but to batch fire every 2 or 4 strokes etc to clean and cool the valves?? or am i missin the point all together??

 

i think that you're missing the point, or at least i don't understand what you're getting at

if the ecu has the ability to do sequential injection (and std cossie ecus did more than 20 years ago), and the mapper has the ability to use it properly, then that is the best method to use.

 

But is it worth paying for the extra mapping for little benfit (playing the devils advocate here)

 

no it wouldn't be.

but it doesn't necessarily need any extra mapping - just use the same timing as a standard cossie and you will probably be better off than if you used batch (unless using batch you can use less injector driver transistors that you need for other things)

 

The advantage of batch firing is that the ECU needs only to know where TDC is.This means that a sync on the cam is not required.The disadvantage to batch firing is that the Injector Dead Time is doubled for the engine's cycle.This means on higher BHP cars the idle quality will suffer enormously.

 

This is true blackadder