On a batch fire car, wouldnt the injector on each cylinder fire 8 times before before it got a spark? Whats keeps the fuel from loading up?

 

Some cylinders fire at the same time or very close to the same. The engine is really rotating too fast for fuel to pool up.

 

I'm pretty sure it fires once per crank rotation. At 600 RPM, the engine is still spinning 10 times a second, and at 5000 rpm it's spinning a full rotation 83 times a second. That wouldn't be anywhere near close enough to flood the motor out

 

Oh, and it would be impossible for the cyl's to fire at the same time, but at 5000 rpm they do only fire .1 second apart. Pretty damn quick

 

I know that. Does a SFI car use a larger injector constant? ie. Pulse Width and Duration

 

I skipped all the posts, please excuse me if I repeat somebody.

In our batch fire EFI cars, all injectors fire all at the same time each rotation of the crankshaft.

Now, with one turn of the crank, I believe 4 sparks plugs will have fired, the other four will fire on the next turn of the crank.

So, for each single fire of the each spark plug, the fuel injectors fire twice.

Also, at 6000RPM, we reach 100% duty cycle if the injector pulse width is 10msec.

 

I wasn't trying to insult you intellegence or anything, I was responding to what Tibo posted up "Some cylinders fire at the same time"

My guess is with yours since the injectors will only fire once per cycle in CFI, but batch would fire twice per 4 stroke cycle. Although I have no idea if PW would be twice the amount of batch. If you find anything out post it up, I'd be curious what it is.

Take care,
Matt

 

From what I have seen with tuning LT1's and L98's, the injector constants are not any different from one motor to the next. The pulse width is also not different. Kind of interesting. You'd think that you'd have a longer PW on an SFI engine to obtain the same amount of fuel. Or... since I don't have a damn clue about how batch fire works. Could it be that 2 batches of 4 fire every other revolution rather than 1 batch of 8 every revolution?! I'm lost now. Thanks guys.