General question

[Fred Miranda]

>> From: pantera at dris.com (David Doddek)
>
>>Tom writes:
>>>On a MGB witha  5 port...
>
>> Actually the injectors could be fires is a batch sceme twice a revolution
>> and still maintain a even fuel distribution.  Firing on the open valve is a
>> contriversial subject.  
>
>Agreed with all the good stuff.
>
>Problem with that siamese ported MGB head is if you batch inject
>the fuel, that 1 and 2 will get different charges of air/fuel.
>
>Firing order is 1 3 4 2 (standard 4 cylinder).
>
>With cylinders 1 & 2 sharing the SAME intake port, (ditto 3 & 4),
>Of a given 720 degrees of crank rotation, cylinder 2 has access
>to 540 degrees intake charge, cylinder 1 has only 180 degrees.
>
>So if you batch ONCE per revoltion... you MIGHT get a double
>dose of fuel into cylinder 2, but ONLY air into cylinder 1!
>Yikes.  
>
>Admitted this applies to the 5 port head, something of which most
>of the members on the list haven't seen. ;-) 
>
>#1 INTAKE OPEN xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>#2 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx INTAKE OPEN  
>
>   ^---------^----------^----------^----------^
>   0        180        360        540        720 crank degrees
>
>   -------------######---------------######---- worse case
>												batch injection
>
>   ---###-------###-------###---------###------- "twice per rev"
>												Uh oh... 
>
>[Please forgive the ASCII art, but this is a neat example
>of odd ball problem].  ###### = injector is on.
>
>
>Sigh, seems like the TBI IS the better solution for this
>engine (compared to Port Injection). So I will kindly eat
>my words that "port injection is preferable over TBI". ;-)
>
forget the batch fire and TBI and go with sequential 

Fred