Injector Sizing: REALLY dumb question

Greg Hermann bearbvd at sni.net
Wed Aug 26 21:10:37 GMT 1998


>>>TBI's have about three days time to think about vaporizing enough
>>>to burn (since the fuel has the extra length of the runners to think
>about
>>>vaporizing).
>>>
>
>Is this is a problem at idle or off-idle? If so, then why not at mid and
>WOT, too? I don't want to revisit the debate of where fuel vaporizes
>(cylinder, valve, runner, any combination of the above), but all of that
>discussion would indicate low throttle settings should have good fuel
>vaporization. (The whine of servos as my CSH raises for furious head
>scratching, unintentionally exposing....Did Darth Vader start out with a
>CSH? Exactly what ARE the long term effects of wearing a CSH?)
>
>>>Also, they (TBI) fire each injector once every ignition pulse (so one
>with
>>>two injectors they alternate).  While on a TPI they fire once every
>>>fourth cylinder firing.
>>>
>
>And this problem could be solved with tighter or finer control over
>injector open times?

Mike--If you cut the minimum injector pulse time which will give you a
repeatable fuel quantity in half, you just doubled the available turn-down
ratio with no other changes. This translates to a motor with enough
injector flow to make twice the horsepower of a stocker being able to idle
like a stocker (if the cam will let it be so). A pretty significant
improvement, eh?

Regards, Greg





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