LS1 is it MFI or SFI???
09-28-2006, 02:41 PM
#1
Staging Lane
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LS1 is it MFI or SFI??? Well reason i ask is i was looking at some stuff and noticed that someone said they had a firehawk that is MFI?? When i look at my window sticker it says my engine is SFI?? I have a 2001 formula... So i was just wondering.
09-28-2006, 11:04 PM
#2
Haha! Its both!
MFI refers to Multiport/Multipoint Fuel Injection, meaning that there is one fuel injector per cylinder. Some vehicles, like older GM trucks, have 2 injectors for 8 cylinders.
SFI refers to Sequential Fuel Injection, meaning that the injectors are fired similar to spark plugs, in firing order. The alternative is Batch Fire, which fires all injectors on the same bank at the same time, regardless of firing order.
MFI refers to Multiport/Multipoint Fuel Injection, meaning that there is one fuel injector per cylinder. Some vehicles, like older GM trucks, have 2 injectors for 8 cylinders.
SFI refers to Sequential Fuel Injection, meaning that the injectors are fired similar to spark plugs, in firing order. The alternative is Batch Fire, which fires all injectors on the same bank at the same time, regardless of firing order.
09-28-2006, 11:15 PM
#3
On the subject of batch-fire injection, someone told me a couple of years back when i had my '89 IROC-Z that the TPI cars operated on a batch-fire program. Is this true?? and WTH was the advantage? Seems like just an added waste of fuel, or was it because early ODB I wasn't sophisticated enough to tolerate operating w/ a fuel injection firing order?
09-28-2006, 11:36 PM
#4
Who knows why GM did that, but it is true. TPI is a batch-fire system, although it is also an MPI setup. LS1 are MPI, but to be more specific it is an SFI setup. MPI can be batch-fire or sequnetial, but it is a system where each cylinder has one fuel injector. Two injectors per engine (or one injector per 4 cylinders) is known as a TBI system = Toilet Bowl Injection ... sorry, I meant Throttle Body Injection.
09-30-2006, 07:42 AM
#5
Originally Posted by Rob M
On the subject of batch-fire injection, someone told me a couple of years back when i had my '89 IROC-Z that the TPI cars operated on a batch-fire program. Is this true?? and WTH was the advantage? Seems like just an added waste of fuel, or was it because early ODB I wasn't sophisticated enough to tolerate operating w/ a fuel injection firing order?
Not only were the TPI cars batch fire, but the early LT1s were also (92-93 IIRC). And with the limited computer technology back then, believe it or not, they often made more power.
Waste of fuel? The TPI 350 cars were rated at 26 or 27MPG highway
12secSS/George P. Lara: Are you the same guy I bought a custom STB off of TGO like a decade ago?
09-30-2006, 08:08 AM
#6
Marc 85Z28,
Good stuff man!! Thats cool I NEVER would've thought about all that stuff bout the age of of the block but your right, it makes sense. I forgot that also like you mentioned the TPI cars didn't have Crank or Cam sensors, that was introduced (atleast in the F-cars) in '96 cause the Timing covers are diff 92-93 are one, 94-95 is another and the 96-97 are the ones with the crank sensor (if i remember correctly....its been a few years since i had an LT1
) Anywho thanks guys for the info, something i've never been able to explain or understand myself
Good stuff man!! Thats cool I NEVER would've thought about all that stuff bout the age of of the block but your right, it makes sense. I forgot that also like you mentioned the TPI cars didn't have Crank or Cam sensors, that was introduced (atleast in the F-cars) in '96 cause the Timing covers are diff 92-93 are one, 94-95 is another and the 96-97 are the ones with the crank sensor (if i remember correctly....its been a few years since i had an LT1
) Anywho thanks guys for the info, something i've never been able to explain or understand myself 