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Guest Message by DevFuse

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spfi and mpfi.. how do they work?

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4 replies to this topic

#1 Guest_subarugsr_*

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Posted 12 August 2003 - 03:55 AM

i am familiar with the workings of mpfi, but is anyone able to explain or diagramitcally show me wat and how SPFI works?

#2 Guest_Skip_*

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Posted 12 August 2003 - 07:55 AM

They both operate basicly the same
when warm they are in closed loop
ECU watches the 02 sensor output and adjusts the pulse width duration to tries to achieve a stoichiometric A/F ratio.
Only diff is the SPFI has one big injector the MPFI has four (two operate simlu so it's not a true "sequential" system, it's called a "batch" system)
Hope this helps

#3 Guest_oobnuker_*

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Posted 12 August 2003 - 08:01 AM

SPFI is basically a glorified carb. It is a single injector, mounted in a throttle body that resembles a traditional carb. There are a lot of electronics involved still, but not as much as an MPFI or Turbo setup.

Hope this helps.

#4 Guest_jon61484_*

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Posted 12 August 2003 - 08:08 AM

SPFI: single port fuel injected (like what he described.)
MPFI: multi port fuel injected (one injector in each cylinder)

and yeah, the SPFI was designed as a replacement for a carburated car. (Fords, Chevys, have single port fuel injector setups that can work right onto the small block manifolds)

#5 Guest_subarugsr_*

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Posted 12 August 2003 - 10:14 PM

i am considering shoving a turbo on an EA71, if i adapted the manifold for a SPFI unit to fit, added computers etc, it would work?

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