THE FUEL INDUCTION HIERARCHY:

[Stewart G Griffin]

Here is what i feel to be the "levels" of fuel induction systems.
The following is more of a question than a statement, so feel free to add/modify.  Also, the smaller the number or letter the lower it is on the hierarchy scale.
Also, let's assume a v-8 engine here.

1) 2 barrel carb with "flat"  single or dual plane manifold.

2) 4 barrel carb with single or dual plane manifold.
a) with hi-rise manifold.
b) with tunnel ram manifold.

3) Three 2-barrels with 3X2 manifold.   (LOGIC: i'm putting this before two 4 barrels because 6 barrels vs. 8 )
a) with tunnel ram manifold, if this exists.

4) Two 4 barrel carbs with 2X4 manifold.
a) with tunnel ram manifold.

5) Four 2 barrel carbs on a 4X2 manifold (the logic here is that four 2 barrels are more responsive than two 4 barrels?)
b) with independant runner manifold---this means only one barrel is dedicated to only one cylinder for all 8 cylinders.

6) mechanical fuel injection
a) constant flow, i.e., rochester
b) timed, i.e., lucas etc.

7) electronic fuel injection
a) throttle body
b) multi port

c) the system that vw has the identifies exactly where each piston is in the stroke and injects each cylinder precisely and appropriately such that there is no need for a starter!

[Captkaos]

7)Electronic (GM only in my example)
a)TBI
b)crossfire
c)multiport batch fire - fires all injectors at once.
  I) CPI - Central port inj
  II)TPI - Tuned Port inj
d)multiport sequential - fires once for every "spark"  sequence

e)IDI (individual direct injection) a throttle/injector for each cylinder (stack systems like crower, Hilborn weber, etc that is electonic controlled.)

[eventhorizon66]

Hey Capt.  You misspelled Crossfire.  It is spelled "Misfire."

[SUX2BU99]

^ LOL! Or 'Nofire'. Neat idea Crossfire was, poor execution though. Or just poor technology at the time.

Was the TPI a batch fire system? Interesting. I figured with an injector per port, it would be a sequential system.

I remember in high school auto shop class back in the early 90's we were looking at a Sunbird that had a typical 4 banger with TBI. We could see the fuel injector spray but it looked constant, yet my shop teacher said it was actually pulsing for each individual cylinders needs. It sure looked constant to me.

One thing I never understood is why GM used what looked to me like a MPI type of system on the 4.3 Vortec engines in the early 90's, and it looked cool too, but then switched to a primitive single-injector setup later on and made the motor much more ugly to look at. This was on the S-series SUV's and trucks anyway.

[Marc]

I don't know how the chevy smallblocks were but the 2.8/3.1/ 3300 and I think early 3800 were all 2-bank batch fire, and the newer series II 3800's were sequential fuel injected.  Batch fire was probably plenty good at the time, even the TBI setup was superior to carburetion in most ways IMO.

[Stewart G Griffin]

1) It's funny because i was just thinking about gm throttle body injection the other day.  And i was thinking about constant flow vs. pulsing!   You would think that constant flow would be better(especially for an 8 cyl)---and then the computer could just control amount of flow based on needs/conditions.  But apparently, the engineers know better?  That is, if in fact it does pulse vs. contant flow?  Seems like constant flow would be simpler?


2) Does everyone agree with #1-5?    Or is there more to add?

[Marc]

IIRC the fuel pressure is constant, and the injectors are either on or off...so the amount/flow of fuel delivered is determined by the on / off pulsewidth. 

[joesgarage71]

3b would be 6 stromburgs on a Offy Manifold (seen one for sale the other day, yup for a small block)

[Stewart G Griffin]

i think that one would probably go under 5a;  The logic here being that the 4X2 with independent runner manifold is more responsive than the 6X2?

Also, maybe this should be left off because it's not very popular and more of a one-off sort of system......maybe?


One of the purposes of this list is sort of a chart for say if someone wanted to start off with something very basic and gradually progress thru all the possible fuel delivery systems so as to learn about each one and discover the incremental power increases/responsiveness of each "level", if any.

[joesgarage71]

Stromburg is a one barrel, and yes 5a then.