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[JamesV6CDX]

I saw a V8 with LPG today. Acquaintance of mine had purchased it and wanted me to look at an LPG problem (which was quickly pinpointed to a faulty LPG injector and sorted)

I had to do a double take. This car had TWO lpg kits fitted!!!!

One tank in boot. Delivering liquid feed to TWO reducers, via a t piece. Two ecus, both for 4 cyl kits, each controlling a bank of cylinders. Two LPG switches in the car!!!

When my laptop is sorted I will post a couple of pics!

Bodddgggggeee!!!!

[Nick W]

Nothing new about that, fuel injected V12 Ferraris use 2 six-cylinder K-Jet systems. Which looks shockingly crap compared to modern ones!

[zirk]

Could be a fuel saving method, big thing in the States at the moment on V8's, switch off some Pots when your just pottering about and save the all eight pots for when you need the grunt. God know how long the engines will last in that senario, there are some piggy back ECU's that do the same automatically, switching off injectors at random when comomg to a halt or throttle position vs low speed. Or it could be just a bodge.

[05omegav6]

Actually an effective way of getting a lower spec system to fuel a more powerful engine

Guess the wiring consists of a common lambda feed from the petrol ecu to each lpg one... the rest is straightforward as the lpg ecu only fires the injector when the engine ecu tells it to... the engine ecu couldn't care where the signal goes as long as the relevant cylinder receives fuel when it's required/expected

Two 200bhp four pot lpg kits will be more cost effective than one 400 bhp 8 pot system, and probably easier to diagnose any faults too...

[Marks DTM Calib]

Could be a fuel saving method, big thing in the States at the moment on V8's, switch off some Pots when your just pottering about and save the all eight pots for when you need the grunt. God know how long the engines will last in that senario, there are some piggy back ECU's that do the same automatically, switching off injectors at random when comomg to a halt or throttle position vs low speed. Or it could be just a bodge.

They last well but thats because they shut off alternat cylinders and sequence them to minimise thermal stresses in the engine and maintain full lubrication

[JamesV6CDX]

Actually an effective way of getting a lower spec system to fuel a more powerful engine

Guess the wiring consists of a common lambda feed from the petrol ecu to each lpg one... the rest is straightforward as the lpg ecu only fires the injector when the engine ecu tells it to... the engine ecu couldn't care where the signal goes as long as the relevant cylinder receives fuel when it's required/expected

Two 200bhp four pot lpg kits will be more cost effective than one 400 bhp 8 pot system, and probably easier to diagnose any faults too...

All good points, and having thought it through, I agree with what you say

In this instance though, I don't think the installer was thinking along the same lines

The loom was like a birds nest under the bonnet

[05omegav6]

The loom arrangement would be all over the place due to the firing order... personally I would have gone with a system for each bank, but sounds like they've gone with 1234/5678...

As for birds nest, presentation isn't always a consideration if it basically works

[Marks DTM Calib]

Struggling to see why the loom should be all over the place on a V8 where the injectors will be mounted on a centre single manifold setup.

[chrisgixer]

Hmmm. Pondering the merits of running opposite banks on different fuel to compare trims, set up, etc.

Fuel saving programme is available on the newer Holden Commadores.