1UR-FSE on LPG

[Arnout]

Anyone seen a 1UR-FSE on LPG yet? A customer of mine bought a LS460 and asked if it's possible to convert to LPG, I assume so but I see problems with the stock system with direct fuel injection v.s. intake injection. Is it possible to piggy back a programmable engine management system on this car?

 

[cribbj]

Haven't done one, but I'd think as long as it has an intake manifold, surely you ought to be able to piggyback a Prins system on it?

This sounds like a really interesting project.

 

[Arnout]

I don't know how forgiving the stock ECU is when switching to LPG. Also the stock system adjusts it's fuel injection timing depending if it wants to inject on the compression stroke or on the intake stroke as I remember reading about direct fuel injection.

 

[MitchP]

I will be piggybacking an AEM on a supercharged one here soon so I will yet you know how that goes but I am not sure LPG is gonna work with the stock direct injectors.

 

[Arnout]

what do you mean if it's gonna work with the stock direct injectors? The LPG has their own injectors in the intake manifold.

 

[MitchP]

Flow rate and spray pattern may not be suitable for liquid LPG. I take it you are looking to use a vapor system?

 

[Arnout]

LPG systems have their own injectors that you must weld or mold into the intake manifold. The liquid LPG injection works at like 30 bars or something, so there is no fuel injector that can open at that pressure, you need special liquid LPG injectors.

 

[cribbj]

Mitch, the LPG injectors look like the photo below. Same electrical connector as the Keihins in Honda cars & bikes, and pretty much the same form factor lengthwise & at the manifold & fuel rail. Just a lot fatter due to the larger solenoids.

I've been meaning to tell you I have 8 of these along with their evaporator/pressure regulators, etc. that we're going to try out with the AEM during one of our next dyno sessions, once we get one of these motors completely sorted out.

They're low impedance, so rather than try to jury rig a resistor box, I'll need to pick up an AEM P&H injector driver box for them.

 

[Arnout]

Those are LPG vapour injectors, I prefer the liquid injection of LPG like the vialle system.

 

[cribbj]

Any pics of the Vialle injectors?

I think liquid LPG injection is great in theory, but keeping the system cold enough to keep the LPG in the fuel rail liquified, and not vapor lock, etc. seems to be quite a hurdle.

 

[Arnout]

the vialle keeps the LPG rail at 30 bars and it has a feed and return system like a stock fuel system. it just doesn't modulate the LPG pressure with the intake vacuum/boost like a regular return type fuel rail does. the injectors look like regular side feed fuel injectors. The idea behind it is a lot better as you can take away a lot of intake temperature with injecting the LPG in liquid forum and also the liquid LPG doesn't compress so it's a lot easier to map the fuelling. The vaporised LPG injection like the prins systems are hard to map as you have the factor LPG vapor pressure which you don't have in a liquid injection system.

 

[Arnout]

just got the wiring diagrams from the lexus dealer. The engine uses 8 injectors on the intake manifold and eight injectors for direct injection. That's nice right? SO yes, sixteen injectors are on the engine. If we're putting the LPG injectors on as well we end up with 24 injectors on one engine
I wonder if the engine accepts the interruption of the stock injectors or how we can faul the engine to run LPG. Might be better off installing an AEM or anything else programmable.

 

[Arnout]

ok discussed the operation with the lexus dealer. This is one very nice engine. I like the direct fuel injection especially. Really want to play with such an engine, anyone already seen one wrecked?

 

[XR8tt]

Silly question ??
Can the outer injectors be replaced with LPG injectors and run both ? Having the direct injection trimmed back and maybe only work when required ??