Liquied Injection Gas

[Dragon3125]

Has anyone thought of running there z, no matter what the motor is on straight gas, in the form of liquid injection ??

[nizm0zed]

It doesnt really matter what the motor is, the system is the same for anything.

That goes for all mods, eg ignition advance mapping, fuel delivery, setting up for higher combustion and exhaust temps, no lubrication source for valve seats ect ect.

pretty much all the stigma that LPG has is due to duel fuel setups using a basic mixer, so if you want to do it, pick either LPG, or Petrol, not both.

 

 

To break it down.

First up you have single point vapor systems, thats what everyone knows when they think of gas systems, Think EL Falcon taxi backfire through the airbox, VN on gas ect ect. Basically just a carbie that injects gas instead of fuel.

this is the pinnacle of crap that gave LPG a real bad name.

 

Next step up is multi point vapour injection.

Still injecting vapour at the injector point, but uses a dedicated LPG injector.

The liquid LPG goes through the converter, into gas, to a distribution block, then through the injector to each point on the manifold.

This is pretty much the 'current' setup you see being fitted to factory setups, Like the BF-FG falcons ect.

Many installers are now moving to these systems as 'standard'

Generally you'll get good economy but a substantial power increase when tuned properly.

 

The last setup is a full on liquid injection setup.

The LPG stays as a liquid right up to the point where its injected into the manifold.

This has some amazing benefits, as the fuel combines with the warm air, it phase changes instantly, dropping the air temp quite substantially in the process.

Obviously this is incredibly beneficial to hot intakes due to superchargers and turbo's, allowing a LOT more boost to be run into the motor.

The downsides? Big.

Cost being a big hurdle, however theoretically any programmable aftermarket EMS can control it.

Next big hurdle is the injectors themselves. Very expensive, somewhat bulky and prone to freezing quite quickly, making reliability difficult to achieve.

next up is the line pressure. Like a modern EFI system, you need to keep the whole system, including the tank, over a certain pressure.

Once you factor in the massive variations in tank pressure even from something simple like the ambient temperature change in a day, this becomes quite a substantial hurdle.

Suffice to say, most full liquid LPG systems are prototypes in testing and virtually impossible to get for the 'average joe'

 

No matter what system you use, you obviously need to tune it.

If you tune for max power, you need to allow for a pretty big swing in fuel quality.

They use Butane as a part mix in the LPG fuel, to adjust for seasonal variations and as a cheap filler.

This can cause the octane rating to change quite a bit compared to Petrol, which is usually quite stable across different brands and locations.

 

A bit of time on google will net you a LOT of subject matter.

[Dragon3125]

 

Suffice to say, most full liquid LPG systems are prototypes in testing and virtually impossible to get for the 'average joe'

 

 

From what i have heard the new fords are coming out with liquid injection systems, which have all been de-tune due to much power for the "average joe"

[nizm0zed]

I doubt very much it would have been de-tuned due to too much power.

the 4.0L N/A engine is a pretty mean beast on its own.

The traction control, ABS, ESP and electronic throttle control do a very nice job of taming it into a refined and smooth powerplant.

It'd all work the same with gas.

If there was any de-tuning, its to do with reliability and seeing the vehicle through the warranty period.

 

fwiw, the ford engineers who were working on the Barra project (BA XR6 Turbo) pushed the development motors pretty far, to see what they were capable of in pretty much standard form.

I dont know what the exact figures they reached were, but rumors of over 30psi and almost 1000kw at the fly seemed to make the rounds.

Its believable though, seeing as tuning houses like Nizpro and CAPA to name two, have done substantial work and reached those figures.

Obviously an engine like that wouldn't make 200,000kms without trashing the turbo, pistons, gearbox, driveline, tyres ect ect.

the warranty costs to Ford would be astronomical.

Hence, detuned down to 240kw for the sake of reliabilty, ease of operation on the road (and less power than the XR8 Model)