Dedicated LPG - Vapor and Injection System

[timbosaurus]

I'll strongly advice against liquid injection Mate. Vapour is near-as-good, for a fraction of the price.

[marc280]

I've got a vapour injection system on my Falcon and it still uses petrol for cold starts. It is setup to run on petrol until the coolant in the engine reaches 40 degrees and then it automatically switches over to LPG. I was told by the installer this is required as below this temp the reducer can't work reliably below this temp to feed the injectors.... It was mentioned above that you can start vapour systems from cold without petrol and just not so sure this is true (well apprently not with the system I have anyway).

As for the ratings per injector I've got a manual for the Prins system (different to mine) and it gives the maximum rating for their largest injector to be 32.5kW. I'd imagine you could probably add two injectors per cylinder although this would mean double the reducers and management etc...

As for vapour injection itself I recon it's great and you can't really notice any difference between LPG an petrol except for when you go to fill up $$$...

The prins manual is too big to attach but I can email it to anyone if they want it.

[amichie]

The prins manual is too big to attach but I can email it to anyone if they want it.

Yes please I'm a sucker for any kind of technical manual.

[email protected]

[timbosaurus]

Marc, you CAN start on LPG, but your setup is designed not to. There are plenty of cars running vapour LPG on gas only to prove that.

It is true that running LPG under low coolant temperatures and high fuel flow (ie: cold morning, full throttle) that the vapouriser (i guess that's what you mean by 'reducer'?) can freeze, leading to stumbling and potentially a brief stall. But that can be overcome by light/medium throttle application for a couple of mins first up and is the downside of running dedicated gas.

Just because your system is setup to start on LPG, does not mean it has to.

[marc280]

Fair enough, I don't have much experience with the systems other than the one I've got. But good to know that it can be setup to run from cold start if needed.

[Radar]

Marc wanna email me that manual as well? lewi_t65 @ hotmail.com
Cheers

[TurboRA28]

Ive got an 80 series landcruiser on LPG with a older style mixer ring thing, or more just a pipe going into the inlet.

Starts on LPG and runs perfect from first turn of the key..

[EnFlaMEd]

Just incase you feel like doing it cheap I have a tank and GRA 280 carb that was fitted to an fj20et engine making 170rwkw and about 490nm torque. Tank and carb are about 2 years old. I live in the Adelaide hills and I never once had a problem with cold starting or the mixer freezing up in the 5 years I owned the car. Once tuned properly it ran like an injected motor.

[celicapain]

imho the order of awesomeness for LPG systems goes like this.
Liquid injection, vapour injection, electronically metered low pressure mixer setups, GRA or impco carbs, polyauto and various other super cheap mixers and converters polluting the wreckers of our land.

Liquid injection is by far the best due to the vaporisation of the fuel in the inlet manifold which gives you a much great charge cooling effect than any of the other systems(or most fuels). It also gives you the precise control of electronic injection and better economy then any other lpg system. With liquid injection you should use 5-10% more LPG then petrol in a modern fuel injected engine.

Vapour injection is great but has lower practical power limits than the other forms of fuel systems. still runs of the computer but not much charge cooling.Not much cheaper than liquid injection but a more mature technology. Uses approx 15-25% more LPG then petrol in a modern fuel injected engine.

electronically metered low pressure mixer setups
i,e BA falcons, work well when calibrated for a particular model engine but are inflexible,restrictive and dont give amazing fuel economy. Uses approx 30-50% more LPG then petrol in a modern fuel injected engine

GRA/Impco mixers
Basically similair to a petrol carburettor thay have pretty much the same advantages and disadvantages.
They are cheap, simple to set up and can supprt serious horsepower in either N/A or boosted engines. There is lots of experience tuning them floating around, and often they are the best way to go on an older tech engine. They give pretty shitty fuel economy compared to other systems with consumption approx 50-100% more running LPG then petrol in a modern fuel injected engine.(p.s still works out cheapr but no where near a much).

various other super cheap mixers and converters polluting the wreckers of our land.
I dont really now much so thats it. have fun. must go and do some actual work on my car instead of procrastinating.....

[timbosaurus]

Hey celicapain.

I tend to agree with you on most things, but... we're not actually seeing the expected 'much greater' charge air cooling. But you are right... the efficiency is nearly the same as petrol.

Also, sequential vapour injection can see the same precise metering. You just need to use the right computer and injectors meant for port injection, setup correctly in the manifold. Not the shitty setup usually seen tin dual-fuel conversions.

[stradlater]

it doesn't surprise me that the liquid injection is not doing much for the charge cooling.

'They' (the designers) couldn't rely on an indeterminate amount of heat/energy being available to 'vapourize' the liquid LPG. That part of the process must be 'calculated'/accounted for elsewhere surely.

[Radar]

Bleh to liquid, still way to far off being made for the backyarder...
Each set injector is made specifically for the engine (MASS R&D), so a set of injectors to suit one 4cyl, wont work on another 4cyl.

Brown Dot vapor injectors are high flow and apparently capable of running more than 49hp/cyl and can be made to run dedicated LPG. Quarter of the of the price of the liquid injection as well.

[celicapain]

Bleh to liquid, still way to far off being made for the backyarder...
Each set injector is made specifically for the engine (MASS R&D), so a set of injectors to suit one 4cyl, wont work on another 4cyl.

Brown Dot vapor injectors are high flow and apparently capable of running more than 49hp/cyl and can be made to run dedicated LPG. Quarter of the of the price of the liquid injection as well.

They must be pretty cheap then! i think it was 5K for a complete Liq inj system, not including la rebate.
They dont build the injectors for engines, they use different sized orifices to match the flow rates of a generic injector body to whatever size car they are installing it on. i think that it would be cool to able to change injector sizes without needing so swap them over.
anyway, im going liquid injection on the next motor in my celica, so ill see how it goes.

[Pube]

I have a BF XR6 Turbo with the JTG liquid LPG setup. Its a neat bit of gear, you can hardly notice it. Its not the cheapest system out there but definately the best. The kits are developed to suit particular cars, so I would say be quite more expensive to develop a one off kit. The gas injectors can be changed to larger flowing units for more power but the standard injectors are nearly perfectly matched to my petrol injectors. The gas injectors can be 'calibrated' for small adjustments to perfectly match the petrol injectors. Another gas pump in the tank would be required with larger gas injectors. I know of one XR6 Turbo which upgraded the gas injectors to suit 42lb petrol injectors also with a 2nd fuel pump which made around 350kw on LPG. My XR6 turbo only makes 236rwkw at 8psi on LPG with the help of a mild tune. Not bad considering that on LPG its costing my less than half the cost of running petrol. My petrol consumption is around 11-12L/100 and my LPG consumption is around 13-14L/100 Even without the help of a tune, straight off the bat the liquid LPG system makes up to 10rwkw more than petrol.

Here is a pic of my engine bay. The only giveaway is the second row of LPG injectors (green electrical connectors)

[marc280]

That's pretty cool. I've always thought that an XR6 Turbo would be a great daily car and being able to run it on LPG would make it quite affordable!

You mind if I ask who did the installation? and do you know if there are many other Falcons around now with the liquid LPG setups?