Thread: isuzu & LPG

Originally Posted by Dougal

If you think mine are far-fetched then you'll hate the guy in the US who fitted compound turbos to his 4BD1T and produces more than 500hp.

The stock injection volumes on a 4BD1T is about 70cc/1000 shots. The injection pumps with the 9.5mm elements have been measured producing 140 cc/1000 shots with the adjusters wound open.
I have a bigger pump again, I have 10mm pump elements. I have more than 200kw of fuel delivery available.

Double 314Nm and what do you get. Over 600 by any chance?
I don't use a landrover gearbox, I have an Isuzu truck 5 speed.

I'm currently running just over 520Nm (74kw to the ground at 2000rpm in 4th) as I still haven't fitted my intercooler.

Of course unlike the new 3.0tdv6 my engine will never meet Euro 5 emissions.

Hi Dougal,
You have proved you know about diesel fuelling and horsepower.

In a previous thread you have proved that diesel gas would be uneconomical in New Zealand under fuel pricing there.

However you have not proved that thousands of happy D-gas operators in Australia are universally deluding themselves about the efficiency and reliability of their engines in 20% addition levels.

There is a case to be made for EGT monitoring in heavily fuelled engines.

The emission laws that prohibit visible smoke emissions ensure that properly set up D-gas installations will either redude LPG or diesel fuelling under full load to ensure compliance with the law. Under this condition it is unlikely to melt your engine.

In the case of Clean32's installation I fitted a limit switch to prevent over fuelling. Then Clean32 took his vehicle to a dyno tuner and reduced his diesel fuelling to enable a higher usage range of LPG. After doing 1000km+ this weekend with a car trailer attatched he will soon know if there is any truth in the rumour that gas wrecks engines.

draged this up to Mt Barker this morning.

no melted pistons yet

and is a bit of a harder hill ( and longer) than climing out of wellington

Oh and for those who missed it, dougal’s scientific experiment that he often refers to.

LPG into an Idling Diesel. | OffroadExpress 4wd Forum

Originally Posted by bee utey

However you have not proved that thousands of happy D-gas operators in Australia are universally deluding themselves about the efficiency and reliability of their engines in 20% addition levels.

Why would I be trying to prove such a thing? I merely wish to discuss the technical aspects. In particular detonation detection and avoidance.

Originally Posted by bee utey

There is a case to be made for EGT monitoring in heavily fuelled engines.

The emission laws that prohibit visible smoke emissions ensure that properly set up D-gas installations will either redude LPG or diesel fuelling under full load to ensure compliance with the law. Under this condition it is unlikely to melt your engine.

In the case of Clean32's installation I fitted a limit switch to prevent over fuelling. Then Clean32 took his vehicle to a dyno tuner and reduced his diesel fuelling to enable a higher usage range of LPG. After doing 1000km+ this weekend with a car trailer attatched he will soon know if there is any truth in the rumour that gas wrecks engines.

So Clean32's engine has been defueled and dyno tuned?
Is there a dyno chart to post up then?

What do you make of the audible detonation in my engine with 0.4% (by volume of intake air) lpg fumigation?
Clean32 has helpfully posted up a video which shows one of my experiments.

Originally Posted by Dougal

What do you make of the audible detonation in my engine with 0.4% (by volume of intake air) lpg fumigation?
Clean32 has helpfully posted up a video which shows one of my experiments.

how do you know that you are running 0.4% LPG we don’t see any flow meter in your clip nor do we see air flow or diesel flow metering. all we can se of your so called experiment is you shoving the rubber hose from your BBQ up your Isuzu and making big claims’ based on that. What a joke

oh by the way just been to Elizabeth and back, no melted pistons

Originally Posted by clean32

how do you know that you are running 0.4% LPG we don’t see any flow meter in your clip nor do we see air flow or diesel flow metering. all we can se of your so called experiment is you shoving the rubber hose from your BBQ up your Isuzu and making big claims’ based on that. What a joke

Full of scorn today aren't we?

The airflow of an idling diesel is very easy to quantify, we know the displacement, we know the rpm.
700 rpm on a 3.9L diesel with 80% ve is 1092 l/min
The gas flow was measured at 16 seconds for 1.2 litres. 4.5 l/min.
4.5/1092 = 0.412%.

Max possible error +/- 50%. This 50% includes rpm fluctuation, VE fluctuation, and scatter in measurements.

Final mix could be anywhere from 0.2-0.6%

Since you paid for a dyno tuner to reduce your fuelling you'd hope you weren't melting pistons. What power figures did they come out with?

Originally Posted by Dougal

What do you make of the audible detonation in my engine with 0.4% (by volume of intake air) lpg fumigation?
Clean32 has helpfully posted up a video which shows one of my experiments.

If I were stupid enough to add enough LPG to cause the engine to shake as in your video I would be a fool indeed. The whole point of adding LPG is to add the right amount. When I set up D-gas I adjust the sensitivity control so that LPG doesn't flow appreciably at idle, and also there is a micro switch that stops flow at zero accel pedal. This prevents over fuelling/wastage of lpg at decel/idle conditions.
Dougal, as I understand it, the reason one adds LPG is to improve combustion. So when there is a small amount of diesel being burnt there should be very little LPG added. I have read about electronically controlled systems that meter a small amount of LPG at idle, and as it is done by precise mapping the engine can be tuned to take advantage. Many hours have been spent by the engineers at various companies to get the lpg flow rate optimised.
My system uses mechanical and electric control of the lpg flow rate to achieve useful economy and power. It is not perfect but a whole lot more sophisticated than a bbq hose stuffed up the intake. The few systems that I have installed up til last week have all without exception met the owner's expectations over many thousands of kilometres. I expect Clean32's system to do likewise.

Dougal, you are a sceptic and that is O.K but do not insult people who have some clear knowledge in certain field unless you are prepared to back them up with facts other than a hose up some intake pipe of a motor.

Let it rest.

Be happy that your motor is so powerful as you state and let others with less powerful motors aspire to your greatness.

Well done to you and that Clean and others get on with their projects.