Thread: isuzu & LPG

lol

Originally Posted by bee utey

Detonation in my P76 engine occurs after combustion starts not before. It is managed by spark retarding which limits the peak cylinder COMBUSTION pressure. I am merely showing that the cylinder pressure to initiate detonation is much higher than achieved by compression alone, making it unlikely to happen even in a diesel unless combustion has also been initiated by diesel injection and the LPG mixture is rich enough.
Enough of this argument, how about some real world testing and less theorising. Next TDi I will see if anything happens at all when I turn off the diesel. Although I have already been there, I want total diesel shut down.

Detonation doesn't occur after combustion, detonation is combustion. It's simply happening in a completely uncontrolled manner.
I didn't know your P76 had knock sensors and electronic spark control to sense knock and retard the timing. Or are you retarding the timing manually in anticipation of detonation?

To get a diesel to run solely on LPG you'll have to add more than the diesel equivalent at idle. About 2-3% of intake air by volume for a 4BD1, which is >5 times more than my 4BD1T was detonating at.

I'm not doing that to my engine.

Originally Posted by Dougal

Detonation doesn't occur after combustion, detonation is combustion. It's simply happening in a completely uncontrolled manner.
I didn't know your P76 had knock sensors and electronic spark control to sense knock and retard the timing. Or are you retarding the timing manually in anticipation of detonation?

To get a diesel to run solely on LPG you'll have to add more than the diesel equivalent at idle. About 2-3% of intake air by volume for a 4BD1, which is >5 times more than my 4BD1T was detonating at.

I'm not doing that to my engine.

With LPG vaporising at 270:1, I doubt enough fuel in vapour form could be drawn in to the combustion chamber to equal the energy value of the diesel injected in anyway. So therefore no go.
Or has this been discussed already??
I know early commercial trials ( indeed some modified vehicles continue to ) inject 5% diesel to obtain ignition. These may inject liquid in to the manifold, but I'm not sure.

Originally Posted by DeeJay

With LPG vaporising at 270:1, I doubt enough fuel in vapour form could be drawn in to the combustion chamber to equal the energy value of the diesel injected in anyway. So therefore no go.
Or has this been discussed already??
I know early commercial trials ( indeed some modified vehicles continue to ) inject 5% diesel to obtain ignition. These may inject liquid in to the manifold, but I'm not sure.

That 2-3% is vapour.
2-3% liquid would be a huge amoun of fuel. A BBQ bottle in under a minute.

Originally Posted by Dougal

That 2-3% is vapour.
2-3% liquid would be a huge amoun of fuel. A BBQ bottle in under a minute.

A dougs you should stay away from examples like BBQ's it only causes a HEATED argument

couldn't help myself.

This is still going.

Can't we just say that those with the D-gas fitted are generally happy and those that don't either wish they had or have a theory that deems such a device un-safe.

I made many calls before fitting my gas and must say I only listened to those with some cold hard facts and experience, those with theories they dreamed up after too much port I disregarded.

For my old (1997) Disco, the gas is great and any one like to drive it to check is welcome to it. Test it, poke it, hell even stick some of those unpronouncable gauges on it.

Just stop the bickering. I thought I was bad with my unreasonable dislike for Isuzu's.

An update, I have been having fun with this.

I had SWMBO on the side of the road as i powered past ( hill) under full load.
Diesel is turned back up to close to where it was, this gives a visible but not black exorst under full load. Turn the LPG on and this color diminishes quite a bit.

This set up gives 10.2 ltrs / 2.5 ltrs per 100.
There is no real power gains at this setup but she seems a bit smother and a bit easier to rev and you can hang on a bit longer in a taller gear.

I think I will leave it at that. But I have another solenoid that I intend to add as a switch on LPG boost for those times you just need a bit more to get over that dune.

NB no melted pistons

What happened to the oil analysis?

http://www.aulro.com/afvb/isuzu-land...ml#post1241777