Outer Limits 4x4 Board

love ke70 wrote:what do you mean you TD hasnt seen diesel in two years?
you running a diesel on straight petrol or have i missed a step?

Nah, dude's running three Hiclones.

fuck, it must fly now!

well back from noosa 2 liters more per 100kays pulling the van from Forest Lake to Tewantin Iam happy about that.

second set of fill ups with the Dgas unit.
11.17L/100km of diesel
and 3.41L/100km of gas.
giving 30.5% gas mix, yes too rich i know. cut it back from a 60 thou jet to a 50 and have started to add a little bit of boost, gonna have a play with it.
but anyway, was alot more go pedal than i would ahve given it before the gas, and also pulling a few trailer loads of heavy shit around.
still costing me less by about 1$/100km, and giving good power, will be great when i finally get the chance to get it tuned properly.

but i dont think ill be happy with any of these units until they operate like a full standalone unit, which injects a 100% varying rate depending on RPM, throttle position and boost. and runs continually at the perfect mix.
which i will argue with anyone til im blue in the face that these basic systems do not do that.

Worth a read re the legalities of LPG installations...

Full article:
http://www.gastek.com.au/cgi-bin/engine ... ml&Rec=169

++++++++++++++++++++++

Did you know that any vehicle manufactured after 2003 must have a emission certified kit?

Australian Standard AS1425 this standard specifies requirements for LP gas systems mounted on motor vehicles. It provides requirements for the design and construction of component parts and their installation in vehicles. The standard states that any vehicle fitted with LP gas that was manufactured on or after the year 2003 must have an emission certified kit fitted. GAS TEK is the only company in Australia currently with emission certified kits. This means that if your vehicle is post 2003 and does not have a Gas Tek system or an emission certified kit, it is liable to rejection by state authorities and may have to be removed. There may also be legal ramifications for installing/running an uncertified kit. So before fitting, ask whether the kit been fitted to your vehicle is emission certified . This will save you from potential prosecution and the trouble and expense of having to remove the system.

++++++++++++++++++++++

I'm now glad I did my homework before installing the system.

BTW, just clocked up over 1,150km on a full tank of D/G - about 15% saving on fuel economy over D only. I'm loving this setup!

So to simplify things for the not so technical or those that simply don't care about the technical side of things (ME).
I am seriuosly looking at doing this to my GQ td42 (after market) which is also used to tow a comp rig.
I will get
more power?
cleaner engine?
Small fuel savings?
a bill for about $2500 after rebate?

does this sound about right?

3.8BUNDY wrote:So to simplify things for the not so technical or those that simply don't care about the technical side of things (ME).
I am seriuosly looking at doing this to my GQ td42 (after market) which is also used to tow a comp rig.
I will get
more power?
cleaner engine?
Small fuel savings?
a bill for about $2500 after rebate?

does this sound about right?

Yes - 15% is what I got
Yes
Yes
I'd shoot for about $3K after rebate.

3.8BUNDY wrote:So to simplify things for the not so technical or those that simply don't care about the technical side of things (ME).
I am seriuosly looking at doing this to my GQ td42 (after market) which is also used to tow a comp rig.
I will get
more power?
cleaner engine?
Small fuel savings?
a bill for about $2500 after rebate?

does this sound about right?

If you aren't turbo'd then it'll do nothing for power.
If you are turbo'd then spending a much smaller sum on a good diesel tuner will also get you more power and probably fuel savings too.

JK wrote:

3.8BUNDY wrote:So to simplify things for the not so technical or those that simply don't care about the technical side of things (ME).
I am seriuosly looking at doing this to my GQ td42 (after market) which is also used to tow a comp rig.
I will get
more power?
cleaner engine?
Small fuel savings?
a bill for about $2500 after rebate?

does this sound about right?

Yes - 15% is what I got
Yes
Yes
I'd shoot for about $3K after rebate.

Thanks JK
Diesal gas at penrith quoted $4750 (Rebate to be deducted) as they have to do an exhaust alteration on lwb GQ.
I'm pretty sure it is the same system you have installed.

3.8BUNDY wrote:

JK wrote:

3.8BUNDY wrote:So to simplify things for the not so technical or those that simply don't care about the technical side of things (ME).
I am seriuosly looking at doing this to my GQ td42 (after market) which is also used to tow a comp rig.
I will get
more power?
cleaner engine?
Small fuel savings?
a bill for about $2500 after rebate?

does this sound about right?

Yes - 15% is what I got
Yes
Yes
I'd shoot for about $3K after rebate.

Thanks JK
Diesal gas at penrith quoted $4750 (Rebate to be deducted) as they have to do an exhaust alteration on lwb GQ.
I'm pretty sure it is the same system you have installed.

Just double check that it's the gastek one with the Sequent II.

Cheers, JK

if you know a friendly gas fitter and can do the work yourself you can sort it out for around the price of the rebate, i did mine for about 1850 or so, but i already had the gas tank, bought the kit direct from D-GAS, but then you cant really take it to one of his fitters as they get a bit upset that they dont get to make the markup on supplying the kit.

but yes, turbo TD42, more power, cleaner engine, less fuel cost to a small degree

got another price from ace diesal gas conversions at Girraween.
He installed the system in my dads 80 ser and a few of his club mates vehicles. About $800 cheaper but I have to find out more about the 2 systems to compare (the non technical guy has to get technical)
My dad and his mates are totally wrapped in their set ups, to the point where he won't shut up about it.

http://www.trakonlineauto.com.au/service-4,5,1329.html

This is the system my Dad used.
Any comments from those who know?

3.8BUNDY wrote:got another price from ace diesal gas conversions at Girraween.
He installed the system in my dads 80 ser and a few of his club mates vehicles. About $800 cheaper but I have to find out more about the 2 systems to compare (the non technical guy has to get technical)
My dad and his mates are totally wrapped in their set ups, to the point where he won't shut up about it.

From what it shows on that website it looks extremely basic compared to the gastek system. In my opinion you can easily see where the extra $800 goes with the electronic injection / engine management on the gastek setup.

Then again if it works for your old man and it's the right price and it's legal...

Cheers, JK

Just a bit on the oil , although the oil in a Gas car stays and looks cleaner
it has a different set of narstys , in the form of acids .
Wouldn,t be much as you guys are only using 15 -30% gas.

Maybe even different residues as the gas is being used as a catalyst .

Dozoor wrote:Maybe even different residues as the gas is being used as a catalyst .

Nope, that's pure marketing BS.

it burns, it isnt a catalyst. they use the catalyst buzz word because it makes the diesel burn happen faster, but not without using the LPG.
less soot in the oil is always a good thing, but i wouldnt extend oil changes based on it without getting oil tested.

A comment made earlier regarding post 2003 vehicles meeting standards - the ADRs were not written with Diesel Gas in mind. As there are no diesel engines manufactured here in Australia, these post 2003 diesels are tested on a engine dynos overseas (yes - out of a vehicle) to meet ADRs.

LPG Australia have commissioned an investigation into the current regulations with the view to having the testing methods amended - or to have LPG considered to be an addative rather than a fuel with it's own testing procedures for diesel gas. Just because LPG is a fuel replacement for petrol engines does not mean that diesels can run on it with-out major modifications - hence it is essentially an addative.

Diesel engine compression does not create enough heat to ignite LPG so preignition can not occur. Compression ignites the diesel which in turn ignites the LPG. LPG is not a cataylist as it is consumed in the reaction - more like an accellerant. It increases the burn rate so that the diesel is burnt more completely before the exhaust valve opens - hence less black smoke, more power & better economy etc.

It will probably take a few tanks of fuel - maybe even a couple of oil changes (depending on how sooty the engine is) before the oil will become cleaner. I would recommend having the oil sampled before making the decision to extend oil change intervals.

Naturally aspirated diesels can & do benefit from diesel gas but nowhere near the same extent as turbo charged vehicles - only because there is not enough air available to obtain a complete burn.

There is nothing wrong with vapour withdrawal systems as long as a converter is still utilised. Should any liquid come from the tank then it is converted to a vapour.

I prefer to change the tanks to vapour withdrawal. The amount of LPG that is utilised on a diesel engine is minimal. Hence if I run vapour withdrawal from the tank to a converter then I do not need to run heater hoses to the converter as it won't ice up. This makes the conevrsion 'less invasive' - you have less chance of something going wrong. If a heater hose wears through or a 'T piece' leaks and engine damage occurs then you're in the poo.

My 2c worth anyway.

Peter K.

bowtie landie wrote: Diesel engine compression does not create enough heat to ignite LPG so preignition can not occur. Compression ignites the diesel which in turn ignites the LPG. LPG is not a cataylist as it is consumed in the reaction - more like an accellerant. It increases the burn rate so that the diesel is burnt more completely before the exhaust valve opens - hence less black smoke, more power & better economy etc.

Why do you say diesels can't create enough heat to ignite lpg? The dedicated propane engines cummins/westport make have a CR of 9:1, their CNG version runs 10:1, the B series diesel it's based on runs ~18:1.

I haven't come across any dedicated lpg engines running more than 14:1 and they were pretty scarce. There are efficiency gains to running higher compression, pre-ignition is about the only reason not to.

(Auto ignition of a fuel is the temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark.)

The auto ignition temperatue for automotive LPG is between 500 and 600 degrees Celcius. Auto ignition temperature for automotive diesel is approximately 210 degrees Celcius. A diesel engine with between 17 & 22:1 compression ratio will typically have compression temperatures of 370-400 degrees Celcius - nowhere near enough to ignite the LPG.

Since the LPG is in mixture with the air, the flame front from the diesel spreads more quickly, and more completely, including igniting the air/fuel mixture which is in contact with the cylinder walls, which are cool in comparison to the super-heated air inside the combustion chamber. Much of the cleaner burning of the fuel is attributed to this ignition against the "cooler" components of the engine, and accounts for raising the percentage of combustion from a typical 75% for a well-tuned diesel engine running on pure diesel fuel alone, to 90-95% with the addition of LPG.

The attached link (I hope it works - you may have to copy it into the address bar) is about a Mercedes truck converted to run on LPG. The report was from the news room of LPG Australia in May 2008.

The compression has been lowered with a swirl plate and the head has been modified to accept spark plugs.

http://www.pressroom.com.au/press_relea ... &prID=3581

Hope this helps.

Peter K.

whats so wonderful about what they have done in that link?
all they did is turn a diesel motor into a petrol motor and run it on LPG.
real efficiency will come when they use LPG as a compression ignition fuel source, which i though someone had done at some stage, with very large power, but couldnt get the rest of the drivetrain to hold up. or so i was told.
think it was cummins or someone.

but that link doesnt really seem like a big technology breakthrough..
10% fleet saving, when LPG is under half the price, it must be chewing through some gas, i wonder how many litres theyre carrying....

bowtie landie wrote:(Auto ignition of a fuel is the temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark.)

The auto ignition temperatue for automotive LPG is between 500 and 600 degrees Celcius. Auto ignition temperature for automotive diesel is approximately 210 degrees Celcius. A diesel engine with between 17 & 22:1 compression ratio will typically have compression temperatures of 370-400 degrees Celcius - nowhere near enough to ignite the LPG.

Since the LPG is in mixture with the air, the flame front from the diesel spreads more quickly, and more completely, including igniting the air/fuel mixture which is in contact with the cylinder walls, which are cool in comparison to the super-heated air inside the combustion chamber. Much of the cleaner burning of the fuel is attributed to this ignition against the "cooler" components of the engine, and accounts for raising the percentage of combustion from a typical 75% for a well-tuned diesel engine running on pure diesel fuel alone, to 90-95% with the addition of LPG.

The attached link (I hope it works - you may have to copy it into the address bar) is about a Mercedes truck converted to run on LPG. The report was from the news room of LPG Australia in May 2008.

The compression has been lowered with a swirl plate and the head has been modified to accept spark plugs.

http://www.pressroom.com.au/press_relea ... &prID=3581

Hope this helps.

Peter K.

love ke70 wrote:but that link doesnt really seem like a big technology breakthrough..
10% fleet saving, when LPG is under half the price, it must be chewing through some gas, i wonder how many litres theyre carrying....

Fleet saving, not fuel saving. To fully recognise what this means we need to know what percentage of total fleet cost goes to fuel.

If fuel cost is 90% of fleet cost, how much does it matter?

If fuel cost is 20% of fleet cost, a 10% saving in fleet cost represents a 50% saving in fuel cost. I'd say that's significant.

If fleet costs are a million dollars per year then a 10% saving is nothing to ignore - whichever way you look at it.

well on gas, the oil changes should be further spaced.
you have more servicables with a spark motor.
how much is the cost of the conversion i wonder..?

bowtie landie wrote:(Auto ignition of a fuel is the temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark.)

The auto ignition temperatue for automotive LPG is between 500 and 600 degrees Celcius. Auto ignition temperature for automotive diesel is approximately 210 degrees Celcius. A diesel engine with between 17 & 22:1 compression ratio will typically have compression temperatures of 370-400 degrees Celcius - nowhere near enough to ignite the LPG.

Since the LPG is in mixture with the air, the flame front from the diesel spreads more quickly, and more completely, including igniting the air/fuel mixture which is in contact with the cylinder walls, which are cool in comparison to the super-heated air inside the combustion chamber. Much of the cleaner burning of the fuel is attributed to this ignition against the "cooler" components of the engine, and accounts for raising the percentage of combustion from a typical 75% for a well-tuned diesel engine running on pure diesel fuel alone, to 90-95% with the addition of LPG.

The attached link (I hope it works - you may have to copy it into the address bar) is about a Mercedes truck converted to run on LPG. The report was from the news room of LPG Australia in May 2008.

The compression has been lowered with a swirl plate and the head has been modified to accept spark plugs.

http://www.pressroom.com.au/press_relea ... &prID=3581

Hope this helps.

Peter K.

The autoignition point of lpg is approx 450-500C, pull up the MSDS from your local gas supplier and they will tell you exactly what it is for their mix.
In contrast the compression temperatures for an 18:1 diesel can reach 650C.

I took a video yesterday of my diesel engine running rough and violently shaking when fed lpg at 0.4% of the intake air volume at idle. PM me your email if you'd like a copy, it's about 3mb.

This 0.4% (even with a 50% possible measurement error) is far below the ~2% flammability limits.

Hi KiwiBacon, I'm interested in having a look at the video - we haven't come across this before. In a vehicle last week we had forgotten to close off the idle circuit on a converter and you could smell the gas out of the exhaust at idle - but it ran smooth.

My information shows autoignition temperatures of LPG to be much higher than your information - so I will review and confirm - although am very confident in the figures. Combustion temperatures of 650 seem unusually high and in this situation pre-ignition could occur and adding LPG would be foolish, however I would be looking to see why the temperatures were so high.

PM sent - thanks

Peter K

bowtie landie wrote:Hi KiwiBacon, I'm interested in having a look at the video - we haven't come across this before. In a vehicle last week we had forgotten to close off the idle circuit on a converter and you could smell the gas out of the exhaust at idle - but it ran smooth.

My information shows autoignition temperatures of LPG to be much higher than your information - so I will review and confirm - although am very confident in the figures. Combustion temperatures of 650 seem unusually high and in this situation pre-ignition could occur and adding LPG would be foolish, however I would be looking to see why the temperatures were so high.

PM sent - thanks

Peter K

I've uploaded the video here:
http://www.offroadexpress.co.nz/node/777

Yes it's a crude test, the lpg flowrate I measured at 4.5 litres/minute. That works out at 0.4% (of the intake air flow) with a decent margin of error.
No unburnt lpg to smell in the exhaust, some smell similar to an lpg forklift, the rest felt like it singed the nostrils.

This is a 3.9 litre direct injection diesel.

Shell have a range of MSDS for their lpg products, some lists the autoignition point as >450C, another at 468C, others no mention.
The BP MSDS doesn't show it (or I missed it).
http://www.shell.com/static/au-en/downl ... tralia.pdf

bowtie landie wrote:
My information shows autoignition temperatures of LPG to be much higher than your information - so I will review and confirm

It is really quite simple. LPG can vary from ~100% propane to about 60%.

Propane has an autoignition temp of 450oC.

http://knowledgeweb.afac.com.au/__data/ ... NG_CNG.pdf

i can do that with the D-GAS system, just earth the hobbs switch so it thinks its seeing boost, and it will knock a couple of times and the idle comes up to 1200rpm or so from 700, and runs smooth as a whistle...

but other cars do knock...

what exactly where u trying to prove with that test?

love ke70 wrote:i can do that with the D-GAS system, just earth the hobbs switch so it thinks its seeing boost, and it will knock a couple of times and the idle comes up to 1200rpm or so from 700, and runs smooth as a whistle...

but other cars do knock...

what exactly where u trying to prove with that test?

What engine are you running?

This engine doesn't increase in revs, just gets really rough. The volume ratio is about 0.4%. Do you know volumes the dieselgas setup runs?

This test was to show people that I have detonation.

TD42
was naturally aspirated.
now turbo.
running about 15psi through a 50thou jet.
NFI what the flow figures are, no one would tell me, i got in trouble for opening the unit, which voided my warranty and he got a bit grumpy when i pointed out how simplistic the system is...
i dont know how to measure how much gas im flowing, but if its simple i will do so...
and its D-GAS, not dieselgas australia, just to be clear.
what setup is it you ahve? or was that just a bbq bottle attached?

i was told my motor would do what yours is doing if i was to add gas at idle but it doesnt.

it MUST have to do with injection timing, as it doesnt burn until the diesel burns so if your injection timing is a little late for diesel, its gonna be right for the increased burn rate with the gas.
which i would guess is your issue with the direct injection, probably easier for them to knock, seeings as the gas is in more direct contact with the flame front...
idunno, over my head but it seems to make sense.

my thoughts on the matter are, if you had a common rail motor, so could monitor exactly how much diesel is being injected, you could inject the exact right amount of gas to keep it at 25 or 30%. whatever ratio you want.

the D-GAS system works by adding X litres at Y pounds of boost.
irrespective of throttle position or RPM, so their claims that it injects the right amount is rubbish in my opinion.
how can it inject the right amount based on boost only, its going to be rich down low and lean up high.
all in my opinion. i am happy with the D-GAS unit, its just not as sophisticated as i would like.
this is the older system, but i think the newer system isnt too much more advanced...

cheers, andy