PETROL VS GAS VS WATER METH INJECTION

[jellis]

im just doing a bit of research on these systems
has any one had any experiences with them
gas
http://www.dieselgasaustralia.com.au/de ... =Technical

petrol
http://chipit.com.au/product-info/diese ... ion-system

water /meth
http://forums.nasioc.com/forums/showthread.php?t=937176

water meth apears to be the cheapest followed by the petrol injection with the
gas system being around the same price but intallation has to be bya licenses gas fitter

so any idea's or thoughts?

[geeves]

option 1 is a common mod and it does work but expensive to do properly. Dont expect the system to pay for itself
2 the link didnt load but if its adding petrol to diesel its a bad idea
3 From what I could work out is designed for petrol engines. Not diesel

[jellis]

the petrol one as far as i know works teh same as the gas using a similar method of injecting it into the air.
the water/ meth system is often used on diesels

[geeves]

injecting petrol in any form into a diesel engine will cause preignition and damage Probably fatal.

[kcsoft]

injecting petrol in any form into a diesel engine will cause preignition and damage Probably fatal.

indeed... hence why they run on diesel not petrol...

[jellis]

So why does LPG work then

Diesel : 210 °C
Gasoline (Petrol): 246–280 °C
Butane: 405 °C


They are the auto ignition temps of the three.
Why do you think petrol is more likely to ignite than diesel?

[kcsoft]

have you ever tried to light diesel with a lighter??
and then try lighting petrol with a lighter
then butane or lpg.

petrol is burnt by a spark in engines, therefore it's not being auto-ignited.

i would think that running petroleum in a high compression engine is going to do some serious damage as it would burn at a higher temperature than diesel causing piston meltdown. not only that petrol may dry the oil up out of the cylinder too causing lack of lube and lots of friction.... also causing high temps.

but i could be wrong.... i'd just be sure to have a spare engine handy when someone tests this out.

the water/metho mix seems safer, i had good results with it on a falcon, the pistons were nice and clean when i pulled it down.

[jellis]

lpg is also ignighted by spark in a petrol car but it works. It is also used quite often on diesel engines?

also hadnt thought about the petrol removing lubrication from the motor.

[superturbocompound]

the lpg and the petrol injection works the same way,they both help the diesel burn more complete,the petrol system needs to be injected far down stream of the engine inlet to have time for it to evaporate,aka gas like qualities,
i have run lpg very rich,and there is a significan knock and all we did was dial down the regulator till the knock dissapeared,i would assume the same for the petrol injection system but working on the other way round by enriching till there is knocking then going back a little.
to understand how these system works, you need to look at the diesel thermodynamics,we all know that our beloved Direct injection engine is some what rattley,the sound is from a pressure spike from the combustion pressure,how this happens is that the injection phase,the diesel manages to pierce deep into the far ends of the piston bowl covering vast amount of area(relatively),having absorb enough heat,the diesel ignites simultaniusly producing a hugh pressure rise and hence the knock sound(having a supercharger help me verify this by swiching on and off the supercharger @ 8psi on idle)when the supercharger is on with 8 psi on hand the rattle diminishes from having extra compression/heat,the diesel actually ignites as it exits the injector.
SO,when these addition fuel (lpg of petrol) are introduced ,the initial cumbustion from the diesel would ignite these fuels,since these fuel have a high flame speed this would increase the pressure inside the cumbustion chamber much faster then diesel would ,creating ideal heat for the diesel to burn earlier in the injection cycle.(hope you all understand the english)

[jellis]

Thanks. Makes sense to me I might give the petrol injection a go will report back with results

[Captcol]

what kind of dollars are involved in these systems?

[jellis]

The petrol one is about the same as a gas setup minus the expensive gas fitter and no yearly inspections. The water meth is the cheapest at around 400 - 600 for a kit
Gas is up to 4500 including installation
Petrol up to 2000 including instalation

[superturbocompound]

have you looked at nitrous?i think this is the best power up grade you can get.all that is mention above have a disadvantage of displacing air cos they are sprayed in to the intake system,remember that we need ignition ,fuel and oxygen to creat cumbustion/power,the more fuel and oxygen you can squeeze in to the cyclinder the more power you get.so to put it simply,let the fuel pump supply the extra fuel,and let the nitrous supply the extra oxygen....and all the engine can remain stock,

http://www.youtube.com/watch?v=hy9vy0pduMA

[Captcol]

in NZ you can not have nitrous connected while on the road.

[geeves]

When petrol burns under high compression it explodes. The pressure at which this happens is how octane rating is derived. LPG does the same thing but its effective octane rating is around 150 or so so its safe in a diesel engine. Alcohol also has an octane rating way in excess of petrol. Diesel wont burn fast enough to have an effective octane rating

[jellis]

sorry been a while since ive checked this thread.
never knew thats how they worked out octane rating thanks geeves.

i think they use the methanol injection for cooling rather than power. but oh well seems like its only for the big guys in anyway

[geeves]

A while ago on here there were several posts on home made lpg injection systems using bbq bottles for the gas. Most also used a tap in the pipe next to the gear stick to control the gas.
The consensus was that they worked well but theres no way any country is going to give your local version of a roadworthy cert to that type of set up. Imagine haveing a bbq bottle that is not transport certified rolling round on the back seat and a rubber line full of gas and a cheap tap right next to you. Especially if you smoke and are in the habit of dropping the but. Pop

[trustytrev]

I have done a little with lpg and diesel, but in the trucking industry. The gains can be incredible (I've felt the difference in some large Kenworths) with trucks. The main point with it is it speeds up the fuel burn under load. It is quite common for a fully loaded diesel engine (particularly a tweaked one) to still be having the fuel burning on its way out of the cylinder (in the manifold). This gives you the high EGT's and lots of soot (soot can be too much excess fuel or/and incomplete combustion of the fuel) as the fuel burns far more completely in the cylinder under pressure. The LPG makes the burn faster and ensures far more of the fuel is burnt in the cylinder expending its heat energy on the piston rather than the manifold and turbo, hence more power and lower EGT's.
This is all assuming its all set up correctly.

In short, if your engine is running soot free, lots of boost, LPG will let you run more fuel (and power) right up to either the engines mechanical limits (rod out the side) or thermal limits (piston meltdown).

BTW, The engines I had the experience with are 15 litre CAT's all with steel piston crowns (take more heat).

[geeves]

lpg injection is common on diesels nowdays. Dont know how it works on common rails though. Might need to be a computer nerd to set it up. It does improve ecconomy and power by more than the amount of lpg added. In NZ though there are 2 things against doing it to small diesels. Cost A proper kit is 3k+ the bbq cylinder way will not pass a wof and there are no guarantees its safe or controllable. Tax LPG for automotive use is taxed the same way as petrol so on a diesel you pay the road tax on this portion of your fuel twice. I doubt most 4wds would get enough benefits to justify the cost

[MrRevhead]

I would think water and water/meth injection would be the most cost effective way to go.
A proper system apparently gets huge gains. It's on my "hope to do" list