F.A.Q.    Register    Login    Home Members    Search

Toymods » Tech & Conversions » 1G-GTE Economy Show: Today's Posts  :: Show Polls  Email to friend

Author	Topic
mrshin Forums Junkie Location: Montrose, VIC Registered: May 2002	Re: 1G-GTE Economy Sun, 28 July 2002 04:36 I run my 4ag turbo on gas, and cost and performance wise I would have to say I'm happy. The question of power/octane/volume/etc. has a few different parts to it, so heres a bit of what I know: 1. LPG is definately a higher octane than petrol, how much by depends on where it comes from. Auto LPG is made up mainly of a mixture of butane and propane. Propane has a higher octane than butane (about 112 RON for propane, 100 for butane), with the overall rating of the fuel depending on how the mix. In Australia, it can be as bad as 50/50, whereas other places like the UK can be lucky to get 100% propane. 2. LPG is a slower burning fuel than petrol. As a result, combustion cannot be as effective with massive revs, kind of like a diesel engine (only nowhere near as bad). The reason diesel engines don't rev too well is because the combustion is too slow, thereby making it absolutely useless. However, this slower combustion can have the advantage of producing a bit more torque at lower revs. 3. A lot of it depends on how its gotten in there! Most LPG systems mix the fuel with the air as a gas vapour. The fuel is passed through a vapouriser, which uses hot water from the cooling system to ensure the fuel is vapourised. Latent heat is the amount of energy absorbed in conversion of a substance from one state to another e.g. liquid to gas (remember, LPG is a liquid while in the tank as its under pressure) LPG has a higher latent heat than petrol, therefore if injected as a liquid into the air, will take more heat from the intake charge than petrol, always a great thing for turbos! By vapourising the fuel before mixing it with the air, this advantage is lost. Also, most LPG systems a pretty crude. They work on some kind of crude carburettor effect to mix the fuel and air, in whatever quantity happens to get there. This also means that there is an air restriction to get the fuel in there, just like a carby. Most LPG conversions meet emmisions standards by crude feedback processors that work by slightly altering fuel pressure with engine vacuum being modulated by a simple circuit connected to the oxygen sensor. There are many other things relevant, but at the end of the day it comes down to not that the fuel is inferior, but the way its generally brought into the engine is! I'm probably going to be doing an LPG 1G project sometime in the next couple of months, just to get an old celica I've got going again. I used LPG on my ae86 for a couple of reasons, namely that I had already converted the car about 12 months before (cost me $500 for the parts, $50 for the compliance) therefore the tank etc. was already in place. Also, cost. I used a Gasresearch LPG system, which only cost me about $500 to buy, and a haltech IG5 for the ignition. This definately cost a lot less to install and tune than an aftermarket management system ($?), as well as fuel pump, bigger injectors, etc. I seem to have rambled on now don't I [Report message to a moderator]

	Subject	Poster	Date
	1G-GTE Economy	CamZH	Tue, 23 July 2002 11:00
	Re: 1G-GTE Economy	Lucid	Tue, 23 July 2002 12:51
	Re: 1G-GTE Economy	Lucid	Tue, 23 July 2002 12:53
	Re: 1G-GTE Economy	Nark	Tue, 23 July 2002 23:59
	Re: 1G-GTE Economy	Fattony	Fri, 26 July 2002 09:34
	Re: 1G-GTE Economy	duckman	Fri, 26 July 2002 09:44
	Re: 1G-GTE Economy	Fattony	Sat, 27 July 2002 10:04
	Re: 1G-GTE Economy	Cory	Sat, 27 July 2002 12:38
	Re: 1G-GTE Economy	Allan	Sat, 27 July 2002 13:31
	Re: 1G-GTE Economy	Cory	Sun, 28 July 2002 01:45
	Re: 1G-GTE Economy	Fattony	Sun, 28 July 2002 02:58
	Re: 1G-GTE Economy	Fattony	Sun, 28 July 2002 03:12
	Re: 1G-GTE Economy	mrshin	Sun, 28 July 2002 04:36
	Re: 1G-GTE Economy	mrshin	Sun, 28 July 2002 04:43
	Re: 1G-GTE Economy	Allan	Sun, 28 July 2002 05:08
	Re: 1G-GTE Economy	mrshin	Sun, 28 July 2002 12:40

Previous Topic:	my super revvy 4ac
Next Topic:	Attn: people with Jap spec T50s....

Powered by: FUDforum 2.3.8
Copyright ©2001-2003 Advanced Internet Designs Inc.