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I ran my Insight at fixed throttle on near level road and was returning 75mpg. Simply by introducing LPG into the air intake my instantaneous mpg went up to 150 mpg as I opened the gas valve. Naturally my mpg did not improve but my running costs must go down as a result of the combined costs of the petrol and lpg used. I am new to Insight ownership (2 weeks) and would like to know if this subject has been aired before and if others have had any success in LPG conversion............
 

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LPG and statistics...

I'd say, at the very least, it would give you a very good ranking on the Lifetime MPG database :) But it's kind of cheating if that's the goal...

I don't know, though, LPG is relatively expensive where I live in Utah, I don't know that it would be much of a cost savings. I'd be interested in your (real) MPG statistics using a logbook to see how much combined petrol/LPG you're using.
 

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Some numbers for conversion:

1 gallon LPG = 95,500 BTU
1 gallon gasoline = 125,000 BTU
1 gallon gas/10%ethanol = 120,500 BTU

LPG is priced "per pound" many places, 1 gallon LPG = ~ 4.4 pounds

So, the price per gallon of LPG should not be more than about 3/4 the price of gasoline per gallon for you to be economically better (ie if gas is $2 per gallon, if you pay any more than (2 x .75) =$1.50 per gallon of LPG your BTU's are costing more)

The up-side is that LPG should have an octane rating in the 110 range, so detonation should not be a problem.

If you decide on a full-blown LPG conversion, let us know how it goes.
 

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I had two Hondas converted to run on natural gas (methane). Because the octane rating was so much higher the timing could be dramatically advanced on the engine and also the fuel mixture really leaned out. As a result of this and the more perfect combustion the BTU ratings above don't apply directly. IE you get better combustion efficiency and therefore more net BTUs from non liquid fuel. The company doing the conversions was working on a direct fuel injection system when the price of natural gas began to skyrocket, thus effectively ending the advantage of conversion. Have fun.
 

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Discussion Starter #7
LPG and Gas blend on my Insight

The price of petrol in the UK is fast approaching £5 per gallon (4.54Liters) LPG is around 50 pence per liter nearly half price. My goal is to run my Insight using CNG (compressed natural gas) which is about 12 pence per liter equivalent. And then I can recharge a small tank at home from the houshold gas supply.

At the moment I am using petrol and as I introduce LPG into the air intake the lamda sensor detects the now rich mixture and backs off the normally injected fuel. I did go a bit to far once and the engine fault light glowed reflecting a problem with fuel management. But the error light went away after the engine was restarted twice. Initial trials indicated I can substitute around 50 to 60% without having to be to sophisticated with a complex conversion. When I'm adjusting the gas level whilst cruising I find it better to change the speedo display to metric mode as the imperial limit is 150mpg but the metric mode goes down to below 0.5 liters per 100 kilometers thats a theoretical mpg limit in excess 500 mpg.
 

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Wow, that's interesting.

I was just thinking....should this arrangement be called "Tribrid" as it is using 3 different energy sources???

Just a thought.

Lean Machine, it would be interesting to see a schematic or actual pics of your setup.
 

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Hey, that's hilarious. Your Insight is going into lean burn because of the LPG. Tanks for natural gas are presurised to 3200 psi. A small tank weighs about 110 pounds and is made of half inch thick cold rolled steel. Changing your back springs is a must! Presure regulators are two stage and are made in Italy where this sort of conversion is very common place. Aluminum tanks are lighter but are rather expensive. You should have a range of a couple of hundred miles. Mixture is regulated by a venturii donut with tiny holes. The vacuum created by the air flow opens the Frizby sized regulator. Home compressors are available. Professional shop manuals for installing these systems are available. I probably have a zeroxed copy of one somewhere.
 

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Tanks for natural gas are presurised to 3200 psi. A small tank weighs about 110 pounds and is made of half inch thick cold rolled steel
Maybe some confusion here...the OP mentioned using LPG (liquefied petroleum gas) which is somewhere around 100 psi depending on temperature. You are thinking CNG (compressed natural gas) which requires the high pressure.
 

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Corey872 said:
Maybe some confusion here...the OP mentioned using LPG (liquefied petroleum gas)...

He did say it was for natural gas (see 2nd sentence). And in Lean Machine's post above my useless one, he says he wants to move to natural gas (see 2nd sentence there too...hmm, that's weird).....
 

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Are you an EPA registered mechanic?
 

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I ran my Insight at fixed throttle on near level road and was returning 75mpg. Simply by introducing LPG into the air intake my instantaneous mpg went up to 150 mpg as I opened the gas valve. Naturally my mpg did not improve but my running costs must go down as a result of the combined costs of the petrol and lpg used. I am new to Insight ownership (2 weeks) and would like to know if this subject has been aired before and if others have had any success in LPG conversion............
Sounds good your experiencing, it's how we learn, be careful on the cheap regulator hook up hoses they are outside vented. They leak little gas here.And are the cause of fires, replace often and check for leaks,
that the resson why they say not to use it in car as air flow will carry fumes away, also the tank vented too.
What dangerious about these gases are they are heavier than air and wil go under your carpet if leaked or vented. they suppose to vent at above 110, but some have seen propane vent earlier.stoves has pilots lights.
Do some reading on safety, handling, and You might start thinking about running the hoses underneet. If your set on running it. And find the tank vented hoses and cut a hole to piped leaks down.
They is a small 3-1/2 pound tank that behind your main gas dealer that you can buy it's might be a better storage tank.;)
 

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there is a guy on youtube claiming he did under 1k conversion , he points to these guys for a kit and tank: conversion kit

Sounds easier and simpler than the one posted by Diamondlarry, as their system just shuts off the injectors and the mixing happens a little before the throttle body.

I would have tried this one , but have a lot of stuff to carry at all times for my job and no space for even a two gallon tank ...
 

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there is a guy on youtube claiming he did under 1k conversion , he points to these guys for a kit and tank: conversion kit

Sounds easier and simpler than the one posted by Diamondlarry, as their system just shuts off the injectors and the mixing happens a little before the throttle body.

I would have tried this one , but have a lot of stuff to carry at all times for my job and no space for even a two gallon tank ...
I like this one much better. I may have to consider it.
 

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I cousin owns a fleet of taxi's (80+ Cars/Vans) in the Philippines. In the past 5 years, he has been converting his fleet to CNG.

It's more economical, and engines do not get gummed up.

He said the switch is simple, it is cheaper to operate. (i don't know the price of CNG, nor gas in Philippines).

I think the US has alot now because of the fracking we are doing.
 

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It almost seems that the diesel kit would be a better fit for the I1 than the gasoline kit. Perhaps a bit of both, but probably a little closer to the diesel. If the tanks weren't so heavy it would be great. I have always thought about owning a CNG civic. If I had the home natural gas compressor, I would be all over this.
 
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