Mirage LPG conversion (Thailand)

[foama]

Question:
Does somebody know for certain if the Mirage engines are on one of the gas-conversion blacklists? On which list in particular?

[uheym]

Found some more pictures and text in Thai ..

https://translate.google.com/transla...4-qbox-hana%2F

[RodeRoNL]

I asked the Mitsubishi importer in the Netherlands about LPG. The reply was that not a single Mitsubishi is suited for LPG. When LPG is used and the engine suffers damage related to LPG use, there is no warranty. The problem is that the use of LPG limits the durability of the valves, valve seats and cylinder heads. As a second opinion, I asked the dealer about specifically the Space Star (Mirage). He also stated that the Space Star (Mirage) was not suited for LPG use.

So, it seems best to close this thread?

[cyclopathic]

This maybe true LPG is said to cause intake valve seat recession on some models due to lack of lubrication.

[91cavgt]

One positive side of LPG conversions is the extended oil change intervals. The oil does not get diluted with fuel the way it does in a gasoline powered engine so you can go longer between oil changes.



It appears as though the setup on the Mirage pictured is a dual purpose setup. One that can run on either gasoline or LPG.

[cyclopathic]

One positive side of LPG conversions is the extended oil change intervals. The oil does not get diluted with fuel the way it does in a gasoline powered engine so you can go longer between oil changes.

It appears as though the setup on the Mirage pictured is a dual purpose setup. One that can run on either gasoline or LPG.

Still doesn't make much sense for US of A.

Cheapest LPG fill at Costco $9.99/tank+tax, and with ~3.6-3.7gal/tank this calculates to ~$2.95/gal. And the energy density of LPG per gal is lower than of gasoline.

[91cavgt]

Still doesn't make much sense for US of A.

Cheapest LPG fill at Costco $9.99/tank+tax, and with ~3.6-3.7gal/tank this calculates to ~$2.95/gal. And the energy density of LPG per gal is lower than of gasoline.

That is for a gas grill propane tank, not for over the road propane cost. Here in Texas, I just looked online and found prices as cheap as $1.59 a gallon. Granted, that still would not be worth it in my opinion due to the lower BTU content than gas. However the other advantages may outweigh the lower fuel economy for some people.


I wonder if propane users have ever thought about installing a very small water injection setup in order to lower combustion temps? My experience with water injection has seen a drop in exhaust gas temps of 200-500 degrees F.

[inuvik]

I wonder if propane users have ever thought about installing a very small water injection setup in order to lower combustion temps? My experience with water injection has seen a drop in exhaust gas temps of 200-500 degrees F.

Years ago I remember seeing a water injection system in the JC Whitney catalog. Worked off a vacuum line. Never knew anyone who had any real world experience with one.

[91cavgt]

Years ago I remember seeing a water injection system in the JC Whitney catalog. Worked off a vacuum line. Never knew anyone who had any real world experience with one.

Those vacuum operated water injection systems did not work very well at all. I have built 2 different water injection systems. A VERY basic one and a much more effective one.

The basic setup included a fuel pump from a Nissan Z car, a fuel pressure regulator from the same car, and a cold start injector from once again the same car. This setup was installed on a 1989 Pontiac Sunbird GT Turbo which at 14 psi of boost lowered EGTs down 200 degrees from 1600 degrees F down to 1400 degrees.

The more proper water injection system was installed on a 2003 Dodge SRT-4 (2.4L turbo running 19 psi of boost). It consisted of a ShurFlow 100 psi RV water pump, 2 Hobbs pressure switches, 2 solenoids, and 2 injectors/nozzles. This setup ran MUCH better as I had it set to activate the small injector at only 7 psi of boost, then the large injector was activated at 14 psi of boost. This setup lowered the exhaust gas temps down from 1720 degrees down to an average of 1400 degrees with an occasional, perfect scenario drop down to 1200 degrees.

A small, basic water injection setup that utilized a small 1 gallon tank in the trunk would easily be able to drop the combustion temps at cruise 100-200 degrees F.

[redline81]

Hi All! Not sure if this is the correct place to post my setup, I'm from Italy and given that my first post (here) raised quite some curiosity I've decided to separately post some pics about the equipment and work done for LPG conversion.

My Mirage was used as demo car by the local Mitsubishi dealer so I got it as-is with only 50 km on the odometer and a good discount. My initial interest was into the dual fuel version (Bi-Fuel) and unfortunately there was no possibility for the dealer, due to the lack of equipment and expertise, to convert my mirage to LPG in a "official" way. They however told me that the LPG equipment supplier for the Bi-Fuel version of our Mirage (Space Star in Italy) is BRC and the engine is 1.2L (must be 3A92 for sure), so I went to a couple of authorized BRC partners in my area for a quotation. One of them immediately told me that BRC initially banned the elder 3A91 engine in Mitsubishi Colt for unspecified issues and in case of installation on those cars, the warranty on the LPG components would be immediately void! He also told me that for 3-inline engines, he has reported intermittent engine shutdowns at minimum RPMs for some BRC installations. Not being sure of the improvements Mitsubishi has made on my 3A92, the LPG specialist told me that
AC-STAG, a professional LPG equipment manifacturer based in Poland, would have been the best fit for the Mirage.
In addition to this, I was not sure of the mechanical improvements needed to 3A92 to run on LPG on my Mirage, such as hardened valve seats. To be sure it would run long enough before wearing valves and seats, the specialist suggested to add a valve protector liquid injection system. Nothing much complicated, just a little 500ml tank which drops a little quantity of liquid valve protector on the intake manifold. Very little quantity, such as 1L every 1000L of LPG.

So let's begin with the tank, a round, nominal 30L fitted in the spare wheel vane:


Tank raised the trunk 2 or 3 cm, looking at the warning sign behind the back seats.



LPG filter, main tubes and ECU connector



LPG injector rail, note that a 4-inline rail was fitted, it had the same cost and provided me a spare injector to use, just in case. The spare one is obviously well capped.



Here the connections with the intake manifolds, very close to the gaskets:



And there's the ECU, fitted with a short bracket on the back side of the battery



The valve protection system:



And its simple, depression-based injection on the intake manifold:



I'm not 100% sure if it's really needed, but given that there's not much literature on the aftermarket 3A92 LPG conversion, I guess it's better to have it.

Last, the level indicator and LPG/Gasoline switch



Hope this will help someone else having a better understanding on the equipment and modifications needed!
So far, I can tell that there no difference in engine power, behavior, reliability whatsoever before or after the mod. The only thing I feel different is a little bit of weight more on the back, but it's really little thing.

Cheers!