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Part 1 - LPG Conversion Research

<< | LPG Conversion Index | Part 2 - LPG Kit >>

This section addresses the research before buying the kit. The second section is the ongoing research with any new information.

Pre-purchase Research

At the time of writing Optimax 98ron fuel was 1.25 per litre and LPG only 0.54 per litre.

Web sources reveled that there are many people who were performing DIY conversions and that this is perfectly legal as long as it is signed off by an LPGA installer afterwards. Here is the best bit, all you have to say to the LPGA installer is that you require your annual safety check and they will issue you with a certificate if/when it passes!

The author contacted his insurance company, who merely said to inform them when the car had been converted. There was no requirement to supply a fitment certificate as the car was insured modified already. For unmodified Subaru's check with your insurance company first.

The author had already visited and also checked out the threads on various Subaru forums, but found it difficult to seek advice from people who had first-hand experience. There was no other information on the web regarding converting these cars!

So even with a whole wealth of knowledge from Scooby forums and a dedicated LPG forum the author was still a little in the dark about LPG on an Impreza. It was clear that a turbo car could be converted successfully without much hassle. The LPG forum had many owners with various turbo cars running without a glitch. Most of these owners were now using multipoint sequential systems that not only removed the poorly performing mixer systems that caused backfires in the manifold but also allowed improved performance similar to that of petrol.

Information on stated that Subaru's with solid valve lifters should not be converted. The reason for this is that any valve wear will not be automatically adjusted and adjusting the tappets is not an easy task. From what people have said around 40-50k miles should be possible without any adjustment. The author will be using a flashlube system to combat this problem so we will see what happens.

The next point of call was Tinleytech (, as these were the only people the author knew of that sold the DIY kits. With a million and one questions in my head that I needed answering before deciding on converting my own car. I should mention that I have since found many other kit suppliers since my own conversion. As I have no experience of these I have simply placed the details within the links page.

After a lengthy discussion with the guys down at Tinleytech, I had more or less decided to buy the kit and get it done. After all, what harm could it do?

So the kit was bought and the conversion started. At this stage there were still many unanswered questions such as what spark plugs to use, will the valve seats be ok, will the car suffer heat issues, will I get detonation on boost, where will the filler be located, exactly how will the tank be mounted, where will I find the space to fit this kit under the bonnet, what do you need to do to inform the DVLA and the list goes on and on. Even though these questions are easily answered for most vehicles, there were no definite answers specific to the Impreza.

What I am hoping that people grasp by the questions shown above is that I more or less jumped in feet first with very little knowledge, that much is true. If you read the other pages all of the questions are answered along the way and you will find that most concerns are bourn from the myths that surround the use of LPG.

Please see the links page for the various sites I used and still use for research.

Ongoing Research

Found some info on a company that has converted an Impreza STI with 300hp to LPG.

And another

Information Source - ScoobyLPG website, republished with permission,

<< | LPG Conversion Index | Part 2 - LPG Kit >>

Page last modified on June 13, 2008, at 06:38 AM
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