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 Post subject: LPG
PostPosted: Wed Sep 25, 2013 6:45 pm 
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Clubman

Joined: Sun Apr 29, 2012 4:23 pm
Posts: 90
Car Model: None
Do we have anyone running an LPG'd Gt-four on the boards?

I quite like the idea of fitting a system as a bit of a project. I noticed you can get branded systems for fair prices these days.
I was thinking of having a torodial tank in the spare wheel well.
Will a generic 4 cylinder sequential kit from the likes of BRC be ok or do you need specific components to support sufficient gas flow for turbo power? I'm not entirely clued up on the different types fo system out there.
Do they 'map' directly off the OEM ECU injector outputs? is it possible to set them up DIY or best to have a qualified installer do it?


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 Post subject: Re: LPG
PostPosted: Wed Sep 25, 2013 6:54 pm 
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Joined: Wed Jul 13, 2005 12:14 am
Posts: 3265
Location: Camberley, Surrey
Car Model: ST205
Nibbles is the person to ask. He has been running LPG on his for ages.

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 Post subject: Re: LPG
PostPosted: Thu Sep 26, 2013 5:53 pm 
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Group B
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Joined: Sat Sep 02, 2006 3:13 pm
Posts: 3679
Location: Bournemouth
Car Model: None
Yup, been running LPG for a lot of miles now. Now had to re-shim the head twice and the engine will soon be coming out for a new clutch so will strip and have a good look at things then. Probably worth going for valve lube too as it looks like the cost per mile is minimal and will save the head wear.

Mine is the Prinz VSI system which piggybacks from the standard injectors to fire the LPG injectors, so all the mapping, safeties and closed loop control of the standard ECU is retained. The LPG injector time is proportional to the time the standard ECU sends drive to the petrol injectors with a 'zero and span' adjustment so it's not the most accurate on fuelling. I think newer system can add a MAP sensor to allow more precise mapping.
Mine doesn't affect ignition timing, and I'm not aware any others do. There are gains to be had by running a bit more advance as LPG is much higher RON and I believe slightly slower burning than petrol.

My setup uses a donut type tank in the spare wheel well, which doesn't leave much boot space when you still want to carry a spare wheel. A small price to pay to be able to run a GT4 for the same fuel cost per mile as a small diesel. The only thing I will point out is that short journeys are not efficient as it needs to run on petrol for a mile or 2 until the engine is warm enough. I still have a small diesel for trips less than 20 miles.

There was someone on the OC who paid near £2K I believe for a full professional install which apparently gave full power on LPG. I did ask for more details on manufacturer details but didn't get any information. He's since sold the car I believe.

One of my friends fitted a secondhand EBAy sysem which cost £200 on his GT4 with similar results to mine. I dodn't know the details of it but I believe it was fitted to a Lancia turbo beforehand.


A few old threads. (I think the ccuk ones are visible without joining but it's not a huge sum and a nice club anyway)

viewtopic.php?f=1&t=6523&hilit=regression

http://www.celica-club.co.uk/forum/inde ... ion-going/

http://www.celica-club.co.uk/forum/inde ... xperience/

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 Post subject: Re: LPG
PostPosted: Sun Sep 29, 2013 8:03 pm 
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Joined: Sun Apr 29, 2012 4:23 pm
Posts: 90
Car Model: None
:D Thanks nibbles,

Quick question - does your system support full power on purely LPG? If not how does the transition from gas to petrol work? Is this something that is a specific feature of the LPG ECU you are using and is there not a high risk of split-second lean conditions?

I saw the thread on GT4OC (can read the forum by spoofing browser as googlebot) of the full power system. I think it used a BRC Genius MAX reducer which from what little data I can find is good for ~350hp. It's a very expensive bit of kit though and the BRC systems don't seem very DIY friendly - you have to get them setup at an approved installer etc and BRC pretty much told me to 'go away' when I requested some info from them :P
I've been reading on LPGforum a fair bit over the weekend - there looks ot be a good few reducers available which support 300hp for not a lot of money. The STAG systems seem to get good writeups, particularly the ECu's.

May I ask the exact size of the donut tank you are using? I noticed when attempting to measure up yesterday that the threaded section used to bolt down the spare wheel is raised up from the wheel well - is the tank able to sit flush in the well?


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 Post subject: Re: LPG
PostPosted: Sun Sep 29, 2013 8:19 pm 
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Joined: Sat Sep 02, 2006 3:13 pm
Posts: 3679
Location: Bournemouth
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The system would support full power if it had bigger injectors (and maybe bigger evaporator). Mine are yellow spot which are second largest in the range.

Transition between systems is far from smooth and is best done manually while the right foot is lifted otherwise you get a pretty big jolt. Basically, it just switches the whole lot in one go - tank solenoid and all injectors. Newer systems do one cylinder at a time so it's smoother.

There is indeed a risk of running lean, and I suspect that is the reason I found a receipt for an engine rebuild a few months after the date on the LPG certificate !!!! The driver must take care with the right foot. I have also disabled the boost solenoid while in LPG mode as it seems able to cope with just actuator boost.

For me, the system is there so I can travel on normal roads at normal road speeds at a sensible cost, as that is probably 99% of the milage I do. For the 1%, there is the petrol mode switch.

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