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Go LPG! Research - Jaguar V12's |
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Jaguar XJS V12 and V12 XJ saloon models
The XJS and XJ12 range begins with uncatalysed cars utilising the 5.3 litre V12 right through to the 6.0 catalysed versions made until 1996. They are magical cars and seem to be ideal conversion candidates as they have relatively high fuel consumption, but like many things in life, it just ain't that simple........
Early (uncatalysed) 5.3 litre cars
These engines can be converted very well with OMVL Open Loop LPG systems. That said, it is NOT correct to call this installation 'Single Point', as it must be dual (or twin) point. The twin 6 cylinder banks of the V12 require it to be treated as TWO separate engines if done properly, meaning that two components (e.g gas mixers, vaporisers) must be used instead of one for a 6 cylinder conversion.
The increased amount of equipment fitted, the difficult and cramped working conditions take their toll in terms of time spent. We can convert THREE 6 cylinder cars in the time it takes to do ONE 12 cylinder. Go LPG will do the job for you, but be ready for a conversion cost of
at least £2200.
Catalysed 5.3 litre cars
The open loop conversion described above can be made closed loop with the addition of two computerised feedback control systems (OMVL Millenium).
This can give all that a catalysed car needs at less cost (£2500) than an injection conversion.
Catalysed 5.3 and 6.0 cars
6.0 litre cars should only be converted using SGi (Multi point sequential injection) systems. Some owners have a preference for an SGi system on a catalysed 5.3 model. To cater for that, we have two ways of installing SGi, but first, the background....
The problem with SGi is that conversion equipment manufacturers make the systems they can sell most of. None of them make 12 cylinder conversion equipment because so few 12 cylinder cars are currently in production. Large volume car manufacturers no longer make a V12 engine variant at all, Jaguar and BMW withdrew theirs V12 a while ago and the V12 conversion market is tiny. As a result, only 3, 4, 5, 6 and 8 cylinder SGi systems are made by the major LPG equipment manufacturers.
Where does this leave the V12 owner?
At present, there are 2 ways to get around this problem - Either;
Use a modified SGi system which uses a single 6 cylinder ECU to fire 2 injectors at once (making 12). It is a good solution but beware that the ECU manufacturers will NOT warrant the ECU against any fault because it is firing two injectors instead of one, it is being put to a task it was not designed for. Likely cost for this system is around £2700 with a single cylinder tank and no ECU warranty.
-OR-
Have 2 x 6 cylinder SGi kits fitted to work in tandem (remembering that we have to buy 2 complete 6 cylinder front end systems, fit them and wire them up in tandem) and run both from a single switch and tank. This is the best way to do the job by far, but bear in mind that the cost of a 6 cylinder SGi conversion is £1850. To convert a V12 in this way we must fit TWO of those (save the second tank and filler).
Cost of the 2x6 conversion is around £3,200 with a single tank.
V12's are not cheap to convert in any of the ways described above. They are not cheap to run on LPG when set against a comparable 4 litre X300 or XJ8 models although running a V12 on petrol could be a fast track to bankruptcy. It must be remembered that even the best quality V12 cars are exceedingly cheap to buy and no other model drives quite like the turbine smooth V12 masterpiece. The Man who buys a V12 gets a a lot of car for his money.
There is another way of looking at conversion cost, The relatively high V12 fuel consumption actually makes 'payback' of the conversion cost a lot closer. LPG is the only way we know of making a V12 into a usable, affordable, everyday car. 
There isn't much space.
Fitting two SGi 'front end' systems in this cramped space takes many times
Expensive it may be, but running your V12 on LPG will save you an absolute fortune.......... |
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conversion of your XJS or XJ12
(Link is currently available only when
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