UNDER CONSTRUCTION

LPG systems on Vauxhall Omegas and some of the issues found. This is from a small number of people who have DIY fitted, bought converted, or have paid to convert a car.

LPG conversions are now becoming a common sight and vary a lot on quality, and some quite bizarre conversion techniques have been found. There are no names mentioned and I am not distinguishing between different vehicles. For information the worst conversion seen was a badly fitted OMVL system, this is not a critisism on OMVL - just this install.

Firstly the downright dodgy work.

On vehicles known about we (some friends and I) have seen some pretty dodgy work. On one vehicle the LPG filter was fitted the wrong way round causing fuel starvation. On another the wiring loom touched part of the exhaust system.

Then the bad choices.

We have found in general mixer systems and Omegas do not mix well, especially on the V6 with two separate inlet tracts. Twin mixers are then required, or in one case a single mixer fitted near the air box.

Of course the over tidy

One of the weirdest was hiding the injectors to try to make the system neat, a conversion had the injector blocks hidden under the inlet ducting, and was fitted with unequal length plumbing. This car was a nightmare to get running right, and ended up with the owner selling as is.

Setup errors

The dodgy injector car was also incorrectly setup for RPM signals, my friend who tidied the system could not get it to measure RPM correctly.

The findings from various conversions.

Hot water feed, use the big pipe from the coolant bridge, nowhere else, just the large pipe to the heater bypass valve. It is up to you if you run serial or parallel with the heater, both work well. The water feed for the throttle bodies does not flow enough to heat a vapouriser.

Vapouriser locations

This is an interesting topic, and two places are in common use. One is under the airbox, and the other is in the wheel arch behind the liner. Under the airbox is tighter fit but easier to maintain.

ECU locations

We have seen them in all sorts of places, in the wheel arch, in the scuttle, in the passenger compartment, in the airbox, on the bulkhead by the wiper motor on a 4 cylinder, and also in the electronics box with a small ECU on a mixer system. All have their advantages and disadvantages, if the ECU is big generally in the scuttle area is the best bet, but you MUST keep the drains clear to prevent drowning, and also changing the pollen filter is harder.

Which kit?

There is a huge choice of kits, from budget to very expensive. Most appear to be mid range systems from the likes of OMVL and Romano. The best conversion kit we know of fitted was a BRC system, Stag is common but does not appear to be able to supply a large V6 at full RPM and throttle, with the 3.0 and 3.2 a 4 hole tank and 8mm supply pipe is recommended. Even the 2.5 and 2.6 are borderline with 6mm supply pipe.