Thread: r/r tuning

Chip won't affect the LPG, try a dyno tuner and get him to check the advance curve on the distributor. If you want power, go gas injection. Member Junosi is importing himself a Marelli kit for his P38A.

There is no better way than more cubic inches.

Get a 4.6 kit, replace the bottom end and keep top and bolt back on.
May be some valve work and a Motec or Haltech computer.
That will make a big difference, rest is just a fiddle with marginal gain.

Been there 3 times and at the ned of day you have a new motor.
Get the high compression one too.
Seems to like gas better.
The 4.6 uses less fuel also as you don't need to step on it as much.

From my experience "sequent LPG injection system" will not work successfully on 3.9 Classic Range Rovers,as they do not have oxygen sensors, and the later model electronics to run with the LPG electronic system.Best you can do is fit a standard LPG system,including a new distributer with advance curve set for LPG,the best 9mm ignition leads, and a blow off valve on air filter or intake hose.
Alternatively buy a post 1999 Disco with a 4.0l "Thor Motor"complete with exhaust, wiring and computer,to replace your system.Should you know of any one who will be willing to do this at a reasonable price and know what they are doing ,let me know as this would be my preferred option. Peter.

I have read the Magneto marelli instructions and guide and see no real reson why it would not work with 14CUX, as it takes the duty cycle of the the injection signal and then translates it to gas.

AFAIK the magneto Marelli is "sequential" but can operate with batch injection ECUs.

This is a quote from the section on injector nozzle size from the magneto Marelli fitting instructions for

Installation and programming of OSCAR-

multipoint sequential gas injection system

.

The table below contains list of nozzle diameters depending on power for 1 cylinder. To read out
the nozzle diameter for given engine correctly it is necessary to divide the engine power by number
of cylinders.
Please note that the figures in the table are only approx values and in some cases may not
agree with real ones.
Such situation can appear in vehicles fitted with semi-sequential or full group injection (all injectors
activated simultaneously) . In such vehicles the nozzle diameters will be smaller than
these given in the table due to the fact that in such type of LPG supply control the volume of
supplied LPG is greater than for full sequence – twice for the semi-sequential and four times for

full group injectors.

14 CUX can be fitted with Lambda sensors but it seems to me from the instructions that the lambda sensors referred to are directly linked to the Gas ECU .

Regards Philip A

Originally Posted by newmanps@bigpond.net.au

From my experience "sequent LPG injection system" will not work successfully on 3.9 Classic Range Rovers,as they do not have oxygen sensors, and the later model electronics to run with the LPG electronic system.Best you can do is fit a standard LPG system,including a new distributer with advance curve set for LPG,the best 9mm ignition leads, and a blow off valve on air filter or intake hose.
Alternatively buy a post 1999 Disco with a 4.0l "Thor Motor"complete with exhaust, wiring and computer,to replace your system.Should you know of any one who will be willing to do this at a reasonable price and know what they are doing ,let me know as this would be my preferred option. Peter.

I have fitted gas injection to a pre-sensor P38A, it ran a treat. Group injection is acceptable too, so the Classic/D1 engine should be fine. I have converted a group firing Volvo 960, the only issue is the noise the converter makes with the larger pressure surges. Since then I have been mounting the converter with a soft rubber mount and flexible supply hose.

Oxygen sensors are readable by the gas injection software, but the gas injection time is set from the petrol injection time. So you can install a sensor just for the diagnosis and use it to set your mixtures, but it won't adjust the running in real time. The most recent injection systems will read the OBD2 data stream to adjust mixtures, but that's optional, and un-neccesary for pre sensor cars.