LPG Discussion Forum

I have been charged, if you will excuse the pun, on fitting a LPG system to my old mates 55 Range Rover Sport Supercharged. I am not to concerned about the mechanical side of things as I have some experience after fitting my own sytem using one of Rosskos kits to my P38 RR.
My question is that what is considered to be the Rolls Royce of Gas systems ? My reasearch is leading me in the direction of Prins. I just wondered if any installers on here have a personal favorite system with regards engineering quality. Does Prins produce an adaptive ECU? I cant find any reference on their site.

Rewmer wrote: My reasearch is leading me in the direction of Prins.

That's what I would use, but I have access to Prins support! This will be a demanding install on the kit, so you are right to consider if the kit is up to it .. but also if you can get support.

I'd approach with caution myself, the Jaguar turbo lays a couple of traps - the commonest pitfall is that it is quite fussy about the injector emulation used (standard Prins emulators won't work, for instance). On some, you may have to deal with petrol pressure issues too.

Rewmer wrote: Does Prins produce an adaptive ECU? I cant find any reference on their site.

No, the car is already fitted with an adaptive ECU and the Prins VSI is enslaved to it.

As Rossko said, you might have the mechanical skills to do a good install but there will be a few things there to trip you up.

The engine is derived from the supercharged Jags and there was an S-Type R owner on here a while back who had some big issues with his conversion that had been carried out by a supposedly professional installer. If memory serves me right one of the problems was to due to where the coolant pipes were tapped into to feed the vapouriser. I know that the supercharged Jags have 3 water pumps and it's definitely not a run of the mill cooling circuit. What you certaintly don't want to do is cause any overheating problems with the supercharger.

Just managed to find that thread about the Jag.

h*t*t*p://my90.co.uk/lpg/viewtopic.php?t=5938&highlight=supercharged+jag

remove the *'s at the start of the url as you cannot post urls on here...

Thanks for the replies guys. I have no doubt it will be a testing install. I had read that post but had only got half way through before dismissing the author as "one of those customers" that we see here in our fab shop once in a blue moon, but reading on it would seem that he did indeed have some valid points re the cooling flow, something that I hadnt considered with the planned install.

The reason I ask about adaptive ECU is that I have read a few posts on the newer gas ECUs reading the fuelling adaptions from the petrol Ecu and therfore staying in tune better. Is this the case, or is it a bit of gimmick ? I also have picked up on the fact that a fpetrol fuel return is required, has any one any experience of how this is acheived ?

I would also be interested in a ball park figure for carrying out the conversion at your works Rossko, feel free to PM me.

Andy

re, the fuel return

As I carried out on my Jag.

It's just a matter of putting a t-piece into the fuel supply line and taking a fuel hose to a 12V solenoid valve which is suitable for petrol then taking a hose back to your tank. The best place to tee into your fuel supply line is as close as possible to the fuel tank therefore your return pipe will be very short. Whether you can do this or not depends on how easy it is to tee into the fuel line and how much room you've got for the solenoid and return hose etc. You also don't want the solenoid valve exposed to the road where it could be damaged by stones as well as corroding. In an ideal world it would great to tee into the fuel line with a nice stainless t-piece and run a steel pipe up inside the rear wheel arch liner close to the petrol filler, couple directly onto the solenoid then directly into the filler neck of the tank without the use of any rubber fuel hose or clips at all.

In order to keep things simple I located my petrol return solenoid inside my engine bay and fed the hose back to the filler neck of my tank protected in some thick wall pvc conduit.

When the temp at my vapouriser reaches the correct temp to vapourise the gas the ECU opens the solenoids on my tank and and in my engine bay and the car switches over to lpg. I've used the 12V gas solenoid supply to also power my petrol return solenoid, so when the gas solenoids open the petrol solenoid also open which allows the petrol to be returned back to the petrol tank. Because the lpg solenoids open a couple of secs before the switch to gas I thought that it might be best to wait a few secs more for the petrol solenoid to operate in order not to reduce the petrol flow too early but it works just fine with all solenoids working at the same time.

I had purchased my kit from a very well known supplier who knew I was fitting the kit to a Jag but they didn't supply me with the petrol return parts as they should have done with the kit, it was indeed Rossko who advised me.

Thanks Redzed, that is indeed a nice tip and will add this to my install info file. May I ask which system you are running and how do you find it ?

I've been running a Bigas system from Tinleytech for 2 years now. It wasn't at all difficult to install if you're a hands on engineer. There's a member on here that installed a Bigas system to his 330bhp Impreza but I have my doubts as to whether the Bigas components will be capable of supplying enough lpg to a 385bhp V8.

The skills required and the conversion procedure is as follows.

Plumbing, to install the gas pipe, ie, cutting the copper pipe and using the supplied compression nuts and olives to connect up to your filler, tank solenoid and engine bay solenoid and vaporiser. You also need to Tee in or re-route your pre-thermostat (heats up quicker) coolant flow to your vapouriser in order to heat up the liquid lpg and vapourise it. You'll also have to tee into a vacuum source to connect one hose to your pressure sensor and from the pressure sensor to one of your lpg injector rails. I found it easier to pick up a vacuum directly from my inlet manifold which involved drilling/tapping an M6 thread and screwing in one of the supplied nozzles.

Mechanical, to attach the copper pipe run from front to back and make any necessary brackets to attach the vapouriser, front engine bay solenoid, injector rails, petrol return solenoid and the ECU. You'll also have to remove the inlet manifold in order to drill and tap each cylinder port and fit your lpg nozzles. In my case it was just a matter of drilling and tapping the inlet manifold as low down and as close as possible to the petrol injectors.

Electrical, very similar to wiring a top end car alarm.

1) splice into the negative/switch wire on each individual injector in order to send the petrol injector signal back to the LPG ECU and switch each petrol injector off in turn (sequential) and and start injecting the lpg instead of the petrol.

2) Plug in the ECU harness to the injector rails.

3) connect the (usually brown) rpm wire to a rpm signal which can either be the rev counter, negative wire on one of your coils, crankshaft sensor or camshaft sensor etc.

4) connect a 12V, LPG on wire to power the 2 lpg and single petrol solenoids. Also feed another (usually white) wire to connect up to the lpg level gauge on your tank. You'll also have to wire up the associated negative 0V wires for these components.

5) connect the (usually purple + purple/black) oxygen sensor wires, to the pre-cat negative oxygen sensors on both banks.

6) connect up the temp sensor wires on your vapouriser and on one of your injector rails.

7) Fix the lpg switch/display somewhere on the dashboard and feed through and connect the wiring.

connect the fused 12V ECU power supply wire and associated earth.

9) plug in the pressure sensor.

I think that's about it

The Bigas system has an Auto Calibration feature which allows you to get the car running on lpg before you fine tune the system.

Redzed, I've not done a Jag turbo myself. Did you need to size a restriction in the fuel spill line? I had to this with a Volvo T5, it has a self-learning pump drive arrangement which all went wrong if either too much or too little fuel passing. Blocked up a pipe with solder and drilled out to about 2.5mm if I recall. Same Ford-based fuel system, I thought.

Did someone say this was going to be easy ?

rossko wrote:Redzed, I've not done a Jag turbo myself. Did you need to size a restriction in the fuel spill line? I had to this with a Volvo T5, it has a self-learning pump drive arrangement which all went wrong if either too much or too little fuel passing. Blocked up a pipe with solder and drilled out to about 2.5mm if I recall. Same Ford-based fuel system, I thought.

Unfortunately Rossko I only have a lowly 3.0 V6.

Rewmer wrote:Thanks Redzed, that is indeed a nice tip and will add this to my install info file. May I ask which system you are running and how do you find it ?

I forgot to say that the Bigas system works very well with no noticeable difference on LPG.

As previously mentioned I'm not too keen on some of the wiring. The injector rails have got wires that go straight into them where many other and even cheaper rails have a superseal socket built into them. An example to use would be the single coils that you'll find on most top end cars these days. You don't get wires coming out of the coils with a superseal connector on the end do you. As confirmed by Rossko a good while back the temp sensor wiring quality leaves a lot to be desired with bugger all support on the wires coming out of the brass body of the sensor. I've since made my own sensors with 4.7k thermistors (also advised by Rossko). It's very handy having my own lathe for such things.

We fit Bigas d have never had a problem with the injector coils but they have now been superceeded (about 2 yrs ago) with the improved black injectors which have superseal plugs on the coils.
We did have a few problem temp sensors but they have now also been improved which seems to have fixed it.
I did my mates supercharged L322 with Bigas and it is fine, definitely need to use the adaptive ecu and petrol return though.

Hi all.
I am currently in the middle of converting my S-Type R (same engine).
After extensive research I went for the Vogas Plus kit from wtv. This uses the Voltran reducer which is good for 400bhp and uses separate injectors rather than a rail.
I'm running a smaller top charger pulley and will soon be getting a larger lower pulley and water/meth injection so i'm fitting two reducers (good for 800bhp!). I also have a Haltech dual map programmable ecu so I can run advanced timing for the LPG.
You should have a lot more room in the engine bay than me so life should be a lot easier. The supercharger has to come off to get the charge coolers and inlet manifolds off. This involves removing intake, throttle body, egr valve and charger intake elbow (all that is to get to the back charger bolt!) then the thermostat housing and hoses at the front need to come off. I had to take a cam cover off to get to the egr bolts.
I've managed to get the nozzles within 20mm of the petrol injectors.
The reducers will be going where the air box was and a custom induction will have to be made.
Hope some of this helps. Let me know if you want to know anything else.
I'm taking my time over this but the engine should be going back together soon.
I'd recommend installing new gaskets wherever you come across them as if anything turns out to be leaking when you've finished then the charger will have to come off again.

May be worth speaking with Richard Strange at Ullswater Road Garage, Penrith Tel: 01768 864546.

He's converted this type of Jag and is a gold mine of information.

I've seen the finished result and it's mighty impressive. He'll give you all the gen on what reducer to use, etc..