Range Rover 4.6 on LPG needs re-map

Hello folks:

I have a '99 4.6 HSE which is LPG converted, but I only get 11.2 MPG on LPG
(OK - I know it's a really big heavy car).

It could be that the "Thor" EMS is confused by the LPG system and is not
advancing the spark enough to cope withthe higher octane LPG.

Anyone know if it is possible to get the chips on the THOR re-mapped?

RPi engineering do it for the earlier GEMS EMS but not for the THOR.

Apparently they get 15% better power and economy too.

All experiences/tips/hints welcome.

Regards,

Dan.

"Danny Clarke" <[email protected]> wrote in message
news:[email protected]...
> Hello folks:
>
> I have a '99 4.6 HSE which is LPG converted, but I only get 11.2 MPG on
> LPG
> (OK - I know it's a really big heavy car).

My 110, with a 4.0 and weighing 2.5 tons, only does 12mpg on LPG. What were
you getting on petrol?

> It could be that the "Thor" EMS is confused by the LPG system and is not
> advancing the spark enough to cope withthe higher octane LPG.

If that were the case, I'd expect it to have gone into limp mode, usually
with the engine check light on the dash illuminated as well.

> Anyone know if it is possible to get the chips on the THOR re-mapped?
>
> RPi engineering do it for the earlier GEMS EMS but not for the THOR.

Dan, as I understand it, the Thor engine IS using the Gems (SAGEM)
management system, the earlier versions of 4.0/4.6 using MEMS and 3.9 using
Lucas 14CUX. Contact them direct and confirm.

> Apparently they get 15% better power and economy too.

Allegedly. You don't get something for nothing, in my book. The main reason
for the re-map is to preserve engine life by correcting the over-lean light
throttle cruise condition.
Badger.

On or around Fri, 10 Jun 2005 23:54:52 +0000 (UTC), "Badger"
<[email protected]> enlightened us thusly:

>My 110, with a 4.0 and weighing 2.5 tons, only does 12mpg on LPG. What were
>you getting on petrol?

Mine used to get about 11 on a good day with a knackerd 3.5. However, the
disco, with a decent 3.5 (and a manual box, FWIW) gets a bit more'n 13.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Appearances: You don't really need make-up. Celebrate your authentic
face by frightening people in the street.
from the Little Book of Complete B***ocks by Alistair Beaton.

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Fri, 10 Jun 2005 23:54:52 +0000 (UTC), "Badger"
> <[email protected]> enlightened us thusly:
>
> >My 110, with a 4.0 and weighing 2.5 tons, only does 12mpg on LPG. What
were
> >you getting on petrol?
>
> Mine used to get about 11 on a good day with a knackerd 3.5. However, the
> disco, with a decent 3.5 (and a manual box, FWIW) gets a bit more'n 13.
>
Are you on open or closed loop? I'm still thinking about closing the loop on
mine - at best I've got 13mpg but its normally about 11.5. 3.5 carbed pre
emission control rangie.

"Andy Warner" <[email protected]> wrote in message
news:[email protected]...
>
> "Austin Shackles" <[email protected]> wrote in message
> news:[email protected]...
>> On or around Fri, 10 Jun 2005 23:54:52 +0000 (UTC), "Badger"
>> <[email protected]> enlightened us thusly:
>>
>> >My 110, with a 4.0 and weighing 2.5 tons, only does 12mpg on LPG. What
> were
>> >you getting on petrol?
>>
>> Mine used to get about 11 on a good day with a knackerd 3.5. However,
>> the
>> disco, with a decent 3.5 (and a manual box, FWIW) gets a bit more'n 13.
>>
> Are you on open or closed loop? I'm still thinking about closing the loop
> on
> mine - at best I've got 13mpg but its normally about 11.5. 3.5 carbed pre
> emission control rangie.
>
>
>
>
My 4.6 does just under 12mpg, but that's almost all town work (with wife
driving).
Much better on a run
nearly 17mpg on LPG. I'm using OMVL sequential.

On or around Sat, 11 Jun 2005 12:14:31 +0100, "Andy Warner"
<[email protected]> enlightened us thusly:

>
>"Austin Shackles" <[email protected]> wrote in message
>news:[email protected]...
>> On or around Fri, 10 Jun 2005 23:54:52 +0000 (UTC), "Badger"
>> <[email protected]> enlightened us thusly:
>>
>> >My 110, with a 4.0 and weighing 2.5 tons, only does 12mpg on LPG. What
>were
>> >you getting on petrol?
>>
>> Mine used to get about 11 on a good day with a knackerd 3.5. However, the
>> disco, with a decent 3.5 (and a manual box, FWIW) gets a bit more'n 13.
>>
>Are you on open or closed loop? I'm still thinking about closing the loop on
>mine - at best I've got 13mpg but its normally about 11.5. 3.5 carbed pre
>emission control rangie.


All mine have been open loop.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"My centre is giving way, my right is in retreat; situation excellent.
I shall attack. - Marshal Foch (1851 - 1929)

>>>>> "Danny" == Danny Clarke <[email protected]> writes:

Danny> Hello folks: I have a '99 4.6 HSE which is LPG converted,
Danny> but I only get 11.2 MPG on LPG (OK - I know it's a really
Danny> big heavy car).

What do you get on petrol? Are you getting a big power difference on
petrol/lpg? And what kind of LPG system do you have fitted?

Danny> RPi engineering do it for the earlier GEMS EMS but not for
Danny> the THOR.
Danny> Apparently they get 15% better power and economy too.

Only on petrol, though they don't go out of their way to point that out!

I think you need to look to the setup of the gas system first....


--
Andy Cunningham -- www.vehicle-diagnostics.co.uk
Feudalism: It's your Count that Votes.
Democracy: It's your Vote that Counts.
Communism: Your Votes don't Count.

"Badger" <[email protected]> wrote in message
news:[email protected]...
>
> Dan, as I understand it, the Thor engine IS using the Gems (SAGEM)
> management system, the earlier versions of 4.0/4.6 using MEMS and 3.9
> using Lucas 14CUX. Contact them direct and confirm.
>
OOps, wrong way round! Thor is Motronic system, not SAGEM. Sorry.
Badger.

"AndyC the WB" <[email protected]> wrote in message
news:[email protected]...
>>>>>> "Danny" == Danny Clarke <[email protected]> writes:
>
> Danny> RPi engineering do it for the earlier GEMS EMS but not for
> Danny> the THOR.
> Danny> Apparently they get 15% better power and economy too.
>
> Only on petrol, though they don't go out of their way to point that out!

Not strictly true Andy, if you are running a modern SGI gas system, the
pulse that initiates gas injection is taken directly from the petrol
injector harness, ie it comes from the petrol ECU. So, if the fuelling
output signal of the ecu is altered, this results in an alteration to the
injector pulse-width, this is picked up by the SGI control unit which in
turn fires the gas injector for a correspondingly longer pulse also. Any
alteration to the petrol ecu is seen at the gas ecu when running on gas.
If you were referring to older standalone gas systems, then you are
perfectly correct, BUT those older systems would never get installed on a
Thor anyway, due to the complexities of the management system.

> I think you need to look to the setup of the gas system first....

Agreed.

--
Badger.
B.H.Engineering,
Rover V8 engine specialists.
www.bhengineering.co.uk
www.roverv8engines.com

Badger wrote:
> Not strictly true Andy, if you are running a modern SGI gas system, the
> pulse that initiates gas injection is taken directly from the petrol
> injector harness, ie it comes from the petrol ECU. So, if the fuelling
> output signal of the ecu is altered, this results in an alteration to the
> injector pulse-width, this is picked up by the SGI control unit which in
> turn fires the gas injector for a correspondingly longer pulse also. Any
> alteration to the petrol ecu is seen at the gas ecu when running on gas.
> If you were referring to older standalone gas systems, then you are
> perfectly correct, BUT those older systems would never get installed on a
> Thor anyway, due to the complexities of the management system.

Hi Badger,

Any point retrofitting closed loop control to a 101 3.5 V8 ?
Thanks.
Steve

"steve Taylor" <[email protected]> wrote in message
news:[email protected]...
> Badger wrote:
>> Not strictly true Andy, if you are running a modern SGI gas system, the
>> pulse that initiates gas injection is taken directly from the petrol
>> injector harness, ie it comes from the petrol ECU. So, if the fuelling
>> output signal of the ecu is altered, this results in an alteration to the
>> injector pulse-width, this is picked up by the SGI control unit which in
>> turn fires the gas injector for a correspondingly longer pulse also. Any
>> alteration to the petrol ecu is seen at the gas ecu when running on gas.
>> If you were referring to older standalone gas systems, then you are
>> perfectly correct, BUT those older systems would never get installed on a
>> Thor anyway, due to the complexities of the management system.
>
> Hi Badger,
>
> Any point retrofitting closed loop control to a 101 3.5 V8 ?

There are good arguments both for and against.
In theory it might improve the fuel consumption by 2 or 3 %, so in that
respect no, it isn't really worth the time and effort I'd say. However, an
added benefit is the closed loop maintaining lambda and preventing the
engine from running lean - with potentially disasterous consequences for the
pistons. In that respect, yes, I'd say it was worth doing.
If you stick a CO meter up it's bum regularly and you know the CO is ok,
then I'd leave well alone if running ok. If you tend to adopt a style more
akin to "reactive maintenance" (Oh ****, it's bust, best I react by fixing
it) then I'd say fit it.
Just remember to fit the lambda probe as high up the downpipe as possible,
and to the rear to protect from direct water splashing. If a hot probe gets
a sudden drenching with cold water, it tends to cease to function! FWIW, I'd
fit the AEB Leonardo (OMVL Millenium) closed-loop system if it were my
decision, bear in mind you'll need a throttle position sensor as well,
shouldn't be too difficult to fit a std EFI one onto a bracket and rig up a
drive from a carb spindle.
Good luck, let me know how you get on if you decide to go for it.

--
Badger.
B.H.Engineering,
Rover V8 engine specialists.
www.bhengineering.co.uk
www.roverv8engines.com