gas

Ok here we go with a can of worms! I have a RR LSe fitted with a 4.6l
chipped RPI engine. Now I want gas to help with the running costs. Now here
is the kicker, do I go for injection or not?
Not too bothered about boot tank as like most tight for cash (christmas etc)
so somesay injection is the way to go others say not worth the cost!
Thoughts please.
John

"jds" <[email protected]> wrote in message
news:[email protected]...
> Ok here we go with a can of worms! I have a RR LSe fitted with a 4.6l
> chipped RPI engine. Now I want gas to help with the running costs. Now
> here is the kicker, do I go for injection or not?
> Not too bothered about boot tank as like most tight for cash (christmas
> etc) so somesay injection is the way to go others say not worth the cost!
> Thoughts please.
> John
Depends on what engine management system you have. If your engine has the
big single rectangular plenum chamber with the throttle body situated
central over the near-side rocker cover like the 3.5/3.9, then go for a
closed-loop vapour system. Something well proven such as AEB's Leonardo for
instance. If, however, you have the later "Thor" setup with the "rams-horns"
inlet manifold and the throttle body at the front nearside, then play safe
and go gas injection. The issue with the later management system is that as
standard it not only has over-run fuel cut (like most), but it also cuts the
spark as well - causing problems for the gas system.
Badger.
B.H.Engineering,
Rover V8 engine specialists.
www.bhengineering.co.uk
www.roverv8engines.com

On or around Sun, 19 Dec 2004 07:49:36 -0000, "jds" <[email protected]>
enlightened us thusly:

>Ok here we go with a can of worms! I have a RR LSe fitted with a 4.6l
>chipped RPI engine. Now I want gas to help with the running costs. Now here
>is the kicker, do I go for injection or not?
>Not too bothered about boot tank as like most tight for cash (christmas etc)
>so somesay injection is the way to go others say not worth the cost!
>Thoughts please.

does the 4.6 still have the normal alloy V8 manifold? I suspect so, and if
so, then a single point system with electronic control (using lambda sensor)
should be OK. make sure the vapouriser and the mixer are big enough for the
engine.

Advice and (fairly expensive) kits from http://www/chrisperfect.com and
while the kits ain't cheap they are available for DIY fitment (not that
difficult if you have moderate-to-good mechanical skills) and are also
pretty good quality, IME - some of the early ones were a bit patchy, but
they seem to be pretty well sorted now. Got a kit derived from what he
sells on my 3.5 hotwire disco, and it works well.

On or around Sun, 19 Dec 2004 10:09:44 +0000 (UTC), "Badger"
<[email protected]> enlightened us thusly:

>The issue with the later management system is that as
>standard it not only has over-run fuel cut (like most), but it also cuts the
>spark as well - causing problems for the gas system.

WTF is that all about? there's no point in cutting the spark as well as the
fuel...

'ere, that's a point. Hotwire systems, over-run cut off. Does it do this,
how and when? I assume it just doesn't just fire the injectors, but
how/when does it trigger?
I doubt it's possible to cross-connect it with the gas system, but it'd be
nice.

someone suggested that the flapper system has a vacuum switch which triggers
the ORFCU - and that I could fit one of them, which is an idea. Since it's
got an ecomax vacuum thing, it shouldn't be too uneconomical on over-run,
but previous experience is that cutting the fuel makes for better engine
braking, which would be handy sometimes.

"Austin Shackles" <[email protected]> wrote in message
news[email protected]...
> On or around Sun, 19 Dec 2004 10:09:44 +0000 (UTC), "Badger"
> <[email protected]> enlightened us thusly:
>
>>The issue with the later management system is that as
>>standard it not only has over-run fuel cut (like most), but it also cuts
>>the
>>spark as well - causing problems for the gas system.
>
> WTF is that all about? there's no point in cutting the spark as well as
> the
> fuel...

My thoughts exactly Austin, but it does! If it senses an overrun condition
it cuts the fuel. If it then senses fuel cut for more than a certain time,
it cuts the ignition until it gets a signal to end the fuel cut - then it
reinstates both fuel and ignition, ignition first. It's the ignition cut
that causes the gas backfire on reinstatement. You "can" wire the gas side
into the coil trigger and in the case of the AEB Leo. it will simply cut the
gas and default to petrol on the overrun as it senses the ignition cut,
thinking the engine has stalled. On resumption of sparks, it will assume
that the previously "stalled" engine has restarted and will change back to
gas. Not ideal, but it works ok - as long as you can refrain from suddenly
flooring it from an overrun condition. Biggest issue on thor engines anyway
is the plug leads and coils breaking down, in my experience.

>
> 'ere, that's a point. Hotwire systems, over-run cut off. Does it do
> this,
> how and when? I assume it just doesn't just fire the injectors, but
> how/when does it trigger?
> I doubt it's possible to cross-connect it with the gas system, but it'd be
> nice.

It does it magically by the ecu detecting high enough rpm's but no fuel
demand (throttle pos'n tx) and cuts / reduces the pulse width supply to the
injectors. I'd imagine you could use an electronic monitoring of the
injector output pulses to control the gas solenoids, or in the case of the
AEB Leo. it has overrun cut-off (variable) already within its programming
and you tell it the rpm / default gas flow when setting up.

>
> someone suggested that the flapper system has a vacuum switch which
> triggers
> the ORFCU - and that I could fit one of them, which is an idea. Since
> it's
> got an ecomax vacuum thing, it shouldn't be too uneconomical on over-run,
> but previous experience is that cutting the fuel makes for better engine
> braking, which would be handy sometimes.
>

I seem to remember discussing that with you well over a year ago now, it's a
vacuum operated switch which operates the relay next to the resistor pack /
coil, lifting the rpm sense lead input from the ecu. Ecu thinks... "no rpm,
best I stop injecting fuel"! As the vacuum level drops (manifold pressure
rises) the trigger is reinstated and the ecu recommences fuelling. Always
thought about rigging it up myself but never bothered due to the low mileage
my 110 does these days.
Badger.
B.H.Engineering,
Rover V8 engine specialists.
www.bhengineering.co.uk
www.roverv8engines.com

>Ok here we go with a can of worms! I have a RR LSe fitted with a 4.6l
>chipped RPI engine. Now I want gas to help with the running costs. Now here
>is the kicker, do I go for injection or not?

If this engine has come with a GEMS management system - like the 4.6
HSEs - don't use a singlepoint LPG system ; the GEMS will (over a
period) try to correct any slight mixture errors, which won't work of
course. The (petrol) mixture setting goes further and further out of
spec while you are running on LPG. The end result is that when you
do run on petrol it will be very poorly. It'll fix itself but it
takes a looong time. The "lambda emulation" used by most singlepoint
LPG systems to try and fool the petrol ECU that all is well just isn't
accurate enough for GEMS. It's fine for earlier 14CUX systems.

LPG injection systems cost more, suit some engine setups better,
aren't prone to backfire, and perform better once setup correctly.

>Not too bothered about boot tank as like most tight for cash (christmas etc)

Have you considered an upright toroid tank? Its a big doughnut that
fits in place of spare wheel on a RR classic. Keep fullsize petrol
tank, keep usual boot space, nothing extra hanging down below. You
end up with a spare tyre to lose somewhere - it could remain on boot
floor - at least its moveable. Or carry outside on a carrier. Tank
costs more than standard cylinder though.

As with any conversion; do your sums to see what's worthwhile.
Running costs approx 45% less, work out the saving over how long you
expect to keep the car. If you do 20,000 miles a year you should
have had a conversion ages ago! If you do 2,000 miles a year it
isn't worth it unless you expect to keep the car for decades.

good luck
Rossko

Thanks for all the replies, Just to clear things up abit.

!993 Range Rover LSE (long wheel base!)
Standard Hot wire fuel injection, Same as 3.9.
Ali plelum Chamber as 3.9
Cracked block in standard 4.2 so fitted An RPI 4.6 still with standard
injection only chipped the ecu.

John
"jds" <[email protected]> wrote in message
news:[email protected]...
> Ok here we go with a can of worms! I have a RR LSe fitted with a 4.6l
> chipped RPI engine. Now I want gas to help with the running costs. Now
> here is the kicker, do I go for injection or not?
> Not too bothered about boot tank as like most tight for cash (christmas
> etc) so somesay injection is the way to go others say not worth the cost!
> Thoughts please.
> John
>

In <[email protected]> jds wrote:
> Thanks for all the replies, Just to clear things up abit.
>
> !993 Range Rover LSE (long wheel base!)
> Standard Hot wire fuel injection, Same as 3.9.
> Ali plelum Chamber as 3.9
> Cracked block in standard 4.2 so fitted An RPI 4.6 still with standard
> injection only chipped the ecu.
>
> John
> "jds" <[email protected]> wrote in message
> news:[email protected]...
>> Ok here we go with a can of worms! I have a RR LSe fitted with a 4.6l
>> chipped RPI engine. Now I want gas to help with the running costs.
>> Now here is the kicker, do I go for injection or not? Not too
>> bothered about boot tank as like most tight for cash (christmas etc)
>> so somesay injection is the way to go others say not worth the cost!
>> Thoughts please.
>> John

I wouldn't go multi point injection with this setup - any minor saving
you make in fuel economy is minimal and the cost of a multi point system
is a lot higher than a single point injection system. Just make sure you
get a decent single point system that will run in closed loop.
Personally I'd recommend the Tartarini Tec 97 or similar as, having had
a number of different LPG systems fitted, each from a different
manufacturer, it's the only one that has run entirely without a hitch
and has never caused a backfire.


cheers

Dave W.
http://www.yorkshireoffroadclub.net/

In message <[email protected]>, Dave White
<[email protected]> writes
>In <[email protected]> jds wrote:
>> Thanks for all the replies, Just to clear things up abit.
>>
>> !993 Range Rover LSE (long wheel base!)
>> Standard Hot wire fuel injection, Same as 3.9.
>> Ali plelum Chamber as 3.9
>> Cracked block in standard 4.2 so fitted An RPI 4.6 still with standard
>> injection only chipped the ecu.
>>
>> John
>> "jds" <[email protected]> wrote in message
>> news:[email protected]...
>>> Ok here we go with a can of worms! I have a RR LSe fitted with a 4.6l
>>> chipped RPI engine. Now I want gas to help with the running costs.
>>> Now here is the kicker, do I go for injection or not? Not too
>>> bothered about boot tank as like most tight for cash (christmas etc)
>>> so somesay injection is the way to go others say not worth the cost!
>>> Thoughts please.
>>> John
>
>I wouldn't go multi point injection with this setup - any minor saving
>you make in fuel economy is minimal and the cost of a multi point system
>is a lot higher than a single point injection system. Just make sure you
>get a decent single point system that will run in closed loop.
>Personally I'd recommend the Tartarini Tec 97 or similar as, having had
>a number of different LPG systems fitted, each from a different
>manufacturer, it's the only one that has run entirely without a hitch
>and has never caused a backfire.
>
>
>cheers
>
>Dave W.
>http://www.yorkshireoffroadclub.net/
Wouldn't recommend a tec 97 on that engine, and it's the engine that
matters not the rest of the vehicle. Injection systems are stable now
and to go for single point is a bit like choosing carbs instead of
injection cos they're a bit cheaper to install.

I have no vested interest in this as I am no longer involved in the
conversion business, I just know what I would do if I was converting my
LR 90 V8(4.0 litre same as P38 RR) from scratch.
--
hugh
Reply to address is valid at the time of posting

"Dave White" <[email protected]> wrote in message
news:[email protected]...
> In <[email protected]> jds wrote:
>> Thanks for all the replies, Just to clear things up abit.
>>
>> !993 Range Rover LSE (long wheel base!)
>> Standard Hot wire fuel injection, Same as 3.9.
>> Ali plelum Chamber as 3.9
>> Cracked block in standard 4.2 so fitted An RPI 4.6 still with standard
>> injection only chipped the ecu.
>>
>> John
>> "jds" <[email protected]> wrote in message
>> news:[email protected]...
>>> Ok here we go with a can of worms! I have a RR LSe fitted with a 4.6l
>>> chipped RPI engine. Now I want gas to help with the running costs.
>>> Now here is the kicker, do I go for injection or not? Not too
>>> bothered about boot tank as like most tight for cash (christmas etc)
>>> so somesay injection is the way to go others say not worth the cost!
>>> Thoughts please.
>>> John
>
> I wouldn't go multi point injection with this setup - any minor saving
> you make in fuel economy is minimal and the cost of a multi point system
> is a lot higher than a single point injection system. Just make sure you
> get a decent single point system that will run in closed loop.
> Personally I'd recommend the Tartarini Tec 97 or similar as, having had
> a number of different LPG systems fitted, each from a different
> manufacturer, it's the only one that has run entirely without a hitch
> and has never caused a backfire.
>
>
5 gas vehicles of my own through time now, 4 on AEB Leonardo, 1 on
star-gas. Never had a backfire on any of the AEB equipped cars, and had
almost no problems at all (bar a P38 with ignition issues) on any others
that I've converted - probably around 30 or so now.
Personally I'd fit the AEB system, but then every installer will have their
own favourite that they are used to.
Badger.

In <[email protected]> hugh wrote:
> Wouldn't recommend a tec 97 on that engine, and it's the engine that
> matters not the rest of the vehicle. Injection systems are stable now
> and to go for single point is a bit like choosing carbs instead of
> injection cos they're a bit cheaper to install.

If they were "a bit" cheaper to install I'd agree but given that the
last time I looked "a bit cheaper" equated to the best part of a grand.
I just don't think you can justify paying near double the amount for a
conversion that gives you no real benefit.

Were it a Thor engine I'd have recommended the multi-point but the Thor
is a completely different kettle of fish to the 4.6 in question. If you
think a multi-point system will give enough of a benefit to justify the
extra cost then I suggest you post that as a reply to the original post
rather than simply criticising someone else who could be bothered to
answer.

cheers

Dave W.
http://www.yorkshireoffroadclub.net/

On or around Sat, 25 Dec 2004 21:49:22 +0000 (UTC), Dave White
<[email protected]> enlightened us thusly:

>In <[email protected]> hugh wrote:
>> Wouldn't recommend a tec 97 on that engine, and it's the engine that
>> matters not the rest of the vehicle. Injection systems are stable now
>> and to go for single point is a bit like choosing carbs instead of
>> injection cos they're a bit cheaper to install.
>
>If they were "a bit" cheaper to install I'd agree but given that the
>last time I looked "a bit cheaper" equated to the best part of a grand.
>I just don't think you can justify paying near double the amount for a
>conversion that gives you no real benefit.
>
>Were it a Thor engine I'd have recommended the multi-point but the Thor
>is a completely different kettle of fish to the 4.6 in question. If you
>think a multi-point system will give enough of a benefit to justify the
>extra cost then I suggest you post that as a reply to the original post
>rather than simply criticising someone else who could be bothered to
>answer.

valid point. Multi-point injection has advantages, but not as many as you
might think and not as many as for petrol. The objection that single-point
is "like a carb" is partly valid, but you can run single point closed loop,
and get the improved mixture control that EFi on petrol gives. The other
point about multi-point injection on petrol is that you're not dealing with
vapour in a petrol system; you're dealing with atomized liquid petrol, like
a cloud is lots of fine water droplets. Running LPG you *are* mixing vapour
with the air, and it both mixes more easily and stays mixed. Petrol,
especially in a cold engine, will tend to condense out of the mixture on
cold surfaces, which is AIUI the main reason why petrol engines need
enrichment to start when cold. The gas systems have no such enrichment and
start fine from cold provided it's not so cold that the gas won't vapourise
in the first place, but you don't get that kind of temperatures much south
of the arctic circle, seeing as we're talking significantly below -30°C.

The really major point about multi-point injection is that you don't fill
the inlet manifold with gas, and thus you (almost) can't get backfires.


There's a lot to be said for liquid-phase injection direct into the
cylinders (like the new petrol GDi engines) - the vaporisation of the liquid
fuel in the cylinder would lower temperatures in the combustion chamber and
would increase efficiency; but the kit to do it is not easily available.
--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Brevis esse laboro, Obscurus fio" (it is when I struggle to be
brief that I become obscure) Horace (65 - 8 BC) Ars Poetica, 25

In message <[email protected]>, Dave White
<[email protected]> writes
>In <[email protected]> hugh wrote:
>> Wouldn't recommend a tec 97 on that engine, and it's the engine that
>> matters not the rest of the vehicle. Injection systems are stable now
>> and to go for single point is a bit like choosing carbs instead of
>> injection cos they're a bit cheaper to install.
>
>If they were "a bit" cheaper to install I'd agree but given that the
>last time I looked "a bit cheaper" equated to the best part of a grand.
>I just don't think you can justify paying near double the amount for a
>conversion that gives you no real benefit.
>
Were do you get you figures from? Round here a multi point injection
costs about £500 - 600 more than single point on a V8.
>Were it a Thor engine I'd have recommended the multi-point but the Thor
>is a completely different kettle of fish to the 4.6 in question. If you
>think a multi-point system will give enough of a benefit to justify the
>extra cost then I suggest you post that as a reply to the original post
>rather than simply criticising someone else who could be bothered to
>answer.
Bit touchy aren't we. I happen to have specific knowledge of tec97 on
4.6 hse but I won't give details publicly. (libel laws and all that) The
OP can make up their own mind can't they?
( The original post has long since been deleted from my news stand.)
--
hugh
Reply to address is valid at the time of posting

In message <[email protected]>, Austin Shackles
<[email protected]> writes
>On or around Sat, 25 Dec 2004 21:49:22 +0000 (UTC), Dave White
><[email protected]> enlightened us thusly:
>
>>In <[email protected]> hugh wrote:
>>> Wouldn't recommend a tec 97 on that engine, and it's the engine that
>>> matters not the rest of the vehicle. Injection systems are stable now
>>> and to go for single point is a bit like choosing carbs instead of
>>> injection cos they're a bit cheaper to install.
>>
>>If they were "a bit" cheaper to install I'd agree but given that the
>>last time I looked "a bit cheaper" equated to the best part of a grand.
>>I just don't think you can justify paying near double the amount for a
>>conversion that gives you no real benefit.
>>
>>Were it a Thor engine I'd have recommended the multi-point but the Thor
>>is a completely different kettle of fish to the 4.6 in question. If you
>>think a multi-point system will give enough of a benefit to justify the
>>extra cost then I suggest you post that as a reply to the original post
>>rather than simply criticising someone else who could be bothered to
>>answer.
>
>valid point. Multi-point injection has advantages, but not as many as you
>might think and not as many as for petrol. The objection that single-point
>is "like a carb" is partly valid, but you can run single point closed loop,
>and get the improved mixture control that EFi on petrol gives.
<Snip>
That's the danger with analogies - they get misinterpreted. I wasn't
suggesting - oh never mind, I'll probably just make the hole deeper.
>The really major point about multi-point injection is that you don't fill
>the inlet manifold with gas, and thus you (almost) can't get backfires.
>
One of the characteristics of the conversion business is that it has
moved on from the pioneer stage to the consumer stage and customers are
less tolerant of what you and I ( and most owners of genuine LRs) would
regard as challenging little technical problems. Consumers will be off
to Trading Standards to complain. From people I've spoken to the
multi-point systems are a lot less hassle once installed and set up
correctly. As one installer told me, "They go out and we never see them
again"
>
>There's a lot to be said for liquid-phase injection direct into the
>cylinders (like the new petrol GDi engines) - the vaporisation of the liquid
>fuel in the cylinder would lower temperatures in the combustion chamber and
>would increase efficiency; but the kit to do it is not easily available.
Is it available at all yet?
--
hugh
Reply to address is valid at the time of posting

"hugh" <hugh@[127.0.0.1]> wrote in message
news:[email protected]...

> Were do you get you figures from? Round here a multi point injection
> costs about £500 - 600 more than single point on a V8.

About £800 difference for a rover V8 (rangie) from my regular supplier.

>>Were it a Thor engine I'd have recommended the multi-point but the Thor
>>is a completely different kettle of fish to the 4.6 in question. If you
>>think a multi-point system will give enough of a benefit to justify the
>>extra cost then I suggest you post that as a reply to the original post
>>rather than simply criticising someone else who could be bothered to
>>answer.
> Bit touchy aren't we. I happen to have specific knowledge of tec97 on 4.6
> hse but I won't give details publicly. (libel laws and all that) The OP
> can make up their own mind can't they?

Hugh, how can you say he is touchy? I think he has a valid point insomuch
as;
A. it isn't a Thor and he's already said that if it were he'd recommend the
multi-point; and
B. You did criticise a response, not answer the OP; and
C. do you honestly believe that the extra complexity of a multi point system
would show an extra £800 worth (my figures) of benefit?

Oh, an if you wish us to believe that you have knowledge of a system, tell
us! Don't say such rubbish as your last paragraph above. How can it be
libellous to say "I converted a "somethingorother" using "kit x" and had the
following problems/observations? Claptrap!

Badger.