hi,
i'm thinking of swapping my lpg single point system from my now dead 4.0 range rover on to my m reg omega 2.5, anyone think this is a good/bad idea and why?
also if you are familiar with the vaux engine it has a dual inlet for the air, is there a mixer for this type of intake or will i need a pair of mixers?
the car only cost me £350 so i dont want to spend on a multi.
also would it be worth buying a couple of them BLOS carbs off ebay and putting one on each intake ?
and finally, is there a device i can use to let off the pressure in case of backfire? i have seen the anti backfire device that blocks the back fire but i'm not convinced, i think something that will allow pressure out but stop air goin in under normal operation i.e under suction from engine? i dont want to blow all the plastic gubbins to bits if it backfires!!
cheers guys!
lpg vauxhall omega
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martin rowe
- Junior Member
- Posts: 16
- Joined: Wed Nov 19, 2008 9:03 am
AFAIK the single point does not work well on V6 Omegas .. some 4-pots have it though.
For much more information try the Omega Owners Forum .. lots of folks there who know far more than me !!!
www.omegaowners.com
Some very friendly guys there ...
For much more information try the Omega Owners Forum .. lots of folks there who know far more than me !!!
www.omegaowners.com
Some very friendly guys there ...
now the obvious question, why is it a bad idea? i mean the principal is the same for all cars isnt it, mix the fuel with the air, fool the car into thinking its still on petrol and cut the petrol??
as said i dont want to spend on a multipoint as the car was/is just a cheap runner, its more of a 'lets see what happens' than a major project but obviously i dont want to go and blow up the engine etc as that would be more than foolish!!
what are the problems that would need to be overcome, is it the mechanical side or the electrical/emulation/software side?
if i decide to go ahead, where would i interupt the petrol feed and connect the emulator, i think i need to read up a bit more!!!
as said i dont want to spend on a multipoint as the car was/is just a cheap runner, its more of a 'lets see what happens' than a major project but obviously i dont want to go and blow up the engine etc as that would be more than foolish!!
what are the problems that would need to be overcome, is it the mechanical side or the electrical/emulation/software side?
if i decide to go ahead, where would i interupt the petrol feed and connect the emulator, i think i need to read up a bit more!!!
I believe its a bad idea for several reasons ...gavbriggs wrote:now the obvious question, why is it a bad idea? i mean the principal is the same for all cars isnt it, mix the fuel with the air, fool the car into thinking its still on petrol and cut the petrol??
as said i dont want to spend on a multipoint as the car was/is just a cheap runner, its more of a 'lets see what happens' than a major project but obviously i dont want to go and blow up the engine etc as that would be more than foolish!!
what are the problems that would need to be overcome, is it the mechanical side or the electrical/emulation/software side?
if i decide to go ahead, where would i interupt the petrol feed and connect the emulator, i think i need to read up a bit more!!!
1) The petrol ECU, and all the relevant sensors are designed to run injectors, so running a system designed for carbs is not ideal, as the signals have to be "bodged" to cope.
2) The V6 intake - as you yourself have stated - is split in two, and complicated by the dual RAMs so the airpath is variable, an SGI system can ignore this as the gas injectors are at the "valve" end .. a single point is at the opposite end
3) The potential "backfiring" can cause tremendous damage to the intake tract as well as numerous sensors therein
At the end of the day . it was told to me thus ... an injected petrol engine needs an injected gas supply .. its not designed otherwise.
I love my injected Omega, and I'm glad I had the job done properly ..
i agree in principal that the injected path is the best for an injected engine but, and there is always a but, the RR p38 that the system is from is also injected. the air intake is a common one for all cyliders though.
also the sensors are pretty much the same, maff and temp. apart from the plastic intake pipes there is very little difference( 6cyl V 8cyl)
if i was to put on two blos carbs(assuming they work as siad on the tin) then each air intake would draw the same amount of fuel relative to the amount of air taken??
i do really want to try it but i need to look at all the information before starting s i want to eliminate potential stumbling blocks, so don't give up on me just yet!!
the mechanical side of things should (ha!) be pretty straight forward, assuming the obstacle are overcome that you have mentioned and i think i may have the answer to! lol!
on the omega intake there is a device that connects both pipes, looks a bit like a carb, what is it and what is its function. i dont want to blow this gadget if i can avoid it!
cheers for the help and any problems you can see or throw at me, no matter how minor or major please do as overcoming these is the key to doing a workable job!!
also in http://www.omegaowners.com/forum/YaBB.p ... 56965728/0 some owners have had single points on em so i am sure its possible, to what degree of success is what i'm trying to find out
once again cheers for help and info!!
also the sensors are pretty much the same, maff and temp. apart from the plastic intake pipes there is very little difference( 6cyl V 8cyl)
if i was to put on two blos carbs(assuming they work as siad on the tin) then each air intake would draw the same amount of fuel relative to the amount of air taken??
i do really want to try it but i need to look at all the information before starting s i want to eliminate potential stumbling blocks, so don't give up on me just yet!!
the mechanical side of things should (ha!) be pretty straight forward, assuming the obstacle are overcome that you have mentioned and i think i may have the answer to! lol!
on the omega intake there is a device that connects both pipes, looks a bit like a carb, what is it and what is its function. i dont want to blow this gadget if i can avoid it!
cheers for the help and any problems you can see or throw at me, no matter how minor or major please do as overcoming these is the key to doing a workable job!!
also in http://www.omegaowners.com/forum/YaBB.p ... 56965728/0 some owners have had single points on em so i am sure its possible, to what degree of success is what i'm trying to find out
once again cheers for help and info!!
That thread from OOF is purely about the 2.0 ltr 4 pot engine ... somewhat diffferent to the V6 !!!
Not certain by what you describe as
My major concern is the multi-ram set up, the air path can have 4 different routes, depending on RPM, and BTW .... the left hand throttle body feeds the right hand bank of cylinders, the paths "crossover" as they leave the plenum and enter the block, achieved by the design of the injector manifold .... done I believe to smooth the air path ...
Some info on the multi-rams
http://www.omegaowners.com/forum/YaBB.pl?num=1153840176
HTH
Not certain by what you describe as
at the top end of the intake pipes is the dual throttle body, the silvery bit between the bagpipes and the plenum, screw that up and its tres expensive ..on the omega intake there is a device that connects both pipes, looks a bit like a carb, what is it and what is its function. i dont want to blow this gadget if i can avoid it!
My major concern is the multi-ram set up, the air path can have 4 different routes, depending on RPM, and BTW .... the left hand throttle body feeds the right hand bank of cylinders, the paths "crossover" as they leave the plenum and enter the block, achieved by the design of the injector manifold .... done I believe to smooth the air path ...
Some info on the multi-rams
http://www.omegaowners.com/forum/YaBB.pl?num=1153840176
HTH
It's not necessarily correct to say that a petrol injected engine must have a gas injection system. I've got an injected Saab 900 with a single mixer in the airbox directly above the throttle body. Many other cars run a similar system, usually, as mine is, with a closed loop controller.
I understand the problem with backfires is often caused by long intake tracts, something which it seems you have with the Omega engine. There's a lot of space there for excess gas to accumulate. I have no doubt it could be done, how successful it would be is a different matter. You'd need an emulator to shut off the petrol injectors while fooling the petrol ECU into thinking they were still working. You'd also need to use a closed loop controller (mines an AEB Leonardo). Setting the controller to shut off the gas on the overrun would also go a long way to reducing any problems with excess gas accumulating in the intake tract. I've got a spring loaded valve in the top of the airbox, that should let any excess pressure out of the airbox in the event of a backfire. However, my car has only backfired once in the time I've owned it and it blew the hose off the auxilliary air valve so it doesn't work as well as it should!
I understand the problem with backfires is often caused by long intake tracts, something which it seems you have with the Omega engine. There's a lot of space there for excess gas to accumulate. I have no doubt it could be done, how successful it would be is a different matter. You'd need an emulator to shut off the petrol injectors while fooling the petrol ECU into thinking they were still working. You'd also need to use a closed loop controller (mines an AEB Leonardo). Setting the controller to shut off the gas on the overrun would also go a long way to reducing any problems with excess gas accumulating in the intake tract. I've got a spring loaded valve in the top of the airbox, that should let any excess pressure out of the airbox in the event of a backfire. However, my car has only backfired once in the time I've owned it and it blew the hose off the auxilliary air valve so it doesn't work as well as it should!
the bit i was talking about seems to be the resonance pipe switch over valve.Entwood wrote:That thread from OOF is purely about the 2.0 ltr 4 pot engine ... somewhat diffferent to the V6 !!!
Not certain by what you describe as
at the top end of the intake pipes is the dual throttle body, the silvery bit between the bagpipes and the plenum, screw that up and its tres expensive ..on the omega intake there is a device that connects both pipes, looks a bit like a carb, what is it and what is its function. i dont want to blow this gadget if i can avoid it!
My major concern is the multi-ram set up, the air path can have 4 different routes, depending on RPM, and BTW .... the left hand throttle body feeds the right hand bank of cylinders, the paths "crossover" as they leave the plenum and enter the block, achieved by the design of the injector manifold .... done I believe to smooth the air path ...
Some info on the multi-rams
http://www.omegaowners.com/forum/YaBB.pl?num=1153840176
HTH
now, looking at diagram 3 on the link you gave, if i was to put 2 blos carb between the plenum and the air intake pipes, would this work. in theory it will take an amount(preset???) of fuel relative to the air bieng drawn in regardless of the direction the air/fuel takes after that point thus allowing the correct fuel air mix to enter the pots??
i thought that engine on there was a 6 pot, he currently drives a 2 ltr saloon, how can you tell the difference from the pics?
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SimonHobson
- Intermediate Member
- Posts: 1125
- Joined: Sat Aug 23, 2008 6:39 pm
- Location: Cumbria
- Contact:
Hmm, having looked at the forum post linked above, it looks like the intake isn't so much changed in length, but there are two valves which can allow movement of air between the two pipes - changing the resonant length in teh same way that the hole on (say) a flute or recorder change the resonant length of the tube and change the note. What it is NOT doing is altering the average air velocity or volume in any part of the intake - at least according to the diagram on page S11-11.
What I would say about it is this :
I'd be inclined to think of fitting a single mixer just upstream of the split in the intake, where there is a single pipe. This completely avoids all the issues related to split airflows etc. The downside is that it leaves a large volume of gas-air mix in the intake, and when a backfire does happen, it's not going to be pretty - especially as I think (from reading the above) that it's a plastic manifold. It's also not exactly ideal from the control point of view. Having said that, it's probably not too far off the setup I had on the 110 - where I had probably over a foot of 2 1/2" inlet pipe from mixer to each carb throttle, and then the rest of the manifold after that.
You could try fitting two mixers close to the throttle body (which is, I assume, up on top of the engine), but my limited experience says that twin mixers can be "tricky" to balance.
You can get backfire protectors - they are in the Autogas Worldwide catalogue but I haven't seen them first hand. From the pics they look like a large poppet valve which I assume is held closed by a light spring and manifold vacuum - but in the event of a backfire they can lift off and let the pressure out. I have considered fitting them on the Land Rover as I've heard of the plenum chamber letting go - but in practice it hasn't gone yet
I had also considered that you could manage something on a DIY basis where there are round(ish) pipes by drilling a series of holes and covering them with a big "elastic band". It would be a compromise - more/bigger holes means more weakening of the manifold, but means less pressure when it goes bang. I'm pretty certain your manifold would not survive a backfire without some serious venting.
When I did my course, part of it was to pass around the exhibits from the collection of horrors. One was (half of) a manifold from (IIRC) a Ford Explorer. The story that went with it was along the lines of : on motorway, backfired, manifold broken, bits of manifold sucked into intakes jamming valves open, piston hits valve, engine stopped dead - and torque converter ripped off back of crankshaft
Overall, I can see why people might recommend an injection system for this engine !
What I would say about it is this :
I'd be inclined to think of fitting a single mixer just upstream of the split in the intake, where there is a single pipe. This completely avoids all the issues related to split airflows etc. The downside is that it leaves a large volume of gas-air mix in the intake, and when a backfire does happen, it's not going to be pretty - especially as I think (from reading the above) that it's a plastic manifold. It's also not exactly ideal from the control point of view. Having said that, it's probably not too far off the setup I had on the 110 - where I had probably over a foot of 2 1/2" inlet pipe from mixer to each carb throttle, and then the rest of the manifold after that.
You could try fitting two mixers close to the throttle body (which is, I assume, up on top of the engine), but my limited experience says that twin mixers can be "tricky" to balance.
You can get backfire protectors - they are in the Autogas Worldwide catalogue but I haven't seen them first hand. From the pics they look like a large poppet valve which I assume is held closed by a light spring and manifold vacuum - but in the event of a backfire they can lift off and let the pressure out. I have considered fitting them on the Land Rover as I've heard of the plenum chamber letting go - but in practice it hasn't gone yet
I had also considered that you could manage something on a DIY basis where there are round(ish) pipes by drilling a series of holes and covering them with a big "elastic band". It would be a compromise - more/bigger holes means more weakening of the manifold, but means less pressure when it goes bang. I'm pretty certain your manifold would not survive a backfire without some serious venting.
When I did my course, part of it was to pass around the exhibits from the collection of horrors. One was (half of) a manifold from (IIRC) a Ford Explorer. The story that went with it was along the lines of : on motorway, backfired, manifold broken, bits of manifold sucked into intakes jamming valves open, piston hits valve, engine stopped dead - and torque converter ripped off back of crankshaft
Overall, I can see why people might recommend an injection system for this engine !
Land Rover 110 V8 LPG
Land Rover 90 petrol (no longer diseasel :D), still awaiting V8 & LPG
http://www.diy-lpg.co.uk
Land Rover 90 petrol (no longer diseasel :D), still awaiting V8 & LPG
http://www.diy-lpg.co.uk
if you look at the attached pics from the links to the omega site, sorry i dont know how to upload the specific pics, i was considering putting blos carbs between the black plastic hose and the metal air ram/plenum. the reason i was going to use blos carbs instead of mixer rings is that they seem(accoring to what ive seen and read) to vary in accordance with air flow and close when there is no air flow thus stopping back flow or backfire. also i was putting them in that location because there will only be a small amount of( probably silicone type) hose between them and the metal parts and it is about as close as you can get to point of ignition in this case.
blos carbs http://cgi.ebay.co.uk/BLOS---Propane-Ca ... 2003r39854
in action: http://www.youtube.com/watch?v=uuDJpbyO ... re=related
sorry for poor quality vid but its on youtube!
blos carbs http://cgi.ebay.co.uk/BLOS---Propane-Ca ... 2003r39854
in action: http://www.youtube.com/watch?v=uuDJpbyO ... re=related
sorry for poor quality vid but its on youtube!
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SimonHobson
- Intermediate Member
- Posts: 1125
- Joined: Sat Aug 23, 2008 6:39 pm
- Location: Cumbria
- Contact:
Are they synchronised to progressive throttles ? Ie, do they work together on one spindle, or does one open on part power and the other start to open later as power is increased ?Entwood wrote:The metal bit at the top end of the black plastic airpipes, that then feeds into the plenum, is the dual throttle body, so you would be putting your BLOS carbs before the throttles. I suppose it would still work, but getting the "balance" could be very tricky. ..
If they are synchronised then the only issue I'd see is balancing them at idle, if progressive then it's a bit harder. But having looked at the Blos thing, it might just cope (depends a lot on whether it shuts off the gas port completely at zero air flow).
Land Rover 110 V8 LPG
Land Rover 90 petrol (no longer diseasel :D), still awaiting V8 & LPG
http://www.diy-lpg.co.uk
Land Rover 90 petrol (no longer diseasel :D), still awaiting V8 & LPG
http://www.diy-lpg.co.uk
the blos carbs would be on the air side of the throttle body so i assume it is the correct location as per the blos carb system,
i have no idea how the throttles work but assume they are on one spindle as i cannot see any other cables etc just the one for the throttle onto a spindle.
i assume the blos carbs have an idle control, and they do seem to be open slightly at tickover according to the youtube videos i have seen. i would still be looking at putting in some kind of pressure relief valve on the plasic bits as a belt and braces type approach. as said before, its a bit of an exorcise to see if it can be done and to what success, i have the single point system and it will be used again if its not found to be succesful on the omega. the blos carbs can also be used again as i think i'm gonna get an older engine for the landy and strip/emulate most of the original engine electrics!(another can we fix it project!!!)
i have no idea how the throttles work but assume they are on one spindle as i cannot see any other cables etc just the one for the throttle onto a spindle.
i assume the blos carbs have an idle control, and they do seem to be open slightly at tickover according to the youtube videos i have seen. i would still be looking at putting in some kind of pressure relief valve on the plasic bits as a belt and braces type approach. as said before, its a bit of an exorcise to see if it can be done and to what success, i have the single point system and it will be used again if its not found to be succesful on the omega. the blos carbs can also be used again as i think i'm gonna get an older engine for the landy and strip/emulate most of the original engine electrics!(another can we fix it project!!!)
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SimonHobson
- Intermediate Member
- Posts: 1125
- Joined: Sat Aug 23, 2008 6:39 pm
- Location: Cumbria
- Contact:
In which case I can't see why a pair of ordinary mixers wouldn't work - apart from the aforementioned balancing issue. I'd think a pair of Blos units would also work.gavbriggs wrote:i have no idea how the throttles work but assume they are on one spindle as i cannot see any other cables etc just the one for the throttle onto a spindle.
It also means that some of the blurb about the operation of the system is just plain wrong
The mean air velocity in each duct will not change regardless of the valve operation - only the resonant length of the duct.BTW - looking at the linked video, and some related ones, is it just me or does there seem to be quite a bit of throttle lag ? Ie, snap open the throttle, engine hesitates before revving up.
Land Rover 110 V8 LPG
Land Rover 90 petrol (no longer diseasel :D), still awaiting V8 & LPG
http://www.diy-lpg.co.uk
Land Rover 90 petrol (no longer diseasel :D), still awaiting V8 & LPG
http://www.diy-lpg.co.uk
Work "side-by-side" on a single spindle, one for each bank.. and due to the inlet manifold design the left hand throttle body feeds the right hand bank, and vice-versaSimonHobson wrote:Are they synchronised to progressive throttles ? Ie, do they work together on one spindle, or does one open on part power and the other start to open later as power is increased ?Entwood wrote:The metal bit at the top end of the black plastic airpipes, that then feeds into the plenum, is the dual throttle body, so you would be putting your BLOS carbs before the throttles. I suppose it would still work, but getting the "balance" could be very tricky. ..
If they are synchronised then the only issue I'd see is balancing them at idle, if progressive then it's a bit harder. But having looked at the Blos thing, it might just cope (depends a lot on whether it shuts off the gas port completely at zero air flow).
i'm not too worried about resposiveness so long as it does respond soon enough after all its a estate car so its not gonna beat any land speed records!
i think it will work, most of the issues seem to be ironed out, it wont be happening till at least the end of the month but it will happen and it will(i hope) prove a worthwhile experience in that i will learn from it!!
thank you for all the advice and arguments for and against. if you can think of any more stumbling blocks, no mater how simple or obvious please do let me know as i have a habit of missing the obvious and finding the ridiculous!!
cheers guys!!
i think it will work, most of the issues seem to be ironed out, it wont be happening till at least the end of the month but it will happen and it will(i hope) prove a worthwhile experience in that i will learn from it!!
thank you for all the advice and arguments for and against. if you can think of any more stumbling blocks, no mater how simple or obvious please do let me know as i have a habit of missing the obvious and finding the ridiculous!!
cheers guys!!
If you are going ahead with this ....you may want to consider... and I know nothing about single point mixer systems .... so I'm probably talking rubbish ..... but here goes ..
Vapourisor positioning and water feed.
Most vapourisors are put on the left hand side (facing into engine bay) in the region behind/under the expansion tank. Some models have a few extra bits tucked in there ... additional heater pump and cruise control bits. This does not leave a lot of room. If you have these, as I do, then another place is right down the front right, just above the horn bracket. This does mean a couple of long water hoses but it is very neat. My fitter said it was easier to put long hoses in than to move all the other stuff !!
Water feed : Several folks who have DIY'd or had cheap & cheerful (ie @!##) installs, have had problems with water temp to the vapourisor. the water feed MUST be taken from "inside" the coolant loop at/near the heater bypass valve ... if taken from the wrong place .. then it is either overly affected by car heater demands, or doesn't heat up until the thermostat opens, the right size pipery must be used as well. Some very poor installs have tried to take the water from areas like the throttle body heat supply ... gets about a gallon of hot water a year as the pipe is so small !!
I know I have a SGI system .. but if you want any photos of any other bits of the install .. just ask ..
Some general pictures of the install on OOF ... I'll take any more specific ones you ask for ..
http://www.omegaowners.com/forum/YaBB.pl?num=1210944190
Vapourisor positioning and water feed.
Most vapourisors are put on the left hand side (facing into engine bay) in the region behind/under the expansion tank. Some models have a few extra bits tucked in there ... additional heater pump and cruise control bits. This does not leave a lot of room. If you have these, as I do, then another place is right down the front right, just above the horn bracket. This does mean a couple of long water hoses but it is very neat. My fitter said it was easier to put long hoses in than to move all the other stuff !!
Water feed : Several folks who have DIY'd or had cheap & cheerful (ie @!##) installs, have had problems with water temp to the vapourisor. the water feed MUST be taken from "inside" the coolant loop at/near the heater bypass valve ... if taken from the wrong place .. then it is either overly affected by car heater demands, or doesn't heat up until the thermostat opens, the right size pipery must be used as well. Some very poor installs have tried to take the water from areas like the throttle body heat supply ... gets about a gallon of hot water a year as the pipe is so small !!
I know I have a SGI system .. but if you want any photos of any other bits of the install .. just ask ..
Some general pictures of the install on OOF ... I'll take any more specific ones you ask for ..
http://www.omegaowners.com/forum/YaBB.pl?num=1210944190
it would be handy if you can to find out where the rpm/coil signal is taken from and also where the coolant pipework is t'd in at. i had a problem with the coolant system on my rangie, the vap was higher than the header so it caused it not to get water and i had to spend hours getting the water feed to it when i drained coolant!!
any detailed pics, up to and including vapouriser would be useful as this will be more or less the same on any system, also my big grey area and challenge will be the electricity side, i'm hoping to make a map from my rangerover of all the wires and then find the same functions on the omega and swap it over!!
i know something will go astray in the swap so i want to cover all bases so at worst its a wuick look on t'internet and get my bearings!!
any detailed pics, up to and including vapouriser would be useful as this will be more or less the same on any system, also my big grey area and challenge will be the electricity side, i'm hoping to make a map from my rangerover of all the wires and then find the same functions on the omega and swap it over!!
i know something will go astray in the swap so i want to cover all bases so at worst its a wuick look on t'internet and get my bearings!!