Pure Rover V8 Pleasure
Discussion
Here I'm just cruising along at 96mph in 5th at a nice safe 14.2:1 AFR....
Like this she'll happily sit all day long with the roof down from London to the South of France.
My St Tropez express next to another rather more expensive to buy and vastly more thirsty version of the same classic GT theme
Like this she'll happily sit all day long with the roof down from London to the South of France.
My St Tropez express next to another rather more expensive to buy and vastly more thirsty version of the same classic GT theme
Edited by ChimpOnGas on Thursday 20th July 08:43
It is an interesting project and I give thumbs up to what you've achieved but it wouldn't be totally honest of me here if I didn't mention the reservations I raised on the other forum concerning gas pressure compensation, temperature compensation and cost/time effectiveness. I meant to reply to your last post on that thread but have been very busy converting many vehicles to LPG since my last post there ;-)
Is the mixture reading compensated for LPG? Stochiometric ratio is 14.7:1 for petrol and 15.4:1 for LPG but since the means of checking mixture relies on measuring residual O2 content in exhaust gas and this content will be the same whether running on petrol at 14.7:1 on petrol or 15.4:1 on LPG, correct mixture (15.4:1 on LPG) will read as 14.7:1 if the metering is calibrated for petrol.
Is the mixture reading compensated for LPG? Stochiometric ratio is 14.7:1 for petrol and 15.4:1 for LPG but since the means of checking mixture relies on measuring residual O2 content in exhaust gas and this content will be the same whether running on petrol at 14.7:1 on petrol or 15.4:1 on LPG, correct mixture (15.4:1 on LPG) will read as 14.7:1 if the metering is calibrated for petrol.
AFR correction is all covered, a reading of 14.7:1 is stoich on either fuels so don't worry yourself on that score Simon 
Lambda one is lambda one, if we hadn't set things up this way we'd need two closed loop target tables which would be an unnecessary complication.
Lambda one is lambda one, if we hadn't set things up this way we'd need two closed loop target tables which would be an unnecessary complication.
Edited by ChimpOnGas on Thursday 20th July 18:11
SILICONEKID 345HP 12.03 said:
Those visits down to Canams and dyno time must add up
They would if I was doing as you suggest Daz, which I'm not. I map it myself, but thats all long since done so TBH I really just drive it... a lot!And yes, my engine management system paid for itself a while back so just money in my pocket these days, I genuinely cringe at the the thought of those £70 petrol fills when I put 300 miles of gas in for just £33.
Has your Emerald paid for itself yet?
t compared with injection!
SimonYorkshire said:
Is the mixture reading compensated for LPG? Stochiometric ratio is 14.7:1 for petrol and 15.4:1 for LPG but since the means of checking mixture relies on measuring residual O2 content in exhaust gas and this content will be the same whether running on petrol at 14.7:1 on petrol or 15.4:1 on LPG, correct mixture (15.4:1 on LPG) will read as 14.7:1 if the metering is calibrated for petrol.
ChimpOnGas said:
AFR correction is all covered, a reading of 14.7:1 is stoich on either fuels so don't worry yourself on that score Simon
Lambda one is lambda one, if we hadn't set things up this way we'd need two closed loop target tables which would be an unnecessary complication.
I wasn't worried mate ;-) That indirectly answers my question - Your AFR readings don't take into account the different fuel, no problem but.... If you have a reading of 14.7:1 when running on LPG, this would represent stoch, but actually that 14.7:1 reading would mean you had an actual AFR of 15.4:1 on LPG. So when you say you have an AFR reading of 14.2 when cruising at 96mph in 5th, what that reading is telling you is that your mixture is about 3% rich (which is fine), so your actual AFR will really be around 14.9:1 (15.4 less 3%, again fine on LPG).A mute point, maybe, but probably worth bringing up in the name of accuracy. Lambda one is lambda one, if we hadn't set things up this way we'd need two closed loop target tables which would be an unnecessary complication.
Edited by ChimpOnGas on Thursday 20th July 18:11
In all other respects you hype the merits of your LPG system running it's own completely separate fuelling table (which I see as effectively indifferent to running a map-able piggyback LPG system) and it's built in separate timing advance map for LPG (which might help a bit but the jury's out on what this could offer in real world benefits over a standalone programmable timing advance processor that costs only around £50). What I'm getting at is that If you think LPG requires so different a shape timing advance curve, and a programmable TAP wouldn't cut it, and a dedicated fuel map because a slave fuel map wouldn't cut it, why would you not then go the whole hog and see 15.4:1 as the true stoch figure for LPG? If you're used to interpreting a reading of 14.7:1 on screen as stoch, then fair enough, but it would still fly in the face of the other points a bit and a percent rich or lean reading would still make more sense / be more of a real world figure.
You may be over-hyping the benefits of your setup over a more conventional type of LPG setup (as discussed on LPGforum) and I do see some points from others on this thread that I might give a nod to such as carb induction roar (which could be maintained with an LPG install if the LPG install were a mixer type setup).
The most special part of this install to me may be the small petrol tank / medium capacity LPG tank setup, I could convert the same model car for a paying customer with either an LPG mixer setup (in case car had carbs) or LPG injection setup (in case car had injection) for less than half the price you paid in parts alone, and I could do that while confidently offering a couple year warranty in case of any LPG problem, and I could have it done in a couple of days... and a driver would probably think the results pretty much indistinguishable from what you've achieved. Consider for a moment what this means - the owner might then put the saved money into other vehicle upgrades, perhaps upgrading the engine mechanics, e.g maybe on a 5.0 bottom end or nice heads. Difficult to see how anyone not actually in a trade can have much more than a bit of insight into that trade but you've hyped this on LPGforum as superior to pros recommendations. Difficult to see how you know how components compare in the real world unless you've fitted a wide range of components on a wide range of vehicles... listening to a layman's views, biased suppliers views or biased manufacturers views won't give you insight into real world performance and longevity of components or how to select components to complement the characteristics of the vehicle. Any pulsed system that does not compensate for gas pressure and temperature is compromised by default, even if it does steer mixture on the basis of a function resembling fuel trims and AFR targets, the mixture on a system without such compensation is more likely to go momentarily wrong when you change throttle position or rpm before the mixture corrects due to the closed loop function.
Say again that I like what you've done, and neatness of install, the obvious amount of thought you've put into it, etc, it is a great achievement. I have no doubt that you'd beat a lot of pros at their own game and over a wide range of vehicles, I would have no cause to write quite in the way I have on the subject if you hadn't toted this over a few forums as superior to what pro's recommendations full stop. The rover V8 is a simple to convert and very low demand beasty, my reputation sees customers coming from all corners to have me convert the most demanding vehicles ever converted and my influence extends across the Atlantic. But even though I convert vehicles to gas for a living, if I want a new central heating boiler I ask my central heating boiler fitter mate for his advice and provide him with info on the number of radiators and design of house I want it fitting in, I don't think I know better, go my own way and then tote it as superior on gas fitters forums, particularly not if every pro points out shortfalls and cost / fitting time / warranty / future servicing implications with my final setup ;-)
Simon
Edited by SimonYorkshire on Friday 21st July 16:53
Thanks for your constructive comments Simon and thank for taking the trouble to chase me over to my home forum to carefully catalog the errors of my ways.
I can see now how foolish I was to do things differently and for not using the services of a traditional LPG fitter (you). While the system I chose has proved itself to perform brilliantly for thousands of miles over the last four years you have helped me see this is really just masking the underlying failures you've invested so much of your time to explain.
As such and following your comments I've decided to rip the whole lot out and go with one of your self calibrating slave ECUs that twists the wrong petrol injector durations in a bid to cook up a calibration that works on LPG.
I'm excited by the prospect of doing away with my unique fuel and ignition tables, and especially losing all control over ignition when I switch to a 110Ron fuel that burns in a very different way.
Many thanks, Dave.
I can see now how foolish I was to do things differently and for not using the services of a traditional LPG fitter (you). While the system I chose has proved itself to perform brilliantly for thousands of miles over the last four years you have helped me see this is really just masking the underlying failures you've invested so much of your time to explain.
As such and following your comments I've decided to rip the whole lot out and go with one of your self calibrating slave ECUs that twists the wrong petrol injector durations in a bid to cook up a calibration that works on LPG.
I'm excited by the prospect of doing away with my unique fuel and ignition tables, and especially losing all control over ignition when I switch to a 110Ron fuel that burns in a very different way.
Many thanks, Dave.
Edited by ChimpOnGas on Sunday 23 July 17:45
ChimpOnGas said:
Thanks for your constructive comments Simon and thank for taking the trouble to chase me over to my home forum to carefully catalog the errors of my ways.
I can see now how foolish I was to do things differently and for not using the services of a traditional LPG fitter (you). While the system I chose has proved itself to perform brilliantly for thousands of miles over the last four years you have helped me see this is really just masking the underlying failures you've invested so much of your time to explain.
As such and following your comments I've decided to rip the whole lot out and go with one of your self calibrating slave ECUs that twists the wrong petrol injector durations in a bid to cook up a calibration that works on LPG.
I'm excited by the prospect of doing away with my unique fuel and ignition tables, and especially losing all control over ignition when I switch to a 110Ron fuel that burns in a very different way.
Many thanks, Dave.
I didn't chase you across forums, I've been visiting PH since before I knew of you or your project, during that time I've written plenty about LPG, lots of threads on lots of different vehicles. Didn't even know you'd be on PH but my first search for the term 'LPG' when I visited PH recently listed your thread right at the top of the list. I can see now how foolish I was to do things differently and for not using the services of a traditional LPG fitter (you). While the system I chose has proved itself to perform brilliantly for thousands of miles over the last four years you have helped me see this is really just masking the underlying failures you've invested so much of your time to explain.
As such and following your comments I've decided to rip the whole lot out and go with one of your self calibrating slave ECUs that twists the wrong petrol injector durations in a bid to cook up a calibration that works on LPG.
I'm excited by the prospect of doing away with my unique fuel and ignition tables, and especially losing all control over ignition when I switch to a 110Ron fuel that burns in a very different way.
Many thanks, Dave.
Edited by ChimpOnGas on Sunday 23 July 17:45
At no point in the thread on LPGforum did it seem you were going to pay anyone to do any LPG work on your car, that didn't matter because no fitter would feel their nose had been pushed out of joint by you taking the DIY route on such a simple to convert vehicle, certainly not me.
Again, the reason why I've taken 'much' of my time (mostly on your LPGforum thread) to explain the shortfalls of your system is because you have taken much of your time to incorrectly explain how your system is superior to what pros like myself achieve. It increasingly seems you misunderstand exactly what pros like myself do/achieve and haven't really got any benchmarks to even compare your results against.
Misunderstandings such as 'my' self calibrating systems. Anyone reading this can look through my many hundreds of posts on LPGforum and read that I am very much against self calibrating systems. Now if you want to be clear with your other points that are intended to reflect negatively on the way I would have advised converting your car you will need to define 'twists', 'bid' and 'work', and then I'll explain why you're wrong again. You might also explain in detail the different ways in which different ron fuels burn... Ron doesn't have much to do with the way fuels burn unless ron is insufficient to prevent knock, in which case the fuel goes up in more of a detonation than a burn, which of course we don't want, but running LPG in an engine with standard compression you could advance timing way too far without even seeing detonation. Advancing timing means pressure from burning the fuel starts to build in the cylinder before the piston reaches top dead centre and any pressure in the cylinder before top dead centre is negative power because the pressure is trying to push the piston against the direction of rotation of the crankshaft. In reality if IT setup for running on petrol could be advantageously tweaked at all for running on LPG we're probably only talking a couple of degrees more advance and at relatively low rpm. Any advantage from such tweak would be negligible, not noticeable seat of the pants, so to set this extra advance up properly you'd be talking expensive dyno resting or rolling road testing where you took full account of the different conditions on the rolling road to on the real road, plus full account of other variables such as weather and humidity. I'll touch on this point again below. If you have any real news on comparison of burn properties, ignition timing, etc and how they all relate to engines in the real world, I imagine you must have spent a lot of money on supercomputer time and/or thousands of hours of engine dyno analyser time... in the hope of achieving that extra half a percent or 2 percent over ignition timing a few degrees different and fuelling slightly away from stoch. And even then you'd be forgetting that you could achieve whatever ignition timing you wanted with a cheap programmable TAProcessor and could have used a slaved LPG system to get the same mixture. I take it you didn't experiment with different head designs, compression ratios, etc, which would be where any real gains could be made.
Almost all Rover V8s that I convert tend to run a better on LPG than on petrol, but I know that if everything was good with both the petrol system and the LPG system they should run just as well on both fuels.. I never claim that anything I convert runs better on LPG than on petrol, only go as far as saying runs as good on LPG as on petrol. The real reason newly converted Rover V8's tend to run better on LPG than on petrol is because the LPG injectors are brand new but the petrol injectors are old and worn. I made notes on the last couple of dozen Rover V8 engine'd vehicles I converted in case the owners have future issues on either fuel, my notes say things like petrol injector number 5 seems to be flowing 10% less fuel than average, petrol injector number 7 suspect slight constant leak. It's quite easy to arrive at such conclusions when you know fully what you're doing and fit a system that can switch individual cylinders between fuels, but this does beg the question if/how you checked for such things.
Now that you've gone this route, the job is done and you're happy with it, nobody is suggesting you do away with it to fit anything different. Everyone here will enjoy car talk but some of us are a bit surprised at the ongoing hype about this one car's fuel system that has been going on 4 years when the results seem nothing exceptional though achieving those results took much more money and time than they could have.
There are things you say and points you make that I am interested in, but I imagine on a thread in this section of this forum will go over a lot of people's heads. For instance, I would be interested to see your ignition timing maps for both fuels so that I might see the comparisons, and maybe at some point I might even fit a cheap TAP and program it to emulate your exact timing results on the same model engine so that I might draw my own conclusions on any quoted advantage of your timing figures. I would be interested to see differences between your fuel maps too, however, we will both no doubt feel the need to point out to others at this point that no direct comparison between fuel maps can be made unless you know the exact nature of your LPG injectors (because all LPG injectors are slower to respond than petrol injectors). Luckily for me I know exactly how your LPG injectors respond because I've fitted them / seem them / diagnosed them on plenty of different engines and have done the same with all types of LPG injectors. Of course to anyone without the same insights it might look like fuelling maps need to change tremendously between fuels, but there's always lambda to go on and the correct amount of fuel is the correct amount of fuel. Got to bring this up again - how can you say a slave map delivers any less accurate fuelling than your system when they both (hopefully) give the same lambda reading? Then there's that other point I made about correct lambda as soon as possible after changing throttle position and/pr rpm.... Your system doesn't compensate for pressure or temperature but does correct mixture via closed loop operation. Slave systems compensate by default via closed loop operation which the petrol system provides, but closed loop operation cannot make up for loss of pressure and temp correction for accurate fuelling with changing throttle or rpm, which I would think more important than usual on a sports car..
Simon
Edited by SimonYorkshire on Tuesday 25th July 20:34
That's it, I'm definitely ripping it all out now.
Having read your 462,000 posts on the LPG Forum, it's now obvious how stupid I was not to go to the only LPG specialist in the whole country who actually knows what he's doing, a message that becomes clear from post two on.
Ironic really as the Canems Dual Fuel ECU is such a niche market system for a niche market situation.
Thanks for helping me see the light Simon.
Having read your 462,000 posts on the LPG Forum, it's now obvious how stupid I was not to go to the only LPG specialist in the whole country who actually knows what he's doing, a message that becomes clear from post two on.
Ironic really as the Canems Dual Fuel ECU is such a niche market system for a niche market situation.
Thanks for helping me see the light Simon.
Edited by ChimpOnGas on Tuesday 25th July 23:21
ChimpOnGas said:
That's it, I'm definitely ripping it all out now.
Having read your 462,000 posts on the LPG Forum, it's now obvious how stupid I was not to go to the only LPG specialist in the whole country who actually knows what he's doing, a message that becomes clear from post two on.
Ironic really as the Canems Dual Fuel ECU is such a niche market system for a niche market situation.
Thanks for helping me see the light Simon.
Having read your 462,000 posts on the LPG Forum, it's now obvious how stupid I was not to go to the only LPG specialist in the whole country who actually knows what he's doing, a message that becomes clear from post two on.
Ironic really as the Canems Dual Fuel ECU is such a niche market system for a niche market situation.
Thanks for helping me see the light Simon.
Edited by ChimpOnGas on Tuesday 25th July 23:21
ChimpOnGas said:
That's it, I'm definitely ripping it all out now.
Having read your 462,000 posts on the LPG Forum, it's now obvious how stupid I was not to go to the only LPG specialist in the whole country who actually knows what he's doing, a message that becomes clear from post two on.
Ironic really as the Canems Dual Fuel ECU is such a niche market system for a niche market situation.
Thanks for helping me see the light Simon.
Every installer advised you not to go the Canems route, not just me.Having read your 462,000 posts on the LPG Forum, it's now obvious how stupid I was not to go to the only LPG specialist in the whole country who actually knows what he's doing, a message that becomes clear from post two on.
Ironic really as the Canems Dual Fuel ECU is such a niche market system for a niche market situation.
Thanks for helping me see the light Simon.
Edited by ChimpOnGas on Tuesday 25th July 23:21
Could have run the standard petrol injection with a slave LPG setup and got near identical results, it would still allow you to set mixture to whatever you liked during open loop operation when running on gas. If you really feel it necessary to also adjust IT you could have run the standard petrol injection system and a slave LPG system in conjunction with a cheap TAP (so now you'd be able to adjust high load fuelling and the IT across the whole rpm/load range). If you really feel the need to run none stoch fuel mixtures you could have run an MS setup with a slave LPG system, like your system that could run different stochs at various rpm/load points depending on which fuel you were running on (not that you'd want to get far from stoch during most conditions anyway, no production car runs none stoch ratios at anything other than high load, evident in 'command lambda' in OBD2 on modern vehicles with wide band sensors which is never further away from 1 than 0.995 or 1.005 during idling and most cruise conditions but may go down to maybe 0.75 when booting it) and would have added the further slight benefit of fully sequential injection rather than the original petrol ECU's and your Canem's ECU's semi sequential injection. All these options would have cost less (very much less at the start of that list) while at the same time featuring (by default) compensation for gas pressure and gas temperature and automatic switch back to petrol when you ran out of gas. The first few options on this list could add a bit more peace of mind, all of them would allow you to continue running on petrol if your LPG system broke, or on the other hand if you broke down due to failure of the petrol ECU you could for example just go to a scrappies and pick up a replacement petrol ECU. With your system you could be waiting for the niche Canems to be sent out and maybe having to wait for it to be programmed to suit your car before it was sent out. I didn't even touch on mixer systems in this list, a mixer system would have allowed you to continue running on gas even if your petrol fuel system completely failed (at least if you fitted an inexpensive MJolt ignition control system as backup to the original ignition control system)..
Still dunno if you arrived at the decision to fit your type of system alone and then fitted it alone or if someone else steered you to decide on your type of system and did much of the work fitting it for you. Still dunno why I received emails from people saying you've already broken down in it abroad leaving you stranded waiting for bits to be sent out, and have had to have it remapped several times. What I do know is, especially with systems in the first part of my list you wouldn't get stranded or need to have it remapped but you'd be thousands of pounds better off and would only have spent a fraction of the time getting it right. I think you may have read into the term 'slave type LPG system' a negative that isn't there - The 'slave' part of the term refers to digital signal processing where the length of the petrol injection pulse (or would be petrol injection pulse because petrol injectors are disconnected from the petrol ECU when running on gas) is measured very accurately by the slave system and some very exacting calculations are done to arrive at the appropriate duration to pulse LPG injectors for, calculations that take into account an extremely adjustable user map, gas temp compensation and gas pressure compensation. It is incorrect to assume the compensations are not necessary because to do so would fly in the face of the laws of physics that say they definitely are necessary and in the face of every bit of experience that pro installers have gained. It is incorrect to assume your Prins reducer (or any reducer) will be completely pressure stable, no aftermarket LPG system ignores the need for pressure and temperature compensation like your system does, not even the Prins system. The 'slave' aspect isn't a negative because there is no loss of accuracy with digital processing (which measures petrol injector pulse length down to the nearest one thousandth of a millisecond(!), the LPG injectors should always pulse for at least as long as the petrol injectors because LPG injectors take longer to open and close than petrol injectors, the start of the LPG injector pulse begins at the exact same moment as the start of a (would be) petrol injection pulse, when the end of the (would be) petrol injection pulse is determined the system calculates the extra time that the LPG injector should remain open for and easily completes that calculation before the point at which the LPG injector pulse should close occurs.. At the end of the day, every digital ECU (which means every vehicle's engine control ECU made since as far back as the early 80's) including your Canems ECU performs digital signal processing to arrive at the correct pulse length for injectors anyway, and it makes no difference if the precursor to LPG injection signals originated in a different ECU (the petrol ECU) to be interpreted by the LPG ECU or if everything is done within one ECU case. There is do disadvantage to this approach. E.g. this message I am typing will probably pass through many computers before it arrives on this forum but it will arrive on this forum exactly as I type it nonetheless, again no loss of accuracy with digital processing! If you are against the multiple ECU (the slave ECU) approach you might as well also feel it necessary to redesign the whole internet so that there is just one mother of all computers running the internet, but if that computer went down the whole internet would go down! From installers points of view your threads needed balance because you hardly touched on the disadvantages of your type of system and readers may have got the impression installers advice/results compared unfavourably to what you've done but I still congratulate you on running on half price fuel, taking an unusual route and pulling it all off to your own satisfaction.
Simon
Edited by SimonYorkshire on Wednesday 26th July 14:00
ChimpOnGas said:
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