LPG Chimaera (Follow My Conversion)
Discussion
ChimpOnGas said:
As part of the continual 'Ol Gasbag' development program I received these little beauties in the post today..
In theory these Hana Golds will support up to 400hp as a set of eight
Famed as the very best 1.9 Ohm LPG injectors in the world, Hana Golds are also lovely looking things to my eyes
Roll on phase three of project 'Ol Gasbag'..
Does that mean you can map it straight off the Emerald with these injectors ? mapping both fuel and spark .In theory these Hana Golds will support up to 400hp as a set of eight
Famed as the very best 1.9 Ohm LPG injectors in the world, Hana Golds are also lovely looking things to my eyes
Roll on phase three of project 'Ol Gasbag'..
What are the two manifolds for ?
SILICONEKID345HP said:
Does that mean you can map it straight off the Emerald with these injectors ? mapping both fuel and spark.
Absolutely not Daz, these injectors are still peak and hold so they still need peak and hold injector drivers which as I've pointed out 100 times you don't have.You can not run peak and hold injectors off your petrol "saturated" injector drivers - FULL STOP, the ECU wouldn't lasts 5 minutes before it cooked itself.
If you did want to convert your TVR to LPG your best bet is to run your Emerald map two through a dedicated LPG piggyback ECU that housed the peak and hold injector drivers needed for the LPG injectors. You could get map 2 there or there abouts on the fuel side so the piggyback doesn't need to do much manipulation, and you could certainly get it spot on in relation to the LPG ignition timing which is very different to that of petrol.
TBH I've taken a second look at some of the latest piggyback ECUs and the the truth is they are becoming extremely sophisticated, the key advantage being they already have a host of dedicated LPG features built in like gas temp & volume correction tables. The problem for you Daz is they're all typically designed to run off an OEM engine management systems so take 90% of their information from the car's OB2 connector which you won't have on your Emerald.
Although I do see that the TVR Power MBE ECU is now offering OB2 connectivity which if its talking the right protocol opens a whole host of possibilities.
For the Emerald I guess you'd need to unpick the connectors that come with the piggyback and make up your own connections, then there would be other additions to your loom for things line the tank solenoid, vaporiser solenoid ect ect.
All in all you'd probably end up with a bit of a bodged up birds nest loom, which is just one of the reasons I went with the Canems Dual Fuel ECU in the first place as it's a proper complete dual fuel engine management system and harness from the get go, so there's no splicing in a piggyback after the event.
But that's not to say you couldn't make your Emerald work very well indeed with the addition of a decent LPG piggyback system and someone with good wiring and mapping skills.
SILICONEKID345HP said:
What are the two manifolds for ?
To mount the injectors in, also being an aluminum manifold they are also ideal to mount my thermostatically controlled injector heaters to.
Ok Gas Sniffers here's some more 'Ol Gasbag' tweaks & developments going on down at the LPG Skunk Works in Wiltshire (Lloyd Specialist Developments).
The project has been a great success but if I'm honest with myself the key pleasure I take from it all is the continual process of development and refinement
1. First up and the key development being the switch from the well behaving but rather crude Magic Jet injectors to the more sophisticated and beautiful Hana Golds.
We've taken advantage of the injector swap to mount these beauties back on the rocker covers as with my earlier 1.2 Ohm Keihns (lets not go there
). This positioning is not only neater and more pleasing to the eye but affords the injectors the gentle warming effect they appreciate without the need for the injector heaters I've been using on the Magic Jets.
Nathan at Lloyds has a unique appreciation for neatness & symmetry so I'm looking forward to seeing his injector mounting handwork.
2. Next up comes the opportunity to move our fairly new LPG pressure and temperature sensor closer to where the corrections (governed by the sensor outputs) actually take place, IE the injectors.
3. With my new lovely injectors in place I got to thinking about improving the filtration, yes the pressure/temp sensor is mounted to an integral filter and housing but could our gaseous state filtration system be better?
Well as it turns out yes it can, in the last 6-12 months a new breed of centrifugal gaseous state filters have entered the market that deliver far superior removal of heavy end deposits from the LPG put there by the refinery compressors when they turn propane into its liquid state.
It's very common for these waxy deposits to find their way into the delicate internals of LPG injectors and overload their coils causing either poor cold running performance until engine heat helps melt the deposits away, or complete and total failure of the injector itself.
Here's the very latest and apparently highly effective solution to this age old problem which as Nathan quite rightly observed works in exactly the same way as a water trap on your workshop compressor.
Goo be gone
4. Adding in some relays, I have three solenoids for safety (one on each tank & one on the vaporiser) and as the Canems ECU only really safely supports two, lets add some proper marine grade waterproof relays and upgrade the solenoid wiring at the same time.
5. A manifold depression dynamic pressure correction circuit (or over pressure circuit to some in the LPG world) to be added to the existing Prins vaporiser. This may or may not offer certain advantages to the mapping process. Prins and some of the other quality LPG vaporiser manufacturers offer this feature so it's there for a reason, however lets just see how it performs on 'Ol Gasbag' that historically has only ever been mapped with the vaporiser operating in static pressure state without direct interference (at the vaporiser) from manifold depression changes.
6. Some 400lb rear springs, to solve the very occasional bottoming out caused by the additional 30kg of weight in the boot. Lets see how she feels on the road?
Not my car but you get the picture
7. Some other undisclosed switch trickery
That's it for now, watch this space Gas Sniffers for the latest installment on project 'Ol Gasbag'
The project has been a great success but if I'm honest with myself the key pleasure I take from it all is the continual process of development and refinement
1. First up and the key development being the switch from the well behaving but rather crude Magic Jet injectors to the more sophisticated and beautiful Hana Golds.
We've taken advantage of the injector swap to mount these beauties back on the rocker covers as with my earlier 1.2 Ohm Keihns (lets not go there
). This positioning is not only neater and more pleasing to the eye but affords the injectors the gentle warming effect they appreciate without the need for the injector heaters I've been using on the Magic Jets.Nathan at Lloyds has a unique appreciation for neatness & symmetry so I'm looking forward to seeing his injector mounting handwork.
2. Next up comes the opportunity to move our fairly new LPG pressure and temperature sensor closer to where the corrections (governed by the sensor outputs) actually take place, IE the injectors.
3. With my new lovely injectors in place I got to thinking about improving the filtration, yes the pressure/temp sensor is mounted to an integral filter and housing but could our gaseous state filtration system be better?
Well as it turns out yes it can, in the last 6-12 months a new breed of centrifugal gaseous state filters have entered the market that deliver far superior removal of heavy end deposits from the LPG put there by the refinery compressors when they turn propane into its liquid state.
It's very common for these waxy deposits to find their way into the delicate internals of LPG injectors and overload their coils causing either poor cold running performance until engine heat helps melt the deposits away, or complete and total failure of the injector itself.
Here's the very latest and apparently highly effective solution to this age old problem which as Nathan quite rightly observed works in exactly the same way as a water trap on your workshop compressor.
Goo be gone
4. Adding in some relays, I have three solenoids for safety (one on each tank & one on the vaporiser) and as the Canems ECU only really safely supports two, lets add some proper marine grade waterproof relays and upgrade the solenoid wiring at the same time.
5. A manifold depression dynamic pressure correction circuit (or over pressure circuit to some in the LPG world) to be added to the existing Prins vaporiser. This may or may not offer certain advantages to the mapping process. Prins and some of the other quality LPG vaporiser manufacturers offer this feature so it's there for a reason, however lets just see how it performs on 'Ol Gasbag' that historically has only ever been mapped with the vaporiser operating in static pressure state without direct interference (at the vaporiser) from manifold depression changes.
6. Some 400lb rear springs, to solve the very occasional bottoming out caused by the additional 30kg of weight in the boot. Lets see how she feels on the road?
Not my car but you get the picture
7. Some other undisclosed switch trickery
That's it for now, watch this space Gas Sniffers for the latest installment on project 'Ol Gasbag'
I've been asked to give a breakdown of what it would cost to replicate my LPG system.
First of all you'd need to already be considering a petrol only engine management upgrade for such a project to be financially viable. Start with treating the project like any other petrol only engine management upgrade (Emerald, Omex, MBE, Canems ect ect) and enjoy the benefits on petrol.
Quite rightly no one ever challenges people who choose to buy such a system on when they'll get their money back in fuel savings, people don't buy buy such systems for fuel savings they buy them for the improved drivability and many other benefits they deliver.
Remember the Canems dual fuel ECU gives you all the well understood petrol only engine management upgrade benefits of an Emerald, Omex, Canems (petrol only) or MBE system but it also gives you the LPG option too, an option you can explore later on should you wish.
Consider now the difference in price between a standard petrol only Canems system and their dual fuel ECU is only £265 and we can start to breakdown the real costs.
Now that's understood lets break the costs down:
At a guess I'd say you could bring the whole project in for £2,500 including the above parts, a custom aluminum petrol tank, the custom LPG tank frame, installation, wiring and mapping.
But like I said at the beginning you'd need to already be considering a petrol only engine management upgrade already for such a project to be financially viable. Start with activating the petrol side and enjoy that element for a while, then when you're ready and funds have recovered you can invest the £2.5k in going LPG.
Is it worth it?
Well that very much depends on how many miles you're doing and how long you feel it's acceptable to wait before the conversion pays for itself.
If you consider you'll save yourself around £0.08p per mile then you'll need to cover 31,250 miles to fully recover your costs. For many TVR owners that's going to take a lifetime but for the few who actually use their car as everyday transport the return on your investment could easily be within three years or less.
The truth is this was a hobby project for me and had little to do with the fuel savings. It had much more to do with me wanting to understand and master a fuel that had fascinated me for years, as such I don't feel I need to justify the project costs anymore than someone who chooses to fit a supercharger or heavily ported cylinder heads and triple plenum.
At the end of the day I haven't really made my car go much faster with all this but I have taught myself an awful lot about engine management systems the unique behavior of gaseous fuels and ultimately extracted huge pleasure from the whole project. I've also proved there's a better way to manage the delivery, metering & combustion of LPG than using the usual LPG systems out there.
Finally I would say the whole thing could be done massively cheaper on a standard Chimaera by keeping the 14CUX, distributor and using one of the better LPG piggyback ECUs out there. It won't be as as efficient or deliver the same levels of performance, refinement & drivability.
But it will work acceptably and start delivering a real saving in half the time of my infinitely more sophisticated system.
Dave.
First of all you'd need to already be considering a petrol only engine management upgrade for such a project to be financially viable. Start with treating the project like any other petrol only engine management upgrade (Emerald, Omex, MBE, Canems ect ect) and enjoy the benefits on petrol.
Quite rightly no one ever challenges people who choose to buy such a system on when they'll get their money back in fuel savings, people don't buy buy such systems for fuel savings they buy them for the improved drivability and many other benefits they deliver.
Remember the Canems dual fuel ECU gives you all the well understood petrol only engine management upgrade benefits of an Emerald, Omex, Canems (petrol only) or MBE system but it also gives you the LPG option too, an option you can explore later on should you wish.
Consider now the difference in price between a standard petrol only Canems system and their dual fuel ECU is only £265 and we can start to breakdown the real costs.
Now that's understood lets break the costs down:
- Canems ECU upgrade to LPG spec: £265
- Gurtner Vapojet Luxe 340HP Vaporizer: £71
- 2 x HANA H2001 Gold 4cyl Rail Type Injectors with Alu Rail: £200
- PRINS VSI Filter - 2 Outlets with BOSCH Sensor: £62
- LPGTECH Perfect Blue Filter: £11
- 1 x 200x1050mm 30 litre single hole LPG tank: £62
- 1 x 244x1040mm 45 litre single hole LPG tank and all fittings: £180
- 200mm Cylindrical 30° Tomasetto AT-02 Multivalve: £39
- Gas Tight Housing for Tomasetto Multivalve: £10
- UK Filling Point (Bayonet) to 8mm - 90 deg: £15.50
- UK Bayonet Filler Cap: £4
- Rubber Boot Cover for 90deg filler: £6
- Vent, tank link, liquid phase, gaseous phase and filler pipework incl all pipe fittings: £38
- Relays, change over switch, wiring sundries, general unspecified sundries: £35
- Custom aluminum petrol tank & fittings, plus LPG tank frame: Ask Lloyd Specialist Developments
- Installation, wiring and mapping: Ask Lloyd Specialist Developments
At a guess I'd say you could bring the whole project in for £2,500 including the above parts, a custom aluminum petrol tank, the custom LPG tank frame, installation, wiring and mapping.
But like I said at the beginning you'd need to already be considering a petrol only engine management upgrade already for such a project to be financially viable. Start with activating the petrol side and enjoy that element for a while, then when you're ready and funds have recovered you can invest the £2.5k in going LPG.
Is it worth it?
Well that very much depends on how many miles you're doing and how long you feel it's acceptable to wait before the conversion pays for itself.
If you consider you'll save yourself around £0.08p per mile then you'll need to cover 31,250 miles to fully recover your costs. For many TVR owners that's going to take a lifetime but for the few who actually use their car as everyday transport the return on your investment could easily be within three years or less.
The truth is this was a hobby project for me and had little to do with the fuel savings. It had much more to do with me wanting to understand and master a fuel that had fascinated me for years, as such I don't feel I need to justify the project costs anymore than someone who chooses to fit a supercharger or heavily ported cylinder heads and triple plenum.
At the end of the day I haven't really made my car go much faster with all this but I have taught myself an awful lot about engine management systems the unique behavior of gaseous fuels and ultimately extracted huge pleasure from the whole project. I've also proved there's a better way to manage the delivery, metering & combustion of LPG than using the usual LPG systems out there.
Finally I would say the whole thing could be done massively cheaper on a standard Chimaera by keeping the 14CUX, distributor and using one of the better LPG piggyback ECUs out there. It won't be as as efficient or deliver the same levels of performance, refinement & drivability.
But it will work acceptably and start delivering a real saving in half the time of my infinitely more sophisticated system.
Dave.
SILICONEKID345HP said:
Is that 2.5k drive in drive out ?
You really would need to talk to Lloyd Specialist Developments Daz, and don't forget your situation is slightly different to the one I'm quoting because you already have an Emerald after market engine management system.This means you'll be needing an LPG piggyback ECU because it wouldn't make any sense to rip out your Emerald and replace it with a Canems dual fuel ECU.
But even one of the better 8 cylinder LPG piggyback ECUs won't be too expensive (you'll need a non-OBD model), for example you could use this well respected one from LPG Tech for just £170 including sensors, filters and wiring loom.
http://www.lpgshop.co.uk/8cyl-ecu-lpgtech-tech-328...
The rest of the conversion costs are as I've described, so while I wouldn't dream of speaking for whoever would install it I think it's fair to say £2,500 for a drive in drive out conversion is not an unreasonable guess on my part.
Remember I've included a bespoke aluminum auxiliary petrol tank and a bespoke steel frame to properly and safely mount the twin stacked LPG cylinder tanks to the rear chassis mounts.
Also keep in mind you'll need to cover just over 30,000 miles on LPG to recover the cost of the conversion and that may not make any financial sense at all for someone who uses their TVR as a weekend toy.
To do it really properly a Chimaera is not necessarily what could be described as a cheap car to convert to gas, but it is probably the very best sports car to convert because it has a huge boot and the Rover V8 engine/heads are well known to be 100% LPG friendly.
Follow my packaging and component recipe, then get the experts to install it. The car will then be just like any other Chimaera to drive, just one that does the cost equivalent of 50mpg.
Actually the truth is 'Ol Gasbag' drives a lot better on LPG than any 14CUX equipped Chimaera does drinking petrol, what you get is a nicer driving car and half the fuel costs
Great to see lpg on another performance car. I've had it on my gt-four (280'ish bhp) for a while now.
I use the Hana blue 1.2ohm injectors with an lpg tech piggyback controller and it's brilliant. Easy to configure yourself with a £20 Usb to rs232 cable.
The injectors are mounted horizontally & are performing the same as they did when new 30k miles ago, I'm sure you will be happy with them.
One thing to add - the quoted flow rates of lpg injectors are not accurate for turbo applications. Hana blue for example are only supposedly rated for 50hp each, but on a turbocharged engine at say 1.0bar, this would be closer to 80hp.
Re the costs, if you diy a piggyback system & use an off the shelf tank size, it won't cost anywhere near £2500. £1100 would he more realistic.
If you ever take it through Luxembourg you will be in for a pleasant surprise. This summer LPG cost 35cents/litre.
I use the Hana blue 1.2ohm injectors with an lpg tech piggyback controller and it's brilliant. Easy to configure yourself with a £20 Usb to rs232 cable.
The injectors are mounted horizontally & are performing the same as they did when new 30k miles ago, I'm sure you will be happy with them.
One thing to add - the quoted flow rates of lpg injectors are not accurate for turbo applications. Hana blue for example are only supposedly rated for 50hp each, but on a turbocharged engine at say 1.0bar, this would be closer to 80hp.
Re the costs, if you diy a piggyback system & use an off the shelf tank size, it won't cost anywhere near £2500. £1100 would he more realistic.
If you ever take it through Luxembourg you will be in for a pleasant surprise. This summer LPG cost 35cents/litre.
Thanks for your comments Dave.
I'm interested in why you went with the Hana blue at 1.2 Ohms not the more common 1.9 Ohm Hana Golds?
And can you tell me if your Toyota ECU plus LPG Tech piggback ECU allows you to alter your ignition timing and curve to take advantage of the different burn rate and higher octane rating of LPG?
You're absolutely right to say you could convert a TVR Chimaera for £1,100, but to be frank it would be full of compromises. Once you really start to understand the limitations the very old technology fuel & ignition systems on a Chimaera impose (not to mention the packaging challenges) you'll soon see where the extra money is going to do the job properly on this car.
I am actually using off the peg LPG cylinder tanks stacked and firmly bolted to the rear of the TVRs tubular steel backbone chassis, its worth noting the Chimaera boot floor is fiberglass so mounting the tanks to the chassis is the only truly safe option. Doing it this way also delivers the required packaging of fuel requirements (both gas & petrol) while still retaining the very practical boot space.
However, doing it this way requires completely removing the original petrol tank and replacing it with the two gas tanks, this makes building a bespoke auxiliary petrol tank essential and so further adds to the cost of the conversion.
Here's how it all this looks on my car.
The above system allows me to carry over 5 gallons of petrol giving a very practical 150 mile range on the expensive stuff, plus 14 gallons of LPG which allows for an easy 320 mile range on gas.
The biggest challenge for a TVR Chimaera owner wanting to to convert to LPG is firstly that the ECU is very dated, for example it doesn't even have an OBD2 connector. Worse still is a Chimaera is burdened with an ancient distributor (remember distributors?) and single canister coil ignition system.
You could treat the conversion in the way you would any early 90's Range Rover which have the same systems, and as we know literally thousands of these vehicles were successfully converted. However, while it's straightforward enough to do and will as you quite righly say only cost around £1,100 the existing petrol & ignition systems on these vehicles makes for a far from ideal platform to go LPG.
If you ditch the old Lucas fuel only ECU and fit an aftermarket ECU you also delete the prehistoric distributor for EDIS wasted spark ignition, so this is really the way to go. But replacing the ECU isn't cheap, so along with the bespoke auxiliary petrol tank fabrication the engine management changes are where we jump from your £1,100 to my £2,500.
There are things that make a TVR Chimaera a fantastic two seat convertible sports car to convert to LPG, the engine is proven gas safe and the car comes with a huge boot. But the ECU & particularly the ancient distributor based ignition system then conspire against you to make properly converting this old school sports car considerably more expensive than other cars.
Cheers for looking in on my project Dave, finally here I am filling up with gas in Luxembourg with a fellow V8 gas sniffer.
Like you say LPG is crazy cheap there
I'm interested in why you went with the Hana blue at 1.2 Ohms not the more common 1.9 Ohm Hana Golds?
And can you tell me if your Toyota ECU plus LPG Tech piggback ECU allows you to alter your ignition timing and curve to take advantage of the different burn rate and higher octane rating of LPG?
You're absolutely right to say you could convert a TVR Chimaera for £1,100, but to be frank it would be full of compromises. Once you really start to understand the limitations the very old technology fuel & ignition systems on a Chimaera impose (not to mention the packaging challenges) you'll soon see where the extra money is going to do the job properly on this car.
I am actually using off the peg LPG cylinder tanks stacked and firmly bolted to the rear of the TVRs tubular steel backbone chassis, its worth noting the Chimaera boot floor is fiberglass so mounting the tanks to the chassis is the only truly safe option. Doing it this way also delivers the required packaging of fuel requirements (both gas & petrol) while still retaining the very practical boot space.
However, doing it this way requires completely removing the original petrol tank and replacing it with the two gas tanks, this makes building a bespoke auxiliary petrol tank essential and so further adds to the cost of the conversion.
Here's how it all this looks on my car.
The above system allows me to carry over 5 gallons of petrol giving a very practical 150 mile range on the expensive stuff, plus 14 gallons of LPG which allows for an easy 320 mile range on gas.
The biggest challenge for a TVR Chimaera owner wanting to to convert to LPG is firstly that the ECU is very dated, for example it doesn't even have an OBD2 connector. Worse still is a Chimaera is burdened with an ancient distributor (remember distributors?) and single canister coil ignition system.
You could treat the conversion in the way you would any early 90's Range Rover which have the same systems, and as we know literally thousands of these vehicles were successfully converted. However, while it's straightforward enough to do and will as you quite righly say only cost around £1,100 the existing petrol & ignition systems on these vehicles makes for a far from ideal platform to go LPG.
If you ditch the old Lucas fuel only ECU and fit an aftermarket ECU you also delete the prehistoric distributor for EDIS wasted spark ignition, so this is really the way to go. But replacing the ECU isn't cheap, so along with the bespoke auxiliary petrol tank fabrication the engine management changes are where we jump from your £1,100 to my £2,500.
There are things that make a TVR Chimaera a fantastic two seat convertible sports car to convert to LPG, the engine is proven gas safe and the car comes with a huge boot. But the ECU & particularly the ancient distributor based ignition system then conspire against you to make properly converting this old school sports car considerably more expensive than other cars.
Cheers for looking in on my project Dave, finally here I am filling up with gas in Luxembourg with a fellow V8 gas sniffer.
Like you say LPG is crazy cheap there
Edited by ChimpOnGas on Sunday 20th September 01:23
To be honest I don't remember the Hana golds being around when I purchased the bits. The Hana blue A+ were the quickest operating highest flowing injectors I could find.
You are right regarding ignition optimisation - my system has no functionality to optimise this between LPG & petrol. However, the jump in cost to add this functionality is excessive imo, & the drive ability difference not noticeable enough to justify this cost. Admittedly I haven't had the car on a dyno, but I drive it every day, am 'in tune' with it (I'm sure you know what I mean) and I can perhaps feel a slight difference between both fuels during a full throttle pull, but it really is slight. I cannot tell any difference in transient response during normal driving.
If I were to do a conversion now, I'd look at the Vialle LSI liquid injection system.
Imagine all that cooling effect currently dealt with by the vaporiser, happening in the inlet manifold! With careful tuning, even with non optimised LPG ignition curves, there would be significant opportunity to increase power on a turbo engine:
Http://www.lpgshop.co.uk/4cyl-vialle-lsi-liquid-in...
You are right regarding ignition optimisation - my system has no functionality to optimise this between LPG & petrol. However, the jump in cost to add this functionality is excessive imo, & the drive ability difference not noticeable enough to justify this cost. Admittedly I haven't had the car on a dyno, but I drive it every day, am 'in tune' with it (I'm sure you know what I mean) and I can perhaps feel a slight difference between both fuels during a full throttle pull, but it really is slight. I cannot tell any difference in transient response during normal driving.
If I were to do a conversion now, I'd look at the Vialle LSI liquid injection system.
Imagine all that cooling effect currently dealt with by the vaporiser, happening in the inlet manifold! With careful tuning, even with non optimised LPG ignition curves, there would be significant opportunity to increase power on a turbo engine:
Http://www.lpgshop.co.uk/4cyl-vialle-lsi-liquid-in...
I've just noticed something interesting you mentioned above under point 5 - does your current prins vaporiser not reference the manifold pressure as standard? Do you know what pressure the gas outlet is set at/can be adjusted to?
That's a very strange configuration & definitely wouldn't work very well on a turbocharged engine.
That's a very strange configuration & definitely wouldn't work very well on a turbocharged engine.
DaveCWK said:
I've just noticed something interesting you mentioned above under point 5 - does your current prins vaporiser not reference the manifold pressure as standard? Do you know what pressure the gas outlet is set at/can be adjusted to?
That's a very strange configuration & definitely wouldn't work very well on a turbocharged engine.
The car has been mapped with and without vac reference, works well either way, adding it just makes low speed/light load mapping a little easier. Forced induction may well be on the cards but for now the 250hp and 260 torques works nicely in car that only weighs 1100kg. To put that into perceptive a car weighing 1,400kg would need to be producing 318hp and 331 ft/lbs of torque to match it's performance.That's a very strange configuration & definitely wouldn't work very well on a turbocharged engine.
If you haven't experienced the benefits of mapping your ignition for the different LPG burn characteristics & resistance to detonation you will be amazed at the advantage it gives.
The Canems Dual Fuel ECU I use is totally different from an LPG piggyback set up, rather than taking the petrol injector information (which ultimately is wrong for LPG) then twisting it in an attempt to get things right for LPG, you actually map the fuels completely independently of each other.
I appreciate LPG ECUs have become quite sophisticated and the LPG Tech offering is one of the better ones out there, but at the end of the day they are working with second hand sensor information that's already passed through the petrol ECU. And of course LPG piggyback ECUs do nothing with the ignition side which ultimately means they completely miss out on the biggest advantage of LPG.
LPG is 110Ron and it's burn speed is totally different to petrol, so forgetting the fuel metering side for a minute that means you definitely need a very different ignition map indeed if you really want to to get the best from the fuel. Once you've deeply studied the unique characteristics of LPG it becomes blindingly obvious you need to build both a fuel and especially an ignition map to respect the differences to petrol.
If you want to maximize your cylinder pressures and really take advantage of all the extra ignition advance the fuel will tolerate before reaching the point of detonation you'll soon acknowledge that you need a very different looking ignition map indeed.
With the Canems system you direct map on petrol and do so using real time sensor data, nothing ground breaking there then as it's just like any other after market ECU. The difference comes when you turn your attention to the LPG side where you start all over again with a clean sheet of paper building your unique LPG specific map which has absolutely zero connection with the petrol one.
The LPG injection table ends up looking very different indeed to the petrol one, and the ignition table is absolutely worlds apart. Best of all and just like the petrol mapping process you are seeing & using real time direct sensor information when building your LPG tables. The sensor data is pure and unadulterated because it hasn't already passed through the petrol ECU as with an LPG piggyback.
Even before you start to build your proper LPG ignition map this direct and completely separate mapping process gives obvious advantages on your fuel tables, but when you start on the ignition side these advantages are taken to a whole new level.
I guess that's why my TVR makes exactly the same power yet more torque on LPG than it does on petrol, it's also why it drives so perfectly on both fuels I need a small LED to tell me what fuel I'm using because without it it would be impossible to tell. Actually that's not quite true because the additional torque on gas delivers an even smoother engine than on petrol during low speed low load driving.
We've been developing this system with the ECU designer and mapping team for three years now and it's definitely delivering all the advantages over a piggyback system that we expected it too. Over time we've added to the system's unique benefits outlined above by experimenting with lots of different components including expensive 1.2 Ohm Keihin injectors which actually over-stressed the injector drivers eventually, cheap 1.9 Ohm Magic Jet injectors that worked well and now the excellent & totally ECU safe 1.9 Ohm Hana Golds. We've added closed loop with our own AFR targets, gas temperature and pressure inputs to calculate the true volume of the gas just before it reaches the Hana Injectors, then built a correction table around further targets to really nail those typically fluctuating LPG AFRs.
Liquid injection certainly has many advantages on paper but it's also in its infancy, there are a number companies out there offering it but the Vialle LPI system certainly seems the most developed so far. The key question mark hanging over all liquid injection systems (even with the Vialle one) is high pressure pump reliability. There's lots of evidence to suggest that the high pressure pump is going to leave to very disappointed sooner or later.
I expect I'll end up playing with liquid LPG injection at some point but I also fully expect it'll require some significant development work to combine it with the Canems Dual Fuel ECU and still take advantage of it's direct fuel and ignition mapping on both fuels. At the end of the day the Vialle LPI ECU is just another piggyback so if I used it what I'd gain going liquid would be lost with the ability to map the fuel properly as I'm able to do with my gaseous system.
So for now I'll stick with my gaseous system as it's 100% proven, reliable and fully direct mappable on both the fuel and ignition, but that doesn't mean the development stops, far from it.
Actually I've already got some ideas to take my gaseous system to the next level
Enjoy your LPG Celica Dave, and remember this isn't just a cheap fuel because if you meter and manage its burn properly it becomes a performance fuel too
Edited by ChimpOnGas on Monday 21st September 08:18
ChimpOnGas said:
Beautiful Hana Golds.
Next up comes the opportunity to move our fairly new LPG pressure and temperature sensor closer to where the corrections (governed by the sensor outputs) actually take place, IE the injectors.
A manifold depression dynamic pressure correction circuit (or over pressure circuit to some in the LPG world) to be added to the existing Prins vaporiser. This may or may not offer certain advantages to the mapping process. Prins and some of the other quality LPG vaporiser manufacturers offer this feature so it's there for a reason, however lets just see how it performs on 'Ol Gasbag' that historically has only ever been mapped with the vaporiser operating in static pressure state without direct interference (at the vaporiser) from manifold depression changes.
Ok well that little lot worked a treat Next up comes the opportunity to move our fairly new LPG pressure and temperature sensor closer to where the corrections (governed by the sensor outputs) actually take place, IE the injectors.
A manifold depression dynamic pressure correction circuit (or over pressure circuit to some in the LPG world) to be added to the existing Prins vaporiser. This may or may not offer certain advantages to the mapping process. Prins and some of the other quality LPG vaporiser manufacturers offer this feature so it's there for a reason, however lets just see how it performs on 'Ol Gasbag' that historically has only ever been mapped with the vaporiser operating in static pressure state without direct interference (at the vaporiser) from manifold depression changes.
I've been real world testing these latest additions and tweaks over the last few months and couldn't be happier with the results
First of all it's conclusive... the Hana Gold injectors are by far the best LPG injectors I've ever used and by a significant margin... these injectors are delivering a full package of improvements... economy, drivability and LPG cold starts are all enhanced.
Performance is totally indistinguishable between fuel types, toggling back and forth from petrol to gas is seamless to the extent I often find myself glancing down at my blue illuminated LPG switch to confirm if I'm burning the cheap stuff or petrol.
Today as a further experiment before setting out on my trip to Lloyds I leaned out out a group of low load sites on the closed loop target map to 16:1, then dialed in some more advance in the corresponding LPG ignition map cells pushing it right to the 49 degree maximum
Now lets look at the results of what was admittedly a fairly tame drive mostly around the 70mph mark.
- Depart with brimmed tanks.
- Distance traveled to Murco Stonehenge: 89.66 (GPS Recorded)
- Liters to brim tanks again at Murco Stonehenge: 16.95 (3.73 Imperial gallons)
- 89.66 / 3.73 = 24.03 MPG (genuine LPG MPG)
- 95 Ron petrol price today at Murco Stonehenge: £1.09 lt
- LPG price today at Murco Stonehenge: £0.479 lt
- £1.09 / £0.479 = 2.275
- 24.03 LPG mpg x 2.275 = 54.67 MPG petrol cost equivalent
So there it is in black & white folks.... we've created a 4.0 litre V8 TVR that's cheaper to fuel than the very latest super sophisticated high tech 1.8 litre four cylinder Japanese hybrid
THE NEXT STEPS
Well, other than going liquid injection which I'll probably implement in 12 months time I need to see if David Hampshire of Canems Engine Mangement Systems can give me more ignition advance.
Currently the maximum I can dial in is 49 degrees and I'm confident there are areas on the LPG map where we could see benefits from running 55 degrees or more. Now my mapping team have a nice hub dyno we can conclusively prove the impacts more or less timing genuinely delivers.
Lets see if David Hampshire can give me the option to run up to 60 degrees of advance
, we can then bolt 'Ol Gasbag' to the hub dyno and start lighting the LPG earlier and earlier until the det cans start warning us of the onset of knock.I'm confident we'll end up with best cylinder pressures on cruise around 55 degrees or more BTDC which in turn could deliver as much as a 8% economy improvement over what we are achieving now with our current maximum of 49 degrees.
Either that... or I'll start melting pistons
Essentially I'm now gunning for a true LPG target of 26 MPG which will give me the petrol cost equivalent of 60 MPG
This must the figment of someone's emagination,, 
It's all just words surely,,,,
Fantastic Dave, you must be so satisfied,,, mine does 27 mpg and I'm well happy with that,,
It's just increadable what your doing with your car,,,
You have blown the lid clean off this Lpg thing,,
Keep up the world class work.
It's all just words surely,,,,
Fantastic Dave, you must be so satisfied,,, mine does 27 mpg and I'm well happy with that,,
It's just increadable what your doing with your car,,,
You have blown the lid clean off this Lpg thing,,
Keep up the world class work.
ClassiChimi said:
This must the figment of someone's emagination,,
It's all just words surely,,,,
Fantastic Dave, you must be so satisfied,,, mine does 27 mpg and I'm well happy with that,,
It's just increadable what your doing with your car,,,
You have blown the lid clean off this Lpg thing,,
Keep up the world class work.
Thanks Alun, I appreciate my project isn't everyone's cup of tea but it's pleasing when people understand what I'm trying to achieve here.It's all just words surely,,,,
Fantastic Dave, you must be so satisfied,,, mine does 27 mpg and I'm well happy with that,,
It's just increadable what your doing with your car,,,
You have blown the lid clean off this Lpg thing,,
Keep up the world class work.
The truth is I'm still not quite hitting my own economy target I set when I embarked on this crazy journey. The measure of success for any LPG project is it's efficiency, and the one unavoidable fact about gaseous LPG systems is the engine will always consume more gas than petrol.
This is due to the lower calorific value of LPG by mass when it's in it's gaseous state, saying that if you keep it compressed at 50-60 psi right up to the injector it will remain in its liquid state. And what a lot of people don't know is that liquid LPG actually has a higher calorific value than petrol by mass so that means more power and more economy than petrol.
However if it remains in it's gaseous state the chemistry is unavoidable, these chemical rules dictate that even the perfect gaseous delivery system working under laboratory conditions would always deliver fuel economy no better than 18% behind what the same engine achieves on petrol.
I've proven my TVR will deliver a consistent 31mpg if driven in the same way as yesterday (70ish mph cruise), so my 24mpg on gas is actually a 22% loss of fuel economy and still a way off the magic 18% I'm trying so hard to achieve.
I believe the secret of turning my 22% into 18% lies in the ignition, we've already proved 110 Ron LPG will tolerate levels of advance that would be engine destroying on petrol. I'm already running right up to the maximum 49 degrees offered by the Canems system in the low load cruise sights and I'm convinced it'll take more without running into detonation.
Of course there comes a point where just adding more and more ignition advance will see cylinder pressures fall away but we haven't reached that point yet, and until David Hampshire at Canems increases the available advance we'll never really know where peak torque (and so maximum economy) exists.
The other idea to accompany the additional ignition advance experiment that may help the economy a fraction more is to go from batch fired injection to fully sequential, injecting the LPG at the back of the inlet valve just as it opens will certainly give a smoother idle and possibly even better refinement up to 2,000rpm. After 2,000 rpm I doubt it'll give much benefit, by that time everything is happening so fast you're more or less back to batch injection anyway.
But fully sequential injection remains an irresistible temptation all the same and if I'm having the ECU adapted for more advance I expect the draw of fully sequential injection will be too hard to resist, even if the likely benefits are small.
With both developments I think my 18% efficiency loss over petrol is a realistic target, and if I hit it 'Ol Gasbag' will be giving me 26mpg on gas which equates to the petrol cost equivalent of 60mpg!
After that only liquid injection will better it... Watch this space gas sniffers the next 'Gasbag' development ideas are already in the pipeline
ClassiChimi said:
So will the said David Hampshire of Canams fame be able to give you that extra bit of advance to accommodate your experiments Dave?
Seems like a darn good idea to me,,
I expect so mate Seems like a darn good idea to me,,
He's already added gas pressure and gas temperature correction tables to the ECU and two additional inputs to accommodate the sensor signals.
The whole idea is we've been developing the system together as a three way team, David Hampshire on the engine management side, the Lloyd boys handling installation & mapping with me just coming up with a few daft ideas and the funding.
Actually everyone has their input so I'm far from being the only one with ideas, there's been a lot of those ideas by the way, they get thrashed out amongst the team with some making the real world but just as many never seeing the light of day after the discussions expose flaws in their theory.
Fundamentally if you boil it all down all we've actually done here is make a Range Rover engine run on LPG, and lets be frank... there's absolutely nothing new in that
TBH I feel we've nailed the project already, if I made no further changes the car would still be a massive success in my mind mostly because it drives nicer than I ever could have expected it too. Thats why I'm starting to look at other areas where I can enhance my driving pleasure such as a lighter clutch and deleting the TVR gear linkage to improve the shift.
With the car running so sweetly and economically I've started to notice those little niggles I've put up with in the past, and they suddenly become the primary areas of focus.
ChimpOnGas said:
I expect so mate
He's already added gas pressure and gas temperature correction tables to the ECU and two additional inputs to accommodate the sensor signals.
The whole idea is we've been developing the system together as a three way team, David Hampshire on the engine management side, the Lloyd boys handling installation & mapping with me just coming up with a few daft ideas and the funding.
Actually everyone has their input so I'm far from being the only one with ideas, there's been a lot of those ideas by the way, they get thrashed out amongst the team with some making the real world but just as many never seeing the light of day after the discussions expose flaws in their theory.
Fundamentally if you boil it all down all we've actually done here is make a Range Rover engine run on LPG, and lets be frank... there's absolutely nothing new in that
TBH I feel we've nailed the project already, if I made no further changes the car would still be a massive success in my mind mostly because it drives nicer than I ever could have expected it too. Thats why I'm starting to look at other areas where I can enhance my driving pleasure such as a lighter clutch and deleting the TVR gear linkage to improve the shift.
With the car running so sweetly and economically I've started to notice those little niggles I've put up with in the past, and they suddenly become the primary areas of focus.
Maybe more development on the lpg is not financially viable ,one or maybe 2 more mpg versus cost is not worth bothering about .He's already added gas pressure and gas temperature correction tables to the ECU and two additional inputs to accommodate the sensor signals.
The whole idea is we've been developing the system together as a three way team, David Hampshire on the engine management side, the Lloyd boys handling installation & mapping with me just coming up with a few daft ideas and the funding.
Actually everyone has their input so I'm far from being the only one with ideas, there's been a lot of those ideas by the way, they get thrashed out amongst the team with some making the real world but just as many never seeing the light of day after the discussions expose flaws in their theory.
Fundamentally if you boil it all down all we've actually done here is make a Range Rover engine run on LPG, and lets be frank... there's absolutely nothing new in that
TBH I feel we've nailed the project already, if I made no further changes the car would still be a massive success in my mind mostly because it drives nicer than I ever could have expected it too. Thats why I'm starting to look at other areas where I can enhance my driving pleasure such as a lighter clutch and deleting the TVR gear linkage to improve the shift.
With the car running so sweetly and economically I've started to notice those little niggles I've put up with in the past, and they suddenly become the primary areas of focus.
Tyre Tread said:
Law of diminishing returns.
However Daz, I still don't think you've grasped Dave's motivation.
However Daz, I still don't think you've grasped Dave's motivation.
,,, As engineering exercise that even laymen like me can grasp, especially the way this thread has been conducted by its OP
Under sometimes heavy scrutinee is a testament to personal belief and sound engineering ideas,,,
To have got to the point of slickening up the gear change,,,
Dave cannot consider the cost when having to prove theory,,
I applaud the lLpg as a masterpiece,
ps Dave, can you consider the next leg too,,,
If the gearbox mods work, can your engineering team thrash out how to tighten up the drive train from gearbox and on to dif and drive wheels,,, mines had most things done and still it seems miss matched ? Sloppy,,,,
Just an idea sir,,,??
ClassiChimi said:
,,, As engineering exercise that even laymen like me can grasp, especially the way this thread has been conducted by its OP
Under sometimes heavy scrutinee is a testament to personal belief and sound engineering ideas,,,
To have got to the point of slickening up the gear change,,,
Dave cannot consider the cost when having to prove theory,,
I applaud the lLpg as a masterpiece,
ps Dave, can you consider the next leg too,,,
If the gearbox mods work, can your engineering team thrash out how to tighten up the drive train from gearbox and on to dif and drive wheels,,, mines had most things done and still it seems miss matched ? Sloppy,,,,
Just an idea sir,,,??
The SC-Power engine mounts are costly so they better last, I'm lead to believe they're a little stiffer than the standard rubber compound, they'll certainly be a lot stiffer than my cracked and soft wit oil originals. So the hope is my new SC-Power engine mounts should at least tie the engine to the chassis a lot better than what I have now which in tun may help a little with the gear shift.
That's the only thing I can suggest to eliminate the slop you describe, assuming your prop UJs, CV joints and diff buses are in good shape I really can't thing of much else in the drive train to look at.
After my last round of tweaks I'll be taking a break from spending on the car.... apart from my annul dash to Le Mans I missed my normal TVR France touring trip this year due to the house renovations, so next year I'll be doing the grand tour again.
I know you'll understand the excitement and anticipation I'm feeling for my 2016 TVR euro tour more than most Alun because road trips are clearly close to your heart too, and I must admit I'm really looking forward to enjoying some 55mpg TVR continental touring in 2016.
Sometimes you reach such a sweet spot in a car's development it makes sense to slow down on all the fettling and just drive the begger
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