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Martin Deer

2017/04/11 at 9:12 pm

Would it be possible for you to publish the MPG figures you achieved at the conclusion of the 10000 mile London durability test? This would be useful in that we could compare the new engine against the old LTI one. In theory your new engine should give better MPG.

2017/04/12 at 7:54 am

Hi Martin,

We are currently at 4000 miles. If you compare MPG between Diesel and LPG, we have achieved an average diesel MPG equivalent for LPG of 32.8MPG during the durability trial.

LPG has less energy per litre (about 40% less), so it’s actual MPG is lower (about 17-18MPG), but because the price of the fuel is lower (£1.189 for Diesel, £0.608 for LPG), we have a saving on fuelcost of 34% compared to a Diesel TX4 (@ 24.4MPG)

Obviously these numbers vary according to the drivestyle and fuel cost. Our best results were 17% higher than what we currently see in MPG. If you can find a cheaper refuelling station, the difference in Fuel savings will further increase.

Martin Deer

2017/04/12 at 1:19 pm

Are you able to give an extimate, using the above mileage figures, on how many miles you would have to drive to recoup the £9800 outlay for the conversion?

2017/04/13 at 1:55 pm

Hi Martin,

Using those mileage figures, the system would pay for itself at 150.000 miles. If you were doing 30,000 miles a year, the fuel saving would be 1900 pounds per year.

However, the fuel prices used for that comparison do not do the comparison real justice. 1.189 for a liter of Diesel is reasonably cheap, 0.609 for a liter of LPG is quite expensive. We are currently limited in how we can fill up, due to the limitations of the trial. LPG can be found a lot cheaper. For example using 0.54 for a liter of LPG, you would be saving 2500 pounds per year, recouping the costs within 4 years.

A side effect of this project will be a serious uptake of LPG in London. Most LPG suppliers will try to gain that volume, expanding LPG sites and lowering the LPG pricing. Have a look at Birmingham where LPG can be found for as little as 0.45 per liter LPG.

Martin Deer

2017/05/09 at 4:55 pm

I have spoken to the mechanic that services my TX4 and he has raised the following points.

Will you supply a service manual for the engine which gives part numbers of the consumables such as filters, belts, water pump, starter motor, gaskets, torque settings etc? and the recommended mileage to change items such as the timing belt for instance?

Will you provide a list of the error codes for the new engine management system?

If the new ECU goes wrong can he get a replacement?

Will he still be able to read the gearbox error codes and will they stay the same as the original TX4 ones?

Can he source and modify an exhaust locally should it need replacing in the future?

If the radiator needs replacing will a standard TX4 one fit, or will he have to modify it in some way?


2017/05/14 at 10:18 am

Hi Martin,

During the Warranty period, all engine maintenance will have to be carried out by an approved service center.

A service manual will be available. It will include:
– Partnumbers (Standard Vauxhall parts and additional parts (plus preferred suppliers))
– Recommended service mileages.
– Torque settings
– list of error-codes for the engine (requires additional diagnostic lead, which can be purchased separately)
– The ECU is custom made, it can be ordered online or at a Service center.
– The OBD for the gearbox will stay the same.
– The downpipe including catalyst is custom (can be ordered online or at a service center). The remaining exhaust (middle- and end pipe) is a standard TX2 exhaust.
– The radiator is a standard TX4 radiator for a TX4 or a standard TX2 radiator for a TX1 or TX2.

We’ve tried to keep everything as standard as possible.

22 thoughts on “Other Questions

  • I have a tx1 which ends its 16th year in November 2017 with Tfl – Can this cab be converted and relicensed by Tfl and if so how much more life/years will I get from it ?

    • Hi Chris,

      Unfortunately TfL does not grant the 5 years excemption (for conversion to LPG) after it’s 15th birthday. We also have not applied to get approval from TfL for our system on the TX1 for that reason. The TX2 will be approved very soon, but for the TX1 in London, we can’t do anything unless TfL decides otherwise.

  • I have four further questions for you.

    1. Can you give an indication on how many miles the converted engine will do before it requires a major overhaul (rebore, pistons)?

    2. You have already converted over 60 taxis in Birmingham, what sort of mileages have they achieved and have their been any problems with the conversion?

    3. There have been previous LPG conversions offered for cabs; unfortunately the companies that supplied the service went out of business, leaving drivers with no spares back up. What assurances can you give that this will not happen to you?

    4. The government are keen to promote cleaner vehicles, are you aware of any proposals to give tax breaks to vehicles that undergo an LPG conversion?

    • Hi Martin,

      1. The engine itself is brandnew. The design life of the engine is 300,000km in it’s original form (280Bhp). Because we’re only using 30% of it’s capacity the life of the engine would logically be a lot longer. Until now, the total warranty claims that Opel in Germany received for this engine are very low (current engine in Astra VXR and Insignia Turbo).

      2. Most taxi’s in Birmingham have now driven between 25k to 35k miles, with some already over 50k miles. So far we’ve experienced a number of teething problems relating with the Cab and some auxiliry items:
      – Heat inside Cab –> Faulty heater control valve on the Cab itself (original TX1) + improved heatshielding on the Catalyst to prevent radiated heat to the bulkhead
      – Leaking of inside radiators –> Cab’s internal radiators were in a bad state
      – Coolant fan failure –> Control driver too weak –> new controldriver designed.
      – Exhaust broke –> front pipe did not have additional support –> Additional support now added
      These issues happened on a number of Cabs. They have all been addressed if it concerned a part supplied by us.
      To prevent any damage to the engine, caused by lack of coolant – leakage due to faulty inside or outside radiators – a temperature controlled switch will in an extreme situation switch the engine off before it overheats. After it has sufficiently cooled down, the engine will start again (>10 min).

      3. While VRS is a relatively new company, it’s employees and the suppliers have been in the LPG conversion business for more then 30 years. Both VRS and suppliers have different revenue streams that ensure that a dip in Sales does not mean the downfall of the company. The technology used in the Cabs is also used in other applications, which also require proper service and warranty requirements.

      4. We are not currently not aware of any grants or tax breaks for the conversion of Cabs. But predicting what the government will do in the future, is an impossible task (they probably don’t know themselves). They very much favour Electric and other Zero-tailpipe emission technologies and Busses are currently the focus for retrofit technology. The Air Quality proposal from last May did include the recommendation of retrofitting Taxi’s to LPG to get the desired Air Quality improvements, but there were no indications on how they plan to promote it.

    • Hi William,

      You would need to ask you insurance company. We can assist in any valuation of the system if the insurance company requires it.
      I haven’t received any issues from the Birmingham drivers about the insurance.

      Depending on how much damage there is to the system, most components can be refitted to another vehicle is the body is a write-off.

  • Hi
    you seem to have all the relating answers to my question here, what i would like to know is that does the air conditioning get retrofitted as in do u have it fitted as part of the opel engine that you receive or do u have a custom bracketing kit to bolt the original air conditioning pump back onto the opel engine.

    Also i have read the part about the modifications of the welding of components to the chasy for the steering, my insurance company said as long as it has been tested and approved by the proper standards rating in the current regulation, i assume they are referring to the crash testing to make sure it does not impact the driving compartment and makes it unsafe?

    • Hi Paul,

      The Aircon unit uses an new electric pump, which is placed separate from the engine. It requires no pulley or belt. It is connected to the original pipes that run to the inside of the cab. The additional benefit is that it works without the engine running.

      About the welding, TfL had the same concerns. The two modifications we make to the TX2 are a minor modification to the steering support steady, and we replace the engine support brackets with the supports used on a TX4. All welding is performed by registered coded welders.

      The mofications were checked according to the following (current) regulations:
      – 1986 No. 1078 Road Vehicles (Construction and Use) Regulations 1986
      – 1981 No. 1694 The Motor Vehicles (Tests) Regulations, 1981
      - 2009 No. 717 The road vehicles approvals regulations (as applicable to Individual
      Vehicle Approval [IVA])

      It was approved at an Single Vehicle Approval inspection at an IVA centre. It was also inspected and approved by the technical department at Millbrook Proving Ground and a qualified Mechanical Engineer. Documentation is available on request.

      A TX4 before 2011 is only modified on the steering support steady and the later TX4’s require no welding at all, as the support steady is inside the cab.

  • With uncertain times ahead for the cab industry in the UK converting to LPG seems like a great option, especially with the extra 5 years
    BUT how do you find a service station that sell, LPG or o gas supplier to get it from
    I have looked and they seem few and far between. Can you enlighten me?

    • Hi Peter,

      Martin suggestion is a good one. There are also Apps in the appstore that look for LPG. The Shell drivers app can also point to LPG sites if you select Autogas as a filter.
      Autogas Limited also post the sites online: http://autogaslimited.co.uk/interactive-map

      We are in contact with several LPG suppliers to get them to increase the LPG filling network. We would liek to ask all drivers that if they find a suitable spot (can be taxi-specific) we can point the suppliers towards putting in a so-called skid-unit, which can be placed relatively quickly.
      As soon as the LPG comes into great demand, a lot of LPG suppliers will try to get more marketshare and put more filling sites in.

      As a thought, it is easier for an LPG supplier to put in a tank in a separate (private, or semi closed) location, then to add it onto an existing Forecourt (underneath fo example the canopy).

    • Hi Martin,

      We’ve decided to do the application for both the TX4 Euro 4 and Euro 5. We’re now converting the Cabs. I’ll keep the latest news section updated over the next weeks.

    • Hi Alex,

      Unfortunately we are not looking to convert the VitoTaxi. It would be quite complex and the developement costs would be too high.

  • Would it be possible to fit a larger capacity petrol tank at the time of the conversion, or retrospectively if so desired?

  • Can you provide a list of the approved service centres in and around the Greater London area for servicing and warranty work.

    • Hi William,

      At the end of February we’ll have 18 Converted London Taxi’s operating in London. For Engine servicing we’re currently setting up the Service Centers. Currently we’re looking at 7 Service Centers of which 4 are Bosch Centers located throughout London. If you can recommend a Garage we can look into including them as a Service Center.

    • Hi Paul,

      The TX4 kit has not been approved yet. We’ve now got a sign off on the relevant paperwork and the first visual inspection. We still need to do 2 more visual inspections, 2 emission tests and a durability trial. View our update page for any progress: http://gascab.co.uk/2017/08/25/tfl-tx4-approval/
      We aim to have the approval before the summer.

  • My tx4 life finishes in 4 years. If I was to have conversion now, would that extend life of my cab by an additional 5 years or just 5 years from date of conversion. So 2027 or just 2023. Thanks

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