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Lpg Conversion (Is300)


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Hi mate.

In my experience LPG is a royal pain in the rear, it burns hotter than petrol so you need a good set of iridium plugs plus there's so many other things that can go wrong.

If you do decide to convert don't go for the "cheap fit it all in one day jobbie" LPG is nasty stuff with a large expansion rate and the system needs to be tested and checked over a 5 to 7 day period for obvious reasons.

Good luck anyway. :phone:

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Hi, thanks, although this is concerning. What problems have you had? (or heard of?)

I should add I've converted my omega to autogas with help from the guys on omegaowners.com and using stag LPG systems, although I'm aware prinz are alleged to be the must nuts in LPG, but refuse sell their kits to DIYers. Only issues I've had is grumpy cold starts in freezing conditions, but that's down to me being tight with early switch over times.

Omega is a 3.2 v6 lump with 4speed auto, very similar power figures to the ls300. The valve seats on the omega are hard enough to take LPG, but I'm told the Toyota lumps need flash lube as the seats are, apparently, slightly softer...? No need for iridium plugs either, one of the guys tried them, made no odds at all.

Anyone know of the inlet is plastic for mounting injector nozzles? Must admit I haven't looked under the bonet thoroughly yet, we haven't had the Is a week yet.

My main concern is how fussy the engine management is on the Lexi's. BMW are known to be somewhat pedantic on gas, for example.

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i have had two IS300's in the past.

cost me £2200 to gas convert 1 of them at the time.

use to average 300 miles £30 quid gas, soft easy driving. which is brilliant.

you have to get the right convertion done & yes flash lube is essential as the valves would burn out in a week!

the ecu is clever. as you drive on gas the fuel gauge will begin to drop. you could be on reserves with a full tank of fuel!

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Anyone converted one of these to dual fuel?

Nice deep wheel well. Can the valve seats take it?

Are you sure it is worth it? To fill up the boot, reduce performance a bit (inherent & unavoidable) and to have to drive at least 12000 miles on LPG alone to recover the costs (using Mr Rudus' figures) - probably including a fair few finding LPG stations. Add to this the real possibility of fitting a system you find causes problems or doesn't live up to expectation.

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Hi Chris,

familiar story here, I also converted a Omega V6 to LPG and ran it for 200,000 miles with few problems, then asked Gastech for advice on a fresh motor, GS300 they advise so off I went buying a 2002 Se (same engine as your Sportcross) and had it converted with Flashlube. Complete disaster, numerous breakdowns ( I can never forget complete shutdown in lane 4 of the M25 near Heathrow) and 2 engine rebuilds later I gave up and bought a GS450 hybrid for work and a Sportcross to take the dog out, at last reliable cars again. Because the Omega ran so well or so long I am sure Gastech fit good kit and know what they are talking about but the GS NEVER ran sweetly on LPG. Hope this helps you to avoid making the same mistake as I made.

Regards Tony ( worried for the health of your Sportcross )

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Stag300plus kit works well. Not top of the range at £700 odd quid in parts for the kit and tank, but it's good enough for omega engine management. Some fiddling is needed to tune nozel sizes to keep fuel trims in check and keep tick over steady, but once the correct size was established each install gave very consistent results.

Needs a live data capable diagnostic tool to confirm fuel trims are within limits though. Does anyone here have one?

Is it worth converting? Well, if it can be set up correctly then yes, there are savings to be had, and DIY keeps costs down and pay back can be had very quickly. Yes it depends on autogas suppliers location etc, and there are cheaper ways to drive. But the way I see it, it merely makes the car I want, and the way I want to drive it cheaper.

We could all buy a diesel sh!t box front wheel drive bra burner, and save even more money. But I'd rather have a decent motor tbh, so that's diesels out IMO.

On the omega, boot it on gas and change back to petrol at any revs and there's no extra take off or surge in power as petrol takes over. Yes gas is less powerfull, but it's really hard to tell. Can always set the parameters to switch back to petrol above, say, 4k rpm for those pesky BMW's if desired. The switch over is seamless though.

Anyway, sounds like some further research is required. What do you guys do for code reading and diagnostics etc?

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you have to go for a good sequential system, DO NOT USE OLD MANUAL ONES!!! http://www.autogas.co.uk/converting-sequential_injection_system.htm

Stag being very similar to that, if this engine is that fussy might look into prinz further though. But worth a price.

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Anyone converted one of these to dual fuel?

Nice deep wheel well. Can the valve seats take it?

Are you sure it is worth it? To fill up the boot, reduce performance a bit (inherent & unavoidable) and to have to drive at least 12000 miles on LPG alone to recover the costs (using Mr Rudus' figures) - probably including a fair few finding LPG stations. Add to this the real possibility of fitting a system you find causes problems or doesn't live up to expectation.

Yep, all very fair points. Omega boot is massive, although the tank does block the though space on the saloon as the seats back drop down, rarely need this usefull feature though, so cheaper fuel takes priority.

Sport cross estate has deep spare wheel well with the option to elevate the floor, so a large teroidal donut tank won't notice at all. Although a wheel bag for the spare isn't ideal, there's always the option to leave the spare at home if the full load space is needed, and risk a puncture.

Finding gas stations gets easier as you get used to thier locations, but it's mostly a daily commute that I plan around, we don't usually fall short on holiday either. I'm more concerned that the Mrs can't re gas the omega tbh. It's big clunky filler system, her little hands don't have the strength, and she doesn't like the gas venting when remove the filler nozzle. (sigh...)

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Anyone converted one of these to dual fuel?

Nice deep wheel well. Can the valve seats take it?

Are you sure it is worth it? To fill up the boot, reduce performance a bit (inherent & unavoidable) and to have to drive at least 12000 miles on LPG alone to recover the costs (using Mr Rudus' figures) - probably including a fair few finding LPG stations. Add to this the real possibility of fitting a system you find causes problems or doesn't live up to expectation.

Yep, all very fair points. Omega boot is massive, although the tank does block the though space on the saloon as the seats back drop down, rarely need this usefull feature though, so cheaper fuel takes priority.

Sport cross estate has deep spare wheel well with the option to elevate the floor, so a large teroidal donut tank won't notice at all. Although a wheel bag for the spare isn't ideal, there's always the option to leave the spare at home if the full load space is needed, and risk a puncture.

Finding gas stations gets easier as you get used to thier locations, but it's mostly a daily commute that I plan around, we don't usually fall short on holiday either. I'm more concerned that the Mrs can't re gas the omega tbh. It's big clunky filler system, her little hands don't have the strength, and she doesn't like the gas venting when remove the filler nozzle. (sigh...)

I suppose there is one final point. If I were looking to buy a 300 Sportcross - a really nice vehicle; my main issue would be how much would it cost to get rid of any LPG conversion which compromises how well it runs both on LPG & petrol. I may be alone in this; but don't think so. IS300s aren't usually chosen for economy :phone:

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Anyone converted one of these to dual fuel?

Nice deep wheel well. Can the valve seats take it?

Are you sure it is worth it? To fill up the boot, reduce performance a bit (inherent & unavoidable) and to have to drive at least 12000 miles on LPG alone to recover the costs (using Mr Rudus' figures) - probably including a fair few finding LPG stations. Add to this the real possibility of fitting a system you find causes problems or doesn't live up to expectation.

Yep, all very fair points. Omega boot is massive, although the tank does block the though space on the saloon as the seats back drop down, rarely need this usefull feature though, so cheaper fuel takes priority.

Sport cross estate has deep spare wheel well with the option to elevate the floor, so a large teroidal donut tank won't notice at all. Although a wheel bag for the spare isn't ideal, there's always the option to leave the spare at home if the full load space is needed, and risk a puncture.

Finding gas stations gets easier as you get used to thier locations, but it's mostly a daily commute that I plan around, we don't usually fall short on holiday either. I'm more concerned that the Mrs can't re gas the omega tbh. It's big clunky filler system, her little hands don't have the strength, and she doesn't like the gas venting when remove the filler nozzle. (sigh...)

This is a DIY project remember, and if an LPG manufacturer or installer can't set the system correctly, what does that tell you about the industry? I agree with your scepticism there, don't worry. Hence the DIY mentality on omegaowners.

But until we have followed up on issues with LPG on this engine, we can't say where the fault lies....can we? (car,installer, kit,engine management)

If I buy a kit, install it, bugger about setting up, decide your right and it's pants, take it off and sell It on for any other 6 cylinder engine what have I lost? A load of time for sure, a new inlet manifold, de solder the loom connections, fill in the wholes the wheel well with some gromits..... Anything else?

....must say Lexus seem far more reliable than omegas, I guess that means no DIY needed generally for you guys. That would make a pleasant change I must say.

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LPG conversion will just spoil the fun factor of having an IS300 and more over you will be driving around with extra weight! as some guys have already mentioned work out how long you looking to keep the car for and the costs of carrying out the conversion against the cost of current petrol prices. Yes petrol prices have shot up but if it will cost you e.g. say a minimum £1000 for the conversion and lets just say your monthly petrol cost has increased by £20 more due to new petrol prices, you will be better off running this car on 100% petrol without the conversion if you are keeping the car for a minimum of 4 years. the conversion will only start paying for it self after 4 years.

lets work this out based on the example above. 1000 / 20 = 50 . 50 /12 = 4.1

Now lets put some logic into the above figures. initial cost of conversion to LPG cost say £1000. extra cost of your monthly petrol expense has gone up £20 every month. so we divide £1000 initial LPG conversion cost by £20 (increased monthly petrol cost) which gives us 50 which means you can drive on 100% petrol for 50 months (4 years 1 month) if you decide not to fork out £1000 in one lump sum for a conversion.

so if you will be keeping the car for 4 years or less, stick with petrol because based on my example above by spending £20 more on your normal monthly fuel expense you will only be at a disadvange after 4 years and 2 months. but if you will keeping the car for more than 4 yrs 1 month then LPG will be beneficial and cost effective. :hocus-pokus: . note: I have not even added the cost of frequent filling up with gas in my example ounce a conversion is done this was only based on initial conversion cost of £1000.

In a nut shell, if you will be keeping the car for 4 years or less, running it on petrol will work out cheaper than an LPG conversion + cost of frequent filling up with Gas after converson.

P.S I drive an IS300 my self and to be honest driven with a light right foot achievs the same mpg as any 2.0litre 4 cylinder petrol engine. but have the advantage for when i need more power :shifty: .

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The extra weight will depend on running with a completely full petrol tank as well, or not, but a good point. But as an estate will it note cope with that extra weight?

However I'm not sure where your going with those figures? Time to payback on the install will depend on how many miles covered. The more miles your doing with general use the quicker payback will arrive, and the sooner we save money. Or, the sooner we stop giving money away to the tax man.

Not sure I understand the negativity here. If the car doesn't cope well with autogas then fair enough, I can understand bad experiences. But there's seems to be something more to it? Reading between the lines...

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I am definately not opposing you or being negative about having an LPG conversion done. I was only making you aware LPG conversion does not always = saving money.

my figures in the first post were fictional figures and might not apply to your circumstance hence I said it was an example based on if the miles you are currently covering has caused your monthly petrol expense to increase by £20 more.

the example shows that if you decide to keep the £1000(fictional conversion cost) in the bank and rather spend £20 more (due to increase in miles/fuel prices) from that money ,the £1000 will last you 50 months(4years 1 month).

1000/20 = 50 50/12= 4.1

so lets just say you were looking to keep the car for a maximum of 3 years by still leaving the £1000(fictional conversion cost) in the bank,and instead carried on using petrol which has worked out £20(example) more every month.

works out £720 over the course of 3 years but this is based on if your extra monthly fuel expense still stays at £20 more.

this is how the £720 was achieved. 12*3=36 36*20 = £720 . 12 months times 3 = 36 months. 36 months times £20(extra fuel expense per month due to more miles) = £720.

so based on these fictional figures which might not apply to your personal circumstane, you will be saving £280 in the bank if you were keeping the car for 3 years and not forking out an initial lump sum cost of £1000 for a conversion + cost of frequent filling up of gas during a 3 year period.

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I am definately not opposing you or being negative about having an LPG conversion done. I was only making you aware LPG conversion does not always = saving money.

my figures in the first post were fictional figures and might not apply to your circumstance hence I said it was an example based on if the miles you are currently covering has caused your monthly petrol expense to increase by £20 more.

the example shows that if you decide to keep the £1000(fictional conversion cost) in the bank and rather spend £20 more (due to increase in miles/fuel prices) from that money ,the £1000 will last you 50 months(4years 1 month).

1000/20 = 50 50/12= 4.1

so lets just say you were looking to keep the car for a maximum of 3 years by still leaving the £1000(fictional conversion cost) in the bank,and instead carried on using petrol which has worked out £20(example) more every month.

works out £720 over the course of 3 years but this is based on if your extra monthly fuel expense still stays at £20 more.

this is how the £720 was achieved. 12*3=36 36*20 = £720 . 12 months times 3 = 36 months. 36 months times £20(extra fuel expense per month due to more miles) = £720.

so based on these fictional figures which might not apply to your personal circumstane, you will be saving £280 in the bank if you were keeping the car for 3 years and not forking out an initial lump sum cost of £1000 for a conversion + cost of frequent filling up of gas during a 3 year period.

it all depends on how many miles your travelling a day/year. If you're doing loads you can start saving in just a year! Your calculations do not apply to everyone and they're not very clear anyway ;)

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If you read my previous two posts you will notice I used the word ‘example’ so no this calculations will not apply to everyone hence I said its fictional figures but my calculations are definitely accurate.

Will use my self as an example to make things easy for you:. Before I got my IS300 it cost me exactly £100 a month to fill up my ford cougar V6 on upgrading to an IS300 it cost me exactly £120 a month to fill up on petrol for work. So this means my monthly fuel expense has increased by £20 a month after my upgrade to an IS300.

Now I get a quote of £1000 inc VAT from an LPG conversion specialist to convert my IS300 to LPG so on getting back home I decided to work the cost of LPG conversion (£1000) against the cost of my increased fuel expense (£20) to see if by having the conversion done works out cheaper against me paying £20 more for petrol over the course of 3 years which is how long I am looking to keep the car for.

So It will cost £1000 for an LPG conversion and £40 a month to fill it up with Gas. 12 months makes 1 year so for 3 years it would cost me 12 months * 3 to make 36 months * my £40 a month Gas cost which works out £1140.

12months*3yrs = 36months 36months* £40 a month = £1140 + the intial LPG Cconversion cost of £1000 = £2140. So as you can see it will cost me £2140 if I am looking to run my car on LPG for 3 years.

Now If I decide not to convert to an LPG on the IS300 but rather pay the fuel expense increase of £20 at the petrol pumps after my upgrade to IS300 to make up for not having an LPG, will work out £720 over a 3 year period.

So using the same formula as above, 12 months makes 1 year so for 3 years it would cost me 12 months * 3 to make 36 months * my £20 a month petrol cost for driving an IS300 over ford cougar V6 which works out £720.

There you have it. It cost me £20 more a month to drive an IS300 over a ford cougar V6 which based on that amount works out to be £720 over 3 years but will cost me £2140 for an LPG coversion + cost of filling up GAS over the same 3 year period if I decide to fore go paying Mr.Shell £20 more for unleaded fuel and convert to GAS. :phone: hope this clears things up

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I suppose a LPG conversion is viable as a DIY project, and it could work out well for you - and if it didn't you could rip it out. Talking to people who have done such conversions over the years, they are rarely trouble-free & don't usually save as much as hoped. There are obviously happy exceptions.

Generally though, LPG conversion seems too often to be a way to turn a nice car into a turd.

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You can do your own conversion,but a registered fitter must comission the system and you must let your insurance company know,and they will want his registrayion code number.

Too right, gas in not to be taken lightly. The guy I use is good. A bit off ish at first on my first install, but once he realised I wanted things right he was very helpfull and positive.

Insurance is straightforward in theory but a lot of jobswoerths in call centres don't see dual fuel cars come up too often, so getting the right response can be difficult.

Plus there's the change in criteria ie, no certificate as such, just a logged reg on the lpguk web site, ins can be a challenge to get cover in place.

They do see sense in the end though.

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If you read my previous two posts you will notice I used the word ‘example’ so no this calculations will not apply to everyone hence I said its fictional figures but my calculations are definitely accurate.

Will use my self as an example to make things easy for you:. Before I got my IS300 it cost me exactly £100 a month to fill up my ford cougar V6 on upgrading to an IS300 it cost me exactly £120 a month to fill up on petrol for work. So this means my monthly fuel expense has increased by £20 a month after my upgrade to an IS300.

Now I get a quote of £1000 inc VAT from an LPG conversion specialist to convert my IS300 to LPG so on getting back home I decided to work the cost of LPG conversion (£1000) against the cost of my increased fuel expense (£20) to see if by having the conversion done works out cheaper against me paying £20 more for petrol over the course of 3 years which is how long I am looking to keep the car for.

So It will cost £1000 for an LPG conversion and £40 a month to fill it up with Gas. 12 months makes 1 year so for 3 years it would cost me 12 months * 3 to make 36 months * my £40 a month Gas cost which works out £1140.

12months*3yrs = 36months 36months* £40 a month = £1140 + the intial LPG Cconversion cost of £1000 = £2140. So as you can see it will cost me £2140 if I am looking to run my car on LPG for 3 years.

Now If I decide not to convert to an LPG on the IS300 but rather pay the fuel expense increase of £20 at the petrol pumps after my upgrade to IS300 to make up for not having an LPG, will work out £720 over a 3 year period.

So using the same formula as above, 12 months makes 1 year so for 3 years it would cost me 12 months * 3 to make 36 months * my £20 a month petrol cost for driving an IS300 over ford cougar V6 which works out £720.

There you have it. It cost me £20 more a month to drive an IS300 over a ford cougar V6 which based on that amount works out to be £720 over 3 years but will cost me £2140 for an LPG coversion + cost of filling up GAS over the same 3 year period if I decide to fore go paying Mr.Shell £20 more for unleaded fuel and convert to GAS. :phone: hope this clears things up

An example based on what exactly? Imaginative accountancy at RBS?

The equation you should be looking at relates to miles covered, gas price v petrol price, install price and pence per mile on gas v petrol.

If the car covers 15000 miles a year, pay back on the install will be archived twice as quick as it would if it covered 7500 miles. Then your looking at pence per mile difference between gas and petrol, of which the saving is about 1/3 less than petrol.

Yes there are cheaper ways of getting from A to B, but then we wouldn't all be driving Lexus in the first place would we.

To me, driving on petrol is peshing money up the wall. Your choice though.

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I do agree but my figures as you can see were accurate based on how much i spent a month compared to how much gasing will have cost me over 3 years and also how much sticking with petrol would have also cost me in three years. this can also be applied to diesel cars which are about 2 to 5 grand more than thier petrol equivalent and also dearer at the pumps! and will take some disel drivers 4 sometime 7 years to recoup the initial expense of going down the diesel route! but as you say I am happy with petrol so will stick to it! good luck with the conversion and keep us updated on how it goes. :zee:

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I don't really think its up to us to bend over backwards to understand your point. If your point isn't clear, that's nobody else's fault but.....

...anyway. I'll take your command to keep you informed as I wish if that's ok. *****. Maybe some work on the manors front wouldn't go amiss? Hmm?

And if I wanted a Diseasal it would have to be BMW, so there's two counts on why that's never ever going to happen.

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