WRX and LPG

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Discussion

anonymous-user

Original Poster:

55 months

Wednesday 28th November 2012
quotequote all
I have read a few thread on various forums and am contemplating this as an option for my next daily car, its probably the only way I would buy one TBH. The wagon is a great fit for my needs...apart from the 20-25mpg that they manage!

Is the PH poster still around with his conversion....

Anyone else please chime in, any advice appreciated.

ScoobieWRX

4,863 posts

227 months

Wednesday 28th November 2012
quotequote all
Yep...

eekNOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!! DON'T DO IT!!eek

v8250

2,724 posts

212 months

Wednesday 28th November 2012
quotequote all
ScoobieWRX said:
Yep...eekNOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!! DON'T DO IT!!eek
why not? i see no technical why any petrol fueled car can not/should not be converted to LPG. there'll be no loss of power. the conversion needs to be completed by a reputable/approved engineering team who specialize in LPG conversions who'll specify a correctly sized toroidal tank that will replace the current spare tyre i.e. 65-80ltrs. the only point i'd flag up would be to have a valve lubrication system fitted at the same time; just in case.

most lpg specialists will prefer to see low mileage cars for obvious reasons i.e. you're not converting an already tired engine. i've recently had fixed quotes for the saab 9-5 aero hot @ £1200+VAT. this gives me a ROI of only 10mths @ 15,000miles per annum.

ScoobieWRX

4,863 posts

227 months

Wednesday 28th November 2012
quotequote all
Technically no reason and i'm sure it will work just fine.....but it's a WRX turbo Impreza!! C'mon!!

If you wanted an economical car why don't you buy an oil burner or tiny petrol guzzler like a Nissan Micra.

Do you really want to add extra weight to what is already a c.1400Kg car?

LPG used to be half the cost of petrol...but not any more.

It's going to take you an absolute age to recoup the money you spend on having a decent quality LPG system fitted, likely you'll sell the car long before that happens and you really need to be doing some serious mileage to make it pay.

This subject has been done to death before and in all honesty although some people, and not many at that, have it done, the consensus is it's just not worth it and not something most of us would do to any Impreza.

You buy an Impreza and expect it to be thirsty. You put petrol in and enjoy the hell out of the car and exploit it to the fullest, then you put more petrol in and do it again. That's what Impreza's are about. You don't buy an Impreza to LPG it.

Don't take offence by my comments as they are not meant to be offensive and are just purely posted IMHO, but buying a WRX just to convert it to LPG is LAME!!!

£1200 for an LPG system fitted is going to be cheap and cheerful. Specialists were charging that 10yrs ago. Add at least another £1000 for a decent LPG system.

Edited by ScoobieWRX on Wednesday 28th November 22:31

v8250

2,724 posts

212 months

Thursday 29th November 2012
quotequote all
ScoobieWRX said:
Technically no reason and i'm sure it will work just fine.....but it's a WRX turbo Impreza!! C'mon!!
If you wanted an economical car why don't you buy an oil burner or tiny petrol guzzler like a Nissan Micra.
Do you really want to add extra weight to what is already a c.1400Kg car?
LPG used to be half the cost of petrol...but not any more.
It's going to take you an absolute age to recoup the money you spend on having a decent quality LPG system fitted, likely you'll sell the car long before that happens and you really need to be doing some serious mileage to make it pay.
This subject has been done to death before and in all honesty although some people, and not many at that, have it done, the consensus is it's just not worth it and not something most of us would do to any Impreza.
You buy an Impreza and expect it to be thirsty. You put petrol in and enjoy the hell out of the car and exploit it to the fullest, then you put more petrol in and do it again. That's what Impreza's are about. You don't buy an Impreza to LPG it.
Don't take offence by my comments as they are not meant to be offensive and are just purely posted IMHO, but buying a WRX just to convert it to LPG is LAME!!!
£1200 for an LPG system fitted is going to be cheap and cheerful. Specialists were charging that 10yrs ago. Add at least another £1000 for a decent LPG system.
Edited by ScoobieWRX on Wednesday 28th November 22:31
Francis, I understand your point of view but your reply is simply misleading to YONEX's original question. Here I will answer each of your points to clarify why there is no negative reason why any petrol fueled Subaru should not be LPG converted should an owner wish to do so.

The Subaru Impreza WRX is an individual car, but, there is nothing overly special about the Impreza; in fact technically they are rather basic by today's standards in comparison to some other cars. The engine's are not advanced in their design, neither in the principle of horizontally opposed cyclinders, turbo charging, nor materials used. They have this psuedo-God-like status because combined with their driveline they offer such all-round capabilities...which does not negate them from being converted to LPG; ala Subaru Legacy's, Outbacks, Foresters.

There is no reason why an owner should not want, nor expect, to be able to acheive greater fuel economy, particularly with the price of petrol in the UK. Your statement intimating LPG is expensive is just plain wrong. LPG's price has increased over the past 5years but is still considerbly cheaper per litre than petrol. If in doubt you can check prices here http://www.filllpg.co.uk/index.php?page=lpg.php

Now the hard facts. As an energy engineer [late 40's, a designer of advanced energy/power systems] using a well proven multi-rail LPG injection system with valve lubrication from PRINS, OMVL, BRC etc, will/does provide significant operational savings with no detriment to power, nor, reliability. You state "It's going to take you an absolute age to recoup the money you spend..." Well, let me be absolutely clear here...a proven expertly installed system described as above will cost £1200+VAT. Fortunately the price of component supply and installation has reduced over the past years and it is this that makes an LPG conversion so viable.

As an example I have recently compiled a spreadsheet for the Saab 9-5 Aero HOT Estate conversion - a car that has comparable BHP, is turbo charged, has better fuel economy than the Impreza and is heavier. I am happy to share this with any Subaru owner as one can change the cell data for each user application/annual mileage/existing mpg etc. The core data of this reads thus:

Install Price: £1200 [incl' price quoted from Oxfordshires most experienced LPG centre]
Average Petrol MPG: 28
Annual Mileage: 15000
Yr.1 Saving £172.38
Yr.2 Saving £1372.38
Yr.3 Saving £1372.38 [ditto for all years thereafter subject to annual mileage, petrol & LPG price/ltr...]

Ultimately, in this modern age one should not expect to buy a car and for that car to be a fuel guzzler; there is no technical excuse for this. Therefore, if there is a logical way to improve a cars fuel economy it should be considered [as above].

YONEX if you'd like a copy of the LPG calculator feel free to PM me. Also there are a number of online calculators readily available i.e.

http://www.autogas.ltd.uk/benefits/savings-calcula...
http://www.lpgservicecentre.co.uk/page3.html
http://www.britishautogas.com/index.php?option=com...

Just because we drive Subarus gives us no excuse to ignore other fuelling options if so required. The LPG subject has not "been done to death..." which is why so many car users have made the necessary changes. And one last point...one would hope that all car drivers have at least some level of environmental consideration/responsibility for their driving actions and total reliance on the combustion engine. We each will save circa' 1.3tonnes CO2 per annum with LPG as a fuel source. Combining the above facts provides a rather compelling case for LPG'ing any Subaru.

Francis, the above is from my humble experience is not intended to offend but to share knowledge smile





anonymous-user

Original Poster:

55 months

Thursday 29th November 2012
quotequote all
That's a great reply..thanks.

I know the purests mught frown on a conversion but it looks like quite a sensible thing to do. A quick, AWD estate with an engine that has a bit of character coupled with half sensible running costs seems like a damn fine idea to me! I have done the diesel thing and fancy something different.

ScoobieWRX

4,863 posts

227 months

Thursday 29th November 2012
quotequote all
I've not taken offence to amything. There's nothing misleading about what i've written, it's just my opinion and nothing more. If the OP wants LPG then he should have LPG. I wouldn't for the reasons i've stated and thats it biggrin Good luck with the conversion and i sincerely hope based on the above numbers and facts it works out for you. thumbup

v8250

2,724 posts

212 months

Thursday 29th November 2012
quotequote all
yonex said:
That's a great reply..thanks. I know the purests mught frown on a conversion but it looks like quite a sensible thing to do. A quick, AWD estate with an engine that has a bit of character coupled with half sensible running costs seems like a damn fine idea to me! I have done the diesel thing and fancy something different.
+1 This I understand having done the diesel thing for many years it makes no sense for a performance car to suffer fuel inefficiencies in this modern age. If one looks at Subaru the manufacturer [Fuji Heavy Industries] one can see the design steps taken over the past few years where they have tried to retain position with greater fuel efficiency improvement i.e. with the introduction of the diesel engines. Plus, I am certain that more people would be driving Subaru's if their overall running costs were lower in the same way BMW, Mercedes and VAG have achieved so successfully.

Two cars that do intrigue me are the 170PS Skoda Yeti and Scout 4x4 models. Both with reasonal power outputs, very well proven 4x4 powertrains, and both with proven market success; particularly overseas. One has to wonder if Subaru with their decades more experience in this sector could 'leap frog' these type of cars and regain some of the ground lost elsewhere. Also of note, is that the slightly larger/SUV 4x4 market has grown enormously over the past 5-8years with L-R and Nissan really capturing this market. It will only take someone like the Tata Group [Jaguar L-R] to decide they want a lower centre of gravity vehicle which can compete in motorsport and they'll seriously look at horizontally opposed engines as an option. Or even more imaginatively, Porsche...imagine if Porsche decided they want a mid-sector performance 4x4/all-rounder sports hatch-cum-estate car; they could wipe the market clean and still provide 65mpg+.

I have a close friend who project leads chassis design at a well known manufacturer. They are cuurently working on weight reduction techniques of 22-27% for their nextgen car range; and from the results I've seen they will do it. Imagine if all car manufacturers achieved this over the next 3-5years...it'll be remarkable. But, Subaru must do the same to remain competitive.

Interestingly, this year I've been studying classic 911's and their respective price increases...first the 2.7RS, then the 2.4S, now the 2.2/2.4T & E's. Also on the increase are the impact bumper models as people realise they're bloody good cars. I can see the same happening with Impreza's in the coming years...for the Classic, Bug Eye and Blob Eye models that are in tip-top condition.

Back on topic...an LPG conversion for a Subaru? Yes, without a moments hesitation. In fact, if one looks at the price of LPG'd Foresters they're nearly always greater than their non-converted counterparts. To be provocative my ultimate Subaru Impreza would be HYDROGEN powered...giving greater BHP and only H2O as its pollution; one day driving

Skyedriver

17,891 posts

283 months

Thursday 29th November 2012
quotequote all
Interesting and seemingly authoratitive reponse to a question I have been pondering for a few weeks since reading into TVR on LPG.
As discussed, yes an Impreza is a performance car, and adding LPG adds weight and slows it down. LPG produces less power than petrol in general so on top of the weight penalty there is a performance penalty.
BUT how often do the average owners use ALL the power.
Why should you compromise your daily driving pleasure by using an oil burner through the week. Been there done that myself. I also used a TVR as my daily for 3 years. Would love to do that again but cannot afford the fuel.
I currently use an old Volvo estate as an everyday, it may soon be replaced by an oil burner we have. Enjoy my daily drive - no.
An impreza on LPG bought at the right price seems a great idea. Have heard reliability concerns due to lubrication etc. Maybe someone who has done big miles in one can resolve those questions.

anonymous-user

Original Poster:

55 months

Thursday 29th November 2012
quotequote all
Skyedriver said:
Interesting and seemingly authoratitive reponse to a question I have been pondering for a few weeks since reading into TVR on LPG.
As discussed, yes an Impreza is a performance car, and adding LPG adds weight and slows it down. LPG produces less power than petrol in general so on top of the weight penalty there is a performance penalty.
BUT how often do the average owners use ALL the power.
Why should you compromise your daily driving pleasure by using an oil burner through the week. Been there done that myself. I also used a TVR as my daily for 3 years. Would love to do that again but cannot afford the fuel.
I currently use an old Volvo estate as an everyday, it may soon be replaced by an oil burner we have. Enjoy my daily drive - no.
An impreza on LPG bought at the right price seems a great idea. Have heard reliability concerns due to lubrication etc. Maybe someone who has done big miles in one can resolve those questions.
There is a seperate injector to protect valve seats IIRC. The piggy back ecu that drives the LPG can be tweaked and when injector demand is over 'x' you switch back onto normal fuel. This seemed to be around the 4-4.5K RPM mark. It just sounds like a great idea. I am going to do some more digging on the subject and speak to a few installers to get a better understanding of the pros and cons.

solan

2 posts

137 months

Wednesday 5th December 2012
quotequote all
you mean lube.It is necessary for the valve seats, only when the air-fuel mixture is lean.new lpg systems - if, of course, a well calibrated - no need to use lube. exception can be porcelain valve seats

v8250

2,724 posts

212 months

Wednesday 5th December 2012
quotequote all
solan said:
you mean lube.It is necessary for the valve seats, only when the air-fuel mixture is lean.new lpg systems - if, of course, a well calibrated - no need to use lube. exception can be porcelain valve seats
be careful with your recommendations ref' valve lube requirements. saab + others have had a devils-own job with LPG coverted cars. it is not the lean air-fuel mixture that causes valve/valve guide/valve seat wear but the fact that LPG is a dry non-lubricating combustive fuel. when under constant flow petrol and diesel are very effective lubricators. the good LPG conversion companies know this and often insist valve lubrication kits are installed. the additional cost is petty-cash when compared to a new engine.

solan

2 posts

137 months

Wednesday 5th December 2012
quotequote all
v8250 said:
be careful with your recommendations ref' valve lube requirements. saab + others have had a devils-own job with LPG coverted cars. it is not the lean air-fuel mixture that causes valve/valve guide/valve seat wear but the fact that LPG is a dry non-lubricating combustive fuel. when under constant flow petrol and diesel are very effective lubricators. the good LPG conversion companies know this and often insist valve lubrication kits are installed. the additional cost is petty-cash when compared to a new engine.
the lean air-fuel mixture means higher combustion temperature.This can cause burning of the valve seats.we mount the lube only when needed, but not very often.

ScoobieWRX

4,863 posts

227 months

Wednesday 5th December 2012
quotequote all
I'd like to know how you tune one of these systems once fitted to make sure it's fuelling properly and not running too lean across all conditions, i.e. steady state, WOT, part throttle etc...

Do these systems take care of that via an ECU? If so is this ECU plumbed into the electrical system and does it take note of the car's MAF, MAP, Lambda, Crank, CAM sensors or does it come with it's own?

I'm really just interested in how it regulates fuelling under any conditions.

ETA: Ignore my reply as i've just done some research and now understand how the more sophisticated systems do it. It reminds me of the system a chap in West Mids Impreza runs on his classic scoob and he can remap his own with the software and cables he has. It looks like scoobs will use the ROMANO type system which looks like it's right up there in LPG terms but they aren't cheap.

I could understand someone putting this on their Forester or Outback, and maybe even the 3.0Ltr Legacy, but not on an Impreza. It's just my opinion so wind your neck in before unwinding it!!

Equally there are some part LPG (30%) part diesel(70%) systems that work well by giving you a cleaner diesel burn and provide more power as a result. Apparently they work very well on older diesels and i'd be quite interested to fit one to my 96 3.0Ltr TD Surf if it provides significant MPG improvements and a little power gain. I guess in this case an 80ltr LPG tank would last a fair while longer than running all LPG.

Edited by ScoobieWRX on Wednesday 5th December 17:39

mmcd87

626 posts

204 months

Wednesday 5th December 2012
quotequote all
How many miles are you doing? I personally wouldn't either. You're committing yourself to a car for 3 years or you lose a heap of cash - what if you need to sell suddenly - it's not going to be worth much more than a standard one. That and you are limiting it's sale market when you sell.

Buy a nice one, run it for a few years and move on. Work out what 25mpg would cost you vs 30mpg of a Golf GTI or whatever.

The up front cost of running a car is not always the full story - the Golf may break down and cost you £600 so your 5mpg saving is gone for the year.

http://www.fuel-economy.co.uk/calc.shtml

v8250

2,724 posts

212 months

Thursday 6th December 2012
quotequote all
mmcd87 said:
How many miles are you doing? I personally wouldn't either. You're committing yourself to a car for 3 years or you lose a heap of cash - what if you need to sell suddenly - it's not going to be worth much more than a standard one. That and you are limiting it's sale market when you sell. Buy a nice one, run it for a few years and move on. Work out what 25mpg would cost you vs 30mpg of a Golf GTI or whatever.The up front cost of running a car is not always the full story - the Golf may break down and cost you £600 so your 5mpg saving is gone for the year.
http://www.fuel-economy.co.uk/calc.shtml
Whilst you are correct in saying an LPG conversion's viability is dependent upon annual mileage, you are absolutely wrong in stating "to commit to the vehicle for 3 years or lose a heap of cash". You clearly miss the point of why so many people very successfully convert to LPG...and your website link is quite ineffective as it does not show direct petrol-to-diesel-to-LPG comparables. Until you have real data your view is purely emotive & non-factual.

As a note regarding vehicle value...there's a very large educated market in the UK of dedicated LPG users who have the knowledge and experience of running LPG fuelled cars for many years. The majority of these would never return to the excessively over-taxed car fuel alternatives. Their issue is that there are simply not enough converted cars readily available to purchase...Autotrader has circa' 379,000 used cars available today - only 209 of these are LPG.

ScoobieWRX

4,863 posts

227 months

Thursday 6th December 2012
quotequote all
From those numbers alone it's clear to see that the percentage of LPG vehicles compared to non LPG vehicles for sale is absolutely miniscule, and is probably a fair reflection of the amount of non-commercial LPG powered vehicles currently in the UK.

I know it's use is much higher and wider for commercial vehicles but then they tend to do astronomical mileages, are converted from nearly new, and clearly LPG makes economic sense in this application. However, it's really not that popular with the majority of UK car owners is it?

If it's that good, will save so much money, and in these times of serious economic austerity when the figures you have quoted make it sound like such economic sense, why isn't everyone catching on?

We have a large population of older, uneconomical used diesel and petrol cars on UK roads. Why aren't more of these used cars being run on LPG, baring in mind LPG has been around for donkeys years and used to be half the price of petrol/diesel?

v8250

2,724 posts

212 months

Thursday 6th December 2012
quotequote all
ScoobieWRX said:
From those numbers alone it's clear to see that the percentage of LPG vehicles compared to non LPG vehicles for sale is absolutely miniscule, and is probably a fair reflection of the amount of non-commercial LPG powered vehicles currently in the UK.

I know it's use is much higher and wider for commercial vehicles but then they tend to do astronomical mileages, are converted from nearly new, and clearly LPG makes economic sense in this application. However, it's really not that popular with the majority of UK car owners is it?

If it's that good, will save so much money, and in these times of serious economic austerity when the figures you have quoted make it sound like such economic sense, why isn't everyone catching on?

We have a large population of older, uneconomical used diesel and petrol cars on UK roads. Why aren't more of these used cars being run on LPG, baring in mind LPG has been around for donkeys years and used to be half the price of petrol/diesel?
Good points...I think it's because of lack of education/understanding, the perceived idea that LPG is 'dangerous'...oh no, can't possibly have a pressurized tank of gas in the car...and that LPG simply doesn't register with the large majority of car owners.

I've been told the issue for higher mileage engines is potential worn tolerances and that many LPG coversion companies are reluctant to guarantee the conversion, prefering lower mileage units. We can imagine a 150k diesel engine, still running perfectly but with internals all nicely carboned & taking up any slack within the cylinder/pistion/valve areas...inject a finely tuned LPG mix and these areas will very soon be all clean & sparkly; and most likely noisy in that worrying rattly way eek Though my gut feel is that this is more heresay rather than actual fact.

ScoobieWRX

4,863 posts

227 months

Thursday 6th December 2012
quotequote all
The same can be said for higher mileage petrol boxer units suffering from piston slap, which is inevitable eventually. Said carbon build-up keeping piston slap nicely cushioned and barely audible, along comes LPG, then you get nice sparkly cylinders to use your analogy, thereafter you get a noisy/slappy petrol engine even when warmed up. No different.

I would rather hold on to my nice quiet barely piston slap audible super quiet when warmed boxer unit with cylinder carbon deposits all in place to give me another 50K miles of whisper quiet good service.

I'm pretty sure if LPG was that good, with a solid proven case for initial outlay v long term returns for your average mileage car, and it was marketed in the same way as electric and hybrid cars have been, then there might be better take up. However, it's been around for long enough, everyone has heard of LPG, and yet educated or not about the pros and cons of LPG, it's still very little used.

Conversely, hybrid and electric cars, compared to LPG haven't been out very long at all and yet they seem to be gaining in popularity quickly amongst those educated and uneducated about electric/hybrid vehicles.

Why aren't those looking for an eco-friendly alternative to petrol/diesel only cars going for LPG instead of electric/hybrid vehicles. It would be considerably cheaper to convert your car to run LPG than buying one of these newfangled efforts.

I think in all honesty it's very little to do with having a pressurised container in the boot baring in mind when hydrogen cars come around in the mainstream, their pressurised tanks make LPG tanks look like paper bags, and you can bet your very last pound that Hydrogen will take off like a rocket, so to speak, and be snapped up by many uneducated about hydrogen!!

LPG has had its day, leave it for your barbecue....Roll on Hydrogen!! In the meantime, while waiting for hydrogen please enjoy your petrol and diesel while it's still available, and Long Live 99RON!! biggrin

Art0ir

9,402 posts

171 months

Thursday 6th December 2012
quotequote all
The biggest users in NI would be taxi drivers. Everything from new Skodas to the black cabs in Belfast.