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AUDI S8 LPG Conversion


mehmaan
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Hi All,

Im new to the forum this is my very first post.I have a question any guidance will be appreciated.

I am going to buy an 1998 Audi S8 (A8) 4.2 Quattro from a mate for a good price and was thinking of getting it converted to LPG. This will be my first LPG converted car, what are the pros and cons of having this converted? is there anything specifically for an s8 engine that I need to be carefull about? thanx in advance <font color="black"> </font>

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Welcome to TSN Mehmaan (or should I say "guest" wink.gif) 169144-ok.gif

There are a couple of guys on here that have done the conversion to thier 4.2 A8's but I'm not sure if anyones done it to thier S8, shouldn't cost more than about £1.5k ish. Someone will be along soon to give more advise on the matter. have you tried doing a search on LPG on this forum? 169144-ok.gif

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Biggest pro/con has to be the cost of conversion vs. savings to be made by cheaper fuel.

Second has to be availability of LPG, fine when your in a routine but a pain imo if you get caught out in an unknown area... like travelling to france.

Not sure if I'd want to convert an 8 year old car though.

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SkA, Sneaky MC, Atomic... Thankyou all for the quick reply and warm welcome...

SkA you worked out the guest thing well.. first time sum1 has said that to me on ne forum fekr.gif hehe

In regards with wether LPG is available or not im in UK so it usually is and even if it isnt I thought the car would run of normal petrol. I'm under the impression you can hit a switch on the dash to choose if you wana use petrol or gas?

What diiference would it make to get a older car converted to LPG than a newer one?

I've seen LPG conversion advertised for £300 but I get the feeling from this board its gona cost more.. Wat do I need to look out for.. Cheers in Adv smile.gif

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A possible problem is the A8 shell is all ally and if the LPG conversion means drilling some holes in the shell to be filled with screws they could corrode the bodywork!

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You having a laugh?

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I'm sure someone told me if you put a steel (or some other metal) against Ally it corrodes, is this not true then?

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There is an issue with steel and aluminium parts being in contact but thats why they are treated and coated in that green stuff (isn't there a metalergist somewhare on TSN) and I think you want to be more worried where your drilling and how much strength you take out in the event of collision than the corrosion factor 169144-ok.gif

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[ QUOTE ]

I think you want to be more worried where your drilling and how much strength you take out in the event of collision than the corrosion factor 169144-ok.gif

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You definitely do want to be watching out for contact corrosion. Plain steel bolts through the aluminium will cause the aluminium around the threads to disappear and you don't want a full 90 litre LPG tank rattling around in the boot unsecured...

Check out these guys. Go-LPG. They're not the cheapest but they have a good reputation, and there's information about A8 and S8 conversions on the site. I very nearly had my S8 converted last year, but decided to move closer to work instead.

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I thought they put the tank in the spare wheel well these days? But I see your point about corrosion and a loose tank in the boot. I was just speaking from an experience someone had when he drilled 8 holes to mount some speakers in the boot- he ended up with the speaker enclosure crushing some of his bones up against the steering and his turned into a SWB M3 shocked.gif

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[ QUOTE ]

he ended up with the speaker enclosure crushing some of his bones up against the steering and his turned into a SWB M3 shocked.gif

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Ow. EEK2.GIF

Choice of LPG tanks depends on the car and the range you want it to have. Cylinder tanks are often used in bigger cars like the A8 because they've got a larger capacity and there's still a lot of boot space left over afterwards. I was toying with having both a cylinder and a spare wheel well tank until Steve at Go-LPG suggested that unless my car had self-levelling rear suspension it'd probably ride a bit low at the back...

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Try the forum at this address - LPG Discussion Forum

I would be wary of anyone who says he can convert your car for less than £1500. This is a specialised job and you need a good quality system that can provide sufficient fuel to 8 cylinders at wide open throttle. I think you mentioned £300 - I don't know anyone who could do a proper job on any car for that amount. I haven't looked into this area for a while, but check what brand of kit your chosen installer intends to use, and google it or check out the views of others on the LPG forum. It used to be that most of the best kits were Italian, as they're a bit ahead of us with LPG use, but I'm not sure if that's still the case. I think you'd definitely want a sequential gas injection (SGI)system, which would fit in with the Audi's advanced engine management. Other than that, check they've previously converted an A8 or S8 and what they intend to do about preventing corrosion. Good luck! 169144-ok.gif

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I investigated LPG for my car before I bought it. I was quoted approx. £2,500 (before haggling) for a decent multipoint system with appropriate mods to the ECU and a 90l tank.

The cost, the lack of range (~200 miles) the fact that the engine is supposed to run hotter and the worry about who would accept responsibility in the event that the engine failed at 100k+ miles made me drop the idea.

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I know a few people that have gone down the lpg routes with various vehicles including a 99 4.2 A8 and a range rover hse.

Some thoughts :

"What diiference would it make to get a older car converted to LPG than a newer one?"

A big difference, its not the age its the mileage on the engine. You will always get a power drop anyway when you go to LPG. On a new engine where everything is "tight" you can expect an 8 - 10% power drop on average. On engines over 50,000 miles, expect as much as a 20% drop in performance. This is well known amongst people with experience in lpg conversions.

It will normally effect the resale value of the motor as most second hand buyers dont understand or want lpg.

Takes up a load of space in the boot. Unless you do stellar mileages and keep the vehicle for years its hard to see you getting a return to make it worth while if done properly.

In short an s8 is a thing of beauty and a performance vehicle, this flys in the face of an lpg conversions.

My personal opinion is its a great idea for Range Rover thats 5 years + old does 8 miles to the gallon gets heavy use as a business vehicle (Why my mate did an lpg conversion) Otherwise UHOH7.GIF

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[ QUOTE ]

A big difference, its not the age its the mileage on the engine. You will always get a power drop anyway when you go to LPG. On a new engine where everything is "tight" you can expect an 8 - 10% power drop on average. On engines over 50,000 miles, expect as much as a 20% drop in performance. This is well known amongst people with experience in lpg conversions.

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Do you have such personal experience?

I'm ready to present (I hope I can find them still) dyno graphs of my previously owned Opel (Vauxhall) Omega MV6 converted to LPG at 150 tkm, showing not only no power drop at all, but even some gain (and dyno itself was not owned by LPG shop cool.gif ).

That depends on quality of installation itself, but even more how skillfull instalator is and his experience with adjusting software for specific vehicle.

Present 4,2Q with 200tkm shows in fact 0,2sec worse 0-60 time on LPG than on gas (before fine tuning of the LPG soft it was something like 0,5sec).

As for the rest - that depends on the personal opinions and area you live. In Poland in most cases you can get more money for LPG converted car.

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