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Economy motoring
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Worksop town centre today at about 1530. Facelift ZS with full 180 kit. Not sure if it was a 180 but omg it was ssooo nice. I think Sunspot is my new favourite ZS colour.:yup::unworthy:
 

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R.I.P [The Red Zed] MG ZS 180
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Economy motoring
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Discussion Starter #3
Pictures can't do that colour justice. Shame that one has a black filler thing slapped on the side:getcoat:
 

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R.I.P [The Red Zed] MG ZS 180
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"60 mpg on LPG!" ??
I'd be surprised if a converted 180 did better than 20 mpg running on LPG. I was lucky to get 25 mpg out of my converted Mondy..and that was a 1.8L.
If you search the forum you will find a few Members who have successfully ran a LPG conversion.

I can safely say the said member got better than 20 Mpg:)
 

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If you search the forum you will find a few Members who have successfully ran a LPG conversion.

I can safely say the said member got better than 20 Mpg:)
I suppose if your 180 can average 23-25 mpg on petrol then you could get over 20 mpg on LPG. Either way, the "60mpg" claim is way OTT. I think he must mean the cost-wise equivalent of 60mpg compared to petrol but it still doesn't add up.
I'm actually a great fan of LPG myself. Well worth it if you're doing the mileage. Only drawback is the occassional whiff of rotten eggs. My Mondy stank to high hell at times. Sometimes it got inside the cabin and caused acute embarrassment with passengers discreetly pulling their windows down and casting accusatory glances in my direction!!
 

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facelift one is across on zs site, its a nice car hes done a lot of work to it in the last few weeks hes owned it.

lpg youll get about the same mpg, only issue is it does burn hotter than petrol so need to make sure your cooling systems up to it or youll get melted valves thrown up in the head lol
 

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facelift one is across on zs site, its a nice car hes done a lot of work to it in the last few weeks hes owned it.

lpg youll get about the same mpg, only issue is it does burn hotter than petrol so need to make sure your cooling systems up to it or youll get melted valves thrown up in the head lol
How can it burn hotter when it has a lower calorific value than petrol?
 

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dunno thats what i got told, seen a few throw valves into the head, know you have to fit different plugs to the engine, believe it burns hotter but for a shorter period of time, i think perhaps the valves in the engine are sometimes different as well if they came from factory lik it
 

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did a bit of googling

Microwelding

In essence, valve wear will occur slightly more quickly when running on LPG simply because it burns much more cleanly. There is no Soot or Dirt to prevent the occurrence of Microwelding. Don't let that worry you, this effect alone is very small. We are still talking about Valve life that is often longer than the life of the car.

Microwelding can be avoided, at least in part, by having the valve head and seat made out of metals that are as dissimilar as possible. Carbon steel valves and Stellite seats provide a good solution here. Another weapon in our anti-Microwelding arsenal is provided by fuel additives such as 'Flashlube'. These come in the form of light Oil which, if introduced in the correct dosage can lubricate the valve head/seat faces and prevent Erosion. Also worth mentioning is that the Flashlube oil will eventually burn. When it does, it will replace the missing Soot (Carbon) that can do a lot to prevent Microwelding. Injection of these tiny amounts of oil must have some cooling effect on the valves (like petrol does) although it is probably so small as to make no difference to valve temperatures.

A word of warning here - If a modern engine is Overdosed with Flashlube or similar, its exhaust emissions may well be compromised and damage to the catalytic converter will probably result.



Running Temperature of the Valves and Seats

The most common misconception you'll hear about LPG is that it makes an engine run hotter than Petrol. This is no more than myth.

LPG has only 85% of the calorific value of the same amount of petrol so it is impossible for it to create more heat. It can only make 85% as much.

There is one factor missing though - The cooling effect that squirting wet petrol mist into the cylinder has on the valves. When running on LPG the gas is injected (most often) as a vapour and does not have quite as much cooling effect on the valves. As a result, LPG running will see very slightly higher valve temperatures. This is why 'soft' valves will tend to recess into their seats when run on LPG. (Go back to the Blacksmith analogy in 'Brinelling' above to refresh yourself on the effect of more heat on the process)

Having established that fact, slightly higher valve temperatures only present more risk of VRS if the valves are too soft for the job. Engines that suffer the most are some of the Ford and Honda engines, ALL Jaguar V6's (actually a Ford engine) ALL Subaru engine variants etc. although over 90% of engines made today are just fine. This is in no way intended as a comprehensive list of unsuitable engines and it would be wise to check with the manufacturer of your engine, and your LPG installer before conversion, to see if your engine has suitably hard valves.


indeed you are right, but still wears out the engine quicker:)
 
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