grahamjames

help please guys.

Have just bought a legacy import estate gt twin turbo with VDC.

Bit of an old mans car by you boys standards perhaps but 297bhp at the wheels on a rolling road seems enough for a pensioner.

Have tried it with a bit of a vengeance this week and could not gat away from an old cossie 500 @ 160. But then he didn't seem able to pass me either. perhaps he wasn't trying?

Now then

i am currently running on optimax which i believe has an octane rating of 98.something but reading the various meandering threads on this site there is a body of opinion which appears to think this not good enough.

I read that LPG is rated @ 117 octane which seems pretty good to me.

But LPG is known for its slowness of burning which seems opposed to the fact that octane rating i thought related to explosiveness.

Anyway what do i know.

Are there any technical wizards out there, or any long term LPG users, who know or can guess intelligently as to what effect LPG would have on a motor like mine considering performance /engine wear in particular.

Forgetting for the moment that an £1,800 conversion would pay me back in fuel cost savings in less than 6 months.

Looking forward to a long and contentious thread.

Graham

Adam M

If so hopeful for a decent thread, why not put it in drivetrain where it belongs?

I am no expert, but the ron rating is more to do with the resistance to burn in the first place. Higher ron is actually less flammable. Similar to having a higher activation energy required to start it burning.

our engines also require a mon rating. I think might well be where lpg falls down. You really are better off looking to an expert rather than us, on such matters.

to my knowledge lpg is supposed to rob you of about 5% power but burn more cleanly. there are rumours that it isnt simply a matter of conversion on forced induction cars as there are oher factors to consider which have not been properly tested yet.

Best bet is to ask one of the conversion companies what the effects are a turbo charged engine.

brickboy

Don't think I've ever seen a truly satisfying answer to the question: "Can a high-performance turbocharged car be converted to LPG and still be a high-performance car?"

If someone could say "A standard Scoob would lose 20bhp at the top end but fuel costs would be halved" then fine. But I've not seen any hard facts on the conversion ...

As for octane, LPG is nominally higher octane but I don't know what *real* difference that makes in practice -- whether a turbo motor would be less prone to det.

Anyone know anything more than me? 'cos I know b*gger all ...

Tim Skerry

There is a place near York, I think in Kexby where they do conversions and they have an LPG impreza turbo that they run around with decals on it saying it has been converted. Don't know any more though.

EvoBarry

LPG has a lower calorific value than petrol, hence the higher mpg issues..it is a cleaner burn though, which means your engine will benefit greatly from running gas....it's reckoned you can double the length of the oil change intervals on gas...

My mate does conversions, his site may give some help...

Its also very much cleaner than petrol and diesel emissions wise..

http://www.poweredbygas.com

[Edited by EvoBarry - 12/19/2001 5:24:29 PM]

MarkJackon

Er, pensioners racing Cosworth RS 500's at 160, Where ?

I think I may avoid the area !

grahamjames

who said we were racing this was a sunday morning pleasure trip before church