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High Performance Engines on LPG?


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#1 twosmoke

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Posted 24 March 2011 - 05:17 PM

With the inevitable ridiculousness of petrol prices looming, have been looking around at alternative fuels.
LPG seems like it could be a good alternative. I know it has a lower calorific value, but the much higher octane could make up for this?

Ideally I wouldn't want to lose any power, but with LPG's high octane, a high-compression high-boost turbo engine could be made, and potentially make up any power losses (and perhaps increase efficiency with such a high effective CR?), given that the engine wouldn't fall to bits.

However, you never hear anyone with LPG cars except standard falcons etc? What are the main disadvantages besides availability?

Note: This is 5% for actually doing it purposes and 95% for learning / some good discussion.

gogogo :D

#2 Unclejake

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Posted 24 March 2011 - 05:26 PM

Dedicated performance LPG engines go very well but a major drawback for an enthusiast (apart from the weight, instal expense, fuel availability, loss of luggage space and sometimes limited range) is that LPG is illegal on race tracks

#3 Hemi

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Posted 24 March 2011 - 05:28 PM

yea whys that?? ,containted under pressure and could nato??

#4 Unclejake

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Posted 24 March 2011 - 05:43 PM

Yeah, it is the fire risk. I expect the pits are the worst place to have a fire. I doubt Feilding could handle it on a big race meeting.

#5 Spencer

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Posted 24 March 2011 - 05:50 PM

Yea dangerous at the track, theres quite a few aussies that run it in modified turbo cars, google it

Would rather run methanol anyday, but that gets expensive fast

Also in a thirsty car (ie my LPG work falcon) the cost savings don't add up that well

#6 twosmoke

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Posted 24 March 2011 - 05:57 PM

Dedicated performance LPG engines go very well but... ...LPG is illegal on race tracks

That is super average. That almost is the worst bit for me, as I am trying to get into more and more motorsport.

theres quite a few aussies that run it in modified turbo cars, google it.
Also in a thirsty car (ie my LPG work falcon) the cost savings don't add up that well

^^ Have seen quite a few make pretty impressive numbers. The octane rating of LPG would also make for a very potent 10:1+ with boost, so would be fairly responsive if the engine could take it. On a high compression engine like that, surely it would be more effficent, therefore using perhaps as much as a petrol car, at a fraction of the price? Could be wrong.

#7 Spencer

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Posted 24 March 2011 - 06:05 PM

Yea but all that extra weight and complexity when you can buy some race gas to produce the same results. Going fast and the cost of fuel are things that don't really go hand in hand

#8 Hemi

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Posted 24 March 2011 - 06:07 PM

yea was thinking similar . still interesting .
what octane is lpg anyway?? 110?? .

#9 Jase

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Posted 24 March 2011 - 06:38 PM

I have a pushbike, costs me about $5 a week to maintain,
rolls me 10km to work everyday and down to the shops if need be.
It means i'll never have to look at alternative fuels in the near future.
The money i save in riding this means motocross and weekend roadies are still all entirely feasible.
Personally i couldn't recommend it more,
Oh yeah and main fuel would be tapwater
i quote people out of context, because douchebag

#10 Hemi

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Posted 24 March 2011 - 07:01 PM

interesting comment there jase , not really related to topic though haha .
i too ride to work most sunny days , its great. glad my ride start with steepdownhill first 100 m because my blood is monograde 40

#11 twosmoke

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Posted 24 March 2011 - 07:03 PM

yea was thinking similar . still interesting .what octane is lpg anyway?? 110?? .

112 RON from wikipedia.

#12 Brock-Lee

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Posted 24 March 2011 - 07:03 PM

Dude at work used to run his (making this number up because I dont know exact figure and KK will know and correct me) 489hp rover on dedicated LPG and he found it sweet for his 12:1 406ci chev. Only reason he swapped to petrol is because as others have said it isnt MANZ approved and also it was hard to find gas stations that supply (was a few years ago)

LPG is octane rating of ~110 but you need to burn a lot more to make the same power

#13 Hemi

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Posted 24 March 2011 - 07:11 PM

yea yea so much like meth then , cept meth is resonably happy to chill out in a container instead of being a teen mike-e

#14 Jase

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Posted 24 March 2011 - 07:16 PM

yeah might as well keep what you have make sure its got a good tune,correct tire pressures and is fit for purpose
ie racecar in the shed,
daily or pushie for running around.
lpg setup costs negate any real benefits that you would have gained spending the same money on engine work,
ie 10g on lpg won't give you the same benifits as 10g on engine work

please don't insult mike-e he is the man ^
i quote people out of context, because douchebag

#15 Hemi

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Posted 24 March 2011 - 07:19 PM

was a lol mang , e's the man/ not anymore now i never see him

#16 shizzl

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Posted 24 March 2011 - 07:21 PM

ive seen some pretty quick 12a turbo set ups on lpg..
cost half as much to run as opposed to pump gas..

but this was in aussy,so not sure what itd be here..
CRASHING SUX!

#17 keltik

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Posted 24 March 2011 - 07:25 PM

Fellah i know/chat to online converted his Subaru EA81 (1800cc) to run on LPG then supercharged it. Apparently it went quite well and was decent on gas until he blew a hole in a piston trying to get some more power again...due to being inexperienced at tuning it.

The next motor he put in was a EJ22 (2200cc) where the higher displacement made up for the lack of a blower. From what i heard, supercharging the 1800 was a piece of cake and made the same power as the 2200 despite being 20 years older and 8v pushrod compared to 16v dohc.

So yeah, performance LPG sounds simple enough - just too many downsides for most people to do it.

#18 Jase

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Posted 24 March 2011 - 07:26 PM

its definitely big over there but unless you got a car running it already it wouldn't be worth doing it
and then you couldn't run it anywhere.
i quote people out of context, because douchebag

#19 Hemi

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Posted 24 March 2011 - 07:29 PM

lawless race days in the outback .. cue mad max

#20 Spencer

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Posted 24 March 2011 - 07:29 PM

Meth is way lusher but you have to burn way more than LPG stoich is ~6:1 so pretty much double compared to petrol. But it offers increased thermal efficiency and has a octane rating of ~114. Meth for president.

And there is no way LPG costs half as much to run! it costs half as much to buy thats for sure. But my shitty ute gets around 18l/100km, I'm sure its petrol equivalent would get much better mileage




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