LPG to fire the beast?

Started by meteor, August 15, 2006, 07:29:20 PM

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meteor

See the price of LPG is about half of petrol.  Even though I dont do that much fuel, spend $40 a week maybe, I still figure it could be a reasonable investment if I could install a system for 1 to 1.5 grand. 

Has anyone got experience with LPG?  I think the power drops a bit although that may be a tuning issue.  I think the octane rating of LPG is pretty high, so my 86qt200 high compression blaster shouldnt retard itself via the knock sensors. 

There must be plenty of lpg systems sitting around in wreckers yards.  Gettng the right fittings for the turbo and fuel spray upstream of the inlet valves on the old KE jetronic could be a mission.   

Probably if doing it, best to make a dedicated lpg and rip out the old tank and get a couple of bottles in??

hitmanGTI

LPG is all the rage in the poorer countries in europe at the moment..

the power loss is definatly a tuning issue

what many people do is get it set sort of half way between one and the other..

or you could set it for all out lpg..

ROC Gas LPG is 99 Octane too!

The Admiral

#2
Quote from: meteor on August 15, 2006, 07:29:20 PM
See the price of LPG is about half of petrol.  Even though I dont do that much fuel, spend $40 a week maybe, I still figure it could be a reasonable investment if I could install a system for 1 to 1.5 grand. 

Has anyone got experience with LPG?  I think the power drops a bit although that may be a tuning issue.  I think the octane rating of LPG is pretty high, so my 86qt200 high compression blaster shouldnt retard itself via the knock sensors. 

There must be plenty of lpg systems sitting around in wreckers yards.  Gettng the right fittings for the turbo and fuel spray upstream of the inlet valves on the old KE jetronic could be a mission.   

Probably if doing it, best to make a dedicated lpg and rip out the old tank and get a couple of bottles in??

I have experience. I had my 1995 8V GTI converted to run on both LPG and petrol.

Power loss is noticable but not hideous. Easy to deal with as you just flick the switch and you're over to petrol and you can stomp on accelerator. So, for normal driving you won't notice th difference.

Range is not as high as with petrol. I had a 60 litre LPG tank and would get about 350 miles (about 560km).

Things to watch out for:
1. There are a few different systems out there. There's the type that just blends the gas with air in the air inlet. These are liable to backfire and blow your airbox apart. Make sure the car is tuned properly and the ignition system in tip-top condition. These mixer type systems are relatively easy to install.

2. Sequential Gas Injection systems inject gas very close to the combustion chamber. The injectors are installed by drilling into the inlet manifold. This system offers (apparantly) no power-loss over petrol as there is no mixer in the inlet tract to restict airflow. The liklihood of backfire is also reduced to zero (again, apparantly).

Octane rating of LPG is high - higher than the super type petrol. Energy density is lower so litre for litre you'll get less energy = less power & less range.

That's it for now!

meteor

Thanks Admiral,
Thats a good summary.  Havnt made any more progress on the idea yet, but keeping it as dual fuel is probably a good idea, I do like to stomp that gas now and again!  Plus extra range is always handy, not sure that there are as many LPG filling stations around as there used to be or not. 

Must talk to some installers re second hand tanks, I think that is where most of the cost is.  The KE jetronic already has fuel injectors in the manifold just upsteam of the inlet valves and they are just a constant spray design.  If it was dual fuel I guess you are right that would need to drill and tap some new fittings. 
I read on a website that they now do direct injection of LPG into the cylinders, I guess for more modern cars. There is a space in the boot of my 200QT just behind the back seat that isnt all that useable but might take a cylinder just fine! 
I dont use the ski bag anyway, made some stainless steel bolt on roof racks from oval tube which are handy for lots of things and solid as!  Must post a photo.  Cheers


orggti

Nice to see another 200TQ owner ;) I have a 86 one too.
To be honest i wouldnt go for the LPG, it can be a big pain and i think its running out as well.
Dual fuel is always a comprimise of either fuel, they are supposed to have a thing that changes the timing for either but they dont seem to work that well.
Some drag guys use LPG tho as its under pressure so you get instant boost if you want it.
If i was going to do it i would have a LPG dedicated car like a corolla DX like my mate had, that way its an economy car period.
If you put it in your audi you would think it was such a slug round town you would have it on petrol anyway.
LPG is better than CNG for grunt tho by a long way.

The Admiral

Quote from: orggti on September 18, 2006, 08:48:44 AM
Nice to see another 200TQ owner ;) I have a 86 one too.
To be honest i wouldnt go for the LPG, it can be a big pain and i think its running out as well.
LPG isn't running out. It's a by-product of refining for petrol and is normally just flared off...

orggti

Oh. cool its CNG thats running out only then. Why dont any cars get produced running LPG then if its so much cheaper and a by product that is normally burnt into the atmosphere doing damage for nothing?

What about my other comments? Do you recon its a good idea to convert a 200TQ to it?

hitmanGTI

Stacks of Cars in Europe are LPG Powerd


The Admiral

Quote from: orggti on September 19, 2006, 08:59:47 AM
Oh. cool its CNG thats running out only then. Why dont any cars get produced running LPG then if its so much cheaper and a by product that is normally burnt into the atmosphere doing damage for nothing?

What about my other comments? Do you recon its a good idea to convert a 200TQ to it?

A few VM's do produce LPG (Dual-fuel - can run on either petrol or LPG) cars out there. I know that Volvo, Ford and Vauxhall (Hold on there) do so. The down sides are..
1. shorter range than petrol (I used to get 350 miles out of 60 litres on my 8V Golf GTI).
2. A rather large tank taking up boot space (out-of-the-factory LPG cars probably don't have this problem.
3. Reduction in power - not really a problem for normal everyday driving.

I have to put my hand up and say that I don't know much about the 200TQ. Sorry! If I were to convert any car now I'd go for LPG injection. It's supposed to be the bees knees with no drop in power and no risk of backfires. Not sure on price though!

Cheers

T.A.