NSW Corvettes
Technical Tips => Pre 84 => Topic started by: Adam on July 04, 2003, 11:29:55 PM
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Recent mods: new high flow thermostat, PERFECT! Warms up quick and stays warm, not hot.
Today I got the vette back after an LPG conversion. Pretty good, runs smoother than ever (although my carburretor did need rebuilding) There is less power, but I havent really tweaked anything yet, it doesnt want to shift up a gear when u floor it, so theres some stuff left to do yet. But otherwise, it doesnt smell, doesnt shake and its quieter (so whats the point your asking) well, today I topped up my 90 liter tank- 45liters and I handed over $15, thats nice.
Need to cheak out some better plugs, previous experience with Bosh super 4's run fantastic with gas.
I did it at The Gas Man in Alexandria, becasue JEff from our club did it there. Howevwer It didnt seem like they remebered anyway. Generally ok, but it felt a bit like that Sienfeld where there all waiting at the Chinese restraunt- "Oh, another 5-10 mins..." it was supposed to take 1 day but it took 3, but hey, its done! Cost=$2100- as per quote.
The whole power loss thing is more of an issue with dual fuel setups where u need to tune the car somwhere in the middle. In a new car, you can get a dual map Unichip and they can set it up so there is vitually no power loss- 1Kw difference- ive seen the dyno.
My vette is gas only, so it can be tuned for maximum gas performance. Havent done any engine mods yet. We'll see how it goes anyway. I'm going away for a week now, so this be my last post till after next week.
Have fun at Motorex!
Adam
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Interesting, never heard of anyone converting a Corvette to LPG. Got any pics of the gizmos you had to install, if any? I've never paid any attention to LPG vehicles so I don't know anything about them, so I'm curious as to why you did it as opposed to all the other options out there.
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There are a couple of reasons we do it over here. Mainly for the overall costs involved and also because that most of our "Gas" stations pretty much all supply LPG for cars as well as petrol. Compare the price of petrol at the moment of around 80+ cents a litre to LPG which is just over 30 c/ltr. Even tho the mileage of gas is slightly higher that Petrol it's still a good saving. Plus the fact that any equipment involved in the conversion process is tax free.
I'm not sure which system WR has in his car, but this one is one of the more popular systems in the land at th moment. They've done a lot of performance work over the years and their equipment can be show quality if needed.
Here's a pic of their twin carb system with a small blower...nice and pretty... and it's yellow too.
(http://www.gasresearch.com.au/g007.jpg)
http://www.gasresearch.com.au/
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hmm .. I think that unless you do a heck of a lotta kms, I'm not sure on the value proposition of a conversion to LPG.
If we assume a tank a week on average, using Shell Optimax, we'd be spending $50. Factoring in WR's $2100 for install that's 42 weeks worth of fuel but let's say a year with some off road time.
Having done the conversion and costing $2100 whlist still using roughly the same amount of fuel would be $2730 for the first year and $630 onwards.
So what we're saying is that without conversion it'd be a consistent $2100 per year whereas converted it's cheaper after the first year.
Yeah I can see that OK ....
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Ok that makes sense, and doesn't look bad either, especially with a blower in there :22
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Originally posted by rebel
hmm .. I think that unless you do a heck of a lotta kms, I'm not sure on the value proposition of a conversion to LPG.
If we assume a tank a week on average, using Shell Optimax, we'd be spending $50. Factoring in WR's $2100 for install that's 42 weeks worth of fuel but let's say a year with some off road time.
Having done the conversion and costing $2100 whlist still using roughly the same amount of fuel would be $2730 for the first year and $630 onwards.
So what we're saying is that without conversion it'd be a consistent $2100 per year whereas converted it's cheaper after the first year.
Yeah I can see that OK ....
Aside from whatever monetary gain may be garnered from doing the conversion the main criterea that would benefit us here is the onset of emmissions testing for registration. LPG = virtually no damning emmissions.
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Here's another question. How does this conversion affect performance mods? Could you convert a radical 383 motor and still have gobs of power or is this a conversion for more basic motors only?
Where I live we have no emissions testing so it's no problems for me, but we do have our fair share of tree hugging freaks that would outlaw all motor vehicles given the chance. Cutting emissions is a good thing, but then there are those that really are kind of "out there" so to speak.
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Originally posted by Scott81
Here's another question. How does this conversion affect performance mods? Could you convert a radical 383 motor and still have gobs of power or is this a conversion for more basic motors only?
Scott...This company built a very healthy 460 BB Ford as their initial demo car and I think it was putting out somewhere in the region of 700hp naturally aspirated. The other thing is that dedicated LPG motors can handle very high compression ratios....17:1 in one case that I know of. The calorific value of LPG is much higher than that of petrol which certainly helps in the application of this medium as a fuel for 'hot' motors. Engines set up for LPG do best with special "gas" cams and single plane manifolds( in the case of V8s) and as seen it can be applied to many other variants such as blowers and fuel injection. So when a motor is built specifially to run on LPG alone the power output can be can be just as good as one running normal petrol......sorry.....gas.
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We have a black/silver '77 on full gas and it goes pretty hard - it kept up with my '77 in the slalom events!
It may be a bit of a pig to start in cold weather though?
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Hey Brutus,
If it's yellow and looks that good, I want one in my 81.
George.
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Well, I'm back and so far so good. Took a look at my plugs and their clean (!) Starting seems a bit better than what it was on petrol.
I'm also told gas is good for starting an engine because it doesnt wash the film of oil on the cylinder walls.
I have only one gas "carburretor" - the stock engine prolly wouldnt need 2 at this stage.
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In my 4wd I run plugs one step colder as I heard this helps with the temps (gas burns hotter). Did you get this advice?
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LPG = virtually no damning emmissions.
LOL
:22
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One thing I'm not is a bleeding heart environmentalist, tree hugging greenie. You know they can run cats inside sidepipes tho.....not that I'd want them of course.:b2
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77- no i havent heard about running plugs a step colder, ill see how these ones fair after a bit longer, its an old engine so dont want em too cold.
As for the enviroment, well, at least it wont kill the neighbours anymore as it sits and warms up. Not to mention if i back it into the garage...
Adam
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Well, I've filled my tank for the first time since the day I got gas (been away for 2 weeks), and reveils that fuel economy around town has been just under 20L per 100km, and at a gas price of 33c thats $6.60 per 100km around town.
Adam
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;) Mongrel! ;)
Enjoy the gas prices as much as you can while it is so cheap!
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Exactly, gas prices seem very unregulated. In 1997 your could find LPG for 19c per liter. Gas prices seem to rise with petrol prices, getting as high as 50c a few years back. Which doesnt make sence since Australia produces a surplus of LPG, and shouldnt be linked with petrol pricers... profiteering?
Another bastard of a thing is the hige differences from station to station, some sell for 32 and others for 45, on the dame day in the metro area. Try going to the country! while gas can be 33c in Sydney, itll be 36 in Canberra, 45 in Cooma and 55 in Jindabyne! 22c in the liter difference?Does transportation really cost that much?
Adam
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Yeah - it gets down to 31 cents at times. Still too much for a surplus by-product. The Gas companies get together every once in a while and bump up the prices. :grr Last time Boral did that they got busted for a couple of million!
As long as it is less that 50% of petrol we are in front.
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Here's a pic of the gas system as installed by "The Gas Man".
EDIT: The uploaded pic is not coming up...???
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FYI....from a NGK site:
THE INFLUENCE OF L.P.G.
An engine converted from petrol to L.P.G. (liquefied petroleum gas) will cause a change in the spark plug operating conditions. Therefore, some consideration should be made on the type of spark plug being installed.
As L.P.G. has different properties to petrol it influences the spark plug operating temperature and required voltage. The extent of this influence can be seen when comparisons are made on spark plugs which were fitted in an engine using L.P.G. and petrol.
Typical results are as follows :
1. Spark Plug Temperature 2. Spark Plug Required Voltage
(http://www.ngkspark.com.au/images/bulletins_T92-1_spark-plug_temp.gif)
Temperatures are higher with L.P.G.
compared to petrol. This occurs due
to L.P.G.'s reduced cooling effect.
(http://www.ngkspark.com.au/images/bulletins_T92-1_spark_plug_voltage.gif)
Required voltage increases with L.P.G.
because of the difference in the bonding
of gas particles between the two fuels.
Recommendation
To eliminate the influence of L.P.G. and to obtain optimum spark plug performance, NGK recommends:
-The use of a spark plug with one heat range colder (if possible) than that listed in the catalogue: eg, BPR6EFS-13 (L.P.G.) instead of BPR5EFS-13 (petrol) for VN 6 Cylinder Commodore.
AND
-The reduction of the electrode gap by 0.1 mm (which lowers the spark plug required voltage)
Or go to: Plugs for LPG (http://www.ngkspark.com.au/bulletin_T92-1.htm)
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Interesting, thanks for the info! Will keep in mind when I get some new plugs- prolly soon.
A small follow up- I drove 128km today, most of which was on the freeway and got 15.6L per 100km "fuel" economy. At an optimistic gas price of 33c thats $5.10 per 100km eheheh...
I recently fitted an alarm too, so now i'm slowly going through the engine bay and trimming some of the wires and hoses. About 50% don't go anywhere anymore and are redundant, (my old carburettor was an early electronic type).
Adam
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Anyway, heres a pic of the gas system in the engine bay. I've since been able to take out a lot of obselite hoses and wires once i found out they didn go anywhere! (I think im still in a "getting to know u" phase of vette ownership.)
(http://homepages.ihug.com.au/~turon/corvette/gas.jpg)