Follow up to re: mpg drop and loss of umph

Reading up, it seems Australia has a problem with the Aborigines sniffing gasoline in Central Au.

I also came across this:

------------------------- Last year there were reports about Opal fuel causing problems with vehicles. Have these reports been addressed? After these reports came to light, BP Australia Pty Ltd spoke to the customers and mechanics who were involved in these complaints. They then conducted tests on fuel samples taken from the vehicles reporting difficulties and where possible on engine parts.

The results of these tests revealed that the mechanical problems were attributed to issues that were not uncommon to the vehicles being tested - doing low mileage; minor age related defects; and corrosion debris from metal fuel lines. Fuel samples were taken and showed that the first vehicle was actually running on premium unleaded petrol - not Opal unleaded fuel. The fuel sample from the second vehicle was a mix of different fuels that showed signs of ageing and loss of light components. This is not unusual for cars that do low mileage. The fuel had past its 'use by' date.

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Suddenly, without warning, GeekBoy exclaimed (23-Apr-07 4:10 AM):

Yes, it's a real problem. And there's quite a propaganda machine trying to convince the NT public that Opal isn't a problem. Don't believe it. I've been talking with mechanics, gas station attendents, and people who've put Opal in their vehicles. I'm *here*, and can say definitively that Opal does affect mileage and power.

Two vehicles out of hundreds/thousands is hardly definitive, and sounds very much like an issues we had at my last base - vehicles started dying at or near the pump, and it was said that there was water in the gas. AAFES denied it vehemently, giving reports very much like the second paragraph.

But, after about a month of this, I walked by the station one day to find them pumping gallons of water from around where the tanks were. The next day, they admitted there was a problem. Had to since they had to close the station (again) to fix it.

Oh, and I don't know how old the above is. At first BP said Opal was safe on ALL vehicles - until older cars started dying on the road. Enough did that the propaganda machine shifted slightly - and started recommending that Opal not be used in vehicles older than 1986 (and there's lots and lots of them around). jmc

From what I have been able to find out about the chemical design of Opal, they reduced the vapor pressue and aromitc content of the fuel and this reduced its rate of vaporization. A carbed vehicle (86 and earlier generally) would likely do very poorly with Opal because of this. TBI would be effected as well though a little less becuase it has some postiive pressure at injection and multi point or port injection would be effected the least because higher injection pressure would help vaporize the fuel better. In theory it has same BTU content but it does not vaporize as well. Another side benifit of Opal (and why it may be widely used one day every where) is that there is reduced loss of fuel to evaporation in storage and refueling due to lower vapor pressure which mean less polution and fuel lost to evaporation when you consider the 100's of million of cars in use world wide.

----------------- TheSnoMan.com