Butch S.
11-11-2005, 10:46 PM
WHAT’S IN YOUR FUEL TANK?
Q. What do late model fuel injected cars and gyros have in common.
A. They both perform badly on poor quality fuel.
Flying gyros is exiting enough without additional problems. Running a mechanical workshop and performance engine building shop, it has come to our attention fuel purchased at different locations can give vastly different performance and or fuel economy. In a car this fuel may cost you some power and economy. But in a gyro, a vehicle putting us 1000 ft in the air, the fuel you use can have some expensive and critical consequences.
Fuel companies are constantly sourcing and blending fuel to meet a universal criteria. Maximum profit!
Ethanol, Methanol, Toluene, Acetone, alcohols and various hydrocarbons (i.e. thinners) all are found in varying quantities in the fuel sold in Australia. The premium blends are not in exception.
Vehicle manufactures knowing the inconsistencies of today’s fuels have needed to engineer closed loop fuel systems for late model fuel injected cars. The computer is sampling the exhaust gases by its oxygen [O2] sensor. Knock sensors have been added as even with a stoichiometric* exhaust reading ethanol rich fuel can burn hot enough to start a death spiral*. The amount of fuel injected into the engine and the timing of the spark is constantly altered for optimum engine performance and most importantly engine protection.
What have YOU done to protect your engine?
Your gyro engine needs to deliver performance and needs to do so reliably and consistently. The first question now to all my customers is ‘what fuel are you running’. The replies can often be the answer to diagnosing a misbehaving gyro. Symptoms of poor fuel are – poor idle, especially with cold engine, pinging sometimes inaudible, spluttering when power is suddenly applied, flat spots, over heating, high egt’s.
As most gyros fuel delivery systems lack the sophistication of late model cars, we found it necessary to be able to tune the gyro engines accurately & continue to monitor them.
Reading spark plugs can no longer be relied upon due to additives giving false readings*.
So we took our gyro 10 years ago to a very well equipped EFI specialist who bravely agreed to help tune the SUB4 webber carby for premium ULP using his $5000.00 test equipment to monitor air/fuel ratio & timing. This done our gyros had given good service but declining fuel quality combined with complacency with checkups [due to the cost and time involved] has led to problems.
Luckily technology has caught up. With accurate air fuel ratio meters now being affordable. We have tried a number of them and now have the best installed in gyros and cars alike. This will allow accurate monitoring of fuel quality & if an obstruction occurs within the carby , efi system [will show lean]
NOW I hear you saying but I don’t have a problem, possibly not BUT by the time you know you have a problem it may be to late with some symptoms being: blown head gaskets, burnt valves, damaged conrod bearings, damaged pistons or worse complete engine failure, all of these costing more than an AFR meter
It has also come to my attention after a dyno tuning session on an EFI gyro motor EA81 that the distributor in these engines have to much advance. As 35deg max advance is all these motors require to produce max HP or can SAFLY handle but the distributors have 15deg mechanical advance & as the distributor spins at half the crank speed this equates to 30deg at the crank so unless you run 5deg BTDC at idol you are running to much advance this is without the vacuum advance which adds up to 12deg more at the crank at full throttle. This may not concern some of you but this combined with large squish area at the bottom of a Subaru and higher compression is the home of detonation and the only cure is correct tuning of the carby & distributor.
FACT FILE
: Ethanol causes corrosion in carburetors
: Adding ethanol, methanol, to fuel makes the mixture burn hotter due in part to the oxygen it contains
: Adding toluene to fuel helps stabilize poorly refined fuel
: Adding acetone to fuel allows for power gains but turns plugs rust red and fouls them
: Adding thinners or any of the above to gasoline reduces the cooling affect within the combustion chamber
· the stoichiometric air/fuel ratio is the chemically correct or theoretical air to fuel ratio which provides the minimum amount of oxygen for the conversion of all the fuel to completely oxidized products.
· * Death spiral & many other technical terms used in this article can be found @
· http://importdesigns.com/index.cfm?fuseaction=view_tech_article&tech_article_id=5
http://www.deh.gov.au/ html atmosphere/ethanol/publications/review-non-automotive/operability-1.
Using our AFR meter we tuned for slightly rich to do this we took a 142 jet out to 155 an addition of 9%
Government testing shows that this would be easily attributed to a 20% addition of ETHANOL as shown in graph below
Q. What do late model fuel injected cars and gyros have in common.
A. They both perform badly on poor quality fuel.
Flying gyros is exiting enough without additional problems. Running a mechanical workshop and performance engine building shop, it has come to our attention fuel purchased at different locations can give vastly different performance and or fuel economy. In a car this fuel may cost you some power and economy. But in a gyro, a vehicle putting us 1000 ft in the air, the fuel you use can have some expensive and critical consequences.
Fuel companies are constantly sourcing and blending fuel to meet a universal criteria. Maximum profit!
Ethanol, Methanol, Toluene, Acetone, alcohols and various hydrocarbons (i.e. thinners) all are found in varying quantities in the fuel sold in Australia. The premium blends are not in exception.
Vehicle manufactures knowing the inconsistencies of today’s fuels have needed to engineer closed loop fuel systems for late model fuel injected cars. The computer is sampling the exhaust gases by its oxygen [O2] sensor. Knock sensors have been added as even with a stoichiometric* exhaust reading ethanol rich fuel can burn hot enough to start a death spiral*. The amount of fuel injected into the engine and the timing of the spark is constantly altered for optimum engine performance and most importantly engine protection.
What have YOU done to protect your engine?
Your gyro engine needs to deliver performance and needs to do so reliably and consistently. The first question now to all my customers is ‘what fuel are you running’. The replies can often be the answer to diagnosing a misbehaving gyro. Symptoms of poor fuel are – poor idle, especially with cold engine, pinging sometimes inaudible, spluttering when power is suddenly applied, flat spots, over heating, high egt’s.
As most gyros fuel delivery systems lack the sophistication of late model cars, we found it necessary to be able to tune the gyro engines accurately & continue to monitor them.
Reading spark plugs can no longer be relied upon due to additives giving false readings*.
So we took our gyro 10 years ago to a very well equipped EFI specialist who bravely agreed to help tune the SUB4 webber carby for premium ULP using his $5000.00 test equipment to monitor air/fuel ratio & timing. This done our gyros had given good service but declining fuel quality combined with complacency with checkups [due to the cost and time involved] has led to problems.
Luckily technology has caught up. With accurate air fuel ratio meters now being affordable. We have tried a number of them and now have the best installed in gyros and cars alike. This will allow accurate monitoring of fuel quality & if an obstruction occurs within the carby , efi system [will show lean]
NOW I hear you saying but I don’t have a problem, possibly not BUT by the time you know you have a problem it may be to late with some symptoms being: blown head gaskets, burnt valves, damaged conrod bearings, damaged pistons or worse complete engine failure, all of these costing more than an AFR meter
It has also come to my attention after a dyno tuning session on an EFI gyro motor EA81 that the distributor in these engines have to much advance. As 35deg max advance is all these motors require to produce max HP or can SAFLY handle but the distributors have 15deg mechanical advance & as the distributor spins at half the crank speed this equates to 30deg at the crank so unless you run 5deg BTDC at idol you are running to much advance this is without the vacuum advance which adds up to 12deg more at the crank at full throttle. This may not concern some of you but this combined with large squish area at the bottom of a Subaru and higher compression is the home of detonation and the only cure is correct tuning of the carby & distributor.
FACT FILE
: Ethanol causes corrosion in carburetors
: Adding ethanol, methanol, to fuel makes the mixture burn hotter due in part to the oxygen it contains
: Adding toluene to fuel helps stabilize poorly refined fuel
: Adding acetone to fuel allows for power gains but turns plugs rust red and fouls them
: Adding thinners or any of the above to gasoline reduces the cooling affect within the combustion chamber
· the stoichiometric air/fuel ratio is the chemically correct or theoretical air to fuel ratio which provides the minimum amount of oxygen for the conversion of all the fuel to completely oxidized products.
· * Death spiral & many other technical terms used in this article can be found @
· http://importdesigns.com/index.cfm?fuseaction=view_tech_article&tech_article_id=5
http://www.deh.gov.au/ html atmosphere/ethanol/publications/review-non-automotive/operability-1.
Using our AFR meter we tuned for slightly rich to do this we took a 142 jet out to 155 an addition of 9%
Government testing shows that this would be easily attributed to a 20% addition of ETHANOL as shown in graph below