using 76 gas
09-16-2007, 02:11 PM
#5
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Just a thought...
Wouldn't an FSI engine not be affected by deposit buildup (on intake valves at least) because only air passes around the intake valves? Been wondering about this for awhile. Anybody know?
09-16-2007, 02:19 PM
#6
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not much.
there's a 'top tier' Shell station near my house that I suspect has some 'floaties' in their tanks. Filled both my car and my wife's on the same day...her in-tank fuel pump died the next day, and my car ran like **** for the next week.
09-17-2007, 10:50 AM
#7
FSI engines are actually more prone to deposits
Deposits come from burnt "crap" from the oil and the fuel. With intake/exhaust valve overlap, some amount of unburnt hydrocarbons are deposited on the backside of the valves. Unfortunately, since fuel does not pass through the valves on the way to the combustion chamber, the detergents are not as heavily deposited as they are with manifold injection.
The same swirl that will bring deposits back to the valves will also bring some of the fuel back there to clean. But, since so little fuel is deposited, there is little cleaning happening. This is probably why Audi is so insistent on top-tier fuels.
The same swirl that will bring deposits back to the valves will also bring some of the fuel back there to clean. But, since so little fuel is deposited, there is little cleaning happening. This is probably why Audi is so insistent on top-tier fuels.
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