Performance Increase Using Higher Octane ?

harryw · 02-11-2006, 04:46 AM

Hi.

I have a A4 B7 1.8T Auto which currently gives 120kw using the recommended 95 octane premium unleaded petrol.
Would I get additional kw's (and if so how much) using 98 octane petrol ?

Regards,

Harry W.

cheesemax · 02-13-2006, 01:15 PM

The reason you need high octane in the 1.8T is due to the high compression level within the engine. Without the higher octane, you would get "engine knocking" and/or "run on" when the engine is turned off. This is caused by the residual gasoline in the cylinders igniting due to the pressure & temp. after the engine is shut down. They say that any improvement in performance from higher (above factory spec) octane gas is largely imagined by the driver. Short of putting in some specialised fuel additive or even "NOS", I wouldn't spend the extra money on the higher octane fuel.

Rgds.

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02-11-2006, 04:46 AM	#1 (permalink)
harryw Newbie Join Date: Apr 2005 Posts: 3 Gallery: (0)	Hi. I have a A4 B7 1.8T Auto which currently gives 120kw using the recommended 95 octane premium unleaded petrol. Would I get additional kw's (and if so how much) using 98 octane petrol ? Regards, Harry W.

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02-13-2006, 01:15 PM	#2 (permalink)
cheesemax Senior Join Date: Feb 2005 Posts: 186 Gallery: (0)	The reason you need high octane in the 1.8T is due to the high compression level within the engine. Without the higher octane, you would get "engine knocking" and/or "run on" when the engine is turned off. This is caused by the residual gasoline in the cylinders igniting due to the pressure & temp. after the engine is shut down. They say that any improvement in performance from higher (above factory spec) octane gas is largely imagined by the driver. Short of putting in some specialised fuel additive or even "NOS", I wouldn't spend the extra money on the higher octane fuel. Rgds.

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