Fuel question...i-VTEC and VTEC

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Sep 11, 2003 | 06:53 PM

Xymox007

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Björkian

Joined: Jul 2003

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From: Pennsylvania

Fuel question...i-VTEC and VTEC

Why is it motors like the new i-VTEC powered Civic Si/ base RSX only require unleaded fuel (owners manual) but our GS-R motors require premium unleaded? :a:

Sep 11, 2003 | 07:18 PM

ADRteg

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Joined: Apr 2003

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From: NoVa / Richmond, VA

GS-R...higher class....no jk :dunno:

Sep 11, 2003 | 07:18 PM

Kai

Rotorphile.

Joined: Mar 2002

Posts: 10,120

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From: Richmond, VA

It's all about the compression ratio.

The base RSX and Civic Si have 9.8:1 compression.

The RSX Type S has 11:1 compression.

Higher compression ratios require higher octane gas to prevent premature detonation of the air/fuel mixture. Premium = higher octane then regular.