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Quattro · 02-19-2009, 02:53 PM

I have a 2001.5 Passat wagon with the 1.8T engine. It calls for 91 octane or higher. For the past year or more, I have been using 87 octane, as the car seems to run just fine on it (no pinging). I rarely challenge the turbo (i.e. accelerate hard), and I haven't had any fuel-related issues.

However, I've been reading about how the computer will adjust timing to compensate for the easier-to-ignite low octane fuel, and how this can effect FE.

Since "premium" (I hate the fuel "grade" system...it's so misleading) costs on average 20 cents per gallon more than "regular", am I offsetting any savings at the pump for a loss in FE? What I mean is, am I coming out even, or am I doing worse by running lower octane than what is recommended?

Since gasoline is so cheap right now, I have no problem paying $2.20 for high octane...but when it was $4.50, for some reason I balked.

Thanks!

02-19-2009, 02:53 PM	#1 (permalink)
Quattro Rolling conundrum Join Date: Feb 2009 Location: Madison, WI Posts: 12 Yota - '99 Toyota 4Runner Limited 90 day: 19.44 mpg (US) Thanks: 0 Thanked 1 Time in 1 Post	87 octane and retarded timing I have a 2001.5 Passat wagon with the 1.8T engine. It calls for 91 octane or higher. For the past year or more, I have been using 87 octane, as the car seems to run just fine on it (no pinging). I rarely challenge the turbo (i.e. accelerate hard), and I haven't had any fuel-related issues. However, I've been reading about how the computer will adjust timing to compensate for the easier-to-ignite low octane fuel, and how this can effect FE. Since "premium" (I hate the fuel "grade" system...it's so misleading) costs on average 20 cents per gallon more than "regular", am I offsetting any savings at the pump for a loss in FE? What I mean is, am I coming out even, or am I doing worse by running lower octane than what is recommended? Since gasoline is so cheap right now, I have no problem paying $2.20 for high octane...but when it was $4.50, for some reason I balked. Thanks!