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Old 10-20-2007, 06:49 AM
McGyver McGyver is offline
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Real Name: Tom
Hybrids: 2007 TCH, Blue
Posts: 142
Default Re: 87 or 91? Regular vs Supreme

Quote:
Originally Posted by talmy View Post
I've got a 2000 Ranger with the 3L V6 and manual transmission that knocks on regular in the summer months and needs midgrade. But it doesn't improve gas mileage.
Carbon build-up in the heads will cause your low-compression (used-to-be-good-at-87 octane) engine to knock. The higher octane gas will compensate for that, much as it does in engines that were DESIGNED as high comp engines. Eventually, you'll be looking at a valve job.
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