Higher compression low octane
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Joined: Jun 2012
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From: Chicagoland
Higher compression low octane
So I'm thinking about a higher compression kit of 10 to 1 for my ultra but am concerned about the lower octane in some states. I plan on touring a lot and would like the extra power but am worried about running lower octane like 87 in a higher compression engine.
Will lower octane be even more noticeable in a higher compression engine?
Will lower octane be even more noticeable in a higher compression engine?
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Joined: Sep 2010
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From: Phoenix '53, '88, '09 Big Twins
octane is the fuel's ability to resist ignition...like compression ignition "dieseling".
this is why hi comp motors require high octane fuel, so that the fuel burns at the correct time, at the correct rate- if the fuel should self ignite while the piston is coming up...it'll try to push the piston down...backwards.
bad
you could carry octane boost with you and become a scientist at the roadside
mike
this is why hi comp motors require high octane fuel, so that the fuel burns at the correct time, at the correct rate- if the fuel should self ignite while the piston is coming up...it'll try to push the piston down...backwards.
bad
you could carry octane boost with you and become a scientist at the roadside
mike
Last edited by mkguitar; Oct 2, 2012 at 02:47 PM.
Outstanding HDF Member
Joined: Jan 2010
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From: earth
Static compression is but one consideration, and it really doesn't mean anything by itself, the cam profile will dictate the static requirement to achieve the proper dynamic compression and more importantly cranking pressure. If you can tighten up the squish band without gaining too much cranking pressure, the motor will be much more efficient and powerful.
Road Captain
Joined: Feb 2006
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From:
Simple, shop only at Major brands. Yes you could get some Unscrupulous dealer that sells regular in the Preium pumps. That you give you the chance to get real frendly with a Lawer. Federial Law mandates the Octane rating.
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From: Nevada
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From: Bellville, Tx
High compression and long strokes benefit from higher octane fuels because the slower burn rate pushes the pistons for a longer duration. Ping results from too low octane because it fires quickly for a short explosion under pressure (heavy acceleration).
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From: Roseville, CA
You can find 91 anywhere in the country, it's what we have in CA and every car sold in the US can run on it from supercharged, turbocharged and ultra-high compression NA motors.
As long as you're tuned for 91 octane, you're good to go.
As long as you're tuned for 91 octane, you're good to go.
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