Georgia Fiero Club Forum
All Things Fiero => Tech Tips, Tech Questions => Topic started by: GTRS Fiero on September 11, 2018, 07:57:13 am
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If your Fiero has DIS, can your engine run equally clean on 87 or 93 octane?
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My Duke has DIS, and is completely happy with 87.
Since you asked about "peculiarities" associated with DIS, I'll mention that it is my understanding that DIS will burn up platinum tipped (I think) spark plugs. It really likes the cheap stock plugs best.
I have heard it blamed on the "wasted spark" system. The coil packs are shared on more than one cylinder, so the plug fires once on the compression stroke, and once on the exhaust stroke.
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So, would there be any difference/benefit/detriment to running higher octane?
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Since you asked about "peculiarities" associated with DIS, I'll mention that it is my understanding that DIS will burn up platinum tipped (I think) spark plugs. It really likes the cheap stock plugs best.
I have heard it blamed on the "wasted spark" system. The coil packs are shared on more than one cylinder, so the plug fires once on the compression stroke, and once on the exhaust stroke.
On a waste spark system, the two cylinders being fired are in series electrically. The electrical resistance of the spark gap in the "waste" cylinder is much lower than the resistance in the compression cylinder, so the spark plug in the waste cylinder acts almost like a closed circuit, and relatively little energy is actually "wasted" in the waste cylinder.
The kind of spark plugs that Fieros don't like (whether DIS dukes or distributor-fired V6's), are the kind with very tiny center electrodes (they look like pins). If they have standard size center electrodes, they'll work fine, even if they are "platinum".
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I think mine has multi-fire plugs.