Detonation and Pre-ignition

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MalcolmV8
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Detonation and Pre-ignition

Post by MalcolmV8 »

Here's a long in depth article on detonation and pre-ignition and related items. I thought it was very well written and covers a lot of detail. Pretty long read but well worth it.

http://forum.tdi-plc.com/white-papers-t ... on-t6.html
92 302 Ranger - sold
94 302 Ranger AWD - sold
07 BMW 335xi - tuned, boost turned up, E85 - sold
04 911 TT - to many mods to list. Over 600 All Wheel HP on pump gas - sold
2015 Coyote - daily driver
03 Cobra - 2.3 TVS on a built 12:1 CR motor with ported heads, cams, long tubes etc.
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E85

Tuned by MD Racing

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cgrey8
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Re: Detonation and Pre-ignition

Post by cgrey8 »

The main thing I got from the article was that pre-ignition can happen MUCH earlier in the process than I expected. I was thinking per-ignition happened, as he said, a few degrees before the spark fired. But he's saying it can happen as early as when the intake valve is still open.

But he did confirm some combustion chamber designs I've read elsewhere that are better for controlling detonation:
  • Small combustion chambers
  • Centered spark plug to produce a faster flame front
  • Intake charge swirl to cool hot-spots in the chamber in an effort to reduce pre-ignition and detonation
  • Compression tumble
  • Large quench pad to keep the combustion gasses cool
  • Flat top pistons to reduce surface area of combustion exposure
He mentioned those, but didn't elaborate on them at all. Although he did go into a fair explanation as to why hemi heads are the absolute opposite of "good" head design.
...Always Somethin'

89 Ranger Supercab, 331, ported GT40p heads w/1.6RRs, Crane Powermax 2020 cam, ported Explorer lower, FMS Explorer (GT40p) headers, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, A9L w/Moates QuarterHorse, Innovate LC-1, James Duff traction bars, iDelta DC Fan controller

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MalcolmV8
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Re: Detonation and Pre-ignition

Post by MalcolmV8 »

lol I did get a chuckle out of the hemi head section and sent it to some of my mopar friends.
92 302 Ranger - sold
94 302 Ranger AWD - sold
07 BMW 335xi - tuned, boost turned up, E85 - sold
04 911 TT - to many mods to list. Over 600 All Wheel HP on pump gas - sold
2015 Coyote - daily driver
03 Cobra - 2.3 TVS on a built 12:1 CR motor with ported heads, cams, long tubes etc.
MD Racing Lean Protection Module
E85

Tuned by MD Racing

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