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Timing vs Octane ????

With gas prices going up I wanted to toy with the idea of running lower octane and adjusting timing.  
What timing numbers are you seeing from 01-10 psi for
85, 87, 91 octane?  

I'm running an MS1, large front mount, stock turbo.  Currently timing is at 0psi-35*  10psi-25* on 91.

How much should I back it off for 85 or 87 octane?  Or should I?

As you're probably well aware, octane requirement increases with boost/cyl pressure. AFAIK (talkin' outta my ass here), increased timing simply exacerbates the cyl pressure that results in detonation/preignition ("pinging"). The ideal solution would be some kinda "variable octane fuel" which of course is non-existent.

OTOH......many of the GN/GNX and Turbo Regal aficionados have successfully used cheap pump gas augmented by alky injection for decades. It's about as close to on-demand octane improvement (more accurately.....detonation suppression) as you're gonna get. It can be "at-the-ready" and triggered only when needed by a Hobbs switch (or two, in stages) that sense(s) manifold pressure/boost. A fluid-level "boost deactivation" system should be incorporated, however, to prevent melting yer pistons when the water/alky tank is depleted.

Try searching the archives, using the criteria "alky injection", "water injection" & "water-meth injection"......looking for posts from currently-inactive member "Ted B".  <thumbup>
Placerville, California
(former)  '78 2.3T Courier w/blow-thru Autolite 2bbl carb ~ (current)  '87 2.3T Ranger w/PiMP’d EFI

I've got a couple alky kits, maybe it's time to install one.. and a turbo upgrade.. and injectors.

Only running 10psi max? I wouldn't even bother with alky. Maybe drop 2-3 degrees with 87 octane.
88 TC: 2.9L tall deck, SVO head, boport header, sheet metal intake, BWS300SXE turbo, AWIC. C4 trans. E85

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