LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Pistons, Dynamic CR + 91 octane =???

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Old Oct 26, 2009 | 08:44 PM
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JB_97ws6TA's Avatar
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Default Pistons, Dynamic CR + 91 octane =???

I have been told that 9.5:1 dynamic CR is about the max you can go to run premium. Now assuming that premium is 93 octane which it is almost everywhere else besides California, what is the highest DCR you can safely run 91 octane with about 4 straight months of 100+ degree weather. I had it all figured out but my build has taken yet another direction soo....any help is, as always, appreciated. Thanks
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Old Oct 26, 2009 | 09:16 PM
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It's all in the tune man.
I'm running 10.55:1 DCR on 91 octane pump gas.
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Old Oct 26, 2009 | 09:21 PM
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is it just the timing adjustment to alleviate any detonation issues?? If so what would be more optimal having the extra compression or having the timing advance or do they kind of cancel each other out? Sorry if it sounds like a stupid question but I do not know the first thing about tuning.
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Old Oct 26, 2009 | 09:46 PM
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Originally Posted by JB_97ws6TA
is it just the timing adjustment to alleviate any detonation issues?? If so what would be more optimal having the extra compression or having the timing advance or do they kind of cancel each other out? Sorry if it sounds like a stupid question but I do not know the first thing about tuning.
Correct, if you increase compression too far, you will have to pull timing.
You want to avoid that whenever possible, it rarely pays off VS CR.
(it does however in the power adder world)
That's something Ed Wright and I discussed prior to my 355 and 383 builds.
(which saved me from making what could have been disastrous decisions with my build choices)

I run 43* at part throttle and 36 at WOT. Pretty typical for an N/A car.


My point was that if you want to push the envelope on CR, enlist a tuner with a solid reputation.
They'll make sure your tune is optimized.
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Old Oct 26, 2009 | 10:57 PM
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The most I trusted was 9.4:1 DCR with shitty CA premium.
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