Milling 5.3 heads and LQ4 Questions!!!
05-10-2009, 03:20 PM
#11
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if youre running a lq9 motor do NOT mill the heads, it will bump your cr way to high just go with a stock gasket, i ran a set of patriot 2.5 heads with 2.02 valves and put down 400+ hp. the cr was close to 12. somewhere around 11.5:1 if youre using a lq4 i would think the cr would be less but wouldnt mill them neither just use a thinner gasket to achieve the cr.
05-10-2009, 03:21 PM
#12
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Anyone here have above 11.0:1 and drive everyday? Also, the only reason I'm wanting to do this is I have a set of 706 heads just sitting in the shop not getting me anywhere.
05-10-2009, 07:16 PM
#13
93 octane
the heads i had are 5.3 stage 2's from patriot they were 706 castings.you might pull little more tq with the truck intake as i was using the vic jr with a 224 cam
by the way, i drove my truck everyday 5 days a week 70 miles one way to work
05-10-2009, 09:33 PM
#14
You have to look at more than just the static compression ratio, it's the dynamic compression ratio that really counts. A cam with long duration and a tight LSA will have big overlap and a sort of EGR affect that wil aid in cooling the cylinders and reducing detonation. Do a search on DCR and SCR and you may find some info that will help. With the right combo, a high static CR isn't that big of a deal. If you look at some cam descriptions, they actually recommend a CR of 11:1 or higher. There are vehicles rolling out of the factories with 11:1...
05-11-2009, 08:53 AM
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You have to look at more than just the static compression ratio, it's the dynamic compression ratio that really counts. A cam with long duration and a tight LSA will have big overlap and a sort of EGR affect that wil aid in cooling the cylinders and reducing detonation. Do a search on DCR and SCR and you may find some info that will help. With the right combo, a high static CR isn't that big of a deal. If you look at some cam descriptions, they actually recommend a CR of 11:1 or higher. There are vehicles rolling out of the factories with 11:1...
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