Just picked up LQ9, some questions
09-25-2009, 04:08 PM
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Just picked up LQ9, some questions i just picked up a 40k mile lq9 from a cadilac and i have a few questions for my twin turbo project. i did a search but didnt find much. I've got a great deal on L92 heads bit i need to know the piston cc and the Piston Deck Clearance to figure out my compression ratio. This build will be e85 based with aprox 15lbs of boost. Assuming the tune is dead on and a possible 11:1 comp ratio, will the e85 be enough so the motor wont detonate? i can run meth if needed.
09-25-2009, 04:19 PM
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11:1 is a big ask at 15psi boost, yes it can be done but it will limit the amount of timing your engine will take without detonation and therfore the power it will make.
09-25-2009, 04:28 PM
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i can put a thicker head gasket on to lower the comp, i just need to know the piston cc and the piston deck clearance in order to calculate the compression and get the right head gasket.
edit: anwsered my own question. piston deck clearnce is .008 above the deck, therefore giving me a 10.6:1 comp ratio with l92 heads; still a bit high though. with $260 titan gaskets (.093") i can get it down one full point. Is there a cheaper head gasket that will be the same thickness?
edit: anwsered my own question. piston deck clearnce is .008 above the deck, therefore giving me a 10.6:1 comp ratio with l92 heads; still a bit high though. with $260 titan gaskets (.093") i can get it down one full point. Is there a cheaper head gasket that will be the same thickness?
Last edited by 94tt383; 09-25-2009 at 04:50 PM.
09-25-2009, 05:26 PM
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I'd have a machine shop do some work on your combustion chambers. Not only would you get a safer lower cc ratio, you'd get rid of all the rough spots that will start detonation.
