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317s vs 243s

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Old 02-16-2009, 03:08 PM
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Default 317s vs 243s
looking to see if anyone has had reasonable gains on a lq4 from putting the243s on. any info would great thanks justin
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Old 02-16-2009, 03:17 PM
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If you plan to keep it NA, or run it with nitrous, the 243's are a decent upgrade over the 317's...
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Old 02-16-2009, 03:21 PM
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------because they will raise your compression ratio quite a bit, they have 64cc chambers as opposed the larger 317's.
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Old 02-16-2009, 03:23 PM
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Originally Posted by trever1t
------because they will raise your compression ratio quite a bit, they have 64cc chambers as opposed the larger 317's.
Thanks coach HAHAHAHA

This is true
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Old 02-16-2009, 03:32 PM
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do u happen to know what the compresion ratio will be.
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Old 02-16-2009, 03:37 PM
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you will lose ~6.5cc's..there is a formula on here somewhere....see if you can find it
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Old 02-16-2009, 03:51 PM
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thank you guys so 4 my set up it would be worth it then. just to get it out there my set up is lq4 .226/.226 ,3800 conv. 4.10s and 42lbs inj. and 200 wet shot thanks 4 the replies
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Old 02-16-2009, 04:20 PM
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Can't you just mill the heads to raise the comp up instead of buying new heads since they flow the same?
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Old 02-16-2009, 05:22 PM
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Originally Posted by Low_LQ4
Can't you just mill the heads to raise the comp up instead of buying new heads since they flow the same?
exactly. or what i would do is put some ported 243 on their then you'll see a huge increase in hp and tq
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Old 02-16-2009, 07:44 PM
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the 243s flow about 5-6cfm more up top. Also, milling the heads reduces your PTV, so if one ever decides to go with a bigger cam its probably best to stay with the 243s. 243s on an Lq4 should yield 10.6:1
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