lq4 compression estimates??
Thread Starter
TECH Apprentice
Joined: Jan 2010
Posts: 382
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lq4 compression estimates?? so what do you think i'll have for compression? lq4, ls3 heads milled to .035, cometic .045 gaskets, piston comes out of bore .005.....any estimates. was thinking around 10.6 but i'm guessing
Thread Starter
TECH Apprentice
Joined: Jan 2010
Posts: 382
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i went with the texas speed cam, 225/230 .617/.612, hopefully its big enough and i'll be happy with it.... http://www.texas-speed.com/shop/item...=1055&catid=44
its made for the ls3 heads supposedly, they told me any bigger and i'd have to flycut alot and would loose comp and it would be a wash.... we'll see
its made for the ls3 heads supposedly, they told me any bigger and i'd have to flycut alot and would loose comp and it would be a wash.... we'll see
Staging Lane
Joined: Oct 2008
Posts: 65
Likes: 0
From: boston MA
Here is a stock bottom end LQ4 compression calc breakdown using stock LS2/LQ4/LQ9 Head Gaskets:
72cc - 9.47:1
71.06cc (stock 317 chamber) - 9.56:1
71cc - 9.57:1
70cc - 9.67:1
69cc - 9.77:1
68cc - 9.87:1
67cc - 9.98:1
66.67cc (stock LS1 241/853) - 10.01:1
66cc - 10.09:1
65cc - 10.20:1
64.45cc (stock LS2/6 243) - 10.26:1
64cc - 10.31:1
63cc - 10.43:1
62cc - 10.55:1
61.15cc (stock 5.3 706/862) - 10.66:1
61cc - 10.68:1
60cc - 10.80:1
59cc - 10.94:1
58cc - 11.07:1
57cc - 11.21:1
56cc - 11.35:1
72cc - 9.47:1
71.06cc (stock 317 chamber) - 9.56:1
71cc - 9.57:1
70cc - 9.67:1
69cc - 9.77:1
68cc - 9.87:1
67cc - 9.98:1
66.67cc (stock LS1 241/853) - 10.01:1
66cc - 10.09:1
65cc - 10.20:1
64.45cc (stock LS2/6 243) - 10.26:1
64cc - 10.31:1
63cc - 10.43:1
62cc - 10.55:1
61.15cc (stock 5.3 706/862) - 10.66:1
61cc - 10.68:1
60cc - 10.80:1
59cc - 10.94:1
58cc - 11.07:1
57cc - 11.21:1
56cc - 11.35:1
That's all fine if he was using those heads and head gaskets. He has LS3 heads and will need to use LS3/L92 head gaskets which have a bigger bore diameter, heads are also milled.
Also, not every one is the same, it depends how far above the deck your piston is also.
Also, not every one is the same, it depends how far above the deck your piston is also.
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Thread Starter
TECH Apprentice
Joined: Jan 2010
Posts: 382
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i thought about going down to .040 off the heads but i didnt want to mess up intake fit, checked it last night and it seems to be right at the limit, any more off the heads and id have to cut the intake too. i probally could of got away with a .030 head gasket too but i settled on the .045's...... waiting on my springs and a push rod checker tool then i can assemble and order the push rods......gettin there!
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