Head gasket thickness: Quench vs Compression
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TECH Fanatic
Joined: Jul 2022
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From: Alaska
Head gasket thickness: Quench vs Compression Trying to understand the relationship between Quench, head gasket thickness, static compresion ratio and octane requirements.
A stock LQ4 at 9.4 static compression, will run day and night towing heavy for 20 years on 87 octane. Adding spark timing, optimized for 90 octane will improve performance markedly.
Assembling the LQ4 with a thinner .027 head gasket will in theory increase static compression to around 9.8 while ALSO bringing piston closer to head, and creating a more efficient QUENCH zone. Will the increased mixture turbulence created by the improved QUENCH at TDC balance out, or mitigate the effect of added compression as it affects the engines OCTANE requirement ?
.
Any other downside from the thinner head gasket ?
Is the Cometic .027" MLS gasket any better or worse at sealing/longevity in mild street boosted application ( say around 12 PSI ) ?
A stock LQ4 at 9.4 static compression, will run day and night towing heavy for 20 years on 87 octane. Adding spark timing, optimized for 90 octane will improve performance markedly.
Assembling the LQ4 with a thinner .027 head gasket will in theory increase static compression to around 9.8 while ALSO bringing piston closer to head, and creating a more efficient QUENCH zone. Will the increased mixture turbulence created by the improved QUENCH at TDC balance out, or mitigate the effect of added compression as it affects the engines OCTANE requirement ?
.
Any other downside from the thinner head gasket ?
Is the Cometic .027" MLS gasket any better or worse at sealing/longevity in mild street boosted application ( say around 12 PSI ) ?
TECH Fanatic
Joined: May 2016
Posts: 1,292
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From: St. Louis
Stock pistons are out of the hole already This is where I always say that blue felpro 0.048" seals really well is more important than a degree of timing because at the end of the day that's probably all you're going to get and it still probably won't be everywhere across the whole curve. Not trying to be grumpy. Just trying to keep you off the side of the road
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