Thoughts on lowering compression...dish pistons or large chambers
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TECH Junkie
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From: East Brady, Pa
Thoughts on lowering compression...dish pistons or large chambers Just curious if there's any up/downside to lowering compression one was or the other. It is better to have a large combustion chamber and solid piston or a dished piston with a smaller chamber....or does it even matter?
Thread Starter
TECH Junkie
iTrader: (71)
Joined: Mar 2002
Posts: 3,703
Likes: 0
From: East Brady, Pa
Here's my story in a nutshell. I have a 408 for a turbo project. I currently have 32cc pistons and 72cc heads giving me around 8.3:1 compression. I found a great set of heads for a good price that are 62cc. In my blind half assed guessing it made more sense to have a bigger combustion chamber but wasn't sure. Then new heads would put me right at 9:1 but I just wanted to double check everything.
I've read that the surface area of a small chamber, small dish, combustion volume is less than that of a large chamber, domed piston, combustion volume. That being the case, the combustion event is spread out over a larger area, taking longer to complete, and in some cases requiring greater spark advance. Most people tend to agree this isn't as efficient.
That said, it's far easier to R&R the heads to change the compression than to swap pistons.
That said, it's far easier to R&R the heads to change the compression than to swap pistons.
