Question what is a good compression ratio? - LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums
 
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post #1 of 5 (permalink) Old 04-18-2019, 10:11 AM Thread Starter
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what is a good compression ratio?

I’m building a 383 lt1 and I’m going to Procharge it with about 15 pounds of boost. I was wondering what a good compression ratio would be for this set up?
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post #2 of 5 (permalink) Old 04-18-2019, 12:06 PM
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When you buy a set of pistons, they list the static compression ratio that pistons give. Hoever, it's the dynamic compression ratio that is the important factor in building a high performance engine.

The dynamic compression ratio, takes into account the duration,lift & lobe timing of cam. The size of the combustion chamber and valve size also are taken into consideration for figuring the DCR. Many other factors also are looked at.

Having said this, I suggest you google static & dynamic compression info. Just out of thin air with 15 pounds of boost, I'm thinking around 8.0 to 1 or 7.5 to 1 static compression ratio. The DCR can't be figured until you know all of the components & machine work that is being done.

As an example stock bore engine will have a lower DCR than say a 30 or 60 over bore. Even though pistons for stock & over bore would have the same static compression ratio SCR.

I'm not an expert on boost, but with 15 pounds of it, if it were my engine, it would have all forged rotating system.

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post #3 of 5 (permalink) Old 04-18-2019, 09:34 PM Thread Starter
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Quote:
Originally Posted by cocobolo95 View Post
When you buy a set of pistons, they list the static compression ratio that pistons give. Hoever, it's the dynamic compression ratio that is the important factor in building a high performance engine.

The dynamic compression ratio, takes into account the duration,lift & lobe timing of cam. The size of the combustion chamber and valve size also are taken into consideration for figuring the DCR. Many other factors also are looked at.

Having said this, I suggest you google static & dynamic compression info. Just out of thin air with 15 pounds of boost, I'm thinking around 8.0 to 1 or 7.5 to 1 static compression ratio. The DCR can't be figured until you know all of the components & machine work that is being done.

As an example stock bore engine will have a lower DCR than say a 30 or 60 over bore. Even though pistons for stock & over bore would have the same static compression ratio SCR.

I'm not an expert on boost, but with 15 pounds of it, if it were my engine, it would have all forged rotating system.
so I calculated the static compression ratio for the set up I want to have and it came out to 8.57:1 so I could run about 15 pounds of boost with an Intercooled?
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post #4 of 5 (permalink) Old 04-19-2019, 07:58 AM
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You can, but I hope your not trying it with a cast crank and pistons.
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post #5 of 5 (permalink) Old 04-19-2019, 09:27 PM Thread Starter
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no I’m getting the Golen 383 boost lt1 short block
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