a question about volumetric efficiency
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Team Owner
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From: I have no tolerence for liberals and fools, but sometimes i repeat myself
CI 3-5-7-8-9 Veteran
St. Jude Donor '08
a question about volumetric efficiency
If you had an engine with x number of cubic inches and a v/e of 95% (just a number, not representative) and you increased the cubic inches by 18%, but using the same Compression ratio, heads, cam, carb and intake would it be a safe bet that the v/e would go down, and if so by what percentage in relation to the additional cubbic inches?
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From: St Marys PA
Originally Posted by vetteman9368
If you had an engine with x number of cubic inches and a v/e of 95% (just a number, not representative) and you increased the cubic inches by 18%, but using the same Compression ratio, heads, cam, carb and intake would it be a safe bet that the v/e would go down, and if so by what percentage in relation to the additional cubbic inches?
Having said that, in your above example, you may or may not see a change in where that particular motor achieves 95% efficiency. In other words, the efficiency may just move up or down in the RPM range.
That is why I harp on well balanced combinations. A well balanced combination will have a "good efficiency" across a broader range of RPM, and be in an RPM range that you can use.
Again this is a very tough question to answer. Which is all the more reason to "copy" good setups as closely as possible, because the work is already done for you.
that is one of my most nerve-racking things with my car, when I change something like the cam, I am entering unchartered waters. It might make a good difference or a bad difference. Only one way to tell - give it a shot.
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Team Owner
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From: I have no tolerence for liberals and fools, but sometimes i repeat myself
CI 3-5-7-8-9 Veteran
St. Jude Donor '08
This is in reference to an NHRA stocker, so I am kinda limited on parts selection. Trying to ballpark a combination that hasn't been in competition in 12-25 years.
Drifting
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From: Reno nevada
From what I understand your 18% would be close with all things else being equal. That is unless the head flow and valve size was excessive on the smaller CI. So additional stroke and valve unshrouding could decrease this 18%
