with my AFR165's, what is my compression ratio?

R

rockin_rick

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Oct 9, 2003

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Jul 27, 2005

#1

• Jul 27, 2005

• #1

I have a stock shortblock (well, really a FRPP shortblock assy made in 2000 (for the explorer) but I believe it's the same), AFR165s (58cc), Felpro 1011-2 head gaskets. What CR does this work out to? It's hard to compute since I don't really know the size of the eyebrows in the pistons and exactly how far up the bore the top of the piston is... Does anyone know for sure?

Thanks,
Rick

 

Grn92LX

Fidanza Man!

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Jan 14, 2001

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Jul 28, 2005

#2

• Jul 28, 2005

• #2

Appx 9.3-9.4:1 should be close enough.

 

R

rockin_rick

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Oct 9, 2003

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Jul 29, 2005

#3

• Jul 29, 2005

• #3

Thanks- is this an educated guess, common belief, personally measured/calculated, or fact? No offense, just trying to judge your confidence level... (I have a calculation/formula which I need to supply the CR, and just want it as accurate as possible to prevent GIGO)

Rick

 

S/CBlack95GT

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Apr 6, 2003

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Jul 29, 2005

#4

• Jul 29, 2005

• #4

Grn92LX said:

Appx 9.3-9.4:1 should be close enough.

Click to expand...

A 9.4:1 with the 58cc heads would be very close.

 

I

igotyofire

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Feb 26, 2004

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Southern California

Jul 30, 2005

#5

• Jul 30, 2005

• #5

S/CBlack95GT said:

A 9.4:1 with the 58cc heads would be very close.

Click to expand...

good enough for 89 octane then right

 

Pokageek

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Jun 10, 2005

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Jul 30, 2005

#6

• Jul 30, 2005

• #6

Interesting. Having flat top pistons I am supposed to be at 10.5 :1 using the same heads. I wonder what the difference in HP would be as upposed to 9:1? They said I would be required to use 93 octane though.

 

Mrgreen94gt

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Jul 30, 2005

#7

• Jul 30, 2005

• #7

I'm not entirely sure, but CHP uses flattops on their 302/306 and it gives near stock compression.

Also, those combustion chambers should be very detonation resistant. So, what kind of gas you use would depend more on your overall timing and A/F ratio as opposed to the bump in compression from the heads.