Modular 4.6L Tech For all your 1996-2005+ 2V, 3V, and 4V modular motor needs.

Compression Ratio Diff

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  #1  
Old 01-26-2010 | 09:44 AM
Graderbird2004's Avatar
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2001 gt stroker
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From: Greenville Ohio
Thumbs up Compression Ratio Diff

Sorry for all the questions all the time. I was trying to find out more info about the compression that i am running..I put the high comp 5.0 saleen stroker kit in my car. The kit says 11to1 on the 3v saleen and i was wondering if there was a way to see how this changes to a 2v. I would think the compression would be higher because of the chambers but i was wondering if anyone knows how to convert them. Just trying to get all the info possible before ordering cams.
 
  #2  
Old 01-26-2010 | 10:15 AM
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3v chamber is 51cc IIRC, which would put your CR somewhere around 12.5-12.8:1 if all my numbers are correct. I'm assuming a -3cc dish on the piston. No wonder your output is so high.
 

Last edited by r3dn3ck; 01-26-2010 at 10:22 AM.
  #3  
Old 01-26-2010 | 10:36 AM
Graderbird2004's Avatar
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2001 gt stroker
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Wow...that is high...i run 93 octane and the engine doesnt ping or make any sounds at all. I might start adding an octane additive or should that high of CR be ok to run...Will that compression work well with the nitrous and should i limit it to what i run.
 
  #4  
Old 01-26-2010 | 10:47 AM
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2001 gt stroker
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The last bit of info about the the kit. The pistons are cp pistons and -6.5cc dish and the exact compression of a 3v is 10.42:1. What is the math that u use to figure that out.
 
  #5  
Old 01-26-2010 | 10:47 AM
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It's a little high for a street car but nitrous loves high compression and if you don't have any pinging on 93 on the street then you should be fine without any additive. Check with your tuner about whether or not to back the timing off when you put the nitrous on. Otherwise, enjoy.

You can toss a bottle of Torco in the tank when you make the nitrous runs if you want.

And with the -6.5 cc dish that takes you down to an even 12:1 which is still tall but not out of sight. Don't ever use crappy gas.
 
  #6  
Old 01-26-2010 | 01:09 PM
r3dn3ck's Avatar
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the math is basically comparative volume calculations and a quick ratio. I don't actually do that though. I use a calculator application specifically for calculating CR's. Google "compression ratio calculator" first one.
 
  #7  
Old 01-26-2010 | 07:12 PM
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2001 gt stroker
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I was also wondering with high compression and nitrous what spark plug i should be using. I have the NGK tr6s now and wondering if that is enough or do i need to go one step colder then those.
 
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