DCR Calculation Help (Piston Selection Issue)

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Jun 23, 2009 | 08:46 AM

Philly-Goat

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From: Williamsburg, VA

DCR Calculation Help (Piston Selection Issue)

Would someone help me with a DCR calculation. I'm having a 418ci build, but I'm having a problem selecting the proper dished piston to get me in the 8.3-8.5 DCR range based these specs.

L92 heads, 64cc
head gasket: .051 & 4.180 (or 4.160)
bore: 4.080
stroke: 4.00
IVC: 71 deg @ .006
cam: 232-238, 595-605, 114 LSA, ICL 110
.010 or .015 dish piston?

Thank You All!

Last edited by Philly-Goat; Jun 23, 2009 at 05:16 PM. Reason: Left out piston info & wrong IVC

Jun 23, 2009 | 02:21 PM

Philly-Goat

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Would someone please chime in and provide some help with this!

Thanks

Jun 23, 2009 | 04:33 PM

405HP_Z06

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From: Arlington, Tx

Quote:

Originally Posted by Philly-Goat

Would someone please chime in and provide some help with this!

Thanks

I'll help you out when I get home, but for DCR (a useless calculation by the way) you need IVC @ .006. The IVC in your post is @ .050. What SCR are you shooting for?

Jun 23, 2009 | 05:24 PM

Philly-Goat

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From: Williamsburg, VA

Quote:

Originally Posted by 405HP_Z06

I'll help you out when I get home, but for DCR (a useless calculation by the way) you need IVC @ .006. The IVC in your post is @ .050. What SCR are you shooting for?

405HP_Z06,

Yeah, I mixxed the IVO (31) & IVC (71) numbers up...it's correct now (71 deg) on the initial thread and that is @ .006.
Also, I am shoot for a SCR of 11.4 or 11.5, but it's still depends upon the piston itself (dished, flat or domed). Yes?

Thank you for all of your help!

Last edited by Philly-Goat; Jun 23, 2009 at 05:36 PM. Reason: Forget the SCR

Jun 23, 2009 | 08:41 PM

405HP_Z06

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You didn't state your piston-to-deck height so I used .010 out of the hole to optimize quench. If you want me to adjust based on a different number let me know.

Here is the calculation with a flat top piston:

Here is the calculation with the piston top adjusted for 11.5 SCR:

Let me know if you want me to make any adjustments anywhere.

Jun 23, 2009 | 10:34 PM

Philly-Goat

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Holy Crap 405HP_Z06!

I wasn't expecting that, WOW!

Anyway, I was told that the piston would be .008 out of the hole and this is a dish piston. Also, please adjust the piston cc to 10 first & 15 the second time. I'm still trying to get to 8.3 to 8.5DRC, but not lower than 8.1! I am open to suggestion to get, if you have any recommendations (i.e. change head gasket or larger cam)? I really appreciate all of your help!