SCR and DCR?
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,743
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From: Stockton Ca
SCR and DCR?
I was assuming my 350 had a SCR of over 10-1 and a DCR of abnout 8.4-1. I didn't caculat the 5cc for the 2 valve reliefs. That would make my 64cc TFS heads a 69cc combustion chamber w/.040 quench. Because of this I had 10o initial and 34o total advance. I haven't had any problems w/detonation so far. The 6" rods and spal fans seem to do their job. I will be setting for 36o total soon. I think that I may have been cheating myself. What is my correct SCR and DCR? I have a CC 270HR w/1.6rrs. 218-224 110lca. TIA
Rick West
Rick West
Melting Slicks
Joined: Dec 2000
Posts: 2,041
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From: Wichita, KS
Re: SCR and DCR? (Taijutsu)
To calculate your dynamic compression ratio you will need your camshaft opening and closing degrees, camshaft intake centerline and overlap, your bore diameter, the distance the piston is down in the bore at top dead canter, the thickness and true bore of your head gasket, the displacement of the valve refiefs in your piston and the cylinder head combustion chamber size.
Pro
Joined: Jun 2001
Posts: 672
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From: Quebec
Re: SCR and DCR? (Taijutsu)
With the info you gave, your Static compression would be 10.24:1 and the Dynamic compression 8.13:1. TFS, are these heads aluminium? If so, you could retard your cam 4 degrees to gain a little top end. From DD2000, it's suppose to gain 13 hp at 5500 RPM.
Stephan
[Modified by American Boy, 9:15 AM 3/20/2004]
[Modified by American Boy, 11:04 AM 3/20/2004]
Stephan
[Modified by American Boy, 9:15 AM 3/20/2004]
[Modified by American Boy, 11:04 AM 3/20/2004]
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Re: SCR and DCR? (American Boy)
Try running 35 - 38 degrees measured with the vacuum advance disconnected. I hope that's how you were measuring your present 34 degrees.
Then also see how many degrees is added when you hook up VA buy watching how much advance you end up with at a stead state 4000 rpm
Then also see how many degrees is added when you hook up VA buy watching how much advance you end up with at a stead state 4000 rpm
