Been doing a lot of searching and reading, trying to understand some things about compression.
I know the what DCR and SCR are.
I know the importance of DCR. But aside from being used to calculate DCR, what is the importance of SCR?
Why are people referring to it by itself? I have been under the impression that only DCR is what matters.
Thanks!
(sorry, read this post to myself and thought I sounded like a pirate)
Most references you see on generic forums and websites, e.g not engine related, are to SCR. Not many people calculate or know how to calculate DCR. Luckily we have a handy calc for that. The DCR is more important it actually engine compression than SCR. SCR is just the figure attributed to the piston, head and crankshaft combo. Basic compression ratio math. When you add in the camshaft it becomes different.
Usually when people reference a compression number they are saying SCR. The camshaft is also how the Chevy/Ford/Dodge V8 guys can run a high compression engine (11:1+) on pump gas. Yes, a lot of compression but a high overlap/late intake closing/ high duration camshaft. While it may make a nice muscle car sound that high compression engine won't get out of its own way until it hits 4000 rpm.
SilverXJ wrote:Usually when people reference a compression number they are saying SCR. The camshaft is also how the Chevy/Ford/Dodge V8 guys can run a high compression engine (11:1+) on pump gas. Yes, a lot of compression but a high overlap/late intake closing/high duration camshaft. While it may make a nice muscle car sound that high compression engine won't get out of its own way until it hits 4000 rpm.
I beg to differ. The new 2014 Corvette is 11.5CR, 450HP/450TQ, 0-60 in 4 secs, 200*I/207*E @ 0.050", 116.5* lobe separation.
Where is the high overlap and high duration?
You know the intake valve closing angle as well? Did you take into consideration that it is an aluminum block and head? 11.5:1 isn't a high compression for that combo.
So my setup with a 54* Ivca (stock 96 cam) & 8.4 Dcr/9.75 scr should kick should have a serious kick in the low end? Issue for me is I need to lower that a bit to have a safe/limp 87oct tune I think?
Clarification on Compression - DCR vs SCR
(sorry, read this post to myself and thought I sounded like a pirate)
