Choose the Optimal DCR - Quench...!
Choose the Optimal DCR - Quench...! Of these three options, which would you choose...and why?
DCR: 8.69
HG Thickness: .054"
DCR: 8.88
HG Thickness: .045"
DCR: 9.00
HG Thickness: .040"
Fuel is 93-pump premium, non-oxygenated. Assume adequate cooling (170/180 t-stat, fans reprogrammed). AFR heads (66cc), ported intake, and headers - so cylinder-fill efficiency will likely be high. Year-round DD usage; summer temps normally 80s with a few (~10-15/year) days in the 90s.
Is it "better" (less prone to detonation) to have a lower DCR with a less-than-optimal quench, or a higher DCR and a "perfect" quench?
DCR: 8.69
HG Thickness: .054"
DCR: 8.88
HG Thickness: .045"
DCR: 9.00
HG Thickness: .040"
Fuel is 93-pump premium, non-oxygenated. Assume adequate cooling (170/180 t-stat, fans reprogrammed). AFR heads (66cc), ported intake, and headers - so cylinder-fill efficiency will likely be high. Year-round DD usage; summer temps normally 80s with a few (~10-15/year) days in the 90s.
Is it "better" (less prone to detonation) to have a lower DCR with a less-than-optimal quench, or a higher DCR and a "perfect" quench?
It's about finding the balance between the two. Higher DCR means higher chance of detonation, no matter what the quench. Of course, the tighter the quench, the more chance you have of staving off that detonation. I would personally find the balance by running the .040" gasket and opening up the cc's on that head a bit. However, if working on the heads is out of the question, then I'd just go with the thicker gasket and less DCR. It's a personal opinion, and I'm sure other people will have different theories. Seeing as how you're in MI where it doesn't get too hot year round and you can run 93, you could prob run a higher DCR (relative to the 8.6 area most people look for).
Everything i've read and seen seem to state that anything over 9.6-1 DCR will need to have a great tune as it's on the edge of detonating with 93 octane. I would stick with the .54 gasket and leave a few ponies on the table in exchange for a long life engine.
