Best balance of boost and compression for a DD
11-20-2006, 06:01 PM
#11
The gn guys upped the compression to 9.5 on some of the motors, but that was for big turbos, loose 9/11 converters, and a v6 so it needed some bottom end help.
I'm like Jerry and the majority 8:5 to 9:1 is about max.
I'm like Jerry and the majority 8:5 to 9:1 is about max.
11-20-2006, 06:02 PM
#12
Originally Posted by vanillagorilla
JE makes them! 
... and I wouldn't go with anything higher than .054 head gasket thickness.
Bill
11-20-2006, 06:08 PM
#13
JE's are nice, total seal or hellfire rings, and thinner head gasket will not only be stronger but in most cases better quench too. If it was me I would go with a 9:1 motor, Im not willing to change pistons in my setup to the best I can get it is 9.3:1 by going from 62cc combustion chambers to 71s.
11-20-2006, 08:02 PM
#15
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8.5-9.0 on a DD 408. The 408 will produce plenty of low end. Diamond pistons are heavier in most cases but they have revised their design recently and using a narower wrist pin and have lightened the pistons by 40-50 grams in most cases. But you can't go wrong with JE pistons.
11-20-2006, 08:13 PM
#16
Originally Posted by thunder550
What material type for the rings? I see chrome, plasma-moly, moly, and iron.
11-20-2006, 08:56 PM
#18
Plasma moly and chrome moly rings are the norm and iron second rings. A regular iron ring doesnt have the durability to last in a compression ring configuration. There is a reason why they are no longer used as a compression ring much less on a high boost application. Im no engine expert but over on tech I havent seen ANY of the big engine builders use a stright iron ring for the compression ring.