Anybody know what the DRC is on the 2.2L ecotec. We know the static compression ratio is 10:1 as stated in numerous posts and around the web.

 

with stock cams im assuming? why would you need to know?

 

was looking to do a NA build and upping the compression ratio however after studying the subject i question whether i will be able to meet my power goals without running race fuel. we have 93 octane but that may not be enough. given that the the L61 runs on 87 i'm trying to find out what the drc is to get a better understanding of how gm setup the engine to run that gas.

 

they have a conservative timing map. the ignitionn advance at WOT is between 15 and 18 degrees depending upon RPM. Adding a higher octane will allow you to get closer to 25+ ignition timing, or you can leave the timing and up the compression. Depending upon the octane you use, you could probably do both. I'd say go to a 11:1 compression ratio, and then just tinker with the timing to squeeze any additional horsepower out of that while staying out of knock

 

ah, makes sense. i'm still toying with my build plans now. i'm deciding now to go with boost but i'm now figuring if i want to keep the stock cr on a forged bottom end and pushing low boost or going with the low cr on a forged bottom and pushing more boost or course. the NA build is gonna have to wait until i get something that can make better use of that type of setup. i'd love to see it on a 4 banger but my 200whp just doesn't seem attainable while maintaining a reliable dd with little to no down time. i find i would need ample time for tuning and i don't have the time to do it on the cobalt at the moment. i'm going to build the motor and tune for the build and by that time there should be a nice stable of 2.2 turbo tunes to work with when i drop my turbo setup in.

 

personally, if your boosting through a M62, i'd keep the CR and go low boost as higher boost pressures result in exponentially higher intake temps due to a restrictive manifold and a blower out of its efficiency range. but if your boosting through a turbo, i'd just up the boost and drop the compression to 9.0:1. get a FAT IC though. Heat is the enemy for these motors