So I am going to be heading to do some dyno tuning time next week and the very last thing I am trying to do is adjust my cam gears and squeeze every last bit of power we can out of the HKS 272/280 cam setup I am running. Mods are in my sig and the cam gears I am using are Skunk 2. So far after talking to many people and bouncing ideas back and forth, these are some of settings I am looking to try and log before the dyno day to try. I have done my research here and have compiled a couple of possibilties. I wanted to start this thread to get peoples input who have experience in this area and b/c I know this isnt a commom setup I am really wanting to dial them in. So far I have: -3/0, -3/-2, +2/0, and 0/-2 as possibilities to try, so what does everyone think? Any input would be much appreciated. And remember this is a 272/280 combo.

+2 Intake, 0 exhaust seems to work best for me on my maxxed out 50 Trim at 30 PSI boost or so.....

that setting gives me the best powerband....

Thanks! Its funny that most people only want to chime in when they have opinions about stuff, but serious threads like this w/ real technical stuff, no one ever answers. I think I know what I am going to try, but I wouldnt mind more feedback.

With those cams you have over 30* of exhaust - intake overlap. On a big turbo this won't be so bad and can actually get some scavaging upon spool, but with a smaller turbo this overlap will cause reversion of exhaust once peak VE is reached if boosting over 20psi (about > 5500rpm).

I would try the -3/0, the IN valves open later so theres a little less overlap, but also, in theory due to later IN valve closing, you will shorten the compression stroke relative to the expansion stroke and increase efficiency(according to the "Miller cycle").

You could theorize all day too but the best possible cam setting for your car will be particular to your car only. The only way to find out what's best is on a dyno. Can be done on the street too while datalogging using a very precise rpm trace (usually from tach signal, not OBDII)

Thanks. Like I said i will be logging some of these settings this week before the dyno and fine tuning on the dyno so we dont waste alot of time messing w/ them on the dyno. Appreciate your input.

I know this will seem less "scientific" but sometimes it's all in the application. Every car is different, so basically you should start with a baseline you think is good and go from there.

For more technical explanations, see people like Aby and Eric (C6C6CH3vo IIRC)