I'll be buying some new JE slugs today, and the question has come up, what CR do you want to run. Off the shelf choices are 9.0:1, or 10.5:1. Using my GSR head, and an oem HG, I'll be looking at 8.8:1, and 10.36:1, respectively.

Here's my scenario.
I'll be running 84mm pistons, with a closed deck.
I plan to run 9psi via jrsc, and water injection for the street/autoX.
For the dragstrip, I'll be running a 50shot of nitrous, along with the jrsc (minus the water).

Will the 10.36:1 CR be too high for the amount of water cooled boost I'm running?

The car gets nothing but 94 octane, and will be Hondata wideband (and egt) tuned.
Something tells me that 8.8:1 CR will be a dog off boost, and given the choice, I'd rather run a fat HG to bring my CR down to around 10:1, while maintaining a solid quench area.

Any ideas or opinions?
cheers!

 

9psi??
stay above 10:1 if at all possible.

 

That's what I was thinking too. I won't be running any serious boost, because of the ineffeciencies of the positive displacement blower. Knowing this, I was hoping to make power in other ways, and a higher CR is one of them. Basically I wanted to mimic the CR of the jdm GSR motor.

In boost, I won't have too many issues with the higher CR. ITR guys do it all day long with the proper tuning. My issue may come from the use of nitrous though. Because the nitrous will increase my cylinder temps, along with the boost, will I destroy my new pistons?
Or will the cooling effects of the nitrous allow me to run a shot for a short time, and still maintain 9psi of virtually uncooled boost?