Higher Compression Pistons

[YochTown240]

okay i just got a couple of questions one the main one does my 1990 240 have 8.6:1 pistons?? the nissan motorsports page sells 9.1:1 pistons and i was wondering if getting these would give me any power and about how much. i am going to have my block ripped up somewhat because i need to fix my timin chain guides and while i was in there i was thinkin of changin the cam and maybe the pistons and rings. anyone got anythin to say about the pistons, cam or the timing chain feel free to say whatever thanks folks!!!!!!!!!

[trpower7]

Cam would be a good thing to do while you are in there, but pistons and rings are a little different. It require a significant amount of extra work to do those, as well as alot more machine work. Yes, higher compression pistons will give you more horsepower but I would NOT recommend getting the high compression pistons if you ever plan to go turbo on that engine. If you are dead set on doing the pistons and rings, here is what I suggest. Tear the whole thing down, and build it forged. Pistons, rings, and rods, maybe even have some crank work done. Get the stock compression pistons, maybe even lower. This way you will be totally ready to rock and roll with a higher PSI turbo system (15-20 PSI) not to mention it will be bulletproof. I estimate (if you do all the work yourself) the pistons, rings and rods will run you a little more than a grand. Just my .02 though, if I wasn't so poor it's what I'd be doing!

[YochTown240]

Thanks dude and im not considering running a turbo setup im going all motor. so factoring in im not goin turbo would just changing the 8.6:1 to 9.1:1 be anymore than take the old ones out and put the new ones in or would i need to work on the rods and crank. Also how much HP would those 9.1:1 pistons give me??

[Daunttless]

They're like 57.50 per piston from Nissan Motorsports, and yes, the 9.1:1 will give you more power. : )

[Daunttless]

You wouldn't need new anything else, it won't be THAT huge of a power increase, but it will be a decent gain. : ) I don't know how much offhand, so you'll have to get some dyno numbers for us. : )

[YochTown240]

Thanks folks! anyone got a ballpark figure like 5hp 10hp 15hp even out of those pistons??

[Nismo_Freak]

10 hp perhaps... torque gains are worth more than the hp. Higher compression should give you more low end torque too.

[hurddawg]

Tear the whole thing down, and build it forged. Pistons, rings, and rods, maybe even have some crank work done. Get the stock compression pistons, maybe even lower....I estimate (if you do all the work yourself) the pistons, rings and rods will run you a little more than a grand. Just my .02 though, if I wasn't so poor it's what I'd be doing!

just the forged pistons (i can't believe the stock pistons are forged, hypers maybe) alone would cost 400-500 dollars.

[Daunttless]

The stock pistons aren't forged. : )

[numatik]

Are there many people out there running 11.6:1 in a KA24DE with a stock bottom end? That seems like a viable upgrade path for one who is going all motor and doesn't want to spend alot of money. Hell, I only run 93 octane anyway.(a little off topic sorry)