Piston Compression question - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

locust13 · 01-09-2008, 03:03 AM

Ordering up all my stuff today for the build up of the SR but I'm not too sure if I want to go 9:1 or 8.5:1 compression on the pistons (86.5mm). I won't be able to run as much boost on 9:1 but it make alil more power. Car is not a daily driver just mostly used for drift events and autox every once in awhile and not street drivin that much. 93 octane, Power FC, 740cc injectors, and for turbo I might keep the my apexi AX53 or i'll just get a new 2871R.

I know its just a half point in compression but i want to be sure it won't cause any headaches in tuning, drivability etc down the road. obv head gasket, cam overlap will play a role in final compression numbers but just give me some feedback on what'll be better for me.

mayco_86 · 01-09-2008, 08:38 AM

Yeah I would definately go with the 9:1 compression because you dont need much boost to make good power. Since the pistons are forged they can take a beatin.

91silvia · 01-09-2008, 03:19 PM

If the car is going to be primarily a drift car, you'll probably want the 9:1's for slightly quicker spool and a little bit more torque. It's not going to make a huge difference, but it will make for a somewhat easier to drive car. Like Mayco said, if you buy a quality forged piston, you should have no problems with your pistons being a weak point as long as you get a good tune.

01-09-2008, 03:03 AM	#1
locust13 Zilvia Member Join Date: Jun 2004 Location: CT Age: 43 Posts: 156 Trader Rating: (2) Feedback Score: 2 reviews	Piston Compression question Ordering up all my stuff today for the build up of the SR but I'm not too sure if I want to go 9:1 or 8.5:1 compression on the pistons (86.5mm). I won't be able to run as much boost on 9:1 but it make alil more power. Car is not a daily driver just mostly used for drift events and autox every once in awhile and not street drivin that much. 93 octane, Power FC, 740cc injectors, and for turbo I might keep the my apexi AX53 or i'll just get a new 2871R. I know its just a half point in compression but i want to be sure it won't cause any headaches in tuning, drivability etc down the road. obv head gasket, cam overlap will play a role in final compression numbers but just give me some feedback on what'll be better for me.

01-09-2008, 08:38 AM	#2
mayco_86 Zilvia Addict Join Date: Mar 2006 Location: Cali Posts: 988 Trader Rating: (9) Feedback Score: 9 reviews	Yeah I would definately go with the 9:1 compression because you dont need much boost to make good power. Since the pistons are forged they can take a beatin.

01-09-2008, 03:19 PM	#3
91silvia Join Date: Aug 2005 Location: indianapolis, IN Posts: 38 Trader Rating: (1) Feedback Score: 1 reviews	If the car is going to be primarily a drift car, you'll probably want the 9:1's for slightly quicker spool and a little bit more torque. It's not going to make a huge difference, but it will make for a somewhat easier to drive car. Like Mayco said, if you buy a quality forged piston, you should have no problems with your pistons being a weak point as long as you get a good tune.