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

shanes14 · 09-03-2008, 03:32 PM

i am working on a ka-t project and I'm not sure what pistons to go with.

i have some cp pistons in my possession, but is low compression the way to go?

i cant decide on if i should use them or not

opinions please?

HalveBlue · 09-03-2008, 03:47 PM

Yes.

Turbo charging = lower compression.

What's the comp on the pistons.

shanes14 · 09-03-2008, 05:18 PM

9.0:1 i believe

drftthatshit · 09-04-2008, 02:36 PM

if you wana push boost in the future because trust me you will get tired of 7psi really quick. I would go to at least 7:0:1 that way your choise of boost range is much more larger...... the only reason i say 7psi is thats all your gonna be able to push with the pistons you have in your possetion hop this helps man

HalveBlue · 09-04-2008, 06:36 PM

Uh...no.

How much boost you run depends on more than just comp ratio. A lot more.

9:1 is perfectly fine.

The SR20DET has an 8.5:1 comp ration from the factory and can run significantly more than 7 psi of boost safely.

Generally speaking lower comp ratios are better for FI engines. If you want to find the optimal comp ration you'll have to do some research and calculations.

FWIW, I'd have no problems throwing those CP's in my engine.

In the end it all comes down to exactly what you want out of the engine.

shanes14 · 09-04-2008, 10:12 PM

i decided that im going to use them, might as well sinse i already have them..

09-03-2008, 03:32 PM	#1
shanes14 Zilvia Addict Join Date: Jul 2008 Location: florida Posts: 662 Trader Rating: (4) Feedback Score: 4 reviews	compression question i am working on a ka-t project and I'm not sure what pistons to go with. i have some cp pistons in my possession, but is low compression the way to go? i cant decide on if i should use them or not opinions please?

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09-03-2008, 03:47 PM	#2
HalveBlue Zilvia FREAK! Join Date: Mar 2004 Location: I'm somewhere where I don't know where I am! Posts: 1,549 Trader Rating: (0) Feedback Score: 0 reviews	Yes. Turbo charging = lower compression. What's the comp on the pistons.

09-03-2008, 05:18 PM	#3
shanes14 Zilvia Addict Join Date: Jul 2008 Location: florida Posts: 662 Trader Rating: (4) Feedback Score: 4 reviews	9.0:1 i believe

09-04-2008, 02:36 PM	#4
drftthatshit Zilvia Member Join Date: Jul 2008 Location: fox lake Age: 33 Posts: 192 Trader Rating: (0) Feedback Score: 0 reviews	if you wana push boost in the future because trust me you will get tired of 7psi really quick. I would go to at least 7:0:1 that way your choise of boost range is much more larger...... the only reason i say 7psi is thats all your gonna be able to push with the pistons you have in your possetion hop this helps man

09-04-2008, 06:36 PM	#5
HalveBlue Zilvia FREAK! Join Date: Mar 2004 Location: I'm somewhere where I don't know where I am! Posts: 1,549 Trader Rating: (0) Feedback Score: 0 reviews	Uh...no. How much boost you run depends on more than just comp ratio. A lot more. 9:1 is perfectly fine. The SR20DET has an 8.5:1 comp ration from the factory and can run significantly more than 7 psi of boost safely. Generally speaking lower comp ratios are better for FI engines. If you want to find the optimal comp ration you'll have to do some research and calculations. FWIW, I'd have no problems throwing those CP's in my engine. In the end it all comes down to exactly what you want out of the engine.

09-04-2008, 10:12 PM	#6
shanes14 Zilvia Addict Join Date: Jul 2008 Location: florida Posts: 662 Trader Rating: (4) Feedback Score: 4 reviews	i decided that im going to use them, might as well sinse i already have them..