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

Strider · 10-30-2001, 09:00 PM

i want to raise my compression ratio on the Ka24de from its current 9.2(if i remember correctly) to atleast to 10.2 - 10.5. Question now is how much HP would that give me and where can i get some good pistons? if this is possible

*Jeff240sx* · 10-30-2001, 09:02 PM

I'm pretty sure it is a 5% hp increase per 1 point compression increase.  And stock is 9.5, isn't it?  I really don't remember.
-Jeff

Strider · 10-30-2001, 09:08 PM

heheh...i don't remember the exact ratio you're probably right though with the 9.5:1. I dunno ::shrugs::

*transient* · 10-30-2001, 09:24 PM

what are the downsides of this? (besides being able to run less boost)

whateverjames · 10-31-2001, 06:04 PM

i've heard the downsides of high compression are reduced durability (talking 10.5 or 11). how much less durable than low compression i don't know. it's what i've heard, can anyone verify this?

*LanceS13* · 10-31-2001, 06:19 PM

I'm pretty sure stock CR is 8.6:1 for S13s and higher (9.5:1?) for S14s to make the same hp with the milder cams.  High compression requires high octane fuel...get too high and you'll be searching for race gas to cure your pinging problems.  You could probably get away with 10.5 or 11.0, though, with 93.

Gold240se · 11-01-2001, 09:41 AM

I'm pretty sure the altima has a 9.2 and the 240 (S14) has a 9.5

**West** · 11-01-2001, 11:20 AM

You can put pistons from the KA24E in and it will up it to 10 or so. Like they said a whole 5% gain.

yenpit · 11-01-2001, 02:38 PM

if ur turbo'd leave compr LOW......
if ur natr'l like lanceS13 says hi'er compr....hi'er octane!!!

10-30-2001, 09:00 PM	#1
Strider Zilvia Junkie Join Date: Sep 2001 Location: SoCal, Corona Posts: 461 Trader Rating: (0) Feedback Score: 0 reviews	i want to raise my compression ratio on the Ka24de from its current 9.2(if i remember correctly) to atleast to 10.2 - 10.5. Question now is how much HP would that give me and where can i get some good pistons? if this is possible

10-30-2001, 09:02 PM	#2
Jeff240sx I hate you too... Join Date: Jul 2001 Location: Tampa, FL Age: 42 Posts: 5,828 Trader Rating: (0) Rides Gallery: Jeff240sx Feedback Score: 0 reviews	I'm pretty sure it is a 5% hp increase per 1 point compression increase.  And stock is 9.5, isn't it?  I really don't remember. -Jeff

10-30-2001, 09:08 PM	#3
Strider Zilvia Junkie Join Date: Sep 2001 Location: SoCal, Corona Posts: 461 Trader Rating: (0) Feedback Score: 0 reviews	heheh...i don't remember the exact ratio you're probably right though with the 9.5:1. I dunno ::shrugs::

10-30-2001, 09:24 PM	#4
transient Premium Member Join Date: Jun 2001 Location: Los Angeles, California Age: 41 Posts: 2,947 Trader Rating: (0) Feedback Score: 0 reviews	what are the downsides of this? (besides being able to run less boost)

10-31-2001, 06:04 PM	#5
whateverjames Nissanaholic! Join Date: Jul 2001 Location: St. Louis Age: 45 Posts: 2,263 Trader Rating: (0) Feedback Score: 0 reviews	i've heard the downsides of high compression are reduced durability (talking 10.5 or 11). how much less durable than low compression i don't know. it's what i've heard, can anyone verify this?

10-31-2001, 06:19 PM	#6
LanceS13 AutoX Junkie Join Date: Jun 2001 Location: MS Age: 43 Posts: 2,044 Trader Rating: (0) Feedback Score: 0 reviews	I'm pretty sure stock CR is 8.6:1 for S13s and higher (9.5:1?) for S14s to make the same hp with the milder cams.  High compression requires high octane fuel...get too high and you'll be searching for race gas to cure your pinging problems.  You could probably get away with 10.5 or 11.0, though, with 93.

11-01-2001, 09:41 AM	#7
Gold240se Leaky Injector Join Date: Oct 2001 Posts: 140 Trader Rating: (0) Feedback Score: 0 reviews	I'm pretty sure the altima has a 9.2 and the 240 (S14) has a 9.5

11-01-2001, 11:20 AM	#8
West OMNOMNOMNOM Join Date: Dec 2000 Location: Denver, CO Age: 44 Posts: 6,456 Trader Rating: (0) Rides Gallery: West Feedback Score: 0 reviews	You can put pistons from the KA24E in and it will up it to 10 or so. Like they said a whole 5% gain.

11-01-2001, 02:38 PM	#9
yenpit Zilvia Addict Join Date: Sep 2001 Location: Holland Michigan Posts: 798 Trader Rating: (0) Feedback Score: 0 reviews	if ur turbo'd leave compr LOW...... if ur natr'l like lanceS13 says hi'er compr....hi'er octane!!!