Compression test for a sr20det-New SR owner - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

S14Raj · 08-02-2015, 07:06 PM

I recently bought a new sr20det notch top. Before I bought it I was reading that anything 150-180 was a good reading for the compression test, and when we did the compression test for the one I bought it was higher than 180. So my question is what is the highest reading anyone has gotten or heard of, from the sr?

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Kingtal0n · 08-02-2015, 08:49 PM

lo. the FSM says that the highest possible is about 154psi. So either you have a naturally aspirated engine, or a bad compression tester.

I have compression tested about 100+ sr20det engines from Japan and the norm is about 130psi.

S14Raj · 08-03-2015, 01:04 AM

Quote:

Originally Posted by Kingtal0n

lo. the FSM says that the highest possible is about 154psi. So either you have a naturally aspirated engine, or a bad compression tester.

I have compression tested about 100+ sr20det engines from Japan and the norm is about 130psi.

The first two engines I looks at were both around the 140-150 range but each cylinder was inconsistent and they had aftermarket parts which I really didn't want. And another one I looked at had very very low compression numbers and looked like a total POS. the one I bought was very consistent and was probably the cleanest engine in the whole wear house and probably the cleanest thing I'd ever seen ever and also bone stock (From what it looks like at least)
Thanks for your your help

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KiLLeR2001 · 08-02-2015, 09:05 PM

Standard is about 160 psi. I've never seen anything higher than 175 psi on stock components... Lowest acceptable amount is 128 psi. Any more than 14 psi difference in between will need a rebuild.

jr_ss · 08-02-2015, 09:25 PM

I've seen 190psi on mine, but it's s bastard child.

KiLLeR2001 · 08-02-2015, 09:57 PM

Quote:

Originally Posted by jr_ss

I've seen 190psi on mine, but it's s bastard child.

Are you talking about your SR20VET? I'm sure that has a higher compression ratio versus a stock SR20DET.

S14Raj · 08-03-2015, 12:56 AM

Quote:

Originally Posted by KiLLeR2001

Are you talking about your SR20VET? I'm sure that has a higher compression ratio versus a stock SR20DET.

Shit well it's funny you say that bc I only heard about the sr20vet about 2 days ago, but I'm almost sure it's a original sr20det. And was reading that some people use the sr20vet head on the sr20det. Do u think that would give me a higher compression. I heard it's a lower compression. I'm just a lil confused. I can't really turn back now I bought it so I'm just gonna deal with what I have. Thanks for the input guys really appreciate it! I'll post pics of my engine and my swap once it gets going

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jr_ss · 08-03-2015, 10:22 AM

Quote:

Originally Posted by KiLLeR2001

Are you talking about your SR20VET? I'm sure that has a higher compression ratio versus a stock SR20DET.

Yessir. Speculation and rough maths put it around 9.5:1 comp ratio.

KiLLeR2001 · 08-03-2015, 01:01 AM

I apologize, my previous post was in reference to jr_ss's post.

S14Raj · 08-03-2015, 01:06 AM

Quote:

Originally Posted by KiLLeR2001

I apologize, my previous post was in reference to jr_ss's post.

Ohh it's ok still could apply I think bc my numbers were higher than that but not by much

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S14Raj · 08-03-2015, 01:08 AM

[QUOTE=S14Raj;5919262]Ohh it's ok still could apply I think bc my numbers were higher than that but not by much

Kinda but like I said I was just curious and Ill eventually get pics up on here so u guys can see my swap

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Koukiii · 08-03-2015, 07:09 AM

Carbon buildup over time adds compression. As long as all the cylinders are close you should be fine.

*TheRealSy90* · 08-03-2015, 07:45 AM

My redtop tests around 180psi consistently. No idea why I've never opened it up in the 6 years that I've had it.

*blksylv* · 08-03-2015, 09:59 AM

I just tested mines last week and got 180 on all 4. Recently had a cosworth 1.1mm hg, arp studs and tomei poncams installed also.

08-02-2015, 07:06 PM	#1
S14Raj Join Date: Nov 2014 Location: Long Island Age: 26 Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	Compression test for a sr20det-New SR owner I recently bought a new sr20det notch top. Before I bought it I was reading that anything 150-180 was a good reading for the compression test, and when we did the compression test for the one I bought it was higher than 180. So my question is what is the highest reading anyone has gotten or heard of, from the sr? Sent from my iPhone using Tapatalk

08-02-2015, 09:05 PM	#4
KiLLeR2001 Post Whore! Join Date: Jun 2007 Location: オーランドフロリダ Posts: 7,955 Trader Rating: (46) Feedback Score: 46 reviews	Standard is about 160 psi. I've never seen anything higher than 175 psi on stock components... Lowest acceptable amount is 128 psi. Any more than 14 psi difference in between will need a rebuild. __________________

08-02-2015, 09:25 PM	#5
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,052 Trader Rating: (34) Feedback Score: 34 reviews	I've seen 190psi on mine, but it's s bastard child. __________________ My SR20VET

08-03-2015, 01:01 AM	#9
KiLLeR2001 Post Whore! Join Date: Jun 2007 Location: オーランドフロリダ Posts: 7,955 Trader Rating: (46) Feedback Score: 46 reviews	I apologize, my previous post was in reference to jr_ss's post. __________________

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08-02-2015, 08:49 PM	#2
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,646 Trader Rating: (17) Feedback Score: 17 reviews	lo. the FSM says that the highest possible is about 154psi. So either you have a naturally aspirated engine, or a bad compression tester. I have compression tested about 100+ sr20det engines from Japan and the norm is about 130psi.

08-03-2015, 01:08 AM	#11
S14Raj Join Date: Nov 2014 Location: Long Island Age: 26 Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	[QUOTE=S14Raj;5919262]Ohh it's ok still could apply I think bc my numbers were higher than that but not by much Kinda but like I said I was just curious and Ill eventually get pics up on here so u guys can see my swap Sent from my iPhone using Tapatalk

08-03-2015, 07:09 AM	#12
Koukiii Zilvia Junkie Join Date: Jun 2015 Location: Miami, FL Age: 29 Posts: 349 Trader Rating: (2) Feedback Score: 2 reviews	Carbon buildup over time adds compression. As long as all the cylinders are close you should be fine.