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Thread: HOW TO: "Indentify" a 10:1 vs 9:5 SR20 motor by Oil Drain Tube?

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Posts: 1-10 of 37
2008-10-28 17:29:59
#1
HOW TO: "Indentify" a 10:1 vs 9:5 SR20 motor by Oil Drain Tube?
The old sr20forum thread with more info on 10:1 vs 9:5

^Ok so I purchased a UK redtop back in "05" when I first joined the forum and didn't really know what I had. As I begin reading over different threads and post getting my newbie skills right. I discovered the differences between 10:1 and 9:5 SR20 motors. Anyway this thread has been created to give "The Dash" some extra info to indentify the UK/JDM 10:1 motors that have anywhere from 7-10 HP's more than the 9:5 SR20 motors. I will also include quotes giving the people credit for there opinions on the topic that I have pieced together.

insane imports - made a post on the old forum with pics showing the oil drain tube differences that he believes tells the difference between the two.



^USDM Oil Drain Tube




^UK/JDM Oil Drain Tube. Now this does not mean that every UK/JDM motor is 10:1 of course. This could also explain why some people that are putting turbos on JDM motors are getting better numbers than others when having the same modsat the same PSI levels. Something else to think about.



MORE THOUGHTS FROM OTHER MEMBERS


Originally Posted by Andreas


Here is my opinion on this.

Every motor that came from Japan with the tubular headers were 10 to 1

Every motor that came with regular headers were 50/50 9.5 to 1 or 10 to 1..


^I guess this makes since and the tubular header could have something to do with this????

Originally Posted by eric96ser
Remove the head.


^This would give you your answer, but shouldn't there be another way to tell besides taking the head off????

Originally Posted by nx2000andy
there is another thread on this exact issue (that confirms this) and someone that had a number of sr20's (8) had them lined up and new through comp tests which was 10:1 amd 9:5:1 and there was a physical difference in the drain tube for the stock oil seperatortlet tubing near the sr20 scribed onto onto engine block10:1 was longer with two bends 9:5:1 shorter one bend..this is a SURE way to tell


^I still never found that thread and I would love to see it.



^This is my UK motor.



^This is the tubular manifold that came off of it.



^This is my JDM motor that I'm trying to figure out if it is a 10:1 or 9:5, now that the oil drain tube theory has came up.



^This is the NON egr cast iron exhaust manifold that came off of my JDM motor when I first got it. Although it used the cast iron header, this motor still had two bends on oil drain tube????
2008-10-28 19:08:33
#2
i thought you could tell the difference from a uk motor and a jdm motor by the stampin on the head, i have a uk head and it says 96j on it and my jdm de says 53j i think or 53r
2008-10-28 19:25:21
#3
Originally Posted by carfreak240
i thought you could tell the difference from a uk motor and a jdm motor by the stampin on the head, i have a uk head and it says 96j on it and my jdm de says 53j i think or 53r


^Yes, but telling when you have a 10:1 or 9:5 UK/JDM motor is my mission. I need to see how well this oil drain tube talk holds up.
2008-10-28 19:59:27
#4
A 10 to 1 motor and 9.5 to 1 motor does not have a 7 to 10 HP diffrence just by compression alone.

Most 10 to 1 compression motors come with tubular headers. This can be seen easily by looking at the UK motor with the Candy Apple Red valve cover rated at 150 HP. We know all these motors are all 10 to 1. The diffrence from 140 HP to 150 HP is 10 HP that 10 HP can be broken down to about 6 HP from the header and 4 HP for the compression.

Trust me when I tell you, all this hassel for a 10 to 1 motor is not worth the effort.

Now, the reason why you see 10 to 1 motors with diffrent oil tubes is because they have the tubular header and heat sheild. If you have a tubular header and heat sheild and try and put it on the regular motor the header will go on but the heatsheild will not fit. The longer tube is done for clearance for the heatsheild.
2008-10-28 20:42:23
#5
^I was trying to look up the compression readings between the two on the board. I didn't really go out to look for a 10:1 motor as I stated in the first post, it somewhat found me. I didn't even now much about the SR20 motor then. I was a GA16 guy all the way and my motor was on it's last leg and I found out about the forum from a co-worker. Thanks for clearing up the break down on the HP. Anyway I just wanted to know if this talks was fact, or fiction.
2008-10-28 22:02:02
#6
FWIW my old lowport redtop came with a stamp on the side " UK 101 " IIRC.

it's been a few years so i may be wrong.
2008-10-28 23:34:08
#7
Originally Posted by Andreas

Most 10 to 1 compression motors come with tubular headers. This can be seen easily by looking at the UK motor with the Candy Apple Red valve cover rated at 150 HP. We know all these motors are all 10 to 1. The diffrence from 140 HP to 150 HP is 10 HP that 10 HP can be broken down to about 6 HP from the header and 4 HP for the compression.


In Europe...

P10 Primera GT 150hp
N14 Sunny GTi 143hp
B13 100NX GTi 143hp

N14 and B13 had silver valve cover. Looks like every JDM hihgport. P10 GT is as you said with candy red valve cover.

All of them got tubular mani.
All of them are 10:1 CR.

We can compare N14/B13 vs. P10 ecuĀ“s if there is any difference in maps.
2008-10-29 05:21:20
#8
another thing, ill chime in since i have the bent tube on my motor i just dissambled is i have dished pistons, so im guessin it is a 9:5:1 i pulled the head off saturday, cause of a fried piston, you posted this earlier so i went to make sure i didnt have a 10:1 motor decided to post up stating that my motor was not 10:1 and it doesnt have the bigger and more faced upward tube
2008-10-29 08:08:31
#9
Originally Posted by carfreak240
another thing, ill chime in since i have the bent tube on my motor i just dissambled is i have dished pistons, so im guessin it is a 9:5:1 i pulled the head off saturday, cause of a fried piston, you posted this earlier so i went to make sure i didnt have a 10:1 motor decided to post up stating that my motor was not 10:1 and it doesnt have the bigger and more faced upward tube



Your motor did not come with the JDM headers correct.

The header and 10 to 1 piston is is a combo that comes together from what I have seen.
2008-10-29 12:35:09
#10
Why not just use a compression tester on your UK, and compare to the readings from the JDM?
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