Notchtop sr low compression??? Help!!!

[Gripless schassis]

Ok guys in need of help/opinions
I've got a Zenki notchtop sr swap in my kouki just recently upgraded to a top mount turbo set up bigger injectors bla bla 15lbs running of the waist gate using apexi power fc we'll decide to do a compression test before upping the boost and tuning it on the dyno and what I found was disturbing and confusing.
Compression numbers across the bord were all 117psi -121psi when I saw this my heart sank
This was tested with the engine thempature right around 175 degrees Fahrenheit all spark plugs out and at wide open throttle.
So decided to simply pour a spoon full of oil in each cylinder prior to the compression test. I tested the cylinder dry and then wet right after and all numbers remain the same one maybe two of the four cylinders jumped up 1psi. So next I pulled the valve cover to see if maybe it jumped a tooth or something,
Well this was also confusing to me there is supposed to be three colored links on the timing chain one to be matched down at the crank and two to match up at the cam gears well all I had one one silver link I marked the one I saw to make damn sure I was not mistaken when seeing it again lol and also wiped off every individual chain link on this damn thing and nothing,
Timing light reads 15 degrees as well as the power fc I'm very lost here car runs and pulls spectacular no smoking, knocking,missing,no blow by. I need help.
I'm going to be looking into doing a leak down test also gotta do some research as to how to do that I've never personally done it. Also Vtc gear is nice and quiet verses being hella loud when there bad any help is much appreciated guys thanks for your time!

[Gripless schassis]

Also motor came in the car so no telling if it is "built" with lower compression pistons or not also the head gasket appears to be stock.

[ANDY black s13]

read your post a couple of times,and only two possibles I have for the low comp readings
and no increase (well 1 psi) when oil is added
is SR can crack the exhaust valves,
and another is the cylinder head can crack around the spark plug hole
both will bleed of a bit of compression,
but needs the head pulled off to check properly
potentially rare for each cylinder to all drop to lower but near equal numbers,

could have lower comp ratio pistons,are the cams & pulleys stock OE?
Try another comp tester just to verify the first readings as well

[Gripless schassis]

Yeah I'll be getting another tester in the morning to make sure the previous one wasent faulty, and have no clue if it has aftermarket pistons I mean from factory they come 8:5:1 idk if they make any lower compression pistons than that lol
After the new confirmed compression test will depend if I do a leak down test.
It's just wired that all four are the same (within 3psi) I've seen perfect on one two and four with super low on three more than a few times lol

[Kingtal0n]

cranking compression can vary depending on engine RPM. When I get a low reading like that across the board, I start by using jumper cables or a booster box to boost the engine cranking RPM.

If you still see 120~psi, and it is across the board even, then the engine simply has high mileage, perhaps 220,000~ or more. The sr20 can last a long time, its just the compression dropping off over time that facilitates the rebuild process. You can replace the rings and order new bearings without any machine work (avoid machine shops) simply hone the cylinders using a tool at home, it can be done.

Otherwise, you can keep driving it that way. power will be a bit lower than it should be but still should drive ok. Perform aleakdown test to confirm that the cylinders are sealed up nicely, however, an even compression test across the board pretty much confirms the situation in each hole is similar/identical.

One other thing, compression testers often vary and can go bad. If you rented one or used an old one there is a high chance it is simply bad. I would perform another test using another tester.