Compression test 2011 sti
09 April 2018 | 08:45 PM
#1
Compression test 2011 sti
Hi I've just done a cold compression test on my stock 2011 sti saloon,
does anyone know the correct stock figures.
cyl 1 o/s/f ,125 psi
Cyl 3 o/s/r ,120 psi
cyl 4 n/s/r 115 psi
cyl2 n/s/f 120 psi
As i have lack of power no smoke but uses a little oil but I think these all do..
does anyone know the correct stock figures.
cyl 1 o/s/f ,125 psi
Cyl 3 o/s/r ,120 psi
cyl 4 n/s/r 115 psi
cyl2 n/s/f 120 psi
As i have lack of power no smoke but uses a little oil but I think these all do..
09 April 2018 | 11:47 PM
#3
Scooby Regular
Joined: Feb 2003
Posts: 7,640
Likes: 772
From: Harpenden
From the manual:
11. Crank the engine by starter motor and read the value when the needle of the compression gauge becomes stable.
NOTE:
• Perform at least two measurements per cylinder, and make sure that the values are correct.
11. Crank the engine by starter motor and read the value when the needle of the compression gauge becomes stable.
NOTE:
• Perform at least two measurements per cylinder, and make sure that the values are correct.
• If the compression pressure is out of standard, check or adjust the pistons, valves and cylinders.
Compression (fully open throttle):
Standard
981 — 1,177 kPa (10 — 12 kgf/cm2, 142 — 171 psi)
Difference between cylinders
49 kPa (0.5 kgf/cm2, 7 psi) or less
Compression (fully open throttle):
Standard
981 — 1,177 kPa (10 — 12 kgf/cm2, 142 — 171 psi)
Difference between cylinders
49 kPa (0.5 kgf/cm2, 7 psi) or less
09 April 2018 | 11:57 PM
#4
From the manual:
11. Crank the engine by starter motor and read the value when the needle of the compression gauge becomes stable.
NOTE:
• Perform at least two measurements per cylinder, and make sure that the values are correct.
11. Crank the engine by starter motor and read the value when the needle of the compression gauge becomes stable.
NOTE:
• Perform at least two measurements per cylinder, and make sure that the values are correct.
• If the compression pressure is out of standard, check or adjust the pistons, valves and cylinders.
Compression (fully open throttle):
Standard
981 — 1,177 kPa (10 — 12 kgf/cm2, 142 — 171 psi)
Difference between cylinders
49 kPa (0.5 kgf/cm2, 7 psi) or less
Compression (fully open throttle):
Standard
981 — 1,177 kPa (10 — 12 kgf/cm2, 142 — 171 psi)
Difference between cylinders
49 kPa (0.5 kgf/cm2, 7 psi) or less
10 April 2018 | 02:27 PM
#7
Don on that disc does it ha e all the procedures and mainly torque figures if I was to rebuild myself.as I'm an engine builder / technician at cummins diesels.so have the know how but need the relavent info..
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10 April 2018 | 04:30 PM
#9
Scooby Regular
Joined: Feb 2003
Posts: 7,640
Likes: 772
From: Harpenden
There is a 2008 WRX/WRX STi manual in the technical archives free workshop manual downloads thread in pdf format, however it is the US version so will have some variations.
Direct link..........
https://www.mediafire.com/?bp5js3yjgcc62#1hkwc5dck3vjm
10 April 2018 | 11:41 PM
#10
I have some questions if you know,it's a 2011 ej257 saloon 6 speed saloon,
if I was to have the bottom end forged,but had standard heads turbo down pipe with cats but a cat back invidia system, etc what is the safest upper limit of bhp I could expect once mapped!!
if I was to have the bottom end forged,but had standard heads turbo down pipe with cats but a cat back invidia system, etc what is the safest upper limit of bhp I could expect once mapped!!
11 April 2018 | 09:52 AM
#11
Scooby Regular
Joined: Sep 2004
Posts: 23,118
Likes: 150
From: Notts
Also worth getting the block closed decked while its out as its only circa £500 on top.
Last edited by Tidgy; 11 April 2018 at 09:53 AM.
11 April 2018 | 10:37 AM
#12
Scooby Regular
Joined: Oct 2016
Posts: 272
Likes: 1
From: Hertfordshire
I think you can get hung up on compression figures when its more important that the figures are all within x% of each other. Cold readings will be lower than hot readings, and stuff like whether you have the throttle wide open or not, whether all plugs are in or not all make a difference (so I've recently found out). I am starting to think of compression testing as being similar to BMI. Some BMI tests will show a person as being unhealthy or even obese when actually they may be very healthy and muscly.
A leak down is a far better test.
A leak down is a far better test.
11 April 2018 | 11:15 PM
#13
Leak down test results.
Cyl1= 5%
cyl3=5%
cyl4=7%
cyl2=7%
compression test done hot all at 125 psi.
add oil too cylinders all average 145 / 150 psi
with air coming from air intake pipe to air box .on all but believe is back feed from the pcv
and from crank case through the oil filler.
But how much is too much from crank case as you will always get some,but in my option seems normal blowbye, and the above confirms that but it the compression is low but all the same.but below what subaru state as a min.
Cyl1= 5%
cyl3=5%
cyl4=7%
cyl2=7%
compression test done hot all at 125 psi.
add oil too cylinders all average 145 / 150 psi
with air coming from air intake pipe to air box .on all but believe is back feed from the pcv
and from crank case through the oil filler.
But how much is too much from crank case as you will always get some,but in my option seems normal blowbye, and the above confirms that but it the compression is low but all the same.but below what subaru state as a min.
Last edited by stevie turbo; 12 April 2018 at 10:59 PM.
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