what is the compression numbers

[eclipsekid1013]

for a 4g63 na what compression should i reas per cylinder with a compressino tster and if the compression is low in 1 outa 4 cylinders what could that mean

 

[eDeclpse92]

My compression in my N/T was around 150 to 160. I believe dealer spec is that the lowest compression has the be within 30 percent of the highest compression. mine was 18 percent and my car runs great. hope this helps.
what are your numbers?

 

[RadDsm]

192 psi Standard

145 psi Service limit

14 psi Maximum difference between cylinders

 

[Hollyweezle_]

if the compression is low in 1 outa 4 cylinders what could that mean

We need to know HOW low. Posting the four readings you took will help the people trying to help you give a more direct and helpful answer.

But in general, you want to see numbers very close to each other (better if exactly the same across), and higher up on the psi scale.

 

[19Eclipse90]

This has been covered and for your particularly engine, RadDsm has it right. From http://www.dsmtuners.com/forums/maintenance-repairs/385834-compression-results-hg.html which is information from DSM factory service manuals:

From the VFAQ:

1G (90-94) T/E/L 1.8L NT engine
Compression ratio 9.0:1
Standard compression 185 psi
Service limit 131 psi

1G (90-94) T/E/L 2.0L NT engine
Compression ratio 9.0:1
Standard compression 192 psi
Service limit 145 psi

1G (90-94) T/E/L 2.0L Turbo engine
Compression ratio 7.8:1
Standard compression 164 psi
Service limit 121 psi

2G (95-99) T/E 2.0L NT 420A engine
Compression ratio 9.8:1
Standard compression 170-225 psi
Service limit 100 psi

2G (95-99) T/E 2.0L 4G63 Turbo engine
Compression ratio 8.5:1
Standard compression 178 psi
Service limit 133 psi

2G (95-99) T/E 2.4L NT Spyder engine
Compression ratio 9.5:1
Standard compression 192 psi
Service limit 146 psi

Hope this helps!

There is also a service limit for maximum allowable pressure difference (MAPD) between any two cylinders. For all engines except the 420A, the MAPD between any two cylinders is 14 psi. The 420A is allowed a 25% difference between cylinders.

 

[eclipsekid1013]

im going to test the numbers right now ill post them when i get them