Im worried my compression is bad what are your guys opinion? Warmed up dry

Cylinders
1= 125
2= 125
3= 125
4= 125

5= 125
6=115
7=115
8= 100

 

Yes, very low. More than low the obvious problem is the big difference between the majority of cylinders and especially #8.

By warmed up I assume that it runs. Did you have the throttle plate propped open for the test? Any other signs of a blown head gasket? Water in oil? White or blue smoke out the exhaust?

 

From what i understand the xkr does not have as high compression as xk8 correct me if im wrong annd throttle body was closed no smoke from the exhaust no bubbles from the coolant.. 116000 milles

 

The throttle plate needs to be open to get an accurate compression reading. With it closed you are just sucking a tiny bit of air of idle significantly lowering the readings without a very extended crank time.

 

While 8 is not great i would not be that worried, squirt a little oil in cylinders and retest. That can be a little carbon deposits on valves and or ring lands. If the compression get so off that it affects the acceleration speed the ecm is looking for at idle or above that is one of the things it will throw a misfire for code for that cylinder

 

Agreed with Brutal.

 

Was there a reason for doing the check in the first place?