Here's the build

-B20 bottom block bored and honed by machine shop to 84.5mm
-RS machine Pistons USDM ITR 84.5 mm with rings
-LS crank
-ACL Rod and Main bearings, (Plastigaged) to fit perfect
-ARP rod Bolts

-LS Head with ARP head studs
-Crower Stage 2 cams
-Crower dual valve springs/retainers
-Crower Titanium valves

-Compression Tested all stock internals was 190 across with complete LS motor.

-Compression Tested with built head listed above and stock LS bottom block 170 across

-Compression Tested with the complete build (built B20 and head) was 130 across all 4 PISTONS!!!

I'm really confused about why the compression is dropping, motor was TDC at the crank and at the cams. The car has basic bolt-ons, test pipe and mugen twin loop. I only made 145 hp and 130 tq with this build. i should be in the 160's hp and at 140 tq range but idk why my compression has dropped. The motor was assembled and DYNO tuned by ASP Located in Fresno CA.

 

simple. you either have the cams out of time, rings haven't seated or there are valve issues.

 

Cams were TDC with the crank... Sprockets were pointed the right direction. Pistons rings set already. did about 7 dyno pulls and about 3 weeks daily driving it. IDK how my valves could be bad. They are all 130 across from Cylinder 1 to Cylinder 4. If my Valves are bad than its once in a life time problem to have all valves bent the same to cause a Compression Ratio of 130 for every cylinder.

 

you try a wet test?
how about a leakdown?

 

Was the engine warm and was the test conducted at 100% throttle?