Hey guys, my mate got an Evo8 running at 25psi with everything stock except fuel pump,exhaust and very well ecu tunning(perfect AFratio)

Yet the turbo just lost the boost pressure 2 days ago on motorway no matter how hard we try, but can't find any leaks after that, turbo seems good but not sure if had any issue or not.

we tested the compression found that cylinder 1(front one near the TB) is lower than other three(about 15% lower) and upto 50% in leak down test while cylinder 2-4 were 0% at all. This is weird cause the idle is good and engine running smooth.

Any good idea? Thanks.

 

My motor is a MAP built motor with 5k on it. It runs & Idles good with no smoke. Cylinder 3 has a 7% loss by the ring and down 20lb on compression. I'm pulling the motor for a rebuild. Check your plug and injector. If they are black most likely its a ring. Oil getting by. Is that cylinder wet? If it is clean it could be in the head.