bluhayz

Hey, I'm thinking of doing a compression test but I won't have the gauge with me. You all have said it should sound like pst pst pst, but i have no idea what pst pst pst sounds like in an engine. So, I'm wondering if anybody could record the sound or something so I know what to listen for. Thank you.

totallimmortal

basicly your listening to hear if every pulse sounds the same, this method can't really tell you if you have good compression just if one apex seal is worse than the others

J-Rat

iTrader: (2)

Generally you will have 2 weak pulses and one strong pulse. Put your hand down there too and feel the pulse, it will help. (wow... that sounds kinda dirty)

SureShot

You can do a fair test just listening the the starter gear noise.
Pull the EGI fuse on an S4 or floor the throttle on an S5 to cut fuel.
Listen for firm steady evenly spaced compression surges in the gear noise.

Compare it with the sound of a known healthy rotary.

When I first was looking at my 91 turbo, I could hear the 10PSI compression difference between the front & rear rotors.
Every other gear noise surge was slightly lower.
Of the 6 compression cycles it takes to turn all rotor faces 1,3,5 were stronger than 2,4,6.