Ok.. I did a compression test today.. My motor has 200K miles. I've been boosting about 4psi for about 4 months. These are the results:

cylinder1= 175
cylinder2= 155
cylinder3= 155
cylinder4= 160
cylinder5= 160
cylinder6= 160

According to spec Normal compression is 185 and the min is 142. I've notice that cylinder 1 seems to have the best compression.. Cylinder 2 and 3 seems a bit week. Hopefully the motor may last me another 100k while boosted...


Any recommendations..

 

What process did you take to do the test?

Did you have the engine warmed up? Did you mash in the gas pedal? Did you do each cylinder about 3 times? Etc....

 

Yes.. The engine was well warmed before the test was conducted.

Step1 - I disconnected all the ignition connectors from all 6 coils..
Step2 - I started with the first cylinder, by removing the spark plug.
Step3 - I inserted compression tester in cylinder #1.
Step4 - I then started the car just by turning the ingition to engine start.

Note: I did not mash the gas pedel.

Step5 - I repeated steps 2-4 on cylinders 2-6. Each cylinder was tested 3 times.

I was'nt aware, you needed to mash the gas pedal while testing compression..

Hope this helps.

 

There are many different opinions on doing compression. Some say remove all plugs, some say mash the gas, some say do this, do that. But in the end what you did was fine as well.

But one thing, you engine wont last another 100k boosted. Gaurantee you that. Why? Compression is already lower than normal and max difference between compressions should not be more than 15psi. You got a 20psi difference. Sign of things to get worse.

Dixit

 

Yeah that is correct.. I did see that indication in the manual. And my difference is 20psi. Looks like I need to startd building a second motor from the ground up. Luckily our motors are dirt cheap. Thanks for the feedback.

 

Just make sure you do it the same way every time, and you'll be fine.

Agreed.