Compression Ratio
No, because there isn't one...................
A compression test has too many "tester" variables for the manufacturer or anyone else to put out a specific number.
Engine temp
battery charge(starter motor speed)
intake open or closed
Gauge
all spark plugs removed(changes starter speed)
On any vehicle with a gas engine you should expect 150 to 180psi
But the point of a compression test is to test all cylinders at the same time, so variables are all the same, and then compare the numbers, they should all be within 10% of each other.
Higher compression is not always good, could be carbon build up.
Lower compression 120psi and down is never good.
3.0l has a 9.3:1 ratio, this is about the top for using regular gasoline, 87 octane, 3.0l like the 2.3l(9.2:1 and 9.4:1) would start pinging if fuel mix or EGR system was not perfect.
All that being said a new 3.0l should show about 175psi with perfect test parameters
A compression test has too many "tester" variables for the manufacturer or anyone else to put out a specific number.
Engine temp
battery charge(starter motor speed)
intake open or closed
Gauge
all spark plugs removed(changes starter speed)
On any vehicle with a gas engine you should expect 150 to 180psi
But the point of a compression test is to test all cylinders at the same time, so variables are all the same, and then compare the numbers, they should all be within 10% of each other.
Higher compression is not always good, could be carbon build up.
Lower compression 120psi and down is never good.
3.0l has a 9.3:1 ratio, this is about the top for using regular gasoline, 87 octane, 3.0l like the 2.3l(9.2:1 and 9.4:1) would start pinging if fuel mix or EGR system was not perfect.
All that being said a new 3.0l should show about 175psi with perfect test parameters
Last edited by RonD; May 6, 2014 at 10:00 PM.
Thread
Thread Starter
Forum
Replies
Last Post
