JerryLH3

So, I am likely to be an RX-8 owner soon. I've had two different FCs over the course of the past 23 years, so rotary life is nothing new to me, but owning an RX-8 would.

I have a tentative deal in place to purchase a car next month and I had asked if by chance they had compression test numbers. They did have a test done back in June when the car would not start due to a dead battery.

Front rotor, 870 870, 890 kPa @ 290 RPM. Normalizes to 817, 817, and 837 kPa or 119, 119, and 121 psi. Sounds perfectly healthy to me.
Rear rotor, 990, 1000, 1010 kPa @ 299 RPM. Normalizes to 916, 923, and 929 kPa or 133, 134, and 135 psi.

The rear rotor is decent bit higher and certainly among the higher numbers I've seen for a 13B-MSP engine. Of course, reporting of test numbers is biased to when there is an issue, not when you have a presumably healthy car. I thought I'd throw it out there to see if anyone thinks they have ever seen numbers that were high on an engine that had a problem. Owners report no issues with this car and it has less than 20k miles.

Am I overthinking this and I need to just go buy it and be happy?

Loki

iTrader: (1)

Sounds pretty good and if it's 20k original Mazda-built miles, it's not crazy. Unusual, but not impossible. Do they premix? If there's extra oil present it could close what small leaks may be present in the sealing surfaces.

If you trust the test was properly done (like, are these warm or cold numbers?), I'd say that's good enough to pull the trigger.
Nice find!

JerryLH3

I trust the test, it was done at a Mazda dealer and the tech noted that it was warmed up and then tested.

neit_jnf

hot or cold?
cold test numbers are usually higher

JerryLH3

It was a hot test.