I was looking for anyone that had solid info on what the compression numbers should be for a IX? I saw a post a few days ago about a IX with 140 across all cylinders, so i did a compression check on my IX to see where mine were at and would like to find out the specs. I tried searching but only find numbers about the 8.

 

Should be identical to the VIII I think.

 

The service manual states 145 with a minimum of 92 and a variation of no more than 14 PSI. A bit different than the 163 of the VIII (138 min, variation is the same 14 PSI).

 

Wow, not what I was expecting!

 

yep my 9 was around 140psi in all cylinders, i was told thats normal

 

why the lower compression on the 9s?

 

Yeah... Why are the expected compression #s different for the IX?

 

compensation for larger turbo and mivec?

 

But both the 8 and the 9 have the same static compression ratio 8.8:1 and the same stroke geometry.

What could explain the difference?

 

Seems low to me too. But if the manual states that then I guess it is

Damn engines are getting efficient of something lol. Nothing compared to my 92 4G63.

 

The mivec accounts for the low compression when cranking. Mivec controls cam overlap. Obviously then the overlap is increased during cranking.

 

But doesnt a standard compression test just measure peak compression? It doesnt take overlap into its calculation. It is just a simple gauge that measures pressure.

EDIT: BTW, I am not doubting you 94AWD, just asking. Anyone that runs low 10s on pump gets my respect.

 

Then my motor is in good shape according to what you guys have said about the numbers.

 

the difference in the 9 is do to the longer durration and higher lift of the intake cam over a stock 8

 

Overlap has nothing to do with static compression testing, only intake valve closing does, which is controlled by mivec along with overlap. So yes, mivec (and the longer intake duration) could be a large source of the lower compression, if not all of it....