[harkes]

Hi

I decided to do a Blackstone test as I have been driving JB4 + methanol and upgraded turbo for the last 35000km and done hundreds of +20psi pulls.

Happy to see that the engine oil is doing a very good job of keeping my engine healthy Next step is a compression test.

How to read the report: http://www.blackstone-labs.com/report-explanation.php

[paimon.soror]

numbers are looking great! I suspect that your compression numbers will be strong. Not much fuel mixing with the oil and whatever is in there is just the nature of direct injection. The lack of coolant mixing with the oil is a good sign .... we know how older bmws loved to consume gaskets like sweet chocolate

[harkes]

Originally Posted by paimon.soror

numbers are looking great! I suspect that your compression numbers will be strong. Not much fuel mixing with the oil and whatever is in there is just the nature of direct injection. The lack of coolant mixing with the oil is a good sign .... we know how older bmws loved to consume gaskets like sweet chocolate

Yes, I am extremely happy with the result. The N55, treated well, looks to provide many years of entertainment

[enjoythemusic]

That's great, thx for sharing! Also why many of us love the n55.

[harkes]

As a part of my 75000km health inspection I also tested compression. Dont know what it is supposwed to be but all 6 read 195psi

[paimon.soror]

Anywhere between 10 bar to 16 bar (145psi - 232psi) w/ minimal deviation between cylinders. Take into account if your are high in the mountains or deep in the valley.


https://www.newtis.info/tisv2/a/en/f...neral/Am0RHXdG

[Polo08816]

Have you head your transmission replaced?

[harkes]

Originally Posted by paimon.soror

Anywhere between 10 bar to 16 bar (145psi - 232psi) w/ minimal deviation between cylinders. Take into account if your are high in the mountains or deep in the valley.


https://www.newtis.info/tisv2/a/en/f...neral/Am0RHXdG

This was at sea level. 145-232 is a huge margin!!! And <30psi variance is considered "ok"... Is it because it's a turbo engine that such high margins can be accepted?
My NSX C30B engine (100.000km) read 180psi and interestingly has the exact same CR as the N55 of 10.2. Still making 290 crank hp though. There should be a direct relationship between CR and compression pressure taking blow by out of the equation right? The B16B with 10.8 CR should make somewhere around 240psi.

[paimon.soror]

def a huge margin. Even on this site ive been seeing people here saying 170 is strong.

Fwiw, typically 5-7psi is acceptable as a variance between cylinders in general.

Either way i'd say you are looking quite fantastic with your engine

[harkes]

Originally Posted by Polo08816

Have you head your transmission replaced?

No transmission is still holding up and works beautifully with rattle and everything. I will probably pull it in a few weeks to see what we can find

[ChristosD]

im looking at using motul xcess 5w40 how has your experience beeen with it?

[harkes]

Originally Posted by ChristosD

im looking at using motul xcess 5w40 how has your experience beeen with it?

Still using it. Changed oil after 11000km last week so will send another sample to Balckstone. I added two liters during that time which I am perfectly happy with as the N55 burn oil exponentially to your loud pedal usage. Rather top up the oil than change bearings

[Zanity]

Originally Posted by harkes

No transmission is still holding up and works beautifully with rattle and everything. I will probably pull it in a few weeks to see what we can find

Did you eventually fix the ZF8 rattle ? I'm curious of the result and cause.

P.S: I grew up in Canada, but I was born in Fuzhou, your neighboring city =) I was just in Xiamen Gu Lang Yu island for my wedding photos haha.

[harkes]

Originally Posted by Zanity

Did you eventually fix the ZF8 rattle ? I'm curious of the result and cause.

P.S: I grew up in Canada, but I was born in Fuzhou, your neighboring city =) I was just in Xiamen Gu Lang Yu island for my wedding photos haha.

Yes the ZF rattle got fixed adding a whole liter of oil extra. I dont understand what went wrong during the oil change as we were very meticulous with the trans temp and running the whole cycle pr ZF instructions. Anyway the gearbox survived almost a whole year of punishment on low oil level so maybe not as sensitive as I heard.

Fuzhou is lovely. Great lake and old city area

[ChristosD]

Originally Posted by harkes

Still using it. Changed oil after 11000km last week so will send another sample to Balckstone. I added two liters during that time which I am perfectly happy with as the N55 burn oil exponentially to your loud pedal usage. Rather top up the oil than change bearings

that is very good news. I'm definitely interested to see that latest report after 11000km

[Zanity]

Originally Posted by harkes

Yes the ZF rattle got fixed adding a whole liter of oil extra. I dont understand what went wrong during the oil change as we were very meticulous with the trans temp and running the whole cycle pr ZF instructions. Anyway the gearbox survived almost a whole year of punishment on low oil level so maybe not as sensitive as I heard.

Fuzhou is lovely. Great lake and old city area

wow, i'm glad to see our ZF8 is this robust!