its not important, but when its cheaper and better to use, im happy.

you have carbon buildup on the rotor taht you used synthetic in because synthetic is not supposed to burn, the only reason why synthetic is not recommended for rotary is because we have oil injection that takes the oil straight out of the oil pan.



i think taking closer pics of the bearings might be a better comparison of synth and mineral oils.



you can also get a lot of carbon buildup on the rotors due to to much fuel

joe.. if you're still using the stock oil metering pump, go back to mineral, just like you planned... if you plan on taking off the oil metering pump or setting up a remote oil resevoir for your omp... then go with the synth.



we had a fairly detailed discussion about this when dragon, goodfellas and a few other were at my house.

pimps own 20b grey fds... but don't actually drive them.

Hahaha $6 a lot?! The Motul Oil I am about to order is $25 for 2L!

Aiee karumba!



And Fikse got to it before me, the difference in those rotors can definitely be due to AFR's and Fuel rather than just the oil type used..eh?

agreed on the a/r , the 13b re on synthetic was using a stock pcm so what ever that amounts to , no wide band was used on that one. the 90 t2 aka the clean rotors and good bearings as well did have a wide band on it , last time i had it on he road was runnin a 13.7-15.9 cruzing and under full load i was runnin a rather rich 9.8,,,,,,,, the car wasnt fully tuned and fell on its face seriously bad.

now im not doggin synthetic as i run mobil 1 in my durango and all my piston vehicals i have owned in the past. im just stating what i have found in the engines i have had and from what i have seen between my stuff and the many freinds i have who run the vr-1. we will never go back to anything other then valvoline vr-1.

Regarding eternal synthetic vs. non-synthetic question:



https://www.nopistons.com/forums/index.php?...76&hl=synthetic



https://www.nopistons.com/forums/index.php?...19&hl=synthetic



https://www.nopistons.com/forums/index.php?...17&hl=synthetic



FWIW, I searched a ton of threads here and on "the evil forum" and chose to go with Mobil 1 synthetic. Better heat tolerance, low ash (will burn just fine) and the best shear strength...IMO, especially important if you deal with fuel dilution between oil changes. I'm running the OMP but also put in about 4 oz. of MMO with each tank of gas.

But irregardless of the type of oil used, vertually everyone agreed that the most important factor was changing you oil regularly (generally 2.5 to 3k miles) with a quality filter.



Regarding the rotors pictured above, seems to me that there are just too many other variables to blame the carbon build-up on synthetic. AFR being just one. But everything from the heat range of the plugs, to the number of miles between oil changes or a combination of several other factors could also account for it. Just my .02. https://www.nopistons.com/forums/pub...>/bigthumb.gif



Jim

yea i just changed out the synth today for 20w50 Vavo VR1 like fc boy said

what do you think of the green color of that ****? anyways i think you will be happy with that.

I didn't really notice the green colour but my oil pressure has gone up by about 20 PSI on the stock guage, now reading around 100 PSI at higher RPM levels and a heavy load.





I mean its kinda hard to tell if the oil is making any difference but I will say that I swapped in all BUR9EQPs and took out the 7s and it runs a lot better especially at idle. No more spark breakup really, just the usual blips here and there. Also, morning startup is better as well.