RX8 Sixth oil sample

[compaddict]

2004 Mazda RX-8

Oil OEM Redline Redline Redline Redline
5w20 5w20 5w20 5w20 5w20 5w20
Oil added 0 0 0 0 0 0
Miles on Oil 1250 1764 1500 1500 3000 4000
Miles on Unit 1250 3014 4520 6067 9166 13221
Date 12-13-03 12-30-03 02-09-04 03-24-04 06-04-04 08-30-04

Aluminum 9 5 5 10 6 6
Chromium 4 5 6 5 6 7
Iron 30 30 33 29 29 35
Copper 18 22 15 10 7 6
Lead 1 2 0 3 3 5
Tin 0 1 4 0 1 1
Moly 480 471 578 599 586 556
Nickel 1 1 1 1 1 1
Manganese 0 1 1 1 0 0
Silver 0 0 0 0 0 0
Titanium 0 0 0 0 0 0
Potassium 0 2 5 4 3 2
Boron 137 71 37 24 17 8
Silicon 42 28 21 17 15 15
Sodium 8 15 18 20 20 22
Calcium 1724 2421 2565 2841 2906 3394
Magnesium 5 6 7 6 6 6
Phosphorous 850 1015 1084 1077 1091 1222
Zinc 884 1236 1165 1236 1362 1371
Barium 1 1 0 0 0 0

SUS Vis@210C 50.3 50.9 53.4 54.1 54.4 58.5
Flashpoint F 335 325 340 370 395 400
Fuel 1.5% 1.5% 1.3% .5 .5 .5
Antifreeze 0 0 0 0 0 0
Water 0.0 0.0 0.0 0.0 0.0 0.0
Insolubles 0.2 0.3 0.4 0.4 0.3 0.2

 

[molechaser]

Interesting that the wear metals for the most part stay at about the same level with the longer interval. Lead wear looks to be roughly 1 ppm/1000 miles similar to mine.

I'm surprised that you could go a 4000 mile interval with no make-up oil. My car is using about a qt per 2000 miles and I top off whenever it is about a half quart low. May be part of the reason that my wear numbers are a bit lower. Also, I suspect that you drive a lot harder than I do

.

I should have a 4000 mile interval report posted in a month or two for comparison. If the 4000 mile analysis looks OK I plan to extend the interval to 5000 miles.

 

[compaddict]

How is your fuel dilution?

Vince

 

[supraturbo]

Correct me if i'm wrong but isn't it a big NO NO to run synthetic in a rotary engine. I know it was with the 13B. Also I would be concerned if you did not burn any oil, there supposed to burn 1 qt every 2k miles by design, I believe the redline is preventing this from happening, which is not good.

 

[zoomzoom]

I would check with mazda before running syn oil in rotary. previuos gen. of rotaries didn't like it...

 

[Mickey_M]

quote:

---

Originally posted by molechaser:
There is no official prohibition on using synthetic oil in the RX-8. Mazda just says to use SL GF-3 5W-20 oil, period. It sure hasn't stopped there from being plenty of debate on the topic

---

There is no current prohibition on using synthetic
motor oil in the Mazda rotary.

There was a clear warranty-voiding prohibition in the past, and it was based on actual experience with synthetics no longer made.

 

[molechaser]

There is no official prohibition on using synthetic oil in the RX-8. Mazda just says to use SL GF-3 5W-20 oil, period. It sure hasn't stopped there from being plenty of debate on the topic

.

Use of synthetics is not likely to affect the oil consumption rate because oil consumption is mostly due to the metering pump that feeds oil through four injection nozzles to combustion chambers. As long as the viscosity is reasonable the metering pump doesn't care what it is pumping.

There are 1.8 quarts between the high and low marks on the oil dipstick so you can go quite a while without adding oil if you choose.

Vince.... on the fuel dilution front, my last analysis showed low dilution. It is not clear to me how Blackstone measures fuel dilution. Their number may be influenced by my change to 10W-30 oil.

 

[Idrinkmotoroil]

i see so few rotary engine comparisons it is hard to say what is happening. I would say chromium is very high but the engine has no piston rings so not sure how the engine design contributes to certain metals. I would also think iron is high but once again maybe the engine design causes this. Plus it is still very new and likely to break in for a while more.

The rest of the metals look to be pretty good for such a high revving motor. It would be nice to see a few more of these motors with UOA's.

 

[compaddict]

I'm also thinking that the data will be a little skewed by where the sample was taken (at the bottom of the pan or mid-stream).

Vince

 

[molechaser]

The high chromium and iron probably are inherent in the engine design. The inner surface of the rotor housings is chrome plated, and the side housings are cast iron.