which oil is good to use?
11-19-08, 07:51 PM
#1
which oil is good to use?
so i read the mazdatrix page about synthetics vs conventional, but i remember seeing or being told that royal purp was good to use as well.
so, should i just forfit and buy the idemitsu oil? or continue the royalty?
so, should i just forfit and buy the idemitsu oil? or continue the royalty?
11-19-08, 10:19 PM
#4
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For street use a good dino oil is fine. For severe service than step up to synthetics. N/A rotaries are very easy on oil. The turbo cars seem to suffer from fuel dilution where frequent oil changes become real important.
11-20-08, 09:21 AM
#6
Engine, Not Motor
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Much of the oil information out there is outdated. Mazda originally said no to synthetics because some of the early synthetics didn't burn cleanly. Now, most of them are fine so you can run whatever you want.
I'll put it this way though: I run 20-50 of whatever oil is on sale when I need it.
I'll put it this way though: I run 20-50 of whatever oil is on sale when I need it.
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11-20-08, 12:54 PM
#8
Former Moderator. RIP Icemark.
Depends on the temperatures in your area.
In starting and operating temperatures below 20F, use 5W30
In starting and operating temperatures between 0F and 80F, use 10W30.
In starting and operating temperatures above 30F, use 20W50
As far as brand any good quality oil that meets the API SL or SM standards (or better) should be fine.
In my area, I see winter temps in the low 30's when starting in the morning, so I use 10W30 in my FC in the winter, but in summer I only use 20W50. because I never see temps below the 50's when starting.
Using the correct thickness will ensure long bearing life. Too thin and you wear though the main bearings as well as loose shear strength.
In starting and operating temperatures below 20F, use 5W30
In starting and operating temperatures between 0F and 80F, use 10W30.
In starting and operating temperatures above 30F, use 20W50
As far as brand any good quality oil that meets the API SL or SM standards (or better) should be fine.
In my area, I see winter temps in the low 30's when starting in the morning, so I use 10W30 in my FC in the winter, but in summer I only use 20W50. because I never see temps below the 50's when starting.
Using the correct thickness will ensure long bearing life. Too thin and you wear though the main bearings as well as loose shear strength.
11-20-08, 02:04 PM
#9
Engine, Not Motor
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I don't drive my car in the winter. A 400+ HP bridgeported FC isn't a very good winter car, and I don't want to watch the salt destroy my hard work.
That said, when I did drive RX-7s in the winter, I always ran 10W-30. You can get away with 10W-30 in the summer in NA cars, I just have not done it for a while and as Icemark posted, Mazda recommends 20W-50.
That said, when I did drive RX-7s in the winter, I always ran 10W-30. You can get away with 10W-30 in the summer in NA cars, I just have not done it for a while and as Icemark posted, Mazda recommends 20W-50.
11-20-08, 10:10 PM
#14
Former Moderator. RIP Icemark.
There is nothing wrong with using a good quality synthetic oil in a rotary engine. Its the crappy ones like Vavoline with its near 2 % ash that should not be used.
11-20-08, 10:17 PM
#15
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royal purple is good.
but i mean who can afford it, plus i mean correct me if im wrong but unless you are premixing then you probably want to stick to conventionals since byproducts left behind by combustion of synthetics might not be very good for your seals, especially if it doesn't burn away and would seemingly just keep building up over time. but that is just my opinion based from my semi-educated mind...hehe 
11-20-08, 10:26 PM
#16
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Personal preference, although some "synthetics" aren't really what they claim. I believe Valvoline is in that boat.
I'll be going with RP or AMSoil... just so you know ;D
I'll be going with RP or AMSoil... just so you know ;D
convetional
synthetic oil
11-23-08, 07:59 PM
#24
Former Moderator. RIP Icemark.
but i mean who can afford it, plus i mean correct me if im wrong but unless you are premixing then you probably want to stick to conventionals since byproducts left behind by combustion of synthetics might not be very good for your seals, especially if it doesn't burn away and would seemingly just keep building up over time. but that is just my opinion based from my semi-educated mind...hehe
#1 Most synthetics burn at or under 500F... considerably lower than what the combustion cycle in a rotary motor is (in fact not unusual to see exhaust temps 3 times 500F).
#2 Most synthetics burn cleaner with less ash, and leftovers than almost all conventional oils. Yes there are a few exceptions, Vavoline and Havoline synthetics have a higher than average ash ratio (what is left after burning the oil) but even in those it is typically less than 1.5 percent. Some like Redline and Amsoil have a less than .5 percent ash ratio. As a comparison, Castrol GTX (probably the most popular oil used on this board) has an ash ratio of about .8 percent.
In conventional oils higher in viscosity additives (such as most 10W40 oils and 5W30 oils) will have a higher ash ratio than oils that have less additives (such as 10W30 or 20W50), however some synthetic oils (Mobil1 for example) have 0 additives for viscosity, again leading to a cleaner engine with less combustion build up.
So actually better for your apex and side seals to use most synthetics...
The only reason not to use a synthetic oil in a rotary is cost. There is no other reason. If you can't afford it, don't use it, other wise a good quality synthetic will be better for your motor in the long run.
Other notes:
The Mazda Factory racing departments recommend and used synthetic oils including the winning 1991 Leman’s 20-G 4 rotor Mazda 787B.
MazdaComp USA printed manual (now Mazdaspeed) recommends the use of synthetic oils for racing conditions.
Redline, Amsoil and Royal Purple Synthetic Motor Oils have been used in rotary engines (both race and street) for twenty plus years with excellent results.
The Speedsource 2 rotor and 3 rotor RX-8 race cars that have won their class in the Daytona 24 hours, 4 out of the last 5 years using Castrol Syntec.
