your choice of 5w20 conventional

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donnyj08

donnyj08

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what would be your choice for a conventional oil for my rx8? Mazda specs 5w20 conventional and the manual recommends against synthetic in the rotary.

since this engine injects a little oil into the combustion cycle all the time the "best" oil in theory would be and oil that burns clean, leaving little residue.

i was thinking of using MS5K as i love that oil, or VWB/Nexgen.

also considering using Idemitsu rotary premix in the fuel.

Im changing the plugs/wires/coils this week as the car is nearing the 30k mile mark.
 
Right now the MS5K is the best deal ($12.97 for the 5 qt. jug at WM). If price weren't a concern, I'd use PYB.
Both are great oils..
 
Originally Posted By: pbm
Right now the MS5K is the best deal ($12.97 for the 5 qt. jug at WM). If price weren't a concern, I'd use PYB.
Both are great oils..

Agree. As a third option, what about Chevron Supreme/Havoline?
 
Do you have a Menards near you? The Formula Shell you're currently using is on sale for $1.99/quart, plus an 11% store credit with their rebate.
 
MS5K.
thumbsup2.gif
 
Originally Posted By: donnyj08
Ms5k is my first choice as well, I will probably go with that.

What are your thoughts on premix in the gas for the rotary?

That so reminds me of when I was racing motocross. Pre-mixed gas/oil through a reed valve. I bet the spark plugs provide some major spark to fire such a mixture in your engine.
 
BlueOval, the Rotary loves a bit of TC-W3 rated 2-t oil in the gas.

FWIW my Honda Fit loves it too.

Just use 1oz. per 5 gal.

Adding TC-W3 to gas for 4 stroke engines is a BITOG favorite UCL and cleaner.

No harm in using it at the above mentioned amounts.
 
Originally Posted By: Falken
BlueOval, the Rotary loves a bit of TC-W3 rated 2-t oil in the gas.

FWIW my Honda Fit loves it too.

Just use 1oz. per 5 gal.

Adding TC-W3 to gas for 4 stroke engines is a BITOG favorite UCL and cleaner.

No harm in using it at the above mentioned amounts.

Honda also has a rotary type engine?
And, this additive, is it a MUST at every gas fill? I would like to learn more about this.
smile.gif
 
Originally Posted By: hardcore302
Formula Shell, which I see is your current fill. What about Valvoline White Bottle.


+1 Valvoline White Bottle.
 
No, the Fit is just a little 4 banger 1.5 L SOHC i-vtec.

It is a smooth high-revving engine that gives 117 hp at 4+ grand so it is high-strung and I don't mind the idea of keeping the rings well lubricated in the top end.

A bit of UCL smooths out the idle, but there are many cleaners and fuel stabilizers in 2t engine oil.

People use TC-W3 rated 2-t engine oil to increase the sealing properties of the apex seals in the Rotary. It helps with ring seal in every engine though. And reduce friction.

A main reason people feel they want to use a UCL is to counter the ethanol in gas, as it removes lubricity from your top ring.

It also helps control hard carbon deposits.

This is the site that started it all:

http://www.ls1.com/forums/f48/been-testing-oil-91206/

Try it out! See how you like it!
 
Choose an oil with the least concentration of VII polymers, highest NOACK and highest HTHS. 5w20 mineral oils are not an ideal choice.

donny, you have a nice newer low mileage rotary, don't screw it up with the 'no-brain' CAFE recommendation - one of the major downfalls of the rotary is that people, including service managers, head office jockeys, think they understand the engine much better than they actually do.

Since you will most likely run the mineral 5w20, I'd put in another solid rec. for the premix.
 
PYB, Valvoline or MS5k all should do very well. I'd lean towards the PYB for it's high detergents and moly.
 
Originally Posted By: jrustles
Choose an oil with the least concentration of VII polymers, highest NOACK and highest HTHS. 5w20 mineral oils are not an ideal choice.

donny, you have a nice newer low mileage rotary, don't screw it up with the 'no-brain' CAFE recommendation - one of the major downfalls of the rotary is that people, including service managers, head office jockeys, think they understand the engine much better than they actually do.

Since you will most likely run the mineral 5w20, I'd put in another solid rec. for the premix.


What do you recommend? Also how does a tc-w3 compare to idemitsu rotary premix? Am I better off to use tv-w3 from Walmart or the specialty mix? I've heard marine 2 cycle oils are not great under high heat
 
I have never even driven a rotary engine but any conventional 5W20 with current specs would perform the same as any other.

Then it comes down to price and brand preference. Also if you want to use "synthetic" oils, this has been discussed before on here.
 
Is it ok to use synthetic? I know a lot of guys use RP. The manual says to not use synthetic, and feelings seem very mixed on the synthetic/conventional debate about the rotary.

I normally use "synthetic"oils. Mostly gp III,s. but I thought maybe it was safest just to follow mazdas instructions.
 
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