Ive heard alot of scary stuff about the Renesis engine, and want to make sure I take care of it. Last (and only) owner had 60k miles with no issues on the engine.

To my understanding, premixing is just funneling in 1/2 an ounce of 2 stroke oil per every gallon, putting it in the gas tank after your done fueling the gas. Is this correct? Want to protect the engine and make sure im doing this right.



Attached above is the bottle of 2-Stroke I bought, Want to make sure this is fine to use

 

i wouldnt use that 2 stroke, most will suggest idmitsu premix. i dont measure it and just dump ~8oz per tank. or install a sohn adapter and keep it topped off

 

does the sohn adapter automatically premix

 

the oil metering pump no longer pulls from engine oil and is a separate tank for premix

SPECS

 

Don't use any ole 2-stroke oil, many leave ash and deposits. Chainsaw and jetski oils are typically not a fit. Look for the JASO FD rating (which yours has, but I'm still skeptical it's ideal). The rating has to do with how cleanly it burns. Snowmobile and motorcycle oils are more likely to have it. You mix 200:1 or so, so 50L of fuel, 0.25L of oil (1cup). Lucas synthetic 2-stroke is a good balance of price, availability and deposit forming qualities.

Sohn adapter serves a different purpose, you can premix AND run a Sohn.

 

Many will disagree, but I say 2oz per gallon. Anything less is a marginal level of protection with most oils especially with OMP at stock setting. That’s still a very low ratio, it’s not going to “carbon up” or “kill your cat”, or any other argument against.

Put oil in tank before filling, not after.

 

I'm not against premixing, let me start there. I also believe that there is no harm in premixing and if I were running a catless exhaust, I might consider premixing. As long as I have owned RX-8's (2008), I have not premixed and I do not premix any of my RX-7's. Their OMP and oil injectors work great and we see zero issues on the early 13B and zero issues whatsoever on 12A cars. My 1980 RX-7 had the 12A and has never been premixed. The engine isboriginal and the compression is more than 100psi on each face on both rotors and the car has almost 120k miles on it. I have had zero issues from not premixing my RX-8 as well. I do not plan on starting to premix. One of the reasons that I don't is because the RX-8 that I drive regularly is all stock and depending on the premix ratio, premixing can damage your catalytic converter over time. On this particular car, I prefer to keep the converter and keep the car quiet. On my Nordic Green RX-8, I have a midpipe that has a hollow cat. On this particular car, I would not hesitate to premix and keep it at 1/2 ounce of premix per gallon of gas put into the tank. Again, no converter, no issues to worry about. If I were to premix, I would definitely go with the Sohn OMP adapter and separate tank. May as well put in clean oil and give the engine the best quality oil available. With this system, I feel its much easier to monitor the amount of oil going in and know what you have available.

 

Unfortunately there is a lot of lore that 2t oil will foul cats. It wont, even at ratios nobody would even consider for car use. 2 stroke oil is several magnitudes less damaging to cats than the 4 stroke oil the factory OMP injects.

The earlier RX had decent OMP rates, there is really no valid comparison. The RX8 has the lowest OMP output but the highest power output except for the FD. But it is very high at full throttle/high rpm, approaching 30:1. Normal driving is what kills these engines quicker, normal driving at highway speeds has the OMP on the stock map at settings of 3 or 5 out of a possible 60. This produces a ratio of somewhere more than 300:1, a ridiculous number, not suitable for more than idle speed, and even then there is no residual oil reserve for throttle opening and power increase. There is no way that high a ratio (of inferior, dirty 4t oil, no less) will protect an engine making 1/4 of rated horsepower going 65-70 mph.

Every and all RX8 teardowns with factory oil regimes show wear to housings that have the classic and uncontestable signs of oil starvation and inadequate lubrication, and poor cooling of apex and side seals and springs.

Also, the RX8 could be as long lived as the FB and FC cars, with 250-300k miles before meaningful compression loss sets in. We put up with short life here, needlessly, in my opinion.

OP has a relatively low mileage car, and wants to preserve it. I say oil it up, and you will preserve what you have.

 

I have contributions, not as a renesis expert, but as a former lube shop manager. As long as your premix oil has the right certifications for combustion, your cat should be fine. Obviously oil made for yard tools etc. doesn't because those are two-stroke, single cylinder engines. Most of the lubricants people have mentioned should be safe for your cat, even when used as a premix. What isn't are the additives manufacturers put in the oil that they don't always list or fully describe. Like the Poulan (which I use all the time for other equipment) will say on the back "formula to reduce friction" yadda yadda yadda. Those additives are specific to each kind of lubricant and the engine type they are made for. In an engine at different compression or temperature, they can either burn or ionize and coat the inside of the engine. That will make your exhaust ports eventually clog up and your vehicle will start to vapor cycle, where it doesn't fully combust, then the cat tries to cycle it back in and it gets worse. Problem is worse in rotary engines, as many topics here describe.

The TL;DR is if you don't want to use the expensive oils recommended specifically, you need to use something that is for high compression engines like a car. So the additives won't burn. So snowmobiles and jet ski oils are good alternatives. Synthetic oils in general don't burn at the range of normal engines. They can still have things like teflon particle additives that are not helpful, but none of them should actually burn.

The car I just bought has totally open exhaust, so I can basically put whatever I want in there and just flush it all out with some airplane fuel every once in a while. Which I haven't seen mentioned here, but I may have missed it. For any rotary I've worked on, this works pretty well assuming your cooling is adequate and you do not have a cat. Go to the airport and get the 125 octane airplane fuel and buy just a small jug of one of the expensive premixes. Then give it just a gallon of the fuel and a generous 2-3 ounces of the oil. Let it warm up and rip it hard as hell. Everything unholy should come right out without harming the engine.