I have a 2004 with no cat. Trying to wash off unburnt Interceptor oil off the bumper was a pain lol.

 

I'm too scared to delete the OMP. I would think extra oil can only be a good thing for the engine. I think the furthest Id go is a SOHN and even then I would still premix. I would think the oil helps cool the engine more than heat it up.

 

Its time to add this jewel to this thread, from Racing Beat. This amount of oil was added to the engine, in addition to OMP operation. Its about 75:1 ratio, plus whatever the OMP is delivering.

So, was the HP increase due to friction reduction, compression, lower octane, or some combination?

RX-8 - Race Tips

While undertaking development work on the RX-8 Renesis engine for SCCA T2/T3 use, we decided to introduce extra oil into the fuel to monitor the effect. To our surprise, this additional oil increased power! Further dyno testing found that by adding 10 oz. of Royal Purple 2-Stroke Oil to 6 gallons of fuel, we gained an average of 1.7 HP from 2000-9000 RPM, along with an increase in peak power of 4 HP. We validated this increase by changing back to a "non-oiled" fuel - and the power returned to the previous level. Later, we tried the same test with another brand of synthetic oil with nearly the same results.

For racing applications, the addition of a high quality synthetic oil increases power and most certainly decreases wear. The only negatives are the cost of the oil and an increase in the tendency to foul the spark plugs. (Note: We have not performed these tests on non-RX-8 engines yet, these results are unknown.)

 

I read that before on the racing beat site. Very curious as to why that worked one theory that was around in snowmobiles. Is it may have been leaning out the afr. So it was very common in two strokes to be able to drop a full jet size when going from 32:1 to 100:1 premix. The thought was that the gas would go through the orifice much faster than the thicker oil. So as you decreased oil the fuel would be allowed to flow faster through the jet.
Maybe this is the opposite. If the oil is thinking I g the fuel. It may be delivered at a slower rate that straight gas. This leaning the mixture a bit. Lean will create more power. Would be interesting to see what the data along with the dyno runs.

 

The oil is diluted in the gas, I don't see how it could separate out and be injected slower or faster. Also the volumes we're talking about are miniscule, 1:100 is 2.5 drops to a cup of gas. More likely, IMO, is the accumulated premix film provides better sealing, which then wears/washes off when switching back to unmixed gas. Remember the OMP oil will have difficulty climbing the side seals against centrifugal force to seal them properly.

Oil might burn hotter, I don't know, but it's also harder to ignite, so in the 1:32 scenario, I wouldn't be surprised if you're losing energy and power on burning the heavy premix fraction.

 

Loki you have valid points. The oil does not separate. The thought was that it thickens the oil and gas mixture. Not by a lot but by enough. But seemed to be enough to to make a difference. It seems like such a small amount but think how tiny a main jet is for a small engine. With a orifice the size of that even the smallest amount of difference could change. That’s why you could get away with a one size leaner. So while I think you are on to something with the more lube side of it. This may also be the causes granted not saying this is it your reason seems more plausible but depending on how the injectors are able to flow this may be the reason. You slightly lean out the afr from to rich and boom more power.
Also if you are wiping unburnt oil off your bumper you have to heavy of mixture. Might be worth backing it down till you notice it not happening.