Hello everyone,

Recently I have purchased VersaTuner and have increased my OMP flow. Compare to other user's OMP setting, my output might have been too high.
I am running SOHN with Idemitsu in it.
I run catless.

Question:
Will too much oil cause any harm? Besides, I still run 7oz a tank of premix.
I know it might foul the plugs, o2 sensor.

The first picture is modified OMP table and the second picture is the stock OMP table.

 

I'm not going to say it is too much, but most people increase it by something like 25%. Some of your cells are increased by several hundred percent. Yeah, it's probably too much.

(The comparison would be much easier to make, if the Y axis lined up.)

 

My bad, I’ll redo the picture ASAP.

But could there be any actual harm except it might foul plugs and o2 sensors? Idemitsu should left very little carbon deposit.
IMO getting sufficient lubrication outruns the costs of replacing plugs and o2 sensors

 

While true, I feel like you're past the point of sufficient lubrication.

You don't need 3 times more oil in the typical cruise configuration of 4500rpm and 0.43 load, or 5 times more in some of the lower load regions. In fact, specifically in the lower load regions I wouldn't go crazy with the additional oil because you're not generating the temperatures and pressures needed for a clean burn.

Being catless means you can experiment if you want, see how long it lasts before you start to have oil contamination on plugs and sensors, but keep an eye on it.

This map reminds me a bit of MazdaManiac's (I think?) oil saturation map, to be used after you performed a decarb or on start up after a rebuild.

 

Interesting point.
One reason I am running a lot of oil is that my engine is at the edge of failing, which is 6.9@250RPM, I want to minimize blow-by by adding oil.

From what I can find Idemitsu premix oil has a flash point around 276.8f (136C), the fire point shouldn't be too much higher, so IMHO they should burn clean, but I am not an expert I can only make my best guess and check the plugs regularly.

I'll keep an eye on my plugs, they are pretty new, probably 2000miles max.

 

BTW, my compression is (Normalized to 250rpm). Idk why front rotor is so bad but the rear is like new??

Front rotor

700,680,700

7.1, 6.9,7.1


Rear rotor

764,744,764

7.8,7.6,7.8

 

You won’t minimize blowby by adding more oil. Your logic on this is not correct.

 

Thanks for the correction Team.
My initial thought is that since seals are wore, adding more oil can help sealing better and add more lubrication.
Still got a whole lot to learn, being to ideal.

 

It will just be in the blowby. It may help cranking compression some, but the much higher combustion pressure along with heat will negate it once the engine is operating at temperature. On a tight engine it might help sealing some. Once the engine reaches a significant blowby/low compression scenario the damage is done.

 

Zhang,

I take a different view than some here, as I feel more oil is almost universally better, since the injection rate on the Renesis is very very low from the factory. Team is right, a lot of your "extra" injected oil will end up in the oil pan, diluting your sump oil with extra injection oil that is blown by the oil seals. But, I believe some (enough) will stay in the chamber and provide benefit in better wear and chamber seal.

However, I believe more oil does increase compression both at low rpm (like in a compression test, which has been proven in both piston and rotary engines) and at higher rpm where it assists the seals. (Not proven, as far as I know.) In fact, I believe the compression increase from extra oil is actually greater at higher rpm, because the time "allowed" for potential leakage is less due to increased rpm. Yes, as Team states, the chamber pressure is much higher, which will serve to squeeze oil past the imperfections in the sealing surface faster than at low rpm and no load, and temperature decreases viscosity of the injected oil, and does burn a lot of it (not all) but the time interval is several orders of magnitude shorter, so it follows that if compression is higher at 250 rpm with extra oil, it will also be higher at 3, 4 or 5000 rpm, than without extra oil.

In 2 stroke piston engines, certain oils and different ratios will actually improve compression by a sizable, measurable amount over others, based on burn rate, viscosity, volatility, and a whole host of factors. This can be noted in better power, torque and throttle response, as well as in standard no-load compression tests.

My thoughts on this apply to increased oil rate using good 2 stroke oil, especially the newer smokeless low ash ISO and FD rated oils. I don't think there is much downside. as far as carbon buildup. Regular motor oil is another story, and the deposits from that stuff can be really nasty.

The low load map in a street Renesis is where the inadequate lubrication problems are, in my opinion. So I agree with increasing it A LOT. You might foul plugs eventually. But, probably not. Most of these engines fail from bad lubrication, NOT carbon buildup. There is evidence of inadequate lubrication even on heavily carboned up teardowns.

Racing Beat notes an increase in horsepower on an otherwise stock Renesis by running what many here might surmise is "too much" oil. (1.6oz per gallon or about 80:1, PLUS whatever the OMP was delivering at that time/condition, which even on the stock tables, is a large amount of oil at high load/high rpm.)

Was it from less friction, faster burn, (oil lowers octane rating), or better sealing? No proof as to the reason, as far as I know.

They note this is for racing applications, of course. (EPA?) (CARB?) But...

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.)

(Above in red is from racing Beat.)


Again , this is just my opinion, and I am sure others will chime in with opposing views.

I think this is a fascinating engine, flawed as delivered from the factory, and some experimentation by the enthusiast/owner is needed/desired/acceptable because of these flaws.

 

Hello Kevink, Thanks for the information
I felt the same way that Renesis are dying due to insufficient lubrication. But from what I found most oil diluting cases are found on FI engines. But I still will keep an eye on my oil dipstick.





Yeah I am running Idemutsu premix oil which is a JASO-FC grade, which I believe should burn very clean

That's also my concern, I used to run stock map without Sohn adapter but I do premix, I kept my RPM high, regular oil change etc, but it still almost fails the compression test after only about 40k miles. Additionally, from my reading I also find that engines that fed with 2 stroke oil have softer carbon deposit, which made me believe that the extra oil also serves as a detergent. Although I have risk of fouling my plugs, a set of plugs will cost me around $85 only. Where a new engine..... I do not have he money for rebuild, and I am still a college student, the best I can do is to spend a bit more on oil, plugs etc, and save my engine.

In the "New and potential owner starts here thread", RIWWP says something like if you believe that the compression is too high, there might be excessive oil left in the combustion chamber.


Again , this is just my opinion, and I am sure others will chime in with opposing views.

Quote:

Originally Posted by kevink0000

I think this is a fascinating engine, flawed as delivered from the factory, and some experimentation by the enthusiast/owner is needed/desired/acceptable because of these flaws.

I can not agree more, this engine is designed to pass EMISSION and whatever fuel consumption requirement, without such regulation.....
Sorry I started day-dreaming again.

 

The RB results are exactly what I was saying regarding a new tight engine (that’s back from around 13 or 14 years ago btw) . I never said not to use any, just that once you get past a certain amount of blowby it isn’t going to stop that really. I don’t think anyone can say what the long term affect is on a street car dumping a bunch of oil on a weak engine either. A lot of wile e coyote geniuses came and went over my 14+ years here with their hare-brained ideas and magic elixir potions ... beep-beep :-p

 

I use only ACME products, btw.

 

Old thread revival. Here's some compression test results. Raw data and normalized data are both provided. 250ml+ premix in each tank.

About 3500 miles of the 4300 miles are traveled with the aggressive OMP table.
Over the summer I have experienced some "overheating" issue (216f/102C maximum), if not backed off it will keep rising, (I personally think if I reach 104C or 220F my engine will immediately blow up lol).
From what I have read it seems that the rear rotor runs hotter than the front rotor, the rear rotor seemed to have dropped more compression than the front rotor, which may be the result of running hotter, I may have warped te rotor housing slightly.

Would like to know everyone's thoughts on the compression numbers and if this is a viable way to prolong the engine life especially with a newly built, well clearanced and full of fresh part engine where blowby is insignficant.

My car havs:
AEM CAI, Sohn, VT canned program with a custom OMP table and a pop and bang map (to **** off pedestrains who runs the redlight). BHR ignition coil, Mishimoto radiator, Re-medy Thermostat, Re-medy water pump, Re-medy OP regulator, ACT clutch, Exedy LW flywheel and TurboXS catless midpipe and catback.

First 121680 miles

Rotor 1 @298RPM 235m @250 0m elevation

Face 1 8 kgf/cm2 114psi 109psi 7.6 kgf/cm2

Face 2 7.8 kgf/cm2 111psi 106psi 7.4 kgf/cm2

Face 3 8 kgf/cm2 114psi 109psi 7.6 kgf/cm2

Rotor 2 @300RPM

Face 1 8.7 kgf/cm2 124psi 118psi 8.3 kgf/cm2

Face 2 8.5 kgf/cm2 121psi 115psi 8.1 kgf/cm2

Face 3 8.7 kgf/cm2 124psi 118psi 8.3 kgf/cm2

Second 125979 miles

Rotor 1 @298

Face 1 7.6 kgf/cm2 108psi 103psi 7.2 kgf/cm2

Face 2 7.7 kgf/cm2 110psi 105psi 7.4 kgf/cm2

Face 3 7.8 kgf/cm2 111psi 106psi 7.5 kgf/cm2

Rotor 2 @302

Face 1 8.1 kgf/cm2 115psi 109psi 7.7 kgf/cm2

Face 2 8.2 kgf/cm2 117psi 111psi 7.8 kgf/cm2

Face 3 8.2 kgf/cm2 117psi 111psi 7.8 kgf/cm2
4299miles traveled over 1 year.

BlackStone oil lab is unable to identify 2 stroke oil in my oil sample however the result is all within spec.

I will still do a compression test next May. And the following May. I will be tracking down the effect of agressive OMP table and 250ml+ of premix in 16galon of fuel have on my engine, which is considered weak my Team.
And please do not turn this thread into a "How to fix your overheating issue". I have been actively working on it.

 

My omp table is similar to yours, albeit 15-16 steps in the low load low rmp areas. I also premix in the gas tank about 300ml/full tank, and I have yet to foul any plugs or o2 sensors in the 8000 miles since I've had this car. I use a jaso FD certified oil though. Shame on people who throw around ideshitsu like they invented the wheel, when other oils are cheaper and better. In Europe you can't even get the stuff, and even if you did, you'd be paying more than on a superior oil.

Compression didn't drop a bit in this 8000 mile interval. If anything, my 7yo battery in the trunk and original 15yo starter still puts out 220 rpm.