Exitist7

1.) I am rebuilding my '86 FC soon and am exploring options as to how set up the lubrication system. I have done extensive research and have heard compelling arguments for stock OMP, adapted OMP with 2cycle tank, and premix respectively. Currently the engine and omp are stock and I use 10w30 Royal Purple synthetic oil. The first (probably very dumb) question I have is would it be a horrible idea to add .5oz/gal or so of a premix such as Idamitsu at fill ups in addition to the Royal Purple which is being delivered from the OMP?

I own the naturally aspirated s4 engine, and am looking to add some power through forced induction when I rebuild. It is my understanding that synthetic oils are recommended for keeping turbos relatively cool and clean, so I would like to continue using RP oil. Is it highly recommended to separate "crank"case oil from seal lubricating oil? I am trying to decide if I should delete the omp entirely after swap and premix or if I should purchase the omp adapter to separate the synthetic from the 2cycle. There seem to be advantages to both, my specific question is keeping the use of synthetic in mind.

2) As I said, I will be rebuilding with turbo power, and am debating whether to swap in a factory Turbo II motor and build off of that, or to try and build off of my NA 6 port. I have heard boosting the 6 ports is not recommended, but I have no personal experience with the matter. Obviously the two engines have different internals creating different compression ratios which also plays a factor. So...turbo charge the current motor or swap in a 13bt? Either way I am planning to open, street port intake, and refresh. My priorities go in this order:

1. Performance / Reliability
2. Cost
3. Time / effort of build

(I'll admit I haven't done much forum research regarding question 2, chances are there are some good threads on the topic which I will look for after posting, I just added as an afterthought to get some more opinions, as I have again heard arguments both ways from local rotary tuners)

WJM ROTARIES

I would not use any synthetic oils in any rotary engine it will damage your oil o rings , I use a 25/70 mineral oil in all my and customer engines . don't use an 6 port motor with turbo is not good for power or reliablety . plus good chance of distorting rotas , higher comp and lighter and thin walled rotas ,not strong enough to take boost

Sgtblue

iTrader: (16)

You'll probably get as many opinions as answers. I'm not a big-brain here, but I'll tell you what I do and why....

*I run synthetic oil in the engine for it's heat tolerance and performance in the turbos. If it was NA, I probably wouldn't. A bit more expensive, but it's a fair-weather car, so I don't change oil as frequently as a DD. I also have the original turbos at 120k boosting fine with no smoking and not nearly as much shaft play as others I've seen. Correlation isn't necessarily causation, but there you go...
*If you add turbos, you'll likely be going to a standalone. On my PFC I noticed my injector-duty went to zero, sometimes for long periods and from relatively high rpm when I lifted throttle...like going down a hill. If I pre-mixed only, that meant no lubrication for the hard seals during these times. On the other hand, I didn't think the stock OMP was ideal as it used synthetic crankcase oil. Another factor was that I had recently done a comprehensive rebuild for a failed coolant seal which included NEW housings. To the extent possible, I wanted to reduce wear.
I added a simple/inexpensive boost-activated AI system and now pre-mix at about half the rate/.5 oz. @ gal. with two-cycle oil and WITH the stock OMP. My plugs are staying cleaner longer so I suspect carbon is being controlled well. With the AI I also have the added benefits of knock suppression and cooling. Stock ignition, stock plug heat ranges and no perceptible break-up or smoke from the tailpipe. Probably ~300 whp at slightly higher than stock boost levels. So far, so good. And I guess we'll see on the housing wear.

*Personally I'm not a believer in the hugely expensive oils ostensibly made specifically for the rotary. I buy ashless two-cycle at the local chain stores and my synthetic on sale...Walmart rocks.

Exitist7

So have you modified the OMP to not pull from the oil sump?

Also I'm not sure what this boost activated AI system is.

I plan on probably using both as I have heard of many instances where injector duty stops and that would make me nervous

Sgtblue

iTrader: (16)

No. The OMP is unmodified stock. Note that I have a FD and their OMPs are both rpm and engine load dependent. I'm not sure how the FC OMPs determine how much oil to inject.

And sorry...AI = Auxillary Injection....usually a mix of methanol and water. In my case it's WI or just (distilled) Water Injection. A small nozzle atomizes a bit of water into the intake air. Boost activated simply means that the water is added when a pre-set boost level is reached...in my case between 1 and 2 psi. There are other systems for controlling it, but boost activated is probably the simplest and least expensive and appropriate for my modest power level.

I don't want to get too far off your topic, and there's a lot of info sources out there for AI. If you're contemplating adding a turbo, it's worth reading up on. There is also an AI section on this forum. Put simply, water is great at carrying heat out with the exhaust from the combustion event. It's also good at reducing knock values (very important in a rotary engine) and de-carboning engine internals. It's the ability to remove carbon that gives me added confidence to run BOTH a working OMP and pre-mix without worry.

Evil Aviator

My opinion is that synthetic engine oil is a waste of money for street cars because there is no need for any extra protection in this case. It would be like paying extra money on your car insurance to protect it against meteor strikes. Other than race cars, the only real use I can see for synthetic engine oil is if you drive your car in sub-zero cold weather.

My 88 RX-7 convertible has been running on regular mineral oil and the original OMP for 26 years and over 200,000 miles now, so it would be pretty difficult to convince me that synthetic oil and pre-mix would make any difference. If you look at the cost difference over this timespan, by not paying extra for synthetic oil there has been enough money saved to buy an engine rebuild kit.

All of the current major brands of mineral oil for gasoline engines are turbo-rated. If you really want your turbo to be cool, then get one that is water-cooled, such as the stock Turbo II unit. The cheapie dry-bearing turbos are best left for museum displays.

For some reason this internet forum tends to use the "AI" (Auxiliary Injection) term for what is properly called ADI (Anti-Detonant Injection). It is a system which injects fluid (typically water or a water/methanol mix) into the engine to help it resist detonation. Boost-activated means that it injects the fluid when a sensor indicates boost pressure in the intake manifold.
Water Injection, Methanol Injection, Alcohol Injection Systems | water injection Coolingmist
Snow Performance : FAQ gasoline

If it bothers you that much, just remove the OMP, block off the injection holes, and run straight pre-mix.

Synthetic oil sold in the USA has a higher standard and will not hurt the O-rings. In fact, it is recommended by Mazdaspeed Motorsports Development, Racing Beat, Mazdatrix, and Downing Atlanta.

25W-70 would be too thick for most situations in the USA, and it could even cause damage in colder parts of the USA and Canada, although I am sure it works great in the Australian desert.

+1

Sgtblue

iTrader: (16)

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