ballzout

Running oil pump now, but I'm concidering just doing pre-mix only this next build.

I know synthetic is best, but how much per gal. or what ratio would be best to race with.??

I realize oil holds heat, so better a bit lean, BUT ,...I have no issue with money or smoke if more is better at 8,500 rpm for 30 minutes !!!

Thanks, Rick

Sgtblue

iTrader: (16)

Any ashless two-cycle oil is fine. Synthetic isn't necessarily better since it's going to burn with the gas.
Oil's heat retention properties have nothing to do with it. I think most owners w/o the OMP pre-mix at a rate of about 1 oz. oil to 1 gallon of gas....or about 1: 128 ratio. I can't remember for sure, but I think that's a little more than the typical working OMP, but if your tracking you'd be better to err a little on the too much oil side IMO.

bmeyer

iTrader: (5)

Running pre-mix is great until that one time you forget the oil and are screwed. I'd stay with the OMP if you're going to run a stock carb.

jduani

iTrader: (1)

I run premix currently. I do a 1 oz of oil to 1 Gallon of gas. Sgtblue is correct comes out to about a 1:128 ratio. I have heard people do .6oz to 1 gallon also. I bought my car with the premix and i cant wait to get rid of it. Its such a headache when getting gas. If i were you id just stick with the OMP

misterstyx69

iTrader: (142)

you Gotta pay to play.
You can premix and still keep the Omp,or delete it all together.
I can't understand HOW premixing is such a burden when it comes to fueling up!
You can get those little bottles of 2stroke for a Chainsaw and carry a bottle or two in your Bin.Just one bottle gives you a 3 gallon fill up(cheap fill up).So really you don't have to be "bang on" with the measurement.Just ADD oil when filling up.
It's like making sure you got your shoes on before walking out the door!

farberio

iTrader: (7)

Stop spreading this BS. If you don't have premix when you fill up guess what happens? NOTHING. You car will not blow up, it will not seize, and if you don't drive for an extended amount of miles or put a huge load on the car you may not even have any wear!!!

Sgtblue

iTrader: (16)

No, it won't blow up and he never actually claimed that. But it's certainly not OK and something WILL happen. To one extent or another you WILL experience accelerated wear on the housings and hard seals. Reduced compression won't be far behind. How much obviously depends on how long and hard you drive it that way.
That said, it does seem like it would be hard to forget.

farberio

iTrader: (7)

He said you were 'screwed' as in major things are going to happen to your car.

Its not okay to forget premix and drive the car hard, but I am willing to bet if you drive the car home or to an auto store and go buy premix you will have no extended wear due to the oil retention of the housings. Hell, I know someone that didn't even realize that his car didn't have an OMP and didn't premix for 10k miles. And he drives his car very hard.

I am not saying its okay to forget, but 'screwed' should not be used to describe what happens when you do forget.

ballzout

OK, I've never driven an RX7 on the street ( race car only) but I bet after something like 2,000 miles you might have to add .5 to 1 quart of motor oil that was sucked from the motor via OMP right?? right !, So I'm figuring, you are all right, it's NOT a whole lot of oil these cars burn in injection, but they do burn it, and it does help. To date, from day one 10 years ago, to now, I still dump about an once of oil per gallon in my tank, and I still have the OMP hooked up!!!!!!!!!!
When I was a kid 40 years ago, I burnt up my 1st motorcycle because of a bad pump NOT injecting 2 stroke oil...from that day on, I have always premixed any 2stroke I've owned, hence the reason for the addition of oil to my tank. BUT I started this post, just wondering what a rotary really needs in the way of oil on the tops of the rotors...now I think I know, and will be taking this under concideration as I rebuild/re-install my motor

farberio

iTrader: (7)

A lot of RX8 guys premix 4oz per tank with their OMP still hooked up.

Remember that the amount of oil the omp injects is relative engine speed and load. If you drive the car harder then you inject more oil. The average consumption is around 1qt per 3k miles.

As far as the car needing premix, well thats a hotly debated topic.

Aaron Cake

iTrader: (1)

Race cars should be running premix. The metering oil pump was not designed to supply the engine for extended periods at WOT.

Sgtblue

iTrader: (16)

^Agreed. Or maybe run both. Since with a PFC, when injector duty cycle goes to zero (relatively long periods of decel from high rpm) so does the oil supply. But the OMP would still be injecting something since it's related, in part, to rpm. Just thinking outloud. I don't see how it could hurt.

KneeDragger85

i would run straight premix esp if its gonna be just a race car.. thats my thoughts. mine fc isnt my daily driver so premixing doesnt bother me. i run quicksilver marine 2cycle tcw3 oil. buy it at walmart i think it comes in a 16 oz bottle, i run the tank almost dry everytime and use the whole bottle upon fillup wich pretty much comes out to 1 oz a gallon

fc3s-ty

iTrader: (11)

(sorry for the ignorance and laziness to search for a thread) but i have heard some run pre-mix even with the OMP? not necessarily a higher ratio than without it, but just curious as to what ppls thoughts were, to run a small amount of oil through the gas, even with the omp, or let it be? thanks

ballzout

It's fine for racing, but for the street, I think of no gains in sight !