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track day pre mix?

Old 07-14-04, 05:49 PM
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track day pre mix?

How much 2 stroke oil should i run in my 91 na for a track day?
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Old 07-14-04, 06:21 PM
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I use 1 oz per gallon (128:1).
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Old 07-14-04, 09:36 PM
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Do you have your stock oil injection pump or not?

-=Russ=-
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Old 07-14-04, 09:37 PM
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That the number for with a working OMP for a margin of safety, or a removed one?
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Old 07-14-04, 11:35 PM
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I'd drop it down to 50:1 to 75:1 ratios.
Dump the whole quart per 3/4 tank of gas.
Try not to run full as it tends to spit back out the filler door!



-Ted
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Old 07-15-04, 03:00 AM
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I myself pre-mix 1 Oz per gallon using 2 stroke oil.
THis was reccomended by Rick at Downing ATL to Evil and I one of the times talking with him.

I have run it on most all my cars, and have had zero problems with very hard use, and many miles.

Obviously you may wanna deviate depending on how hard you are running your motor.
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Old 07-15-04, 08:26 AM
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Is there a difference in the amount you use depending on whether or not you eliminated your MOP?
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Old 07-15-04, 08:31 AM
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Originally posted by racerjason
Is there a difference in the amount you use depending on whether or not you eliminated your MOP?
YES. Everyone has their favorite ratio but if you have no OMP you run a lot more premix to account for the lack of oil injection.
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Old 07-15-04, 06:05 PM
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I have no mop and run 50:1 at the track. 100:1 on the street. So far so good.
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Old 07-15-04, 08:08 PM
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With working OMP, I like to just add a quarter of a 16oz bottle (i.e. 4 ounces). Without OMP, I use a full bottle per tank or a bit richer, depending on the situation. My preferred brand is Royal Purple.

1 ounce per gallon is 128:1 ratio. That's basically one bottle per tankfull, or close enough.
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Old 07-15-04, 09:19 PM
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Without OMP, I use a full bottle per tank or a bit richer, depending on the situation.
More oil actually leans out your combustable mixture. The oil displaces the gasoline so you have less gas per volume of air.
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Old 07-15-04, 11:28 PM
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moot point at best, especially at these ratios. Besides, rotaries already inject oil.
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Old 07-15-04, 11:30 PM
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So, any consensus on W/OMP? Why would you need more than what the OMP supplies? (yes, I am playing dumb...)
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Old 07-16-04, 12:25 PM
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The OMP is intended to lubricate through a range of RPM/load conditions and, like any mechanical device, is subject to failure. Racing involves extended operation at high RPMs, which might exceed the lubrication capacity of the OMP, and certainly any outright failure would cause extraordinary wear and tear on apex seals and housings. Also, when and where the lubrication is provided is critical. Premix is suspended in the fuel whereas the stock OMP usually "leaks" some the housing and some in the manifold. This might be great for a street car, but some question the lubrication effectiveness for racing when pinpointed in this manner. Premix is very effective at going anywhere the fuel goes, including to the housings and apex seals.

Basically, I'd call a splash of premix in a car with a functioning OMP, driven on track, to be preventive maintenance; a good idea to prevent excessive wear and tear. On the street, it's just insurance you may never need. Either way, there is no real downside to using it, IMHO.
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Old 07-18-04, 03:24 PM
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Also.. about pre-mixing.. you are increasing the BTU IIRC.. plus it will increase the sealing etc..
I myself havent experimented with the extremes.. BUT.. I do know a very hard core racer who designs his own chassis as well as runs a racing team that ran rotaries in formula cars in the recent past.
He was telling me about running really SILLY oil to fuel ratios.. to the point where you had realllly blue exhaust.... He would up the pre-mix to the point where it was JUST not detonating. O.O Turns out they would make a decent amount of more power.. (With tuning of course) Enough to justify the fouling of the plugs at idle etc..
Turns out the extra sealing combined with the BTUs added up to a worthy amount of more power.. (cough and less mosquitos)

For me.. I am sticking with 1oz per Gal at this point pre-mix only. I will prolly up it on the track though. But not a lot.. no reason to be silly.. and have everyone laugh that I have blown oil control seals..
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Old 01-17-07, 11:53 AM
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3.5 oz to every 5 gallons if reving above 10,000 rpm i`d use 4oz instead. Recomended oil is the Castrol Competion A747

Works Fine 4 me.
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Old 01-17-07, 12:02 PM
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I run 100:1 on my PP 13B road racer (no OMP) with '91 rotors and 3mm carbon seals. The smoke is visible.
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Old 01-17-07, 02:00 PM
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I'm running with omp and adding about 1oz per gallon, Singled FD. I've heard that adding oil lowers the octane of the fuel.
Does anyone know the calculation or reduction amount?
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Old 01-17-07, 02:22 PM
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I run 4 oz of Amzoil mix per 5 gallons in my big street port EP racer. Keep in mind that the long skinny combustion chamber is less than ideal. The long distance the flame front has to cover is helped by the dual plugs. Premix definitely reduces your octane, and octane is roughly translated into a resistance to ignition. Depending on timing and about a thousand other factors, this can actually help burn some of the mixture at the outside of the combustion path. Rotaries that don't have forced induction don't have high octane requirements generally, and I have been told by several builders that theoretically an octane number in the high 70's might be ideal. Hard to say where they get their information, but it is likely some hard science has been applied somewhere in Mazda's development process!

Last edited by Boswoj; 01-17-07 at 02:33 PM.
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Old 01-17-07, 04:55 PM
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100:1. 50:1, what do those translate to and what do you mean, 100 parts gasoline to 1 part oil? i have no O.M.P. and run a largely unmodified 12a, 1984 w/ oil/water exchanger beehive (RB road race header, no emissions, strait through exhaust 2"), currently adding 1 0z of oil for 1 gallon of gas, suggestions on changing the mixture?
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Old 01-18-07, 10:15 AM
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Originally Posted by hyochem
100:1. 50:1, what do those translate to and what do you mean, 100 parts gasoline to 1 part oil? i have no O.M.P. and run a largely unmodified 12a, 1984 w/ oil/water exchanger beehive (RB road race header, no emissions, strait through exhaust 2"), currently adding 1 0z of oil for 1 gallon of gas, suggestions on changing the mixture?
Yes 100 parts gas to 1 part oil. I would also like to say that 1oz of oil for 1 gal. of gas is plenty, probably more than enough.

Lets see say the OMP injects 1qt per 1000miles and say you get 12mpg., so 1000/12=83.33gal, 83 gal=10624oz, so 1qt=32oz per 10624oz, 10624oz/32=332:1

So even if the OMP uses 2qts per 1000mi. that is 168:1.
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Old 01-25-07, 02:35 PM
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great thanks!
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