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pre-mix.... effect octane???

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Old 01-15-04, 01:22 AM
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pre-mix.... effect octane???

does premixing effect the octane? i tried running a search but couldnt find it , but what i hear its good i have been doing it lately but just thought i would ask about the octane. btw i use MMO
Old 01-15-04, 02:02 AM
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I think it probably does lower the octane level a bit, as you dilute the petrol - there might also be chemical reactions which make things worse
I use fully synthetic 2 stroke motorcycle oil in my petrol
100 ml per tank (76lt)
Old 01-15-04, 06:19 AM
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moderation is key...its very easy to add too much...keep it minimal and be conservative with your ratios....and if your worried about octane after premixing...dont premix...let the OMP do the work....
Old 01-15-04, 09:23 AM
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affect = verb
effect = noun



oil causes detonation when it's in large quantities in the combustion chamber, so be conservative like BoostCrzy said
Old 01-15-04, 09:54 AM
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Technically premix does affect octane but you would have to be using huge amounts to make a noticable difference.

There are 128 ounces to a gallon. A twenty gallon FD tanks holds 2560 ounces and lets say you are using 10oz (that's a lot unless you disabled the OMP) of premix per tank full.

That means you just dilluted the gas by .39%.


Like I said, it ain't much.
Old 01-15-04, 10:09 AM
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very good point

so without running an OMP, how much premix would you run ?
Old 01-15-04, 10:30 AM
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i have been premixing latly, i have been doing the 4oz per tank. im not too worried about it i just wanted to know if it was a big difference.. thanks for the responces
Old 01-15-04, 11:48 AM
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Question:
No MMO here, so does it matter which 2stroke synthethic oil to use??
Old 01-15-04, 11:51 AM
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Has anyone noted higher compression after starting to premix? I really don't see the point unless the OMP is failing or gone.
Old 01-15-04, 11:54 AM
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safety and piece of mind. also if you saw a torn-down engine that premixed vs a omp one ther is a noticble difference in wear.
Old 01-15-04, 12:00 PM
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In what areas of the motor? And how can you positively correlate that to OMP vs. premix?
Old 01-15-04, 12:05 PM
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If you can afford and hassle of add 2 stroke oil. I think every rotary need to be premix. they are design to burn oil however due to the tide emssison law. OMP can only inj min need of oil to engine.
Old 01-15-04, 12:07 PM
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less scoring of the rotor housings. and positivly well in similarly maintained cars i have seen a difference. yes the omp works and works well but once you start moding the car everything helps
Old 01-15-04, 12:10 PM
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Good enough of an explenation for me. I don't know if I'll do it all of the time, but definitely if I start really modding the car.
Old 01-15-04, 01:31 PM
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I have not seen it first hand but numerous engine builders say premix along with the OMP is better. The idea is that since the premix is in the fuel is distributes inside the engine better than what comes out the oil injectors on its own.

Again I have not seen it firsthand but it makes sense to me. I don't premix day to day, but I do premix when racing. I use Penzoil synthetic 2 stroke oil. You can get a whole gallon at Wal-Mart for cheap.
Old 01-15-04, 01:52 PM
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How much is it DamonB?
Old 01-15-04, 02:02 PM
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Originally posted by Rated R1
How much is it DamonB?
I don't remember exactly. $15? It's definitely less than a tank of gas and a gallon lasts me a looooooong time
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