Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: richard cash on July 29, 2006, 03:51:43 PM

Title: premix, what are the effects of the octane levels??
Post by: richard cash on July 29, 2006, 03:51:43 PM
Im just wondering about premixing, im not intending to do it but more of an interest.

what happens to the fuel when you "dilute" it with oil. Surely say optimax wouldnt remain at 98 ron and so it would reduce meaning it couldnt be tuned to as much power. And with the same thought, if youve had a car mapped on a certain fuel then you shouldnt add 2stroke because it will create more det.
Title: premix, what are the effects of the octane levels??
Post by: maximtaylor on July 29, 2006, 08:34:19 PM
The amount of oil is so little, it does not affect the tune.
Title: premix, what are the effects of the octane levels??
Post by: Grizzly on July 29, 2006, 09:21:36 PM
They say Synthetic 2 stroke oil is also designed not to effect the octain level so even though its small quantites it may be worth using good stuff.
Title: premix, what are the effects of the octane levels??
Post by: Mr_7 on July 30, 2006, 04:05:26 PM
why are you wanting to mix mix your petrol?

i take it this is for your fd- what bennefits are you expecting from that?
Title: premix, what are the effects of the octane levels??
Post by: richard cash on July 30, 2006, 04:31:23 PM
personally im not doing it but aparently 2stroke oil can be mixed with the petrol to give lubrication to the seals. This way all the oil pump and metering system can be thrown out and it means theres always lubrication. Assuming you never forget of course. Ive also been told that you can keep your oil system and just add 2stroke in 200:1 ratio. this way if your oil system does go then youve still got lubrication until you get the problem fixed.
Title: premix, what are the effects of the octane levels??
Post by: Grizzly on July 30, 2006, 04:39:54 PM
I woud\'nt bin the stock Omp unless its not working or your using an EMS that does\'nt have a Omp Driver.

BUT!! as alot of people will tell you pre mix is a more efective way of oiling the Internal parts (apex\'s etc) and for a motor that is getting alot of abuse or running big hp you want to make sure its as well lubed as possable at all times so if you use synthetic that does\'nt drop your octane levels at all why not??
Title: premix, what are the effects of the octane levels??
Post by: Mr_7 on July 30, 2006, 04:47:59 PM
i see makes sense you can loose the pumps etc but the hassle of filling up and getting the right ratio would be a nightmare alot easier just to leave it.

i can only think like grizzly said it would be used in extreme conditions. the two stroke principle works well and is (correct me if im wrong) more eficent than four stroke however its hard to regulate and fit in with eu laws hence them dissapearing
Title: premix, what are the effects of the octane levels??
Post by: Grizzly on July 30, 2006, 05:01:00 PM
Quote from: Mr_7however its hard to regulate and fit in with eu laws hence them dissapearing
Sorry this confuses me? Pre mix is\'nt a stock feature on the engines? The 2 stroke oil is designed to burn cleanly and not leave and deposits, the std 10/40\'s is not designed to burn and so leaves deposits arount the hot area\'s of the engine (apex grooves, Rotor housings etc) if anything the Cleaning agents in the 2 storoke oil helps brake down the Oily deposits left but the oil. But whats even worse is the deposits left by Syntetic 10/40\'s type motor oil which is also not designed to burn (well 90% of them Royal Purple excluded) they tend to block up the oiler holes in the housings causing lube problems.
Title: premix, what are the effects of the octane levels??
Post by: Mr_7 on July 30, 2006, 05:08:34 PM
i see yes but thats in the case of a premix fuel system in the case of two strokes its hard to regulate as there are only two strokes per cycle so to get eveything in and out is hard where as a four stroke os more accurate no?
Title: premix, what are the effects of the octane levels??
Post by: Grizzly on July 30, 2006, 05:18:48 PM
Sorry your over Complicating it, every time a bath passes the oiler (the small hole drilled in the rotor housing above the inlet) there is oil droped onto the Housing and the apex\'s scrape it up thus oiling, the Pre mix basicly does the same but it is sprayed in with the fuel as a vapor so it covers more of the Rotor/Apex\'s etc quicker. its not like a Boinger where there is two strokes an inlet and an Exhaust the rotary is one action the whole Intake exhaust etc is one rotation of one bath (if you gt where i\'m coing from?? basicly one rev of the Rotor does it all)
Title: premix, what are the effects of the octane levels??
Post by: Mr_7 on July 30, 2006, 09:55:06 PM
yes that makes loads of sense now thinking bout it, lubing the whole revolution. is there many people that have done this conversion then i see it as a ag but with hughe benifits
Title: premix, what are the effects of the octane levels??
Post by: monkey-fd3s on July 31, 2006, 02:49:55 PM
I\'ve just removed the OMP on my street driven car and am running pre-mix.

I had a frank discussion with the tuner who built my engine and they were more for it than against it.  As long as you have a good memory you will be fine.

I am using a 1/120 ratio of oil to fuel and just using the same oil I use in the engine; this was the reccomendation from the engine builder so I\'m more than happy to follow these instructions.  Essentially for 70 Litres of fuel (think that\'s what the tank holds) would mean 600ml of oil.

Got a nice 1L oil safe container to make the petrol station/fill ups clean and easy and I can measure how much i\'ve put it.  

I just pop the oil in first then fill up the tank :)
Title: premix, what are the effects of the octane levels??
Post by: Grizzly on July 31, 2006, 05:48:05 PM
O course you know not to remove the OMP with a stock ECU don\'t you :)
Title: premix, what are the effects of the octane levels??
Post by: Red and Single on July 31, 2006, 07:29:47 PM
I can\'t imagine any tuner telling you anything other than premix is a far superior solution to apex seal lubrication. It just has to be better.

Not only that but as I understand it if you bin the OMP then you can run super high grade synthetic oils in the engine too offering more protection all round !!
Title: premix, what are the effects of the octane levels??
Post by: Headmaster on July 31, 2006, 09:13:43 PM
This is a very interesting thread...
Title: premix, what are the effects of the octane levels??
Post by: oldone on July 31, 2006, 10:37:42 PM
Been premixing for 12 years !!!!!!!!!!!!!!!!!!!!! :yes :3gears-rh ,been using full castor based oils,the only downside I found is the dirty exhaust ports,not that it is a problem........:guinness
Title: premix, what are the effects of the octane levels??
Post by: Grizzly on July 31, 2006, 11:41:45 PM
You can of course convert the OMP to draw 2 stroke oil, There is a spacer you can buy but i don\'t recomend it for two reasons. The First is you tend to forget easyer if you don\'t have to fill it every Fuel stop, the second is the fact you can\'t seem to turn it down enough.
Title: premix, what are the effects of the octane levels??
Post by: Iwan on August 06, 2006, 03:13:55 PM
Quote from: GrizzlySorry this confuses me? Pre mix is\'nt a stock feature on the engines? The 2 stroke oil is designed to burn cleanly and not leave and deposits, the std 10/40\'s is not designed to burn and so leaves deposits arount the hot area\'s of the engine (apex grooves, Rotor housings etc) if anything the Cleaning agents in the 2 storoke oil helps brake down the Oily deposits left but the oil. But whats even worse is the deposits left by Syntetic 10/40\'s type motor oil which is also not designed to burn (well 90% of them Royal Purple excluded) they tend to block up the oiler holes in the housings causing lube problems.

Sorry mate but you may be wrong.

Just rebuild my engine which was running on premix for about 10k kms. I used Castrol 15W/40 to premix which is known to be mineral oil. I has had very little to no deposit on my rotors or grooves.
my premix was about 100:1 wich is very simple to calculate..... 50 Liters of fuel will give you 500ml of oil.

REgards
Iwan
Title: premix, what are the effects of the octane levels??
Post by: Red and Single on August 06, 2006, 07:02:07 PM
Quote from: IwanSorry mate but you may be wrong.

Just rebuild my engine which was running on premix for about 10k kms. I used Castrol 15W/40 to premix which is known to be mineral oil. I has had very little to no deposit on my rotors or grooves.
my premix was about 100:1 wich is very simple to calculate..... 50 Liters of fuel will give you 500ml of oil.

REgards
Iwan

I\'m confused here !!! You both seem to agree ??
Title: premix, what are the effects of the octane levels??
Post by: Grizzly on August 06, 2006, 07:20:03 PM
You do of course know why 2 stroke oil is better?

2 stroke oil has a Higher VI rating so in other words the diffrence between the Viscosity cold and Hot is alot less, i.e. 10/40 will get thinner and less effective the hotter it gets where as 2 stroke oil is designed to Burn. So basicly what you are getting is The higher the VI number the more resistant the oil to changes in viscosity as its temperature changes. Perfect base oil would have no viscosity change at all with temperature change. The 4 stroke oil reducing it\'s Viscosity so much just before its burns that is isn\'t doing alot. So thats why you don\'t have oily deposits.

The thing is all oils are designed for diffrent jobs. Like every thing its made to do its job well at a set Temp.