E46Fanatics - View Single Post - Has anyone ever mixed 2 stroke in their gas?
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Old 02-12-2013, 07:32 AM   #26
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Originally Posted by tmr931 View Post
makes sense
No it doesn't.

Originally Posted by wildirish317 View Post
And I forgot to include the statement that caused me to respond in the first place. Does 2 cycle oil have a higher btu/lb content than gasoline? If that's the case, why don't we run our engines on it to begin with? How much btu does it add to a tank of gas? How much does it cost per gallon?
Actually I think it may (not btu/lb but btu/gal). The more refined a fuel is, the lower it's energy density (in general). The "density" part of that statement is important. That is a rating of megajoules per liter (or btu/gal) whereas specific energy is megajoules per kilogram (or btu/lb). Specific energy remains about the same for all oils from crude to aviation fuel (when you start adding ethanol you get killed). Energy density has a well defined downward trend. Take these densities/specific energies for example:

Type: E Density ; Specific E

Crude Oil: 37 MJ/L ; 46.3 MJ/kg
Diesel: 35.9 MJ/L ; 43.1 MJ/kg
Gasoline: 34.2 MJ/L ; 46.4 MJ/kg
E10 "Gasohol": 33.18 MJ/L ; 43.54 MJ/kg
E85 "Gasohol": 25.65 MJ/L ; 33.1 MJ/kg

2-stroke oil is going to be somewhere between crude and diesel. It is harder to combust completely and that's part of the reason 2-stroke engines have horrible emissions (apart from the less efficient cycle). The only reason 2 stroke engines have this additive is for it's primary lubrication in the crank. I'm not going to explain the 2-stroke cycle and it's method of induction/exhaust and fuel/air mixing, but it NEEDS this oil. A 4 stroke absolutely does not.

Also, you can see why E10 and E85 suck. They do burn more efficiently and a little more cleanly, but you are getting less energy per unit volume and per unit mass.

Originally Posted by rudycoop View Post
It has been extensively tested on other forums and I will say it again, 51 pages of positive results. I have been doing it and my 325 runs and idles like new.

Check it out:
I don't care what 51 pages of the LS1 forums say (I'm not going to waste my time reading that many pages). It probably doesn't hurt anything seriously, but there is no way this increases HP or MPG. All it's going to do is foul your plugs more quickly than pure gasoline. Who knows what it may do to your cats. As far as lubricating the fuel pump, that may be true, but the pump is designed to be adequately lubricated by gasoline. Anyway, the fuel pump failure on these cars seems to be a motor issue, not an issue with the pumping mechanism itself wearing out.

All I really have to say is that there is no need for this "additive" even if it did help. Our engines last a very long time as it is with regular oil changes. That is the only oil your engine needs. The oil system adequately lubricates the engine at all times, unless the oil pump nut comes off. In that case, some 2-stroke additive is not going to help you.

Originally Posted by Rubenk View Post
I have heard and seen it on a few occasions where running a bit of ATF can clean things up due to all the "detergents", but I still wouldnt recommend it on a modern engine. An old carbeurated farm truck? Sure, throw whatever you want in there, but probably not the best idea on a new ride(granted that E46's arent that new anymore).
First of all, the ATF thing is a myth and that myth involves adding it to your oil, not to your gasoline.

Second, our cars may be 10 years old, but their technology matches the lower level brands made in the past few years. It's not quite as refined (VANOS problems), but BMW pioneers technology before most other car makers by several years.

Last edited by WDE46; 02-12-2013 at 07:52 AM. Reason: Auto-save 1360673525
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