Twostroke oil mix ratio vs. engine power output?

Oil Ratio

Flummo said:

To begin with: Yes, I DID search, but only found people asking about how much oil they should use, not the result of varying it.

Click to expand...

Flummo -

There was a detailed test done with numerous oil mixtures. Check the "advanced engineering" section/forum here, it's on the first or second page, I believe (reference to).

EDIT: Anecdotal test -
http://www.dirtrider.net/forums3/showthread.php?t=108727&highlight=oil+ratio+test

EDIT: I went to the advanced forum, and searched on "oil ratio test" and found some stuff.

The bottom line was that HP did not DECREASE until you were running extremely high amounts of oil. 10:1 or more, as I (poorly) remember.

Of course, this leans the mixture out and you must rejet (larger jets).

I have a racing 2 stroke engine, and run 20:1. I also use very expensive oil. Lifespan of the engine is far more important than the cost. Or, you can buy one of the synthetics and run 50:1 or 100:1. After a detailed study, the idea of doing so terrifies me, but my engine is more valuable than yours, and folks get away with it.

Oil mixture should have little or no impact on a well-jetted engine. I got a lot of spooge at first until I jetted correctly, little now.

Enjoy!

I think McColuh (spelling ??? ) chain saw company did some of this testing way back . Maybe Rich will chime in .

CB23 has nailed this question. The only thin I can add is from personal observation a properly jetted 2 stroke works very well at 32 to 1.

D

Interesting question. I think that if you continue to richen up the fuel/oil ratio and continue installing larger jets to compensate for the additional oil you would actually be displacing air in the intake charge with the oil. Which to me would mean that the difference would be a minimal power loss up to the point where you could no longer jet the carb any richer.

Years ago ( early '70's ) Dirt Bike Magazine did an oil shootout.

Maybe someone can find it. I've got it somewhere, but I have no idea where.

Rotor

Just use 32:1 up to 40:1 and jet accordingly. Unless you are just interested in the learning experience and are just curious don't bother messing with it, it could cost you your engine. The theory on hand is correct but unless you are into a pro career and can afford to rebuild your engine every race or "outing", don't mess with what already works for so many, you won't gain that much hp in that you'll have the extra edge on your competitors.
There are better and more efficient ways to extract power from a 2 stroke. If it's just the knowledge you seek then Godspeed my bretheren! Good luck to you.