I believe that most people mix 1oz per gallon which is around 125:1, i saw on Royal purples site that you can go a lot more, even up to 600:1 and thats for racing applications, thats with the stock oil injection removed. Heres the link. http://www.royalpurple.com/techa/faqsa.html#re2
Anyone try going 300:1 for street use. I'm running around 150:1, i removed the stock oil injection system. I'm thinking about increasing the ratio, but i dont know by how much.

 

you have your ratio's backwards... 600:1 means 600 parts of gasoline to 1 part of premix... vs 125 parts of gasoline to 1 part of premix.... 125:1 has 5 times more premix than 600:1

and 1 ounce per gallon is the reccomended amount after you remove the omp... so you should be fine doing that

 

600:1 would be useless for lubricating the hard seals, gasoline itself would probably do a better job...

After at least a year of testing different ratios, I've come to the conclusion that anything between 95:1 and 105:1 is optimal. Anything "under" 85:1 shows fuel economy improvements, but at the cost of "adding" premix to your oil supply (got new oil control rings, and still the compression manages to push it past). Anything much "over" 105:1 tends to degrade the mileage, which means friction is starting to rear its ugly head. I'm guessing since most guys on the forum stick with the 128:1 ratios (1 once/gal), it should be OK. It won't hurt to "lower" the ratio to 100:1, though you might see some blowby at that point...

I've finally settled at 102:1 or so- last fillup netted 27.4 mpg...Still a little "blowby", but not much, nothing the 3K oil changes can't take care of...

 

I dont have my ratios back wards, i guess my heading is kind of confusing. I'm thinking of running less premix per tank of gas, like from my current 150:1 to something higher. I had the same reasoning as the royal purple link. Why do you have to use so much more premix than you would normally use with the omp. I never really put much thought into it but i guess after reading the link, it got me thinking.

 

listen to Wayne, he has spent waaaay to much time on the issue, lol

one thing to note is that most premix oils are only stated to be fully effective at ratios of 100:1 or lower. something about the particles not being distributed evenly at higher than 100:1. i'm sure it's nothing siginificant, mostly due to the fact that 2-stroke engines in lawnmowers, snowmobiles, etc. will most always use lower than a 100:1 ratio, like 50:1 or whatever...

- Aaron