My turbo motor smokes and will have oil on top of the pistons on straight 93 octane but its dry and no smoke if i run those cheap octane boosters. I know they really dont raise your octane much at all which is why im perplexed. Its not only in boost, even just putting around town on the low cam in vacuum it will smoke. Adding like 1/4 bottle to around 3/4 tank of gas does the trick. Why would running the booster have this effect?. I feel the tune is appropriate. 14.5-15:1, 34-40 degrees just cruising and no det on the porcelain or on the knocksense (hard to read the ground strap when its orange...). The motor is pretty healthy and runs strong, 200-205 psi and 3-5% leak across all 4 cyls. 84.5x89mm cp's and eagles. ptw right about .004, mains are .002 as are rods. ring gaps iirc were .023/.026 and .002-.003 for the oils. its probably got around 2000 miles on it and has been like this since day 1 last spring when I put it together. I guess Im gonna stick with it because it works just wondering how and why its working

 

That makes no sense.

Probably blow by at the rings. What oil are you running?

 

castrol gtx 10-w40 conventional. the leakdown from each cylinder is through the rings, but the catchcan (2 -12 vents off the valvecover) even under good boost stays pretty empty just some condensation

 

You sure it's not a valve stem issue?

 

I am leaning more towards piston rings. valve stems usually smoke on start up and decel. I had perfect compression and great leakdown numbers but the oil control rings were fried. I had the same symptoms. Its all in your head about the gas. 87 octane or Q16 will have no effect on oil consumption while cruising.

 

Put some Rotella T6 5w40 in it and report back.

 

I think he will have even more issues with that lower temperature oil despite the difference in quality.

 

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