[Nitefall17]

Originally Posted by 1LEThumper

I don't know how many of you have seen this, dealt with it, or wondered....


So my stock 2020 SS 1LE started to get a lot of build up on the tail pipes around 10-11k miles for what seemed like no reason. Depending on the light, I could at times see puffs of smoke come out of the tail pipe during a 3rd gear or 4th gear pull as it was long enough I could kind of watch the mirror if the road was clear. Typically when you get puffs during a pull it means it's knocking. I could never really hear the engine knock so I don't know if it was false knock or not. I tried a tank of 100 octane...car wouldn't do it. Back to 93 and it would do it again. I tried a few different octane boosters and some would clear it up while others just seemed to make it better but still there.



What I didn't do was do a ECU log to see if it was knocking. I don't have access to HP Tuners at home so I had to go off feel and just the visual signs of it.



Now this is a daily driver with maybe a trip or two to the track during the year if I have time so it sees a lot of stop and go as well as some decent hard driving at times.



I was thinking I would try a slightly colder plug on the car as well as a few other things.



I'm going to bring up oil....personally I wouldn't think this would matter much but I did two changes this past weekend. One was move from the Driven DI40 oil to the DI30 oil as well as move to the NGK 6 heat range plug.



The plug to me was an easy choice. It probably isn't that far off from needing a 6 range anyway. My GT350 uses a 6 heat range plug stock and they don't make that much power than the LT1 (526 vs 460) so to me that's within range of something to try even stock.



On the oil side of things...I have read for years on the low speed knock events with DI cars so I have been using Driven in it since it was new and went DI40 since they call for a 0-40 oil in them anyway. I figured I would ask Lake Speed to see what he thought about it and this is part of what he had told me..

"If your 2020 has the stock bearing clearance, go with the DI30 instead. The lower the viscosity, the less knock tendency......


The 5W-30 will be better for the short trip driving. Using either the 100 Octane as an “additive” or the Driven Defender Plus Booster will also give you a little more protection, but I’d just try the DI30 first.....

Yeah, the knock in DI engines is a thing. The oil can help. I bet the colder plug will help as well. The knock is worse at low engine temps, so that is one reason the lower viscosity oil helps.

Lake Speed, Jr.
Total Seal Piston Rings"


I am sending off the DI40 that I drained from the car for an oil analysis by Lake to just see what comes of it.



Since last weekend I can say there is no real change in oil pressure. I figured it would be slightly lower but from the PDR file logs so far if it is, it didn't change more than 1-2 psi from what I can see. So far on this tank of fuel it would appear that build up on the tips has been greatly reduced but there is still some there. I have not seen any puffs but time will tell I guess if any of this. will help / stop or do anything to protect it.





Take with it what you will, just figured I would try a few things without going flex fuel or E85 all of the time. Shocks me the car would have issues on pump fuel and I don't know if I am the only one that sees things like this with theirs or not.

Do you have catch can???