Under 4K? That is going to be very hard to do, with this engine. You may end up lugging it. Which is just as bad as over-revving it, IMHO.

 

Under 4000RPM seems scientific AF.

 

Lol just drain and refill it if you're losing sleep, OP. None of us have any stake in your car. If you're still thinking about it, then buy a jug (plus 1 quart) of oil for $25-35 in the correct weight.

You'll be out a heart stopping $25-35...and yes...its wasteful. But chalk it up to a mistake and just drain and refill. It might be worth peace of mind.

If you've gone on living your life, and you're not worried about it...then leave it.

It almost surely won't cause any damage. Even if you rev it past the scientfically proven point of 4000 RPM.

 

Lubrication is lubrication at this point. I'm changing it in less than 2,000 miles, so I am going to just run it easy. Maybe not under 4,000 all the time, but definitely like a regular commuter car for the next 2 months.

 

 

I would just change the oil if you are worried about it still. I'd rather spend the money and know that the correct weight of oil is in the engine than worry about potentially causing some kind of damage or more wear on the engine. Good luck!

 

Id be more concerned of the fussy TCT operation in this motor by weight of oil then the engine itself under normal DD duress. But no, regardless I still wouldn't be able to sleep at night running 0-20 in this engine, its worth far more then a $30 experiment to me. I run whats called for, 10/30 and when boosted I ran 5/40. Always full syn. Mobil 1 in this engine gets eaten up the quickest in my experience, so I dont bother with it. It becomes annoying and more expensive on longer change intervals. There are plenty of other good/better options out there that dont have the high amount of evaporative compounds Mobil 1 has.

 

A well known member at bobistheoilguy.com is Dr. Haas, and he has been running a 20 weight oil in his Ferrari for a number of years. The Ferrari calls for a 40 weight oil. This is just anecdotal evidence but it proves that such an oil can be used without harm if you understand the basics of engine oil and you use the car in an appropriate manner. He has an interesting set of articles at the website called Oil university or something like that, well worth the read.

 

That's great. But its always about cost vs benefit, risk vs reward. So what is the reward of running a 20w vs a 30w or 40w, and is it warranted?

Are we arguing that you could run a 20w if you had to, or are we arguing that its better?

Again, my position is that I'm not interested in experimenting on different engine lubrication from the known that works well, when as far as I can see there is no benefit to doing so, only risk potential.