with such tight tolerances, what weight motor oil is used?
Depends on the team since each team is sponsored by the same oil and gas manufacturer. Mercedes uses Petronas Syntium oil as well as Petronas gas. Ferrari uses Shell Helix oil and Shell gas. The weight would factor into what track and ambient temperature. I would assume, don't quote me, but at hotter temperatures, they probably use a weight higher than 20W-50. Probably a 50W.
They choose the grade according to circumstances, and that may change from FP1 on Friday to the race on Sunday, during a weekend. Unlike for street cars, F1s don't use multigrade oil.
The current oil would be similar to a 5W30(not far is his quote). Similar but not exact. I wont elaborate further as the mix/package are proprietary of course. This from my Total oil engineer mate who was tied to Renault, RedBull and Lotus in the past. We just chatted. The V8's used an oil with a consistency/formula that was 10W equivalent. The oil is replaced as its used vs a normal 'change'. Oil samples are constantly taken/monitored per session of course.
I won’t attempt to offer an oil weight as I do not know. That said F1 engines operate in incredibly controlled conditions compared to a street car allowing for some real specialized oil to be used. All the engine manufacturers have oil engineers constantly tweaking formulations for optimal performance. In addition F1 engines are careful pre-warmed all around including all of the fluids. It has been like this since the late 80’s again making the operating conditions very controlled. This includes dimensional tolerances within the engine as it would not turn at room temperature because the tolerances would be off. Racing oils are typically single weight because warm up flow characteristics are not considered. Again I don’t know the weight but I do know the oils differ massively from what you would put in your road car.
I wouldn’t be surprised if F1 motors ran a “straight weight” oil - e.g a 30 weight - and doubtlessly one with a pretty sophisticated additives package. Unlike our cars at home, they’re not going to be driven in winter or have to endure a lot of temperature swings, particularly since a F1 engine’s oil will be pre-warmed, etc
They almost certainly run a straight weight. They don't have cold starts. They heat the oil and water up and feed it into the car like an IV.
A lot thinner than most think. The tight tolerances means thin oil takes longer to flow across a bearing surface--just the same amount of time a thicker oil would take to flow across a bearing surface with greater clearances. Also note: Thinner oil cleans and lubricates piston rings better than thicker oil. Pretty sure the oil has little acid neutralizers since it is change after each run. The V10s used a heavy dose of ZDDP and Molybdenum, but the turbo V6s run too little RPMs to need that kind of anti-wear package.
There was a video on youtube(I'd have to try and find it) but it was a late 80's/early 90's mclaren and they were dumping the oil in and it almost looked like brown water, very thin.