To answer your question, you have to take in account the tolerances inside the engine. You can't run really thick oil on these cars without issues. One grade up won't hurt anything, but I wouldn't run several grades up like going from a 5W-20 to a 20W-50. First off, you don't need a thicker oil at start up so anything 0W or 5W on these cars is fine, but no need to go for 10W or higher. With that said, thinner oils are used in almost all cars these days because of technological advancement in motor oil and CAFE standards. Thinner oil means less friction which equates to slightly better fuel mileage. Thicker oil not only causes worse gas mileage, but it can also lead to slightly reduced horsepower. You have to find a happy medium. With the Accord, it simply isn't made for really thick oil. Before my Accord 2.0T, I had a highly modified Mustang with a modified Coyote in it. The low-level trims called for 5W-20 and the higher-level trim called the Track Pack called for 5W-50 because Ford considered that trim level a track ready vehicle. I always ran 0W-30 in that car and oil temperatures never got out of hand. Of course, that car had an 8.5-quart oil capacity (the new Mustangs with the Coyote, 2018 and newer, have a 10-quart oil capacity) so you could run it hard and not have to change the oil often. I bet the Accords is around 5 to 5.3 quarts oil capacity, so the oil degrades quicker when running it hard.
Monitor your oil temperature, your EGT (exhaust gas temperature), and coolant/head temperature. If all is in check, send it!
One thing to note... most vehicles, including those that claim they are track ready aren't really track ready. They would overheat within a few laps on a track. Either cooking the brakes leading to brake fade or flat out brake failure, cooking the differential fluid in the front or rear differentials leading to gear issues or at least gear whine, or overheating due to high oil temperatures. A proper track car needs several different coolers including an oil cooler, a differential cooler, and a trans cooler. The Accord simply isn't made for the track and it would take a lot of work to make it track ready regardless if you are running 5W-20 or 10W-40.
If you are simply running autocross or a few drag strip runs, any synthetic oil will do, even stock 0W-20 will do fine here. Just let the Accord run for a minute or two to bring down temps before cutting the car off.
Also, catch cans are useless on any engine that is direct injection only.
This guy's first post was talking about how bad the Accord was because it was missing all these features the Camry had, yet here he is. The Accord is on another level compared to the Camry. The driving experience can't be compared. Of course, I'm talking 10th gen Accord here. I have no doubt the Camry is better than the 11th gen Accord LOL.
