What do I need to change in the engine if the engine is loud while running at around 80-85mph? It feels like I will blow the engine if I hit an ave speed of 90mph.

its loud like your car is racing at a 110 mph even though I'm running at 80 mph

Is your transmission going into overdrive or staying in drive?

staying in drive. never went to overdrive unless its a steep hill

Overdrive is a "taller" gear so your engine doesn't have to work as hard. You're supposed to take it out of overdrive and go back into drive or drive/low when going up steep hills

no, but overall, the car engine is just loud when I reach the 80-85mph speed. regardless of what drive I'm in. How much do you guys think would it cost to get the engine checked out?

It would help if you described the noise - pinging, knocking, ticking, lower end or top end? Exhaust noise? For a shop to check it out they may have to pull the valve covers. All I can suggest to you is that if the noise is an indication of something wrong, continuing to drive it 90MPH isn't going to help.

I totally understand. I don't think that there's a knocking, pinging, ticking anywhere. It's like when your driving your car fast, the engine tends to be really loud that it came to a point that it's burning oil. I also pay attention to that part but regardless of what synthetic oil I put, it always lead to the same sound as it reaches 80mph. I really hope I'm making sense. Sorry for being confusing.

Rev the engine up to whatever RPMs you have when going 90MPH. Does it sound the same as when you have the noise issue? I assume, since you don't mention it, there is no turbo on this car.

No turbo at all. Just a regular Honda accord with no tune ups

@ 3100rpm -4000rpm the engine is overworking to haul the car