Is your stabilizer trim setting correct? What speed are you achieving by the end of the runway? V2 for your scenario looks to be about 156 knots, which is the speed you should be at when you are at 35 feet height over the end of the runway. Liftoff should occur at a lower speed. If you are not achieving V2 speed without lifting off, then maybe the engines are "underpowered" as you say. But, if you are accelerating okay, but not lifting off, then it is either in the liftoff simulation, or possibly your technique or trim setting.

I checked the trim. The problem is the runway lenght . The acceleration is much slower as the engine fails and by the time I am at the middle of my rotation like say 6-7 degrees I am at the end of the runway.

I read it that V1 is VEF + 1 SEC as well.

I was wrong about the 2 seconds thing. I looked back at one of my old study books and it quotes a 2 second gap (years gone by JAA rules), but reading EASA CS25 the time between Vef and V1 is determined by the manufacturer. I presume FAR 25 is the same. Sorry for the blind alley. so far a productive discussion