I drive a 98 sc400 vvti with upgraded 2.25" custom exhaust piping. I've removed all the resonators towards the rear, "X" pipe setup, and kept the stock mufflers. It drones on the freeway and is annoying as hell. I noticed that once I pass 70mph per hr, you hear less to no droning. It's right at around 55-65mph when you seriously hear it. I've thought about installing 1 performance resonator behind the "X" pipe, just before it splits into 2 pipes towards the mufflers. Does anyone think this will solve the problem? And what size resonator do you recommend that won't cause too much a loss of back pressure? I've always had customized exhaust setups on both of my sc300's from the past, and either it was too loud or not loud enough, but never did it drone.

 

Well man it looks like you have to put some resonators back on it sadly. Just get 2 with the 2.25 inlet and outlet before the mufflers if you can fit them near the transmission before the x pipe. It sounds like a battle you can't be happy with lol.

 

That's why every car is said to be different! A friend of mine with a 99 sc400 vvti has the same exact exhaust setup as mine. It's also done by the same shop here and no droning issues.