You can hear it in the video over the engine. Did and single turbo swap and the whistle was there before and after the build. Any suggestions? Nothing seemed to be cracked.

Gasket leak on the cat-back maybe. Does the muffler has a drain hole? Since it was there before and after the single conversion I wouldn’t think it be too hard to track down. I’d look at everything you DIDN’T change on the exhaust first.

Completely different exhaust. It was an N/A when I got it. It comes from the engine bay but no idea where. Tore the upper half of the engine apart to get rod of the rats nest and installed new injectors and fuel system. New gaskets and the issue is still there.

So you had a FD that had a 13bREW engine that was NA? And you added a single turbo?

Have you checked the couplers?
There’s an ‘O’ ring on the elbow to throttle-body, as well as the throttle-body gasket. Though I think a leak in the latter would affect idle quality and be apparent for other reasons.

Yeah. I wanted more power so went all out. I’ll have to check that o ring out. My tuner said it doesn’t effect the car in any way other than that loud whistle but I hate it. My tuner who did the build even said nothing was cracked or out of shape. The wonders of a rotary haha

Of course you know that your car came with twin turbos. Probably why you had the whistle previously. And given the difficulty, it’s VERY unlikely that it was ever “N/A”.

It actually was NA haha. Was an endurance race car from the previous owner