370Z Drifting Video from Japan 12.18.08

Namir

Isn't that sound bad? The infamous flutter.. I thought that means the spring for the blow off valve is too tight so it quickly opens and closes repeatedly rather than smoothly releasing built up turbo pressure.

RCZ

Only partly right. The bov isnt opening at low boost or at all. May be because of the spring or because its stuck shut. The flutter you hear is called surge or boost surge or turbo surge. Its air looking for the path of least resistance back out of the air intake system. This happens to be the turbo. It can cause a lot of pressure on the turbo and can make the impeller on the turbo actually spin backwards or stop very suddenly as the air is going back out. Depending on just how much pressure isnt being released, this can be harmless at low levels or it can be pretty bad at high levels. It makes the fluttering sound because the air is bouncing in and back out of the intake system. When it is a purr, its usually OK. When you hear fewer really loud sorta flutter bounce sounds like the one in the video then you should start to take notice. Although some cars that run really high boost kinda run into this problem if they are using bov's that can leak at high boost because they need to run stiffer springs in the bov. Stiffer springs means leak protection, but it also means that you need to reach higher levels of boost for the vacuum pressure differential to open the bov. In other words, it wont open at lower boost and surge occurs..

I know I couldve made it simpler...

SnakeBitten

Nothing wrong with 20's for a street car imho and on the 370z its only a +1 increase. Just like everybody rocked 19's on the 350z cause it was only +1. 20's will make the 370z look good. Those weel wells are huge and 20's will fill them out nicely without killing the balance much as it is just +1. I dont feel those on the 370z either. Love the rims but doesnt do much for the 370z imho.

__________________

Namir

Thanks for the explanation, it made sense. I used to think that flutter was always bad because it was stressing the turbo, but I guess its only bad if its excessive. I've always been a fan of N/A cars anyway, I can't stand power surge from the turbo half way through the rev band.