fluttering or compressor surge?

Turbo Miata's first start.

Category:

Autos & Vehicles

Tags:

• Miata
• fluttering
• compressor
• surge

[juicyhung]

It was the first time I started the car so I had the radiator cap off to bleed off any air in the lines; since I also replaced the coolant.

[juicyhung]

After I replaced Flyin Miata's crappy BOV with a Mitsubishi 3000GT valve it no longer flutters.

[munnsey]

thats fluttering you have there, completely harmless and you are only hearing it because of the big cone filter and presumably no BOV fitted. If you are running high boost 15psi or more then you should use a BOV, otherwise it wont matter. Compressor surge is actualy when you get a similar sound to flutter but it occurs during actual boosting, not after throttle release. Its when the turbo is pumping in more air then the engine can swallow.

[metalseanhead]

You guys are idiots, surge sounds cool but it can actually kill your turbo.

IF you don't sort it out though it will split your compressor wheel nut off, which destroys the thrust bearings and bends the compressor blades backwards.

SO you guys are dicks for not sorting out compressor surge when it occurs. you don't deserve a car if you want to destroy it cause it sounds cool to do so.

[MrShakotan]

@Migillicuty420a flutter normally happens when the BOV doesnt open at all or there isnt one. My car will flutter sometimes if i let off the throttle as its building boost as these only a couple of psi at most and its not enough to open the BOV. My complete turbo system is basically stock except the FMIC, BOV is stock. Search 'real compressor surge' there is a red r33 on a dyno that is showing what compressor surge actually is.

[Migillicuty420a]

@MrShakotan So is flutter just when the blow off valve opens and shuts really quick? My friends dad owns High Tech Turbo Co and I have personally seen in their shop what any air going back out on the turbo can do to the inconel shaft.

[MrShakotan]

@Migillicuty420a no no no no no. this is flutter, compressor surge is completely different. Who ever started saying that this will kill turbos should get a kick in the pants.

[Migillicuty420a]

According to Wikipedia Surge is the rate of change of acceleration in physics. The air in the intake got stopped dead in its tracks when the throttle plate closed and now has to equalize as fast as possible. The only way out is the way it came in...the turbo. Air going the opposite direction on those compressor blades is going to try and make the turbo spin the exact opposite way it did to compress the air. This is why some turbo shafts get bent. Flutter and surge are the same thing. BAD

[liledd8728]

that is compressor surge. Your blow off valve is not opening up early enough to let the pressure built by the turbo out. just adjust your blow off valve and everything will be fine.

[tehbabyjebus]

Also so far what I have asessed from what I have read.. is that my HKS SSQV is not supposed to do this at all? It is supposed to have a clean release at all boost levels? and the adjustment nut does nothing to help.. I just don't want to have to replace an expensive ass turbo.. thanks to any help.. (video is my only upload)

[tehbabyjebus]

Instead of reading pages of comments.. if anyone wants to look at my only video upload and let me know if I am compressor surging or just fluttering please do and inbox me/ reply2comment.. Im getting paranoid because I don't have the money to replace a turbo.. Mine only flutters when I let off the throttle, not during boost.. So I am assuming it is safe.. but I have also heard stories about new bovs or rerouting vaccum lines solving flutter.. help?

[cruiserboy1000]

@munnsey Thank god someone else understands! on low boost, 12-15 PSI turbo 'flutter' is harmless, above that, damage may be caused, and plus, flutter is really only slowing down and already slowing down turbo, where as compressor surge is exactly as you mention, presurised air trying to punch back through a turbo whilst under boost!

[bonecrime]

@killacamry24 When you close the throttle, wont the pressure build up over 1bar in the intercooler and pipes when the air has nowhere to go?

[bonecrime]

@cruiserboy1000 So? It's the same process, with either a closed or open throttle. I'd guess neither is very good for the turbo...