Chozen

Here's what I have. a 91 S13 with a KA-T setup, GT28R, around 8 psi. I was running an HKS SSQV. I was getting the chatter/flutter at low boost and even in vacuum at part throttle. So, I modded the SSQV with softer springs and ran a larger diameter vaccum line to it, to no avail.

Today I installed a 1G DSM bypass valve. When I first started it up, I revved the engine a little and could hear a faint 'chssssh', so I was happy because I thought the valve was so responsive that it would even open a little in vacuum with no load. This is recirculated by the way. Took the car for a drive and I still get the flutter like described above. I am about out of ideas. I am almost certain this is compressor surge. I was thinking there was a slight chance that maybe it is the external wastegate, which is a knock off Tial. I hear that is a myth.

The only other thing I think it may be is the fact that the recirculation hose attaches to a large fitting, but it is necked down drastically to about 3/8" as it goes through a grommet in my preturbo intake pipe. I dont really see how the air coming out of the bypass valve could fill that 3ft. plus hose and not be able to escape fast enough. Is any of this making sense to any of you?

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built not bought.