95630706

MY Tial BOV (QR) opens and stutters while on boost (before lifting throttle). The car is running V7 SD and I have noticed that playing with the MAP/VE/RPM table effects it, although I have not been able to fix it.

Is this purely a function of the spring in the BOV or is it related to my load and pressure settings for SD?

Any help or previous experience appreciated

05VIII

iTrader: (17)

nothing to do with the bov. you are experiencing compressor surge.

search.

95630706

Nice. Anyone else?

F0RSAKEN

iTrader: (34)

Too much boost, too little throttle butterfly opening = compressor surge.

EvoPower81

iTrader: (14)

This is exactly what i'm experiencing with my black on light throttle. Whats the fix?

deej1

If using ECU controlled boost (3 port) then adjust TPS WGDC Correction table to reduce boost on partial throttle

EvoJoeIX

iTrader: (16)

Are you using the right spring according to the vacuum chart for tials bov?

project_skyline

iTrader: (30)

What RPM/gear does it occur at?

95630706

I consistantly log -7/-8 PSIg at idle and I specified an "8" PSI spring when I ordered from Tial...

However I also specified silver and they sent me a red one so I guess that could also be a question.

I can hear the piston stuttering in the BOV and looking at my logged boost and WGDC I think I can rule out surge.

It seems to be sensitive to getting the load/pressure correct on my SD settings. My setting look a little different than the tuners that know thier SD so I'll start there.

Does anyone know if springs are interchangeable between the 50mm to the QR?

Thanks guys!

EvoPower81

iTrader: (14)

Lets me know how if your fix works. Unfortunately im using a hallman pro MBC. Could it be due to my car being a 2.4 my forge RS BOV is not releasing enough air?

FlintownKilla

iTrader: (2)

I vote the spring is too stiff, drivability is directly affected by the bov being adj. correctly. I lucked out with a APS twin vent and when the spring is too stiff, there is part throttle flutter and abrupt blow off under heavy throttle light lift-off

Mike01gsr

iTrader: (33)

^^ What he said! On boost flutter has nothing to do with BOV.

95630706

Yeah... I was initially annoyed by his post mostly due to the "search" comment, but after lowering WGDC in the problem areas it went away, so I guess I stand corrected. FORSAKEN's post was more helpful .

Throttle lift-off also makes a similar messy stutter instead of blowing off cleanly, this may be too (soft?) a spring?

**edit** saw post above, perhaps I should try an even soffter spring? Someone had good results on a 3 psi spring above...

95630706

I'm too stupid to figure out boost error correction LOL. I 'm currently just using gear dependant WGDC like an EBC with everything else 0'd out. I think that will be my next venture once I get my SD tune nailed down. but yea that seems to be it.

F0RSAKEN

iTrader: (34)

ECU controlled boost or a larger turbo I think are about the only ways to completely cure compressor surge, which I battle constantly due to my EBC/stock turbo. I build 24lbs of boost at half throttle @ 3500-4000rpm if I'm not careful how I accelerate. Drives me crazy.

Larger turbo wont build as much boost at part throttle, and ECU controlled boost will allow you to tune your boost curve according to throttle/load, so you can set it to build only 5-10lbs at normal driving, then full boost whenever you need it. This will be my next step....if the BT doesn't come first