Noticed over the last couple days. Will either happen in 3rd, 4th, or 5th gear. Doesnt do it everytime. giving the car slight gas(doesnt really do it often under heavy load) and let off slowly or quickly, the car sometimes seems to jolt pretty hard, doesnt do it everytime, weird. Are you supposed to hear a slight bang sometimes when shifitng into 2nd or 3rd (sounds kind of like the rear diff. locking) i think i heard it mostly when im shifiting around turns but im not sure. thanks for any insight in advance.

 

I am not sure I see 2 issues, but the one thing I'm pretty sure you're describing is called "compressor surge." This is what happens when you build boost, then close the throttle and send the boost back down to the turbo. If the amount of boost built does not exceed the purge setting on your BOV, then the BOV won't open, which sends the boost pressure back to the turbo, thus causing compressor surge. Basically, it is like trying to spin the turbo backwards while it's in forward motion. I think that's what you're describing when you say that you give slight gas then let off.

 

Yea sounds right, but I never noticed that before when i had the stocker, until till after i put the stock one back on after i took of my mr valve. before anyone asks, its in correctly and everything is tight. Not really that i think i have a problem, just more like I want reassurance its normal .

 

Does anyone else get compressor surge on the stock diverter valve? I'm the only one ive heard of so far, maybe the stock valve went bad?

 

here you go grasshopper..i have had 5 diff bovs now..stock works best..

i will be honest im now back to the factory... what im going to do is make the spring on the tial really weak.. ( didnt work, check my carpics thread) being how i have everything opened up i can really hear what goes on with the turbo... the factory is open 70% of the time when we drive, even at idle.. its for the mass airflow meter.. and the way mitsu designed our turbo setup... since i have everything opened up, it makes the prob even worse.. if you buy a bigger turbo it will solve the prob.. its just that our turbos spool so easy they dont want to slow down.. the waste gate should regulate it but its to small of a vacuum drop for it to open.. thats why the factory bov has a weak spring to bleed of the pressure.. but if your on it the bov will stay shut because the pressure in the i/c pipe ( trying to open the bov) and the pressure going to the top of the bov, (vacuum line going to the bov ) are equal and the spring holds it shut... my advice to you is lighten up the spring till you dont hear any flutter, but tight enough to keep it closed under full throttle... mine will open up even if i keep the boost up to 15 psi very light load on the motor.. but if i give it a just a little gas it will shut till the load lessens on the motor and then the bov will start to open letting some pressure out for the turbo to scroll down.. long answer huh... i have been meaning to write this up just havent had the chance yet. so now i wrote most the story up.. and i can copy and paste... so i guess thanks.. keep an eye open i will post the link in my sig when done.. oh yeah most vendors will not accknowledge this prob..

 

I've never used the term "diverter valve," but I do experience compressor surge at times, but only when I make a mistake. If I'm intending to drive hard, quick shift into a new gear while keeping the boost up, then quickly decide I don't want to hit full boost in that gear (traffic, etc), then I get compressor surge as soon as I let off the throttle. I don't consider it a flaw, but rather a driving mistake.