I've been getting a problem with sputtering or slight jerking in 5th gear on the highway. I'm getting this while in 5th gear accelerating then slowing decelerating. Its happening on the decelleration. Now if I let if off the pedal super fast, then the car seems fine(accelerate then left of very fast).

heres the setup

Stock evo 8 with

trust exhaust
ETS intercooler
LICP
turbosmart dual vent(all the way down as stiff as possible)
no cat
tephra on v5.10
Tuned for a/f 11.5
stock boost

It was fine when it had everything minus the cat but now that its catless, its doing that jerking. I find it odd.

Please advise me how to fix it or is it acceptable?

 

Your BOV is too tight, try loosening it up. When you let of the gas it needs to vent and if its too tight, it can't vent as much as it needs to, so you are probably feeling compressor surge.

 

I agree 100%..

 

200%

 

Ahh. Great! I'll try that. I didn't now that it would be that tight. I'll try that

 

Not trying to hijack your thread but, i think im getting the same thing, but my cars a little different.

Evo9
Tanabe hyper medallion TBE
Injen intake, Lic, Uic and intercooler
Stock Evo9 Bov

 

DV/BOV on backwards will do this. Bottom port needs to go to the UICP

 

I know mine is in the right position. So I've loosen it up a bit and its doing less but I think if I loosen it too much, then it probably wont hold boost. Is this a common problem?

 

the adjustment does not control how much boost the valve holds

 

Correct but wouldn't I be more prone to boost leak under high boost if the spring is not stiffened up. Thats my concern.

 

I don't think so, If you are under boost, the boost is holding the valve closed, the valve opens when you let off the throttle and that's why the vacuum hose attaches to the valve.

 

Yes. I understand that. Thats the basics of a dv or bov but I know that those who are boosting 30+ psi dont use the stock evo 8 bov because it can't hold(it leaks boost under high boost). Correct me if I'm wrong. Your statement suggest that it'll hold regardless but I think its only good to a certain point. My concern is that if I loosen the turbosmart too much (to the point where the cap is going to fall off) then it wouldn't be able to hold high boost.

have you experience the same problem I'm experiencing in? Shine some light on the topic.

 

I have experienced the same problem, thats why I posted. You just gotta keep playing around with it until you get a setting that is comfortable for you. You don't want it too loose or too tight, just in between at a point that suits your driving. I have the Perrin BOV. It says it will hold boost even without the spring. I copy and pasted this from the manual so this might help explain things a little better:

Adjusting Spring Tension
• Adjusting the spring tension is the PERRIN BOV doesn’t adjust the amount of boost it holds. Because of our unique
design, no spring is needed to hold boost. The spring is used to adjust how quickly the BOV vents boost, and when the
BOV vents boost while backing off of the throttle.
• Adjusting the spring tension tighter will make the BOV vent slower, and in turn, vent closer to zero percent throttle.
• Adjusting the spring tension looser will make the BOV vent quicker, and in turn vent closer to when throttle is initially lifted.
• Adjusting of spring tension effects the amount BOV flows when BOV vents. When adjusting spring tension, either remove
flow control screw, or thread screw all the way down.
• Please note there are grooves on body to indicate spring tension. Cap must be screwed down far enough to cover o-ring
on body, or a boost leak will occur.

 

Ahh. I'll try to loosen it some more to see how it responds. I'm still getting slight sputter when letting off the throttle. Thanks

 

What does that mean? how can i put it on backwards? it can only be put on 1 way