Hmm, I have had a problem with my blow-off valve for some time now, but it's getting worse at the moment...
What happens is that it starts fluttering (opening and closing at a high frequency) between 0,7-0,9 bar. Below that it's ok and above that also. Very weird. I think it has something to do with the actuator pressure which is at 0,75....
Any ideas??

 

Nobody know the answer to this? Come, US turbo guys...

 

MK,
Is this at part throttle?
If it is it could be due to the differential pressure across the diaphragm in the BOV causing the valve to open slightly and leak boost pressure. THis would happen at part throttle because of the pressure drop across the throttle butterfly at part openings.

Andy

 

YES Andy, it's at part throttle!!! Thinking about what you say, that's exactly what it is. A little throttle it's fine, full throttle also, but in between it flutters. How can I fix this? Or does this mean I have to buy a new BOV?

 

MK,
I would say that the easiest way to fix it would be to get a BOV with a stronger spring that doesn't open as easily on part throttle.

Andy

 

Yep, someone else also told me that the spring is probably knackered. That also explains how it got worse gradually... Hmmm, looks like a Forge recirculating for me then, or maybe some dirty VTA shiat....:headbng2:

 

it took me so lond to log on i forgot the question
no still standard vta

andrew

 

I have an HKS SSQ BOV. it sounded great at first. as time went on, it made a fluttering noise. I don't know if it's the same fluttering you experiencing. but a friend who has experience with the HKS says thats how its supposed to sound. I don't know. just my 2 cents

 

yeah i am back to the standard bov, but venting it to air
i can do this because i am not using air flow sensing so no idle problems

i was plagued by a similar problem - the flutter is the wategate i think but the problem is most likely the bov, strangely its actually more likely to be the bov NOT releasing when it should, check the control line and also take it off and check its not sticking

btw hks sequential no good drivability wise once you up the flow and boost, long explanation why

claudius to keep the turbo spinning between changes once you have your mappable, fully retard the timing above 4500 or so at no load, and go up hard up on the fuel, this will run a lot of unburnt fuel through the motor and i guess you know the rest

also some xtra air is good which can be done too

andrew

 

I have the HKS on my evo V. I've been having idling problems...between shifts in neutral, RPM goes down to 200!!! on lancerregister, some guys with evo IVs had problems with the HKS too. do a search there!

 

i have exactly the same fluttering with my HKS SSQV, i am going to put it back to standard to see if it is better

lee