I have tried different configurations with the dv from push to pull with ports a or b and all 3 different springs. No matter what I do I get flutter on part throttle. Currently I have the synapse yellow spring with about 6-7 turns of preload in push mode IIRC and port b with A vta. This has done better but the flutter is still there. I'm considering swapping it out for a Tial q but o don't want to spend the money on one to just get the same fluttering effect.

Any recommendations?

 

get rid of all the preload if it's fluttering on part throttle. the only reason for preloading the spring would be if it's leaking under full boost, which i highly doubt it is

the soft spring is good, but having the preload in there makes the spring similar to the stiffer springs which isn't what you want

I'd try pull mode first instead of push mode, 0 preload, and port B

 

Thanks I'll give it another shot. The reason for the preload was to prevent the DV from opening during part throttle

 

Keep it. Last year was a year of hell for me and compressor surge and BOV's while running autocross. That was also across three different turbos as well (all similar sized) and two sets of cams. I had run a HKS SSQV (yes, a real one) and Tial Q. For the HKS I even sourced a lighter spring and ran the correct spring on the Tial that just kept it closed at idle. And on the Tial I even changed to a different spring with the cams as my vacuum at idle changed.

That takes me to this year.... changed back over to the factory MAF and ECU and with that needed something to recirculate. The recirculation housing for the Tial was out of stock and I had run the larger Synapse BOV in the past with good results.... so this time I went with the DV as I liked the clamp setup versus setscrews and has a small footprint. All that I can say is game over. I ran it is the fastest reacting position which is in the pull configuration (like an HKS) with only one vacuum line attached (will have to look and confirm which port). I also ran the light spring and no preload. Needless to say it has resolved 90% of my problems. Just as an FYI I do run it recirculated as I have a MAF on the car.

With this I have not run into surge on the track at all where I always did previously with any other BOV. I was going to go back to a stock valve, but I just couldn't bring myself to do that and was the final factor as to why I went to the Synapse DV. I will also follow up with that on the street I still get some surge/ flutter here and there, mostly when you are in the upper gears cruising and want to pass and get on the throttle part way and boost comes up.... valve is shut and the turbo is outside of its happy place. The stock valves leak and this masks the problem. What to do? One of three things... First is what I do... I deal with it as it is far and few between for me and I have learned to keep it to a minimum. The second is to turn your boost down while driving around town/ commuting. That can help as usually I have found it does it only when my boost is set above 18-19psi. The third is to change turbos and go with one that is truly better matched to the car. Of course the last one is the most fun, but also the most expensive

 

Technical10 thanks for your input. After driving it again today it doesn't seem to be as bad as I was thinking. I have heard worse. It doesn't open during the pull partial or full. It's definitely a lot sensitive than stock. So if I left just a tad it will relieve pressure. But it seems to flutter past 20psi so I'm thinking it's the turbo not liking it not the DV itself.

Here's a vid I took today

This is with the yellow spring in push mode and port b connected with A venting and about 6 turns of preload. Car is tuned on speed density so the DV is VTA

 

I don't hear it fluttering in the video, but go take all of the preload out of the DV and test it again.

I'd start in pull mode (not push like you have), 0 preload, port B. If that doesn't work, port A, then A+B, then push mode with the same three configurations

 

The flutter now happens above 20psi during the partial throttle "pull". More noticeable in 4th and 5th gear. In the video listen to the last pull (0.25s) before the video ends. You'll hear it.

The problem I was having before with no preload was that it would open during a partial throttle "pull" making the car lose all momentum.

But I'll test it again

 

Yes, that's why I suggested putting the DV in pull mode and not push like you have it

 

Here is a vid of it in pull mode, port B connected and A open.

 

the part at the end of that video i heard; that's the distinctive noise i couldn't hear in the other videos

is that with 0 preload also? keep testing the other port configurations if so. I started at B, went to A+B, then to A before mine was working without fluttering

 

That noise is more pronounced in 5th gear. I can get it in 4th as well but over 20+psi.

This has 1 turn and it was to help it not open during part throttle. In this configuration it seems to boost less during 3rd gear part throttle pulls. The video shows it hitting 10psi in3rd while the other video shows 20psi.

Ill play around with the ports tomorrow

 

It should be opening during part throttle though, otherwise the DV is not doing it's job

If the motor doesn't have enough load to require the air that is being pushed through by the turbo, it is the sole job of the DV to relieve that pressure, otherwise you're going to run wonky during those situations

do you have a picture of how your DV is installed also?

 

Here is how it's currently installed. Pull w/ port A connected and b venting. I ran it this way today but I will do more driving tomorrow





Here's a quick video

 

if i try to generate to much boost, during low / med throttle conditions, i can get my dv to go crazy.

so i reduce the amount of duty that is happening during that very rpm, boost & throttle position.

it comes down to pressure differential. for example, if you have ~30psi between the turbo & throttle blade (partial throttle) & only ~16psi within the plenum, the dv may struggle.

i see in your sig, your running both the ebc & mbc? have you ever just tried running just the mbc or ebc?

does it happen during wot conditions as well or only partial throttle?

 

Aby,

It doesn't do it during WOT. It seems to do it in part throttle over 20psi only. I do not recall it being this way while on the MAF setup and just the MBC but it's been a while so I don't really remember.

I think I just need to find the right setting lol