So Ive had evo for a couple of days now after getting the gtx3576r installed on e85. The car is making closer to 500hp on 26psi on a dynojet. What Ive notice is when im around 4.5k on 5th gear going anything lower than 80mph i get a chug chug sounds when i get on the gas, not wot. when this happens my boost gauge starts going crazy kinda like fluttering. is this the surge everyone is talking about? it sounds like the bov/wastegate is trying to open or close. Its almost like the car is buckling for half a second. My tuner is telling me it can be my bov not holding boost. My evo is an 08 so it might be going bad? any idea on what it could be?

 

anybody? bueller?

 

It's the BOV.

When there is strong vacuum in the intake manifold, it holds the BOV open. Then when you have boost in the intake manifold, the spring and pressure hold it closed.

So at highway cruising, the pressure in the intake manifold is a little bit of vacuum, right at the border between vacuum and boost. The pressure in front of the throttle body is a few psi because the turbo is spooled up a bit. The throttle body causes a pressure drop because it's only partially open at cruise load so the pressure in the intake manifold is lower. So the BOV has the spring force pushing the valve closed (not enough vacuum to hold it open) and the boost in the IC pipe pushing it open. So it's at this weird point where the spring isn't strong enough to hold the valve closed. It tries to close, gets blown open, closes again, gets blown open again. Chug chug, boost flutter.

I would initially say you need a softer spring in the BOV..... so it would stay open until you gave it more throttle than just highway cruising.... but, are you using the stock BOV? If so, maybe it needs a bit stiffer spring so maybe try the old school DSM crushed BOV mod.

 

Thanks for the feedback. Yeah I'm on the stock bov. I replace it was a turbosmart dual port that I had lying around but it was worst! So when I'm cruising around 80mph and get on it the pressure is too high that the bov "pops" open? What does "crush" mean?

 

get a synapse DV and call it a day.

 

Just ordered 1

 

nice, mine has done me well holding over 30psi on an old tune with no bucking flutter of any kind.

 

How do I get the yellow spring everyone is talking about?

 

when i ordered mine i called them and asked them to include it.

 

Anyone order from synapse website recently? I get no reponse to email and my order hasn't been process yet.

 

Well Ive been dealing with the DV from Synapse and im very disappointed. On my stock bov and turbosmart i can blow air into the bov and get absolutly no leak but on the DV i can blow air into the piston and its leaking. I tried taking the DV apart cleaning it making it sits right. So at this point im about to go back to my Mhi and sell the gtx3576r! Ill have another tuner look at it. if he tells me its normal cause its too big of a turbo then ill sell it. I dont know anyone that can drive with this turbo! your constantly having to downshift just to get the car up and going! it surge in 3rd, 4th, and 5th! doesnt matter how fast im going.

 

Man.... Well, I hate to tell you to throw parts at the car. But I'm thinking try the Turbosmart Kompact Plumback with the softest spring in it. That should be the blue spring. If it doesn't work, you can sell it. It's cheaper than doing a full turbo swap and all that.

I do think it's bizarre though as PLENTY of guys are running this turbo. So, it could be the tune.

 

I understand how a DV/bov works but how does it cause compressor surge? When I let go of the gas I get a clean release from the dv. The surge happens when I get on it. The only time it does not do it is when I go WOT in each gear. But if I'm slowing down and try to pass a car I would downshift but surge comes on at 4k. How would a softer spring help? Would a harder spring be better? Your trying to keep the DV piston close when on boost. Getting a softer spring will cause it to "pop" open. The turbosmart that I have can be adjusted to soft and it still does it.

 

When you're getting the bucking and surge, are you around 25% throttle or 50%-75%? I can see the BOV going nuts when you're almost at positive boost. In this case, a softer spring would keep the BOV open which is what you want with the manifold still in vacuum. If you're at 50%-75% throttle where you should be making like 10+psi of boost and it's surging, that's probably real compressor surge and not the BOV acting weird.

You have the turbosmart dual port right? That dumps some air to atmosphere right? If so, then if it's open under the case of little vacuum in the intake manifold, it's going cause the car to run rich because air measured by the MAF is getting dumped.

What intake are you running? A restrictive intake will cause the compressor to go into surge more easily because it reduces the pressure at the compressor inlet.

 

I have the Torque solution intake..you think that's the problem? It has a 3.5 opening.

Yeah I don't think it's the DV it's doing what it's suppose to when I shift. Its real compressor surge.