I've searched this, and I'm hoping I'm wrong...

[~Barn~]

So I need some help...

After putting a TMIC on my car the other day, I noticed that when my BPV actuates with a high boost load, I hear somewhat of a flutter or echo almost, of the pressure recirc. Previously I would just get one loud Pssshhhtt sound from my Synapse, across my entire rev-range.

So right now, under lighter pressure loads but still WOT, I'll let off, and it still does sound like a single, distinguishable actuation.... However, when I'm under heavy WOT acceleration, deep in the powerband, and I release a large amount of recirc, it's more of a fast Psshtt-shu-shu-shu-shu sound.

The best way I can describe this, as I mentioned, is a "flutter" sound. From what I've read on this forum and some others, it may be compressor surge, and that's making me a bit nervous.

Anybody have any thoughts on this, or any troubleshooting I can try? If it is compressor surge, then I suspect that's a failure of the BPV, right?

Judges?

[~Barn~]

Here's something from another forum, that I hope could be legit. (?)

What you are probably hearing is Wastegate flutter. My understanding is that the wastegate is rapidly fluttering to control boost (opening\closing so to speak so it doesn't surge). Mine does this lightly. When letting off from WOT. Its normal and not an issue according to tuner and Forced Performance. Compressor surge you hear even when accelerating and this is bad. I spoke to Forced Performance on this and that is what they explained so I am just reposting it here.

[I`m Batman]

I'm not familiar with Synapse... I'll let the experts answer

Anyway, I really miss that TMIC. I hope I didn't make a mistake by selling it. I can feel a huge difference with the stocker on. My boost temp is much higher and would not drop nearly as quickly as before. I guess I better get moving on the new intercooler.

[~Barn~]

Yeah, I can imagine. This fluttering side effect aside, I can really feel the improved throttle response and increased power with the cooler boost temperatures. I haven't data logged anything yet, but the butt-dyno says things are more sparkly.

The highest boost temperature that I hit in August 2010 (with my stocker) was 185.6F, per the historical data logs that I have. I want to take this thing out in the heat of the day and see how high I can get it. I have a feeling I'm not going to get anywhere near that high.

[~Barn~]

Update:

So I had to go put gas in, and just for the sake of "rebooting", I uninstalled the performance map, and got back to stock MS6 brains. Upon hard WOT recircs, I'm not getting any sort of flutter anymore. The BOV sounds anemic due to the fact I'm not boosting hard now, but the flutter situation had cleared. The throttle is choppy, but I think the ECU is just learning its way again. Another drive should tell the story.

Anyhow... On the topic of actual boost temperatures, I saw 141 as the highest temperature under load. Right now, it's 91 degrees F in Englewood, per 9News. Once I go back to a performance map, I'm eager to see what the delta will be.

[~Barn~]

Update #2:

The performance map is back on, and the flutter is back. Coincidentally, I also noticed that I have a bit of a "fitment" issue with my Synapse BPV. There are two small lines/hoses that extend out from what I would call the front of the BPV. Because it's angled upward toward the hood, I either have a pinch or a rub on one of the two hoses, and it's wearing holes into the rubber.

Too be honest, it doesn't look like there is a lot of wiggle-room for changing the pitch of how that Synapse is bolted on, so now I'm wondering how I'm going to fix this. Do any of you know if somebody makes steelbraided vacuum lines?

[erod550]

You can rotate the Synapse as much as you want by loosening the two small screws where it attaches to the flange.

Did you flash a new map to account for the intercooler? That might be part of the problem.

[kingtut]

To add to what erod said-- There are two more screws near where the recirc hose connects (iirc), I'd make sure those are tight as well.

You do have the third line connected to the hot pipe?

The Synapse is a big sob, but you should be able to adjust it to where there is no rubbing issues.

[~Barn~]

Sweet guys, thanks for the suggestions!

Eric, I will look for those flange screws. I think if I can rotate it so it's a bit more horizontal, my fitment problem will be solved. Hopefully the plumbing of the lines will allow it. And too your question, I'm using the same map that I always have. It's the Stage2+SF 93 octane OTS map from Cobb. Of all the ots maps from Cobb, this one shoots for the highest psi, and I've never had any bad side-effects from it. My KR is mostly non-existant, and I think I have safe AFRs under load. Those are about the only metrics I know well enough to check.

Nate, is the "hot pipe", the larger diameter hose at the back/bottom of the Synapse?

Sorry that I'm not more familar with which end is which, but the two smaller lines (one of which rubs), have a Y-merge as soon as they come out from the synapse, and that single line then routes to the large diameter airhose (tapped) that leads from the turbo into the intercooler. Am I assuming correctly, that that is the "recirc"?

Where is the hose that comes into the bottom of the Synapse coming from? At a glance, it looks about 1 inch in diameter.

[kingtut]

Sounds like you have it right, Barn. It's the third line (not the two that go into the "y") that should be tapped to the hose that connects the intercooler to the turbo.

The larger hose is the recirc tube. Those can get torn as well (mine did) causing a leak, etc. So you may want to check that too. That hose is being re-routed back into your TIP. (tip, ha ha)

[~Barn~]

Hmm.... Well I guess I need to have another look at it then, to make sure I'm seeing things right. I know there's a larger diameter hose at the bottom, which I hear you telling me now is the recirc.

The top end of the BPV has only 2 nozzles, and the hoses coming from those nozzles are do the 2-into-1 "Y". It's that line, that taps back into the intercooler (hot) hose. So unless you're calling that 2-into-1 single hose "the 3rd" line, I don't recall seeing a 3rd line. (?)

[kingtut]

Have you looked at this thread: http://www.coloradomazdaclub.com/forums/showthread.php?t=4261&highlight=synapse&page=2

On the second page, there's a good pic of what it should look like.

[erod550]

That's a map that's designed for 93 octane, which we don't have, and a full exhaust including a downpipe, which you don't have. Also, the SF maps are for the Cobb intake while you have the Mazdaspeed intake. I think you need to find a new map. I'd try one of the newer ones that say they are for the MS3. Like the Stage 1+MSCAI2 91 Octane. Or if you want to try one similar to what you've been running but that will account for the TMIC, try the Stage2+MSCAI2+TMIC 93 Octane. Either way you should run a map designed for the Mazdaspeed CAI, not the the Cobb SF intake.

And the third nozzle tut is talking about is the one that comes off the side of the BPV.



It needs to be connected to a boost only source. Most people tap the hot pipe, which is the pipe that connects to the intercooler closest to the firewall (furthest from the BPV). The one I'm sure you had to play around with to get it to fit because of the angle of the rear pipe on the intercooler (that was my intercooler before it was Batman's, heh).

[~Barn~]

Okay, so I went and had a quick look just now. Here's what I found:

A.) I did find the 3rd hose, and you're exactly right... It is this hose (not the 2-into-1 hose) that routes back to (what I presume is called) the hot pipe into the TMIC. It looks good with no holes or kinks or loose fittings.

B.) The "Y" hose routes down somewhere to the engine block, so far as I can tell. Aside from the holes in one of the Y hoses, it looks to be in good shape with secure fittings and no kinks. Can somebody tell me what those hoses do, and are called? Are they flowing pressure into, or out of the Synapse?

C.) Knowing that the Synapse swivels now, I managed to muscle it into a more horizontal position. In doing this however, I appear to have loosened it and so now it just rotates somewhat freely back to that steeper angle. I guess I need to reposition it how I want, and tighten it back up. Do I do this with the small hex screws up front? Those were about the only screws I could see, from the vantage I had. Maybe I'll be able to see others, if I disco the flange. (?)

D.) The right side of the "Y" hose (as you're looking at the picture), is the one with the holes worn into it. Once I get the BPV locked into place how I need it for clearance, I will get a new vacuum hose.

[erod550]

B.) The Y-hoses that go to the engine (to the intake manifold) provide a vacuum/boost source for the BPV. It's what tells the BPV to open when you let off the gas and the engine goes into vacuum.

C.) Yes, the small hex screws are what hold the BPV to the flange. You may have gouged a groove into the plastic though by turning the BPV without loosening the screws first, which would explain it being easy to go back to the original position. You can try tightening it down more at the new position and see what happens.