Holy Compressor Surge Batman!
 

Ok, I'll try to get a video but here is my setup:

Greddy manifold
TD04h-19T Turbo
2.5" Exhaust
Ghetto Fabbed FMIC setup with a TurboXS RFL bov. 2.5" Piping with a 10x12x3" CORE intercooler.


Just got boost control working a bit better and an injector O-ring air leak fixed. At 14 psi the car has really bad compressor surge, though it is dumping through the BOV you can hear it clear as day coming from the air filter pipe.

BOV is getting source from the TB source that had a cap for cruise control.


Any ideas on what could be causing it? It became a lot more noticeable when I put a pipe/filter on the turbo.

If you have EBC, I would eliminate the boost control and and just run the wastegate straight off from an intake manifold source and see if the surging stops. It could be a poorly adjusted boost control setting.

I'll bypass the EBC tomorrow.

How would EBC cause that, I'm just trying to figure out what is going on. I'm running a boost solenoid through MS if it matter any.

are you saying its surging when boosting 14psi, when spooling to 14psi, or when blowing off at 14psi?

It does some weird sound between 12-15 psi when at part throttle but it does not sound like surge exactly...more of a very fast fluttering, I just assumed that was the MAC valve.

When I blow off at 14 psi it surges like a mother though, I get a second surge/high pitched whooshing air sound coming from the filter and that is what really concerns me.

Braineack, could you point me in a direct for how you have your boost control setup just so I can get a feel for it.

I have a feeling your BOX might not be operating correctly/leaking or something bogus.

I have my targets looking like this:

http://boostedmiata.com/MS/EBC/dc_targets2.jpg

I have boost creep so in order to see flat boost I have to make more or less open fully at redline for flat boooooost.

Hmmm.

What is your wastegate good for? I still have the super shitty greddy wastegate and I know I'm asking a lot out of it to hit 14 psi. I need to get a newer one soon. I also get 4/5th gear creep if I'm not WOT (if I pull from like 2k it just slaps the 16psi limiter boost cut) I'm assuming that is what that is.


Why not use the TPS % though? Not that big of a deal or more of a hindrance to the device? Anything I should check on the box itself? Did you teflon tape the screws to prevent leaking or use something else?

How's your BOV setup? Are you running it VTA or bypass? Where is it relative to the IC?

Have you checked the compressor map to see if your in the surge area?

I don't see how this is wastegate related, sounds like your BOV isn't running right, I'd check to see if you're getting strong vacuum on the downshift and check the action of the BOV at idle.

Turbo XS is garbage and their RFL is a stupid noisemaker, you're probably surging before you dump any air as it opens too late. If its not adjustable get a better valve, preferrably not from a discount eBay seller.


Bypass valve should be close to the throttle body getting a clean vacuum source with a large diameter line (3/16 if you're feeling frisky) and the valve adjusted to stay slightly open around 15inHg* but close around 5inHg, most stock valves stay open at cruise for various reasons. My 1G DSM recirc valve stays open at high vacuum cruise.

* requires a recirced setup don't know if turboxs has ever heard of doing it that way lol

Why would he need to recirc? Are you suggesting to set the BOV so that it opens when there's partial vacuum upstream of the throttle plate?

The bov is about on the cold side, about halfway between the throttle body and the IC exit. It is vta.

I got everything IC related used in a package deal for stupid cheap, this definitely is not my first choice in bov...very loud. It worked fine for a while, but when I upped the boost it started to surge and stuff.

I'd use a better BOV, recirc if you don't want the noise.

I don't mind the noise, g/f hates it so she'd be happy for something else. I may take it apart and make sure it is clean, but I wont mind replacing it. I can't loose money on the deal.


Any suggestions on a decent bov for not a ton of money? I might as well replace it and the piping when I reclock the turbo and install a larger IC....might even look into a new wastegate for this POS greddy one >.<

good vta are the hks and greddy good bypass is the forge that is adjustable i got it and love it and it makes a nice sound still unlike the other bovs or bypasses.

http://www.forgemotorsport.com/conte...roduct=FMDVRSR

i got it in black

I love my Go Fast Bits BOV
I wouldnt trade it for anything... maybe an HKS SSQV.. but maybe not.
It's louder than hell, I didnt think so at first until I rode in some other cars with BOVs that were thought to be fairly loud.

Ive got a CX racing cheepy guy and it works way better than my HKS ever did. cxracing.com: Blow Off Valve

Just take out one of the two springs that are inside out and your good to go.

I was running a Bailey VTA, decent middle-of-the-road BOV, not adjustable though and I had surge on the downshift.

I'm running a Greddy Type RS VTA now, can be made to run recirc. I got mine used for $50, well worth it.

I guess I'll just shop around and when the time comes try and pick something up.

Why would it not surge, and now all of a sudden it is? It is a simple valve isn't it...how does that fuck up?


Edit: 2 Questions...what is with the dual port BOV...how does that work/what is the point. And how do the adjustable BOVs work?

You up the boost, you up the flow-rate and inertia of the turbo. On the downshift you have to vent more air, if the BOV doesn't flow enough you surge.

sounds like its just a pos i had a turbosx mbc and it worked for shit on my dsm i got a better one from forge worked great. turbosx is just junk i think of them as ebay brand almost. but it sounds like it is opening and not staying closed so even tho you gauge says 15psi your turbo is spinning for 20psi to make up for what it is losing.