My bypass valve is, uh.. Not bypassing
 

Took the miata out for the first time under boost today. Pulls nice, but my bypass valve isnt relieving the pressure from the charge pipes. Its a 1g DSM (uncrushed) bypass valve, and I ran the signal line after the TB. I thought maby it was because it was after the throttle plate, but I looked at a friends setup and his was after the throttle plate too.. The valve itself is installed correctly so I dont know why it isnt opening. :td: Any ideas? The valve itself isnt seized, I played with it quite a bit before installing it.

if it's installed correctly, and you're sure it's not siezed it could be one of 2 things that i can think of before my morning coffee: kink in the line or leak in the diaphram.

yep the bov needs a good vaccum source so a dedicated line from after the TB, is perfect. So check your diaprhagm and is there a adjustment bolt?

You've gotta post a couple pics if you want us to help you out with this one. You say it's a good piece, and you've mounted it correctly, and you're giving it a good source.... but it's not working?

If it's a good piece, then something is wrong with your setup. Post pics!

Take the vac/boost source straight from the intake manifold to the 1G BOV.

You do know they leak air (not fully closed) at idle? Unless you are running it recirculated or a MAP system, this will cause issues for you.

I will try to get some pics tomorrow night, but i'll be swapping in a new mitsu bypass valve as well to see if it was just a bad BPV. I don't think it is the setup but this is my first boosted car so i'm bound to make some mistakes that I wont realize right away. I have the valve installed about 6" after the compressor outlet, and recirculated about 6" before the compressor inlet, after the MAF. I have the flanged end of the BPV on the pressure side (compressor outlet), and the tubed end going back into the intake. Appears to be the same way that its installed on DSMs.

Uploaded pics to my VBgarage, I put a line on the flange just to give reference since the pic is pretty dark. The other pic is just showing that I have it going to the manifold.

https://www.miataturbo.net/forums/vb...o=view&id=2536

are you sure you just cant hear it? they are pretty quite.

To be honest, i'm not sure and I think that may be a good possibility. I swapped in a new 2g DSM bpv, and I dont notice much difference. I am open down pipe, so I probobly just cant hear it.. Plus now that I think of it, I didnt hear any compressor surge, then again im sure I wouldnt hear it over the exhaust anyways. Maby I just went alittle over board with the turbo size itself hah.

yeah, you aint going to hear the loudest BOV over that noise :gay:

2G DSM BOV is a plastic POS.

You should be able to hear the 1g over the open dp at part throttle when letting off boost. Compressor surge too.

You can remove the recirc pipe as well temporarily (you will run rich at idle, car will want to die) but once you get moving it should run fine, just to hear it more clearly if you can't at part throttle.

It's a decent low cost BOV (can find them < 20$), just it would be nice if it didn't leak air at idle (which is a non issue with a MAP based system like MS.)

Hope that helps.

I put the 2g on just to see if it made a difference, it wont be staying on. Won't the idle leak with the 1g not cause any ill effects since its being recirced back into my intake post MAF? I think i'm going to vent the 1g for a trip around the block to see if i'm just being an idiot or if it really isnt opening.

I said above that yes it would.

How does it cause issues though? I mean all of the metered air is staying in the system, so I didnt think it would be a biggie. BTW you can mod the 1g to stay closed at idle, i just dont have the drive to do so at the moment lol. I may buy my friends Greddy RS and recirc that for now.

if the thing was gutted/ported/wide open at idle with the thing recirculating back into the intake there would be no ill effect.

I said it would only cause effects if the recirc pipe was removed. Which is what you wanted to do, to check if it was actually working.

Oh my misunderstanding, I get what you meant now.