ZX-Tex

iTrader: (15)

OK so if you go to the build thread link in my sig you will see the BEGi-S install as well as the cowl CAI system I am running. One thing about the CAI I did not like is the loud compressor surge coupled with the low frequency fart sound every time I let off the throttle. It is loud, much louder than the normal suction under boost sound. Annoying IMO.

The accepted wisdom is that for low boost (7.5 psi max in my case) that a BOV is not really necessary as the surge is not bad enough to damage the compressor. Even so I decided to give a BOV a try to see if that would help with the crappy off-throttle sound. After agonizing over what to get, thinking about how to modify the charge pipes, etc etc this solution hit me as easy, cheap and plausible.

So here is what you do.

Buy one of these 2" t-fittings and install it in place of the coupler BEGi gives you to join the two intake tubes (between the turbo and the throttle body, in front of the valve cover). This gives you a 1" connection point for the BOV. It takes all of 5 minutes to install. I bought mine from Forge.
http://www.forgemotorsport.com/conte...roduct=FMTP-51

Then all you need is a BOV with a 1" inlet. I bought this Bosch-like recirculating valve from an Ebay seller. It looks just like a Bosch, but has an black (powder coated?) aluminum housing and a piston valve instead of a diaphragm. And the springs are easily interchangeable.
http://cgi.ebay.com/ebaymotors/ws/eB...D77%26_fvi%3D1

The whole install took less than 15 minutes easily. I used the vacuum fitting on top of the manifold near the throttle body for the BOV vacuum connection. I do not have it recirculating, just VTA. Started the engine, revved the engine a couple of times with my hand by the BOV outlet, valve works. And better yet, no compressor surge farts! I took it for a drive and it sounds great, soooo much better than before. It makes a not too loud pffffffftttt sound with a little bit of a high-pitched whistle. Better yet the turbo seems to stay spooled better between shifts, or at least the lurching from on-throttle/off-throttle/on-throttle transitions is much better.

So, if you have a BEGi-S, and hate the compressor surge farts like I do, consider this option. It will take you less than 15 minutes to install and cost less than $100. Assuming the BOV holds up I am quite pleased.

Picture below. Sorry for the crappy photo quality all I had was my camera phone. But you get the idea.

cjernigan

iTrader: (13)

Looks good man, anything is better than compressor surge.

ZX-Tex

iTrader: (15)

One thing that would make it look even better is if I had bought a BLACK coupler instead of that BLUE color which I dislike. I thought I ordered black, oh well. I'm still pleased.

chriscar

iTrader: (24)

Nice job. That eBay bov, is a total clone of a Forge 007. Looks like they ran it through a copy machine.

C

ZX-Tex

iTrader: (15)

I went to the Forge site and found the valve you mentioned. Very very similar. The main difference I can see is this one uses an aluminum piston with an o-ring to seal the small domed end against the inlet hole. The Forge version uses a plastic piston. Not necessarily worse, just different.

elesjuan

iTrader: (11)

Cool, Looks great man!

I bought a knockoff Greddy Type-S from someone on here, which looks 100% identical to a real Greddy aside from "Greddy" cast into the base, and the sticker on top.



The thing works perfectly. Took me all of five minutes to get it adjusted to a setting I like and it cured my Mazdaspeed6's Boost leak issue. Boost gauge would actually rattle under hard acceleration, solved 100%. Has a neat little whistle to it too. These Knock-offs seem like they're really good quality much to my surprise!

driftbandito

props on being creative

chriscar

iTrader: (24)

Where'd you see that? This is what is inside a 007.




C

Ben

iTrader: (33)

Might be a good idea to put a filter at the open port of the BOV

PAT!

iTrader: (1)

We haven't used a plastic piston in years. Our instructions and the like might still show the plastic pistons though.

cardriverx

iTrader: (12)

you work for forge? Where is our forge i/c kits? haha

ZX-Tex

iTrader: (15)

Got it right here, from a link on the Forge web site on the 007 description page.
http://www.audiworld.com/tech/eng16.shtml
As said by Pat that must be an old version.

Yep I am either going to add a filter or go to a recirc setup. The filter will be easier and the BOV is not too loud. You can just hear it with the windows rolled up and the hard top on but it is not screaming for attention.

chriscar

iTrader: (24)

Yeah, that was from 2001. I bought a used 007 and needed a different spring for it. I called Forger, and they sent me the spring AND a rebuild kit which IIRC contained a new piston for free. I love stuff like that. These knockoff products are making it tough for the good guys, but it's hard to resist them sometimes.

Sorry to hijack your thread.

C

ZX-Tex

iTrader: (15)

No problem. I really had no idea it was a knockoff until you pointed out the one on the Forge page.

samnavy

iTrader: (7)

ZX, that exact T-coupler and a OEM Bosch BOV off a Saab is what I use. I've had it 2 years now with ZERO issues. If it ever fails, I'll just swap to a crushed all-metal valve from a DSM.

budget racer

iTrader: (1)

nice and easy.....i'm totally stealing this idea

ZX-Tex

iTrader: (15)

OK not that I was expecting any trouble but I've put a couple hundred miles on it and I'm still liking this mod. I like it a lot actually. I am still very pleased to be rid of the compressor surge farts. It is also easier to hear the turbo spooling up and down.

I added a filter to the BOV. It is one of those valve cover breather filters from Auto Zone on the same aisle as all of the ricer stuff. It has a 1" nipple on it, same size as the BOV. I browsed the hose aisle behind the counter and found a small 1" hose with a 90 deg bend that fit perfectly. It looks like it is a heater core hose for some unknown to me vehicle.

Adding the filter to the BOV was an easy mod; I did it in the Auto Zone parking lot in about 2 minutes.

ZX-Tex

iTrader: (15)

Update. Over 1000 miles at this point and all is still well. I did make one significant change however. After reading this thread I switched the inlet and outlets on the BOV. I also switched out the soft spring to the blue spring.
https://www.miataturbo.net/forum/showthread.php?t=20366
The sound is much better and I am glad to be rid of that whistling/ringing noise. Now it is just a high pitched hiss, and it is noticeably quieter as well.

Here are some pictures of how it is now attached.

disturbedfan121

iTrader: (5)

awesome man, i just found this, I'm def going to do this when my kit comes in next week