Recommend the best BOV for my boost levels.
 

Like many, my eBay Blow off valve is not cutting it anymore.

It is the ultra-simple recirculating style, and it really doesn't work horribly considering I got it for free, but I get a little compressor surge still and (more importantly) it's not sealing well until about 4psi, meaning I get epic turbo lag at times. Funny thing is It seems to seal pretty well at idle.

I'm fine with spending some "real money" to get a "real" BOV - but want to make sure I get the right one, as I know many are made for pretty high amounts of boost. I'm only running around 8-10psi, and will probably never go to 12psi as I'm trying to take it easy on my daily driver.

Sealing at idle, no compressor surge, and no closing lag are a must. Make your recommendation!

Turbosmart kompact.

That's the one FM sells, right? How's it sound? I like it being loud I just don't like the ricey high pitched "ping" sound. The eBay unit I have actually sounds really cool because it's just a big woosh sound.

Are you not going to recirculate it? I recommend a Mitsubishi on one. The one begi sells, you can buy it at the dealer for less. From a 1995 3000gt

My only suggestion is that you purchase whatever BOV you wish for youor ride from an authorized dealer as nowadays most BOVs you find on EGay are fine replicas of the real thing.

Do your research on this when you buy a TIAL, GREDDY or. HKS. The Tial BOV replica is extremely identical to the original side by side. Read below link

http://www.tialsport.com/index.php/authenticity/117-sct

Nah, I like the sound of it vented to atmosphere, as well as I don't really have a reason to recirculate since I have MS3X.

Is that the Bosch unit? I have heard mixed reviews, but I know it's pretty cheap so I'm happy to try it.

Turbosmart Kompact Dual Port, can do VTA or recirc

forge or turbosmart for the simple/compact ones
tial for the not so compact but great anyway

just outa curiosity: what do you have now? like which exact one? link?

Dual port seems pretty cool, sounds great, and is $163 (cheapest I found so far) which is really not bad at all.

18psi: I will have to take pics of it, I've actually never been able to find this one for sale. I think its a relatively old piece, more when the chinese first started figuring out how to make super-simple BOV's.

It is not the bosch unit, this one looks and feels a lot more sturdy. It is designed to be recirculated so I'm not sure how it would sound vta

http://www.discountmitsubishiparts.c.../MD162219.html

Depending on your flange setup you may be limited. Or is it connected via hose?

I recently picked up a red limited edition greddy fv bov, much wooooosh. Actually sounds like a compressor release. Overall I'm very happy with my purchase, solved my leaky bov issue, crap idle, and no more compressor surge (egay greddy rs copy)

the FV also seals at idle due to the new spring design, lovin it.

If I were to recirc I'd pick up a GFB bov, their site has a great selection that may work for your application. They also have vent to atmo bov as well.

Holy tits the FV is expensive, but looks like a great design.

I'm connected via hose but thankfully the BOV section of my intercooler piping is a separate piece connected by couplers, so not a big deal to change it.

Yeah, it seems like a nice BOV solves half the issues everyone ever complains about. Right now I'm really leaning towards the Turbosmart Kompact Dual Port. Good sound, good value, and small size. I will probably pick it up when I get my paycheck this week; I'll report back.

One more question: With the Turbosmart, it comes in 20mm, 25mm, and 34mm outlets. Which would be best for my boost levels? I would assume bigger is needed for higher boost?

Stop associating bov size with boost levels. Its silly, becuase in our case even something like 15mm would be able to relieve pressure enough to get the job done.

it might be an issue if you drove a supra with a giant snail at 50psi....

....what I'm saying is: doesn't matter. get what fits your hose best

I'll recomend the same shit i recommend to everyone. If you want VTA, get a Forge.

https://www.miataturbo.net/attachmen...ine=1411487668

Which Forge specifically? I see they make a single and dual piston - I would assume dual is better and it's also cheaper...

seems legit

Not sure if sarcasm.

Yes dual valve has a block that stops air from entering/leaking out when on part throttle/idle.

yep, used one of those and loved it, can't go wrong

And it's only like $135 for the dual piston. Heck yeah. That's not much more than some of the knockoffs out there.

Any idea where they are made?

Why would one ever use the single piston, at the same price? School me on the pros and cons, please.

No idea but been running mine for 3 years now. The only thing i've replaced has been the Orings but those are 30 cents a piece, 2 total.

Single piston is 10 bucks cheaper. It's also simpler so less failure points. Also the secondary piston blocks some air flow on cars that matters. I dont know if there is any difference in the design of the main piston.
This one basically behaves like the Tial bovs. It's completely open at idle, and deceleration and partly open at cruise.

I was gonna say: on some cars you actually want it open at idle.

Our cars are not those cars though, we ditch the maf as the 1st order of business :party:

Come on guys I can't believe you aren't answering the important questions here.



Like can I put a duck call on it?

Duck call? Not on the VTA forge. Those are pain in the ass to modify since theres holes in all directions. You need something with a nasty hole like the diverter valves.
http://www.forgemotorsport.com/conte...oduct=FMDV006A

You can however put the inner tube on your exhaust and sound like an F1 car at times.

you'd need a bpv style for that :giggle:

Oh man oh man, I'm so putting a duck call in my eBay one before I swap it!!

Anyone try "Go Fast Bits" TMS BOVs?

I am considering something like this: http://www.gfb.com.au/products/blow-...730-817-by-gfb

Basically it's an adjustable BOV that goes from full VTA to full recirc. Mainly I like the idea of recirc for stealthy reasons but I like the ability to go full VTA if I want.

Am I being stupid?

gfb is pretty nice too

I honestly don't see the point of that though: on a car that routes the air back into stock airbox, and it is truly stealth, that would be cool. but on our setups, the difference between the settings would be loud and LOUD. Neither would truly be stealth...IMO

You can use a foot long rubber hose that will still be VTA however it will be quieter because of the additional tubing. Basically you'll get just an air rushing through noise instead of a pss.

It's a nice bov but imo it's useless for us guys that are running a map sensor and dont care about recirculating. The extra cost is only good for the MAF setups that go wonky.

IMO the Mach 1 is a better choice if u want to go that route

GFB unit looks like quality imo. Aside from MCM, I havent seen too many in action. Having the ability to go stealthy or vta can be a plus if you want the best of both worlds where as others dont care of the sound and just recirc. I would choose the manual adjustment vs the electronic motor.

Also, It looks like it would be a great fit for a begi pipe style bov replacement :bigtu:

I've owned a car with a GFB valve on it. Seriously the loudest thing ever. You drive your 200hp Miata around feeling ashamed because you're making noises that would shame a 1000hp Supra.

It is. FM used to use them on their kits before moving to Turbosmarts.

Just ordered the Forge Dual Piston with side mooted vacuum hose inlet. Should be perfect for my setup, made in UK, and only $150 out the door after shipping. I'm pretty satisfied already, I figured I would be spending $250+ on a Greddy or HKS!

Do you have a link by chance? Can't seem to find it anywhere.

Edit: Just kidding I found it.

Lol dude, I was gonna say, epic Google ninja fail.

Since I already copied the link, for anyone who is lazy: http://www.forgemotorsport.com/content.asp?inc=product&product=FMDV004A_[New%20Code]-[New%20Code]

Definitely will last longer than the condom diaphragm bovs.

True, but then you won't get the warming or cooling sensations.

I bought Vlad's Forge.... Haven't finished my motor yet but I can't wait to see how it sounds!

https://www.miataturbo.net/attachmen...ine=1411696566

you know its gon sound extra sexy just cause it was mine :dealwithit:

As someone said long time ago.. it sounds like an alien giving birth.

Sounds kinda like that but this is a bad video. You can however hear the harmonic pew going off. If you like it, do not touch anything on the holes. On the other hand if you want the regular ol air compressor sound you can enlarge them. Wish i had known that before i chopped mine up.

Enlarge holes? Alien births? Chopped yours up? Whats all this?

Sounds like my Friday night. I can't wait.

https://www.miataturbo.net/attachmen...ine=1411792862

https://www.miataturbo.net/attachmen...ine=1411792862

https://www.miataturbo.net/attachmen...ine=1411792862

Stock

http://i205.photobucket.com/albums/b...r/complete.jpg

My local supplier gets better discount for turbosmart than for forge. Anyone see any glaring problems with Turbosmart Vee Port Pro? It sounds ok on youtube...

Vee Port PRO BOVs

And comments on this: leaking under partial boost?
SI #10

Cruise leaks is not uncommon. My forge leaks between 60-80kpa however once i get to 80kpa it shuts closed again while under that the secondary white valve keeps it from leaking.

Cruise is a bit different though, since you really aren't using the turbo at all. My issue is that the eBay BOV won't close until like 4,000RPM's even at WOT most times.

Forge will be here Thursday. Stoked.

Kinda sorta related. I have this old FM Bov. Anyone know much about it? It seems to work well for all the different setups I've had on it but I haven't tried anything else and can't tell if it leaks because it's currently in my fender. I prefer little spring pressure so it vents as much as possible therefore open at idle but I run a filter on the open at idle side. Should I buy something new? Am I loosing 100 hp running this?! it's so quiet.

I've taken it apart a few times and rehoned the ID so it still slides smoooooth as butter.

http://rs192.pbsrc.com/albums/z146/f...e40c1.jpg~c200

https://www.miataturbo.net/attachmen...ve-fm-bov1-jpg

https://www.miataturbo.net/attachmen...ine=1325715660

Isn't that just an FM-badged GFB?

It very well could be, I still don't know if it's 'bad' or why. Seems to be fine but I'm missing something, like:

Huh? If you had a maf you'd want that shit closed so you aren't venting the MAF'ed air out.

On our man cars you'd want it open at idle, no? This is why I like my FM with it's filter and why I haven't gone with a tial Q.

I use a Vee-Port Pro. I had the model before it as well. Think it was just called a Vee-Port. And I used one on my WRX awhile back too. I have really liked turbosmart products. I have a 38mm UltraGate that I will be using on the new setup.

So I got my Forge today. STOKED. Put it on. Massive compressor surge.... Opened it up... sent me the yellow spring instead of lighter green one. Ugh. Called. New one is on its way.

This brings me to the question: what spring do you guys use on the idle side, to keep it closed during idle? I have red, yellow, blue, green, and the stock one in it which is very light. Idle did seem to be much different as soon as I installed the new valve over the old China one so I'm assuming its either sealing a lot better or leaking a lot better, but don't know how to test it hahaha.

you're not venting it out, it goes back to the inlet after the maf and right before the turbo. the stocker actually opens at idle a little too, I think its to keep the car happy and not surging when letting off (that roughness for a split second right after easing off the throttle when the bov goes between open/closed a few times)


TEST:
1-put in softest spring
2-observe if its open at idle
3-replace spring with stiffer one until it doesn't, without making it surge like crazy
4-????
5-Profit

On MS controlled miata's I've actually had much better luck maintaining a rock solid idle with the bov not open at idle. I don't think there's a drastic difference either way, just my preference. I know some people swear by having it closed at idle.

Umm you want the main valve to be open at idle.

I cannot imagine that there would be very much differnece if the BOV is or is not open at idle (filtered). Very little air acutally flows as there is very little pressure diffence. On one side (at the outlet port) there is atmosphere +/- whatever the fan might be inducing. On the other side (charge pipe) there is atmosphere +/- filter drop +/- idleing compressor - charge pipe drop (at idle).

On my Mitsubishi BOV, open at idle, I put a plastic bag on it at idle and it neither inflated nor pulled into the filter.

AND all of this is occurring upstream of the throttle and AIC valve.

At idle you want maximum vacuum. with it closed you get maximum vacuum.

Its likely not a big difference, I'm just sharing what worked for me.

Interesting. I would think logically it should be closed. I've never used a 2 stage BOV so I didn't know if there was a process like "tune this then that" or anything, thats all. I'll just screw with it.

its not two stage
its just dual piston. so even with the softest piston it should still remain closed at idle.

so you will likely be ok even with the softest spring

+1 to closed BOVs, :party:

In my case using the MAF still, anything not through the MAF is air not accounted for. Once I got my greddy fv, I re-tuned the idle and its butta at 14.7 afr & no more crap idle.

Follow 18's test recommendation, you'll be set in no time.

Not AFAIK.

I had that FM valve on my original kit (2002-vintage 2-cat 99 CARB-approved kit w/ Link Piggyback). It's huge, much bigger than the GFB valve that came when I upgraded to the modern FM2 hardware a couple years ago.

The old FM valve was dual port -- if the piston moved a little bit, then it opened the recirculation port (the one with a flange on it), but if it moved a lot then it opened up a second port on the other side that did VTA. It didn't leak through the VTA port at idle, so didn't piss off cars that still had the stock ECU with the MAF hooked up (like with the Link Piggy).

Aside from being huge and comparatively heavy, the main downside was that the recirc port flange was not retained very well and had a tendency to come off. It was basically pressed into the housing with a few punched retaining points around the circumference, but mine kept coming apart. I eventually JB welded it on.

--Ian