I just wanted to pass on my horrible experience. I have been unable to get my car to run right for quite a while. First I found a leak in the crappy GReddy couplers..a well known common problem. Fixed that. It helped a lot, but I still had major problems. Rough idle, bucking, can't tune the boost controller, etc. I discovered that my GReddy Type RS BOV is broken. I disconnected the vacuum line to it, plugged that line off, and all my problems practically disappeared. The valve still opens some even without the actuation vacuum line connected! Now it makes a chattering sound when changing gears, so obviously the spring has gone to hell. I suspect that it is constantly leaking air. My car was backfiring too, but now that is cured. So if you have this valve and you are having issues with power, acceleration, bucking, etc., check your BOV!! I'm going to remove it for now, and consider whether to fix it, or just get another vendor's BOV. I think I will go with another. Any recommendations would be appreciated. As much as I am thrilled I found the issue, I am very disappointed at the same time. It is ridiculous that the spring has given way after so little use.

 

hks ssqv is said to be the best around here ....

 

Either that or the Synapse, depending on preference.

 

i have both the hks ssq and greddy rs bov's (i run a adapter so i can switch back) the hks is a night and day difference and runs awesome unrecirc. by the issues your describing which where the same as mine with the greddy rs i bet you the rubber seal inside is bunched/overlapping not the spring failing, its a common issue and may be under warranty by greddy..unfortunately its a design flaw..take it apart and inspect the rubber seal..my vote goes with the hks bov (you can source a greddy to hks flange from "dejon" they are a major dsm aftermarket part supplier)

 

For sure go with the HKS one. I run it and like greg said, it works like it is recirc'd. My car has only backfired once and that was cause I hit the gas on and off real quick and the car didnt like it, lol, but during shifts never once backfired. Plus it sounds 1000 times better than the ricey Psssshhhhtt the Greddy produces. Plus its impossible for them to leak cause the more boost you run, the tighter it pushes the valve closed and theres no tuning.

 

Have you tried tightening the BOV? Have you verified its closed when your reving the car to 2-3k and holding it there?

thewird

 

Thanks for the replies everybody. I have that joker as tight as she'll go, and still leaking. The bizarre whistling I had on decel stopped, so that was definitely coming from the BOV. I didn't know where that pesky squeak was coming from.

I looked at the Synaptics. I like the design, using a piston. I watched some videos on youtube of it in action. It has a superfast reaction time I haven't looked at the HKS, but I will check it today. Can you get an adapter for the HKS (from GReddy to HKS)? You can for the Synaptics. It'd be nice to to have to do any welding.

As far as recirculation goes, do most of you recirculate or do you generally not have problems bogging down?

Thanks again for the input.

 

there is a greddy to hks adaper that is a bolt on option..call this place
http://dsm.dejonpowerhouse.com/
myself and konig are both using the adaper with no issues

 

Do you realize your problem is coming from not recirculating? With a MAF based system you have to recirculate or you'll have issues like the ones your having >_>

thewird

 

^^ you don't HAVE to recirculate on our cars.

 

You don't have to reciruclate on any car but then you will have similiar problems because the MAF has already counted X amount of air and will be injecting Y amount of fuel. If W amount of air escapes through the BOV, the car will go rich and bog when the BOV opens. This will happen with any BOV that isn't recirculated.

thewird

 

thewired speaks the truth.... your BOV may be jacked - but as long as you VTA you are going to have some kind of over-rich issues.

 

+1 on synapse

 

Yeah Synapse is the bomb.

 

is that cuz you blew an apex

 

ha

















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ha

 

yeah - a bit lame sorry dude

 

Just raw curiosity I'll claim ignorance if I go no duh after I read answer, but couldn't you just place the BOV before the MAFS? Only downsides I can think of is slight delay from distance to throttle body, but shouldn't be enough to effect its purpose. Other being your not putting the little spit of positive pressure back into the intake. Seems like the benefit if this is even slightly an issue would outweigh that spit of air. Oh I suppose if you don't like the noise that could be an issue too, but meh. Read alot of placement cold versus hot side of innercooler for other cars, but i'm saying still on cold side just before mafs readings.

 

maf sensor is before turbo and blow through maf has not been used successfully with flash tuner ............... yet .

 

Yeah...why can't the ecm view the air flow past the turbo? I'm tired, i'm missing something I know I am. I've seen a probe setup with the MAFS past a supercharger so what is changing through the turbo?

 

A probe setup, like a ford? That's a VAF. There probably isn't a legit reason the blow through wouldn't work unless the MAF its self doesn't like positive pressure. Then again, it's about about how consistent and precise your readings are. Preturbo, you have ~atmospheric presure air running by at roughly ambient temperature. Post turbo, you have air at varying pressures and temperatures. The MAF its self only returns one value so I could see getting consistent performance on a blow through to be tough.

 

Yeah yeah yeah here we go.
2006 Miata with MAFS in stock location
http://www.turbomagazine.com/feature.../photo_02.html
So why doesn't this work for us?

 

I don't think anyone said it couldn't be done, only that it hasn't been done yet.

 

I don't think there is anything wrong with this guys BOV. You just can't run an open BOV with a MAF and expect perfect drivability. One of the advantages of running a MAP over a MAF, you can run an open BOV.

There would be no way to correctly do a recirculation if the MAF is after the turbo. The air would be backfeeding through the MAF when it is released or even feeding through depending on BOV placement causing weird readings and incorrect fueling.

thewird

 

No my post was based on open venting the BOV. It would be (from engine) Throttle body, MAFS, BOV, IC, Turbo. Eliminate the need for recirculation all together.
I was just curious why it hasn't been done this way? Has to be a reason. Seems like more effort to put in the recirculation and re position the MAFS. Would save on cost (slightly) to stop piping at the stock location of the MAFS.