Actually - tuning the Synapse itself it about the same as a BC....that thing is cool!


But otherwise - you still want to use the UIM...especially with a good BOV.

I would tune to Port C personally; since I like the Fail Open option. Even though as arghrx7 said it is supposed to be wired to Port A

 

Yea, Port C gave me about 6 PSI so having that with the BC should allow me to adjust out to 10-12PSI nicely. I'm currently running Port D without the BC for about 7.5 PSI, while it would be nice to have the option of 15PSI on demand an unexpected BC fail could get ugly.

 

You can swap springs too.

 

I'm using the lighter spring now, if I went to the higher it would limit my port options since they would all make too much boost in a BC fail situation Unless I just put in the higher spring and didnt bother with the BC.

 

Fixed


.... awaits attack from soldering iron LOL

 

Ahhh I see, I think I just caught up. You guys arent debating where to get the boost reference for the WG or BC solenoid. You guys are debating if the BC Sensor Signal should be WITH the boost reference or off the manifold pressure? Hmm..well since I'm using an AEM Tru-boost, my BC signal is also my boost guage signal so its UIM for me.

 

Correct .
BTW you still get the same boost reading at WOT if you take it before the throttle plate . Just at part throttle you will see higher boost than at the UIM and you wont see any vacuum ....

 

If I were rich, I would just buy you the damn BOV... rather than have you doing all this wacky stuff.

 

What about all the Greddy owners out there with crappy BOVs ? This thread was aimed at helping those guys as well .
I just wish you or MM would test this out and stop rubbishing the idea based on your perception of what is correct rather than from having actually tried it out .

 

hks ssqv pwns synapse

 

I test it every time I drive my MS6 or RX8... just not the way you want me to.

If I am half throttle and then start to modulate it - I can hear the bov venting air; closing, venting again as I toggle around with the throttle instantly.

And then when I mash it - I get full boost instantly since my turbo is still spooled up.

The BOV I have is less than $300...

 

HKS and Synapse are both piston type BOV's... so they basically work the same - the HKS just doesn't open in vacuum and it sounds like a kazoo.

 

LOL kazoo; yeah it kinda does

I would give the synapse a go but there is too much to tune...I have enough to worry about with tuning a BC lol...
The HKS is right up my alley...install it and drive.

 

Thankyou -we are getting somewhere . Is that a recirculated BOV ?

 

Yeah Synapse on recirculate. It doesn't have to be tuned - it just has to be hooked up right.... 3 signal lines, boost only, and two vacuum lines.

When the boost line is ANY higher than the UIM vacuum lines - it opens.... too easy.

 

i like the 1 signal line....haha

meh, I may try it eventually. I get bored of parts on my car quickly and like to switch stuff out.

Do you think it's a big step up over the HKS?

 

OK . Now imagine you put a TurboXS vent to atmosphere BOV on there with the stock spring in it (what I have FWIW) . That thing will not open until there is a pressure differential between the UIM and the charge pipe of around 15psi or more . It can't because it would leak at idle otherwise and your idle would turn to crap.
Now you accelerate in partial throttle - somewhere between 0and 5psi at the UIM .
Bam ! 15-20 PSI in the charge tube and an extremely twitchy throttle .

Plumb your boost control before the throttle plate and this wont happen but you will still have the boost you programed in sitting there so no lag whatsoever .

 

I think so - but Jeff say's it opens TOO early... HAHA; but ask Ray - I keep selling them out of BOV's as my buds try out mine.

With slower spool.... don't make changes due to poor designed parts - get better designed parts.... how is this even an argument?

 

I will take your word for it; I think you know what you are talking about

 

It's an argument because most guys that fit a Greddy turbo also fit a cheap BOV or a vent to atmos BOV and will have this issue . They will tolerate it thinking that is just how it is so live with it . I'm saying there is is a way to use those parts and still get great throttle control and not overly stress the charge tubing .

 

BTW - the VTA issue doesn't matter for BC purposes; just for tuning.

 

.
A VTA BOV cannot allow leakage at idle on a MAF based system so needs a higher operating pressure differential to prevent that . Hence the problem at part throttle with such a BOV.

.
If it opens the way you descibed I'm inclined to agree with him

If it opens they way you described I'll bet my setup actually spools way quicker than yours (from a partial throttle situation)

 

If your turbo (spinning at less RPM due to your open / partially opened wastegate) spools faster than mine (spinning at the appropriate RPM with wastegate closed)... then you've got me...

 

/\ lots of people like to run a VTA BOV . I'm saying that if they do that , they will have much better throttle control if set up the way I described .

Re the spooling - you forget that I already have pressure behind the throttle plate (as much as 10psi) even though the UIM may be at 0psi .
At the same load you will have less pressure in the charge tubes and the turbo will need to pressurise them when you open the throttle .
Can't see how you could possibly think that yours would spool faster under that scenario .

Actually : on reflection I can see it is not such a clear cut argument . Your turbo would be flowing more air but my charge tubes will be at a higher pressure so it could well be much of a muchness ...................Probably nothing in it .

 

What did I just say a few posts back?

Of COURSE I've tried it.

More important is the fact that you guys STILL don't seem to get the idea behind flow.
What is all this BS about pressure? Who cares?
Ask yourself - at your pre-throttle 10 PSI or whatever, how much is the turbo flowing?
That is why we want the turbo to be pushing ahead of the engine demand.