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Old 09-24-2010, 11:03 AM   #251
Davenow
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Originally Posted by sky3 View Post
Ok, I read the first page, and I got a question.

I do not know for sure how my HKS SSQV BOV is set up, it was on the car when I bought it, granted, I didn't know much about EM so I just figured it wouldn't do any harm. Now, I'd like to adjust it, but have no idea how...

This something I can google to adjust? Or should I just take it out since I'm on stock turbo boosting around 16psi...
Its been a long time since I had one of those in my hands. Honestly, the SSQV is one of the most leak prone valves on the market. They tend to leak at stock boost. Your best option is to sell it and get something else. If you like the sound, I would highly recommend the TurboXS Type H, the Perrin, the APS, and if you can find the adaptor, the TIAL is the best on the market by a large margin.
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Old 09-24-2010, 11:34 AM   #252
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You do not need to adjust the HKS valve. It works backwards from other valves. The adjustment just seats the valve down.

C
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Old 09-30-2010, 10:55 AM   #253
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Originally Posted by Clark Turner View Post
You do not need to adjust the HKS valve. It works backwards from other valves. The adjustment just seats the valve down.

C

There ya go
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Old 09-30-2010, 02:17 PM   #254
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I have been reading almost all the comments, but i havent read about the worx, i bought it use, what i have read is that this bov seems to be closer to the stock one but i dont know how to adjust it. should i put the stock back?
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Old 09-30-2010, 08:41 PM   #255
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Originally Posted by SubiSam View Post
Ok, I really hate to start the debate back up. I will be as nuetral as possible. I just don't see how in the world anyone would honestly think a VTA valve wouldn't throw fuel trims off. The comment about the rich spike only happening for a short period of time during shifts is indeed accurate. Furthermore, there is no A/F learning going on when the throttle is closed and the car is moving.

However, any time the valve opens and the throttle is not fully closed is a different story and this is usually not just a short period of time. It's almost constantly while cruising around town from stoplight to stoplight. Every time you hear the valve blow off it is dumping excess fuel, and every time it does it in closed loop it will try to make corrections and learn. LTFT will not be accurate with a VTA BOV. That means load calculations will also not be accurate.
If the BOV is sounding off while you're "cruising around town from stoplight to stoplight" then the BOV should be adjusted to stop that from happening.

You're correct that this will screw up the AF Learning - I saw it first-hand immediately after putting a BOV on my car. But, the problem went away after tightening up the BOV to prevent it from opening during normal driving.

It's not an inherent side-effect of running a BOV. It's an inherent side-effect of running a poorly adjusted BOV, or a non-adjustable BOV that just plain sucks.

(FWIW, the short rich spikes and afterfires from shifting in boost were still a big enough nuisance that I ended up going back to a BPV.)
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Old 09-30-2010, 09:02 PM   #256
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The maf table will be very different between open and closed loop bovs. This will be evident in the learning, sometimes the knock learning and of course the soot on your rear bumper
C
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Old 09-30-2010, 10:10 PM   #257
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Are you saying that you change the MAF scaling to mitigate the rich spike that comes from venting metered air?

EDIT: so, for example, when your BPV MAF scaling would say 75 g/s (for example), your BOV MAF scaling would says 68 g/s (for example) to fool the ECU into delivering 10% less fuel?

Last edited by NSFW; 09-30-2010 at 10:33 PM.
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Old 09-30-2010, 10:55 PM   #258
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Thats not the stratagy I use. I am not sure that would work. You would not be able to find each and every spot without trashing the table for cruise or full throttle.

C
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Old 09-30-2010, 11:52 PM   #259
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That's why I asked... I don't see how you can tailor the MAF table to compensate for a BOV's richness, without creating a lean spot when you just roll on the throttle and go through the same MAF-voltage range.

So, what did you mean by using a different MAF table when using a BOV?
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Old 10-08-2010, 12:48 PM   #260
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very useful thread!
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Old 10-08-2010, 10:00 PM   #261
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There's only one MAF scaling in the Subaru ECUs I'm familiar with, Clark. If you're tweaking it to fix the BOV problem, your customers are running lean when they roll on the throttle.
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Old 10-09-2010, 02:11 AM   #262
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The rich condition is so small and for such a brief period of time, that 99% of people who even mention it, would never, EVER see any negative affects from it.


The problems that people experience that they almost always blame on the rich spot, come from improper maint/install/adjustment of the BOV itself.

And there is no tuning for a BOV. You cant predict when/where/how much it will vent, so any attempts to compensate for it, are counterproductive and a waste of time.
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Old 10-12-2010, 06:01 PM   #263
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Great post Dave, thanks for clearing the air. Interesting feedback from the original turbologist, Corky Bell, regarding compressor surge. Everyone is so quick to join the witch hunt. I think these days, with so many modern turbos using 360-degree thrust bearings, I might go as far as to say it's inconsequential to most builds.

As a matter of fact, we don't run any BPV at all on one of our race cars in the Czech Republic, just a blanking plate on the TMIC. For disclosure's sake, that particular car runs a twin-scroll VF36 (so far without issue in multiple events, I might add).

On my RSTI with an APS SR55, the first owner ran an HKS SSQV with the adjustment bolt JB-welded into place. I am sure it leaked and provided for off-throttle inconsistencies, so I switched it out for an original TiAL 50mm mounted with an adapter flange on the OE TMIC.

I was experiencing some idle flux with the 11psi spring, so I swapped for the 12psi spring and never had another problem, anywhere in the rpm range. Of course it chattered at low boost, but it opened "cleanly" and quickly at high boost and that's all that matters.

Don't even get me started on those bootleg Synapse YouTube videos that try so desperately to villainize TiAL.
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Old 10-12-2010, 06:52 PM   #264
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Nobody has tuned more subaru maf tables then me on planet earth. Dont suggest idiotic things like my tunes are lean. The vent to atmosphere bov cant be tuned using three simple meathods in the ecu. This is why I have seperate files for both setups and even some for different styles, like HKS or Tial.

C

Quote:
Originally Posted by NSFW View Post
There's only one MAF scaling in the Subaru ECUs I'm familiar with, Clark. If you're tweaking it to fix the BOV problem, your customers are running lean when they roll on the throttle.
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Old 10-12-2010, 06:57 PM   #265
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Quote:
Originally Posted by Davenow View Post
The rich condition is so small and for such a brief period of time, that 99% of people who even mention it, would never, EVER see any negative affects from it.


The problems that people experience that they almost always blame on the rich spot, come from improper maint/install/adjustment of the BOV itself.

And there is no tuning for a BOV. You cant predict when/where/how much it will vent, so any attempts to compensate for it, are counterproductive and a waste of time.
Dave, I dont agree with you on the adjustment not having any effect. There are many types of valves. The big thing that must be done is to stiffen the spring or adjust the valve so the thing does not:

1. Open or leak at idle.
2. Open or leak at cruise or on Decel, (heavy vacuum)
3. Does not blow off if you let off the gas on a shift under 0 manifold.

99% of these damn things are way way to weak and they are open way to much. The only time it should open, Is when you have positive manifold pressure and need to release it. Not while shifting around town from a stop light.

as for the synapse, It wont work correctly on the subaru. It leaks like a SOB and makes drivability ****ty.


C
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Old 10-12-2010, 09:28 PM   #266
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Quote:
Originally Posted by Clark Turner View Post
Dave, I dont agree with you on the adjustment not having any effect. There are many types of valves. The big thing that must be done is to stiffen the spring or adjust the valve so the thing does not:

1. Open or leak at idle.
2. Open or leak at cruise or on Decel, (heavy vacuum)
3. Does not blow off if you let off the gas on a shift under 0 manifold.

99% of these damn things are way way to weak and they are open way to much. The only time it should open, Is when you have positive manifold pressure and need to release it. Not while shifting around town from a stop light.

as for the synapse, It wont work correctly on the subaru. It leaks like a SOB and makes drivability ****ty.


C
That's all it took for my TiAL 50mm to work properly. It seems many folks are sold on the 11psi spring for Subarus in general (based upon a collective, average vacuum reading at idle), but I found it to be too soft. The 12psi spring did the trick. As I wrote, a bit of chatter at low boost, but entirely inconsequential as low boost driveability was greatly improved, idle included.
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Old 10-12-2010, 09:46 PM   #267
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Some will disagree with me just because its me making the statement. But in reality, I have spent alot of time with these cars. You are better off with the heavy spring in all cases. Alot of times, I use washers or loose change in my pocket to preload these bovs. Once I do that, the car runs better and I have to use less trickery in the load system.

The tial Q is one that comes with a spring way way to light. These things are open at idle which makes tuning the thing nearly impossible. Put in the heavy spring and your good.

The best on a MAF car is really to just vent back to the intake. Sometimes thats not possible or might not be the best solution. But if you have street car running 20 psi or less on a small to medium turbo, Vent back if you can.

C
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Old 10-12-2010, 11:12 PM   #268
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Quote:
Originally Posted by Clark Turner View Post
Nobody has tuned more subaru maf tables then me on planet earth. Dont suggest idiotic things like my tunes are lean.
I'll retract that statement if you'll explain how tweaking the MAF table to compensate for a BOV isn't an idiotic thing.

Last edited by NSFW; 10-12-2010 at 11:31 PM.
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Old 10-12-2010, 11:26 PM   #269
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I am not here to argue with you. Your here to try to make me look bad. Its stupid. Just stop man.

C
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Old 10-12-2010, 11:31 PM   #270
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I'm not really here to make anyone look bad, all I care about is correctness of the information that's posted.

I'll remove the last sentence from that post, that was unnecessary.
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Old 10-12-2010, 11:38 PM   #271
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Old 10-13-2010, 10:20 AM   #272
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Quote:
Originally Posted by Clark Turner View Post
Some will disagree with me just because its me making the statement. But in reality, I have spent alot of time with these cars. You are better off with the heavy spring in all cases. Alot of times, I use washers or loose change in my pocket to preload these bovs. Once I do that, the car runs better and I have to use less trickery in the load system.

The tial Q is one that comes with a spring way way to light. These things are open at idle which makes tuning the thing nearly impossible. Put in the heavy spring and your good.

The best on a MAF car is really to just vent back to the intake. Sometimes thats not possible or might not be the best solution. But if you have street car running 20 psi or less on a small to medium turbo, Vent back if you can.

C

Yup, even the original TiAL 50mm opens at idle with the 11psi spring. I originally got a TiAL Q, but quickly found out that it will not clear the intake manifold when mounted on the OE TMIC with an adapter flange. So, I traded Junior for his OG 50mm since he's got a giant FMIC on his RSTI build and clearance isn't an issue.

I have since sold the car, but I'll probably try the latest TiAL recirc valve on my next build.

http://tialsport.com/prod_bv_qr.htm

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Old 10-24-2010, 11:24 PM   #273
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Awesome write-up for sure.I was planning on a recirc valve on my audi because of the same reasons stated, and I think I will be just leaving the stock one then for the Legacy. Thanks for the insight. I will be sticking with a 50mm Tial for my VW though ( no MAF )
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Old 11-07-2010, 10:46 PM   #274
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Good Write-up.. There should be a thread like this on Accessports...
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Old 11-09-2010, 09:10 PM   #275
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Alright new guy here not just to subarus but forced induction. So I'm on info overload right now, I'm trying to do as much research as I can so I dont just throw money at my car and make it slower. I cant seem to find info about the wastegate, I've read tons of stuff about bovs, intercoolers, tuners, exhaust, etc but not much about the need to upgrade the wastegate. Is whatever is on the turbo good enough. I'm sure some one might call me an idiot or something for asking but if I dont ask I wont know the answer.
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