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Old 07-26-2004, 03:05 AM   #1
98kPa
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Question VF34 ignores boost control, what else to check?

My fairly new VF34 loves to boost, no matter how I try to stop it. After trying a few things with my EBC I took it out of the picture and put a line from the compressor nipple directly to the wastegate. It still will boost at a normal climb to 20PSI if I try (and higher if I foolishly keep laying on the throttle). I believe the wastegate on a standard VF34 is set to around 10PSI, yes?

Now this is NOT creep. I don't try to maintain, say, 16 or 17PSI and it slowly creeps to 20. If anything its more like spiking, but its not really spiking. Its all running on wastegate tension and boost climbs at a decent rate (I can watch it digitally) to 20PSI. It seems to me that the wastegate just isn't openning, as though its stuck or the actuator is malfunctioning.

The next thing I might try is to check out the actuator's rod. I believe there's an adjustment screw/nut, isn't there?

Any ideas or suggestions?


'02 WRX, Stage 4 UTEC (helix up/dp, hks catback, STi pinks, vf34, stock TMIC, Blitz SpecR inplace of UTEC for boost control). The map I am running right I've tuned quite conservatively. If anything it errs on the rich side. Timing is down to the point where I get no (known) knock, except when I'm hitting 20PSI...

jason
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Old 07-26-2004, 03:17 AM   #2
batmanalan
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did you put an extra spring on it? buy it used? hmmm
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Old 07-26-2004, 12:00 PM   #3
subieworx
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Is the WG stuck closed?
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Old 07-26-2004, 12:41 PM   #4
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Quote:
Originally Posted by batmanalan
did you put an extra spring on it? buy it used? hmmm
Nope and nope.

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Old 07-26-2004, 12:41 PM   #5
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Quote:
Originally Posted by subieworx
Is the WG stuck closed?
Get some coffee and reread the 1st post in the thread

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Old 07-26-2004, 12:51 PM   #6
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Quote:
Originally Posted by MMBOOST
Get some coffee and reread the 1st post in the thread

jason
Must have skipped that part. Unhook the WG arm and see if the flapper door is stuck. That way you will be able to narrow it down even further.
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Old 07-26-2004, 03:10 PM   #7
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Quote:
Originally Posted by subieworx
Must have skipped that part. Unhook the WG arm and see if the flapper door is stuck. That way you will be able to narrow it down even further.

Thanx.... hmmm. What to look for? If I unhook, the WG should drop freely? Is there a way to adjust it? Whats bugging me is that it was working and not its not - makes me thing something became misadjusted. (if that's a word).

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Old 07-26-2004, 03:11 PM   #8
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Catless?

Sounds like a classic case of creep.

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Old 07-26-2004, 04:20 PM   #9
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Catless yes... but I have pretty much no control over limiting boost. Like I said, it doesn't get limited and then creep up slower than it originally rose. And its not a momentary spike. This rise in boost is seems completely normal... it just doesn't want to stop.

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Old 07-26-2004, 04:23 PM   #10
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Quote:
Originally Posted by MMBOOST
Catless yes... but I have pretty much no control over limiting boost. Like I said, it doesn't get limited and then creep up slower than it originally rose. And its not a momentary spike. This rise in boost is seems completely normal... it just doesn't want to stop.

jason
It's cause your catless.....

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Old 07-26-2004, 04:50 PM   #11
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Quote:
Originally Posted by RiftsWRX
It's cause your catless.....

Jorge (RiftsWRX)
www.ProjectWRX.com
That doesn't really make any sense. I have seen plenty of catless wrx's with VF34's who have not had this problem. Besides what he is describing does not sound like creep. Creep is just that, not a complete loss of control. It moves slowly, thissounds like it just wants to build infinite boost.
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Old 07-26-2004, 05:06 PM   #12
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hahahaha, you should have been for rides with me when I had a catless setup on a VF34!

I'd hit 3rd gear and SLAM the needle to 22-23 PSI where it would stay until around 5500 RPM, where it would start coming back to earth... why? because the wheel simply couldn't keep up anymore.

Do what you will... But if the wastegate isn't stuck (which is what I'm gathering in this conversation), it's creep.

If not then you have a severe boost control issue. Hook a hose straight up between the compressor and the wastegate, and drive up to the speeds where your noticing this happen.

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Old 07-26-2004, 05:50 PM   #13
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Quote:
Originally Posted by RiftsWRX
hahahaha, you should have been for rides with me when I had a catless setup on a VF34!

I'd hit 3rd gear and SLAM the needle to 22-23 PSI where it would stay until around 5500 RPM, where it would start coming back to earth... why? because the wheel simply couldn't keep up anymore.

Do what you will... But if the wastegate isn't stuck (which is what I'm gathering in this conversation), it's creep.

If not then you have a severe boost control issue. Hook a hose straight up between the compressor and the wastegate, and drive up to the speeds where your noticing this happen.

Jorge (RiftsWRX)
www.ProjectWRX.com
He already did that with the same results.
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Old 07-26-2004, 05:56 PM   #14
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Default Sorry,

but I'm completely catless with VF34, Deadbolt pnp, and the only time I made over 20 lbs of boost is when I had my AVC-R hoses hooked up wrong. I make the boost I want, everytime. You have a problem, and it's not creep.

San
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Old 07-26-2004, 06:45 PM   #15
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Yes, for the past few days I have been running WASTEGATE ONLY. No boost control at all. With a, uh, "pleasant" boost accelleration I hit 20PSI, no problem. I'm going to inspect the actuator rod tonight.

Please, keep the suggestions coming... but at least read the first post in its entirety

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Old 07-26-2004, 06:53 PM   #16
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Default Fwiw,

my actuator rod doesn't have a nut for adjustability.

San
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Old 07-26-2004, 06:57 PM   #17
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vf34?

When there is a nut for adjustability, where is it?

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Old 07-26-2004, 08:54 PM   #18
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Default It's on the

actuator rod. On one end it's threaded so you can effectively "shorten" or lengthen the rod. There's a lengthy thread on this forum that had a good pic of it. But after checking mine, I don't have one.

San
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Old 07-26-2004, 09:05 PM   #19
oldmansan
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Default Here's

a link to the page of the thread with the pic.

http://forums.nasioc.com/forums/show...8&page=3&pp=25

San
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Old 07-27-2004, 05:48 AM   #20
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Oh my god guys this is SO boost creep.

98kpa: Port your wastegate, port your wastegate, port your wastegate!

With a hose directly from compressor cover to wastegate arm you should see no higher than 8-10psi EVER! If you do, your wastegate is either stuck shut (the rod only moves about half an inch btw if you want to manually test) or your wastegate hole is ineffective at keeping boost at 8psi. I'd bet on the latter given you'd likely see more than 20 psi at redline (in 3rd) if the former was the case.

Boost control only assists in holding the wastegate shut (by routing pressure away from the wastegate) until desired boost is reached in which case it routes positive pressure from the comp cover to the wastegate. Boost control never ADDs its own positive pressure to open a wastegate and thereby reduce boost.

I had this _exact_ same issue with my install of VF34 recently, which was solved COMPLETELY when I ported the wastegate. (MY02 WRX - 290awhp)

Here is my story (see page 6 and 7 for pics): http://www.wrx.com.au/forum/viewtopi...r=asc&start=75

I hope this helps Sorry if I seem a little over zealous, I just find misinformation frustrating.

Last edited by clutchcargo; 07-27-2004 at 05:55 AM.
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Old 07-27-2004, 06:14 AM   #21
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Every vf30/34 I've seen has had creep unless it's been ported or there's a cat. If you're gonna pull off your turbo you might as well port the wastegate while you're at it. Here's a link, it's pretty easy.

http://forums.nasioc.com/forums/show...hlight=porting
http://forums.nasioc.com/forums/show...hreadid=300296
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Old 07-27-2004, 06:59 AM   #22
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I've got a ported vf34 with sports cat in the DP and still get creep to 18psi.

The solution - run 20psi boost

Simon
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Old 07-27-2004, 07:43 AM   #23
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VF30, no cats- no creep. All I get is WG flutter at 4th and 5th gear
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Old 07-27-2004, 07:51 AM   #24
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A ported turbo isn't the same as a ported wastegate. Actually, if you have a ported turbo (i.e. compressor side is ported to increase flow) it might exacerbate a boost creep issue (which is why deadbolt fit larger flappers I suspect).

And yes, not every VFxx install will incurr boost creep, there are other factors in play, such as how good the flow is on exhaust AND intake side is (e.g. silicone intake + pod + no cat will increase the chance of boost creep quite a deal) and whether your turbo has manufactured imperfections (e.g. in exhaust side - impeding flow to wastegate).

So port your wastegate and then you can safely run 18psi without fear your car is going to boost like crazy on a cold day...
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Old 07-27-2004, 12:26 PM   #25
98kPa
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There seems to be a trend here... people claim this is boost creep, then they actually read the thread and start to reconsider.

Lets review some things...

- this wasn't happening in the first 2 weeks I had this turbo. now it is happen. I now have NO peak boost control
- occurs just the same with boost control or no boost control
- How is this boost creep when it isn't creeeeeeeeeeeping?!

Does this look like boost creep?
Code:
                     Load Knock                     Mod   Mod        Mod
  RPM   MAP MAF TPS Site Count   AFR Ign#1  Inj#1   Ign  Fuel  Boost MAF
       psia  V   %                     deg   duty   deg     %   (CL)   V
 3875 +13.3 3.9 100  80    00   rich +15.8   55.9 +13.6  +1.0 245.00 3.5
 4001 +14.3 3.9 100  80    00   rich +16.4   55.7 +13.2  +0.9 245.00 3.5
 4011 +15.3 3.9 100  90    00   rich +16.7   60.1 +13.0  +1.0 245.00 3.5
 4125 +15.9 3.9 100  90    00   rich +16.3   60.8 +13.0  +1.0 245.00 3.5
 4240 +16.4 3.9 100  90    00   rich +16.3   60.1 +13.0  +1.1 245.00 3.6
 4284 +16.4 3.9 100  90    00   rich +15.7   65.6 +13.0  +1.1 245.00 3.5
 4409 +16.4 3.9 100  90    00   rich +15.1   64.0 +13.0  +1.1 245.00 3.6
 4522 +16.4 4.0 100  90    00   rich +15.6   67.1 +13.0  +1.0 245.00 3.7
 4597 +16.4 4.0 100  90    00   rich +16.6   68.3 +13.3  +1.0 245.00 3.7
 4636 +16.6 4.1 100  90    00   rich +18.4   72.9 +13.8  +1.0 245.00 3.7
 4782 +16.8 4.1 100  90    00   rich +19.1   73.6 +13.9  +0.8 245.00 3.8
 4852 +17.0 4.1 100  90    00   rich +20.7   72.1 +14.0  +0.4 245.00 3.8
 4960 +16.8 4.1 100  90    00   rich +21.0   75.2 +14.0  +0.4 245.00 3.8
 5012 +16.4 4.2 100  90    00   rich +21.9   75.0 +14.0  -0.2 250.00 3.8
 5096 +16.4 4.1 100  90    00   rich +22.3   77.8 +14.0  -0.3 250.00 3.9
 5175 +16.4 4.2 100  90    00   rich +23.0   78.5 +14.0  -0.4 250.00 3.8
 5402 +16.1 4.2 100  90    00   rich +23.5   80.0 +14.4  -0.5 250.00 3.9
 5333 +16.8 4.3 100  90    00   rich +23.2   81.8 +14.4  -0.5 250.00 3.9
 5376 +17.4 4.3 100 100    00   rich +22.5   84.9 +14.0  -0.4 250.00 3.9
 5537 +18.0 4.3 100 100    00   rich +23.0   85.4 +14.0  -0.3 250.00 4.0
 5640 +19.0 4.4 100 100    00   rich +23.2   88.0 +14.0  -0.3 250.00 4.0
 5649 +18.8 4.3 100 100    00   rich +23.3   87.5 +14.0  -0.4 250.00 4.0
 5787 +18.2 4.4 100  90    00   rich +23.1   89.2 +15.0  -0.4 250.00 4.0
 5931 +18.4 4.4 101 100    00   rich +23.4   93.0 +14.6  -0.4 250.00 4.0
 5952 +18.2 4.4 100 100    00   rich +24.0   94.1 +14.8  -0.4 250.00 4.0
 6038 +18.2 4.4 100 100    00   rich +24.9   94.7 +15.5  -0.5 250.00 4.0
or this
Code:
                     Load Knock                     Mod   Mod        Mod
  RPM   MAP MAF TPS Site Count   AFR Ign#1  Inj#1   Ign  Fuel  Boost MAF
       psia  V   %                     deg   duty   deg     %   (CL)   V
 3805 +13.5 3.8 100  80    00   rich +16.8   49.2 +13.7  +1.0 245.00 3.4
 3840 +15.1 3.7 101  80    00   rich +16.4   49.9 +13.6  +1.0 245.00 3.5
 3916 +15.5 3.8 100  80    00   rich +16.8   52.3 +13.2  +0.9 245.00 3.5
 4025 +15.7 3.7 100  90    00   rich +16.7   57.7 +13.0  +1.0 245.00 3.5
 4135 +16.4 3.8 100  90    00   rich +16.8   58.2 +13.0  +1.0 245.00 3.6
 4192 +16.1 3.9 100  90    00   rich +16.8   57.8 +13.0  +1.0 245.00 3.5
 4273 +15.9 4.0 100  80    00   rich +16.2   64.0 +13.0  +1.0 245.00 3.6
 4329 +15.7 3.9 101  80    00   rich +16.4   62.8 +13.0  +1.0 245.00 3.6
 4450 +15.3 4.0 100  80    00   rich +15.6   64.8 +13.0  +1.0 245.00 3.7
 4535 +15.9 3.9 101  90    00   rich +16.5   70.4 +13.1  +1.0 245.00 3.7
 4668 +16.4 4.0 100  90    00   rich +16.8   71.1 +13.7  +1.0 245.00 3.7
 4694 +16.4 4.0 100  90    00   rich +18.3   69.6 +13.8  +1.0 245.00 3.7
 4761 +16.8 4.1 100  90    00   rich +19.1   74.8 +14.0  +0.9 245.00 3.8
 4859 +16.6 4.1 100  90    00   rich +20.7   73.7 +14.0  +0.2 245.00 3.8
 5035 +17.0 4.1 100  90    00   rich +21.6   76.2 +14.0  -0.4 245.00 3.8
 4982 +17.4 4.1 100 100    00   rich +20.9   81.5 +14.0  -0.2 250.00 3.8
 5081 +17.0 4.1 100  90    00   rich +22.8   77.3 +14.0  -0.4 250.00 3.9
 5184 +17.2 4.2 100  90    00   rich +23.0   79.3 +14.0  -0.5 250.00 3.9
 5282 +16.8 4.3 100  90    00   rich +23.0   84.5 +14.3  -0.5 250.00 3.9
 5385 +16.8 4.3 100  90    00   rich +22.6   82.3 +14.4  -0.5 250.00 4.0
 5546 +17.4 4.3 100 100    00   rich +22.5   85.4 +14.0  -0.3 250.00 4.0
 5527 +17.6 4.3 100 100    00   rich +22.4   87.1 +14.0  -0.3 250.00 4.0
 5611 +17.8 4.4 100 100    00   rich +22.6   89.0 +14.0  -0.3 250.00 4.0
 5777 +18.8 4.4 100 100    00   rich +23.0   92.9 +14.0  -0.4 250.00 4.0
 5868 +19.8 4.4 100 100    00   rich +23.1   93.0 +14.3  -0.3 250.00 4.1
 5858 +20.2 4.4 100 100    00   rich +23.5   94.1 +14.0  -0.4 250.00 4.0
 5920 +20.2 4.0 100 100    00   22.7 +28.3   62.3 +14.3  -0.3 250.00 3.6
(heh, like that nasty last line? out of "rich" and then suddenly +28.3 deg? That's been fixed )

jason
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