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Old 01-26-2008, 06:29 PM   #1
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Default Massive boost creep

I've been trying to get my boost level under control for the last few days. At first I figured I'd forgotten how to work the AVC-R. That's not the case as I've verified my methodology with Apexi.

I am running a 0.600 bar 8.702psi spring in a Tial 38mm external wastegate. Thinking I didn't have the boost controller hooked up correctly I bypassed it alltogether. Running the comressor signal line directly to the bottom port on the wastegate yields over 1bar at redline.

Is there anything I can do about this? The manifold has a flange for a 38mm gate. Welding on a flange for a 44mm isn't out of the question, but with that much creep I'm not sure it'll make a difference.

Thanks,
Pat
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Old 01-26-2008, 07:09 PM   #2
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Running the comressor signal line directly to the bottom port on the wastegate yields over 1bar at redline.
Corky said to move it to the side fitting. The bottom fitting should be open.
Stephanie
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Old 01-26-2008, 07:45 PM   #3
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Like stephanie said. The wastegate has two ports, the top one is for EBC and the side one is for the wastegate signal. Is that how you have it now?
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Old 01-27-2008, 12:56 AM   #4
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Sorry, I have my terminology backwards. The signal line is on the side port.
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Old 01-27-2008, 01:22 AM   #5
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I would dissasemble and clean the WG rod and make sure you have no binding issues then take a bicycle pump and verify the spring pressure once it is all back together and lubed abit. If the diagphram is leakign you will not actuate correctly but the spring will keep you shut making boost until you lift engine laod. If one port does not work for you try the other. I would not do it with the turbo boost from the motor though, verify it the safe way with a pump, and a vac/boost gauge. If anything this will give you slightly lower boost than you want and you can tune it up a little until it is just right. If the diagphram proves to be leaking after cleaning lube etc i suggest you look into replacing it.
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Old 01-27-2008, 03:28 PM   #6
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I removed the wastegate from the manifold and applied pressure with a bicycle pump. It begins opening at 4psi and is fully open by 7.

In the process of removing the wastegate tailpipe both bolts snapped off in the flange. I have no idea how bolts that were installed two weeks ago soften to the point of snapping. Looks like I'll have to track down a drill press and get those out.

To test I fabbed a block off plate for the wastegate tailpipe thinking I could create a path of lesser resistance than plumbing back to the exhaust. With the wastegate dumping to atmosphere the boost creep is reduced. At redline I'm seeing .73 bar which is substantially better than the 1bar plus with it connected. It is still 1.5-2psi higher than dictated by the wastegate spring.

Anyone know what to look at next? Is there too much backpressure in the tailpipe? Not enough flow to the wastegate port?

Thanks,
Pat
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Old 01-27-2008, 04:53 PM   #7
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To much back pressuer esp if you have the stock exhaust, and to little flow depending on the WG placement.

Last edited by magnamx-5; 01-27-2008 at 05:48 PM.
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Old 01-27-2008, 05:02 PM   #8
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In the process of removing the wastegate tailpipe both bolts snapped off in the flange. I have no idea how bolts that were installed two weeks ago soften to the point of snapping. Looks like I'll have to track down a drill press and get those out.
I had the same problem, 3 of my downpipe studs broke when I tried to take them off after using the BEGI TURBO for 4 days.
I called them and they said they where going to send new ones (that was 2 weeks ago and I havent received anything)
Then I tried to take the turbo out of the exhaust mani and one of the 10mm studs broke... its just bullshit
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Old 01-27-2008, 05:48 PM   #9
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Get with Stephanie on this ussualy Begi is very good with getting people there stuff but stuff does fall through the cracks occasionally.
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Old 01-27-2008, 05:59 PM   #10
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I am running a 3 inch exhaust all the way back. I don't think it's possible to get much more flow.


My issue with shearing bolts is a Tial issue, not Begi.
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Old 01-27-2008, 09:40 PM   #11
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Do you run a Cat? if the answer is no then my money is on improper WG placement you could port the opening abit put a weaker spring in there, or find a better placement. I would try in that order. GL
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Old 01-28-2008, 01:35 PM   #12
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I am running the Begi 3in. cat.

I installed the wastegate spring that came with the kit (12psi IIRC) as a test. The car left two solid black stripes about 25 feet long, and the AVC-R peak display feature read 1.38bar. So much for that.
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Old 01-28-2008, 07:30 PM   #13
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You do realize that ambient pressure is 1 bar right? You need to clarify if you are talking about absolute pressure or relative pressure here.
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Old 01-29-2008, 09:43 AM   #14
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Relative. I wouldn't be here trying to diagnose this problem if I was seeing .38 bar over ambient.
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Old 01-29-2008, 03:22 PM   #15
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Want to try a 4 psi spring?
I will let you know when I hear from Tial.
Stephanie
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Old 01-29-2008, 09:37 PM   #16
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I guess it wouldn't hurt. If it'll pop open early enough I can get the boost up with the EBC.

If Tial doesn't get back to you I can get the remnants of the bolts out locally. It's just weird these snapped off. This is my third Tial wastegate and I've never had this happen, even after years of flogging on the car.
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Old 01-30-2008, 12:49 AM   #17
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Steph, it may be worth investigating those "new" Synapse wastegates. With the adjustable tension, it would be easier to sell one of those with a kit and not ever sweat again a customer who wants a different spring with the kit. As Forrest Gump says "one less thang".
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Old 01-30-2008, 11:33 AM   #18
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We have one of those on the Hex. Synapse sent us one to test out. The car is running, but we are working on a PWS issue, so we have not done much testing yet. Once we can, i will let you know how it goes.
Stephanie
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Old 03-17-2008, 02:05 AM   #19
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Originally Posted by Stephanie Turner View Post
We have one of those on the Hex. Synapse sent us one to test out. The car is running, but we are working on a PWS issue, so we have not done much testing yet. Once we can, i will let you know how it goes.
Stephanie

Any info on these new Synapse wastegates?
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