AutosportsNorthwest.org

penderperson · Joined: 08 Dec 2009 Posts: 46 Location: Spokane, WA

I'm in need of some help troubleshooting my WRX.

Mostly i'd like to swap a couple parts from a known good car and see if i can isolate the cause of some boost surge i've had for a while.

Pm me if you're willing to help!
Thanks,
Rob
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05' CMG WRX
85 STX

bryan · Posted: Sun Mar 18, 2012 10:32 am Post subject:

I'd be happy to swap engines with you. I guarantee you won't have any more boost surges!

--Bryan

penderperson · Joined: 08 Dec 2009 Posts: 46 Location: Spokane, WA

Very funny Bryan Rolling Eyes

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05' CMG WRX
85 STX

Skid · Posted: Mon Mar 19, 2012 2:27 pm Post subject:

Rob,

I'm not sure I've got much that will just swap interchangeably, but if you think of something that would come off my car and you'd like to try - let me know.

As a refresher, I'm running the 22T shortblock with 20H heads and manifold. I've got an AVO turbo running wastegate (and soon to be aftermarket EBC) and a piggyback EM.

So I'm not sure I'll have any of the big items you'd be looking to swap such as BOV/BPV, BCS, or if any of my map sensors would work for you. But I do have some extra BPV's and what-nots lying around.

I don't have extra turbo's lying around anymore.

Otherwise, if there's something you think I may have that'd be helpful - just let me know and I'll be happy to try and support. My car's still down and out for another few weeks but I'm hoping to get it back on the road by the 7th or so of April.

What kind of surging are you experiencing? Is the boost spiking over your sets, if so, how much? Fluctuating through the RPM band? Any issues building boost, i.e. still hitting when it should? How are you currently managing your boost settings? Stock TD-04? *Feel free to take this to PM's if you wish as well.

Just let me know if I can help.
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93' Legacy SS, #555
96' Legacy Outback

penderperson · Joined: 08 Dec 2009 Posts: 46 Location: Spokane, WA

I am running stock td04, stock bcs, wastegate and 3" turbo back. Boost is tuned to 15 psi tapering to 12, the surging goes up to 17 pulling strong and normal, then immediately drops to 10-12, then continues to surge until the turbo can't surge.

From what I've found, the waste gate should open around 6, and be fully open at9. I measured mine opening at 9, fully open at 12-15. So i think it makes a lot of sense that the wastegate is bad.
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05' CMG WRX
85 STX

Skid · Posted: Mon Mar 19, 2012 6:38 pm Post subject:

Hmm... okay. From your description I'd be inclined to agree that the wastegate may be suspect.

There aren't that many variables that control boost and if the engine seems plenty happy otherwise then I would tend to narrow the options down to the turbo, BCS/ECU, and wastegate.

You are correct that the stock wastegate should be open at 9psi. Have you tried dropping in a MBC to take the BCS/ECU out of the equation? If so, is it still surging?

If it is still surging then I'd say plump your wastegate straight to your pressure signal and let it run just off the wastegate. Fairly quick to test and if you do, you should run a simple and steady 9ish psi from onset all the way through redline. If you're getting a lot of fluctation still then I think you'd know your answer. A cracked diaphram can cause a lot of problems.

You'd be welcome to try the wastegate off my car if you wanted, should fit up. Granted my wastegate is an AVO brand so it's sprung a little stronger but mounting is the same.

Let me know about the wastegate and if there's anything else I can do to help.
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93' Legacy SS, #555
96' Legacy Outback

Captain_Kirk · Joined: 04 Mar 2010 Posts: 25 Location: Colbert, WA

I have an adjustable rod wastegate off a Garret turbo from a Saab. Shoot me a PM with a cell number or email and I'll send a phone pic of it.
Captain
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'77 Porsche 924 na
Cone Colored Orange