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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 03-22-2012, 05:19 AM   #21
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pretty much been covered, but I ran open dump on IWG like this before. Other than boost control/creep issue, it ran absolutely fine. There was a divider plate welded into the turbine housing, and there were absolutely no leaks from wastegate side to turbine flow side... I suspect that is your issue as well. I also ran no gasket from turbo to DP, again to ensure there was zero crossflow between the two areas.

Anyways, sounds like you're on the right path to troubleshooting this. FYI it was obnoxiously loud and I got tired of quickly. When I went EWG, i had it rerouted back into the exhaust. lol



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Old 03-22-2012, 09:01 PM   #22
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Did you ever run the same IWG turbo with the wastegate tube routed into the DP?
Id be curious if the creep would be better or worse with the VTA setup.

At one point I was going to go VTA in hopes of helping decrease creep because I figured that the wastegate flow was being inhibited by the backpressure in the exhaust.
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Old 03-22-2012, 09:55 PM   #23
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the flow problem is not after the port.
the flow problem is before and at the port.

so vta past the port doesn't resolve anything
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Old 03-22-2012, 11:34 PM   #24
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That's an interesting vacuum generator...

I've been troubleshooting pneumatic circuits all day and trust me you've made a vacuum generator (just like others have said).

The fast high volume exhaust creates a vacuum (low pressure area) in the dump pipe as it passes the venturi (inlet to the down pipe). This has a small orifice connecting it to the dump pipe which causes a syphoning action of the air in the dump into the exhaust resulting in crazy AFR's.

Seal the wastegate port or put the pipe back the way it was.
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Old 03-24-2012, 03:54 AM   #25
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Quote:
Originally Posted by Full_Tilt_Boogie View Post
Did you ever run the same IWG turbo with the wastegate tube routed into the DP?
Id be curious if the creep would be better or worse with the VTA setup.

At one point I was going to go VTA in hopes of helping decrease creep because I figured that the wastegate flow was being inhibited by the backpressure in the exhaust.
Yeah, made no difference. The issue with mine was almost certainly too long of a dump tube. Long tube + small diameter (dictated by IWG size/space), it was too large of a restriction. Short tube IWG dumped to atm would probably work, problem is where to dump it outside the engine bay. EWG is probably only realistic option where you can make the dump pipe diameter much larger to compensate for the longer length.
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Old 03-24-2012, 06:49 PM   #26
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Why not run a cutout after the sensor?
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Old 03-25-2012, 03:02 AM   #27
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Got the downpipe re-welded back to being recirculated. Also fixed some other things and sealed everything up tight. Car is still idling a little bit weird and running lean in boost. Better and smoother than it was though. Not sure exactly what I'm going to do. Probably look at the fuel pressure under boost and see if I'm getting enough fuel.

Anyways, this was at the top of the downpipe to divide the two, not sure how much it helped, but it looks pretty good.

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Old 03-25-2012, 03:44 AM   #28
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yeah that almost certainly didn't seal well enough to work dumping the wastegate gasses. Begi welds the plate into the turbine housing now (like in the pic i posted)
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Old 03-25-2012, 06:55 PM   #29
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I almost wouldn't care, that thing sounded ------- awesome at WOT!!
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Old 03-26-2012, 09:20 PM   #30
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I bought a used BEGI downpipe that someone did this mod to. Ran it like that for a few months and tuned the car like that. I got fed up of the sound. It really sounded ----. It sounded like a blowing exhaust all the time, and not like a cool EWG screamer pipe. I eventually had it flipped round and plumbed back into the DP. Lost a bit of spool, but it sounded so much better.

For what it's worth, I experienced no issues after I reintroduced it into the main DP. I think your problem is unrelated.
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