Think I need to port the wastegate hole??
- Thread starter Flyin Brian
- Start date
Flyin Brian
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- Jun 18, 2011
The diagram above shows the way I had it hooked up before. Diagram not seem to be the same as what you are describing in your previous post? I just got the 7 lb spring back in there. Almost ready for a test drive.
Flyin Brian
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- Jun 18, 2011
This configuration got me 31 psi boost before I lifted.
Flyin Brian
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- Jun 18, 2011
Thanks Bryan. I hooked a line from the turbo straight to the lower port tonight, no boost controller and top port on wastegate open. Still have the 7 lb spring in there. Going to do a run tomorrow and see what it does. Also going to try and borrow a bore scope tomorrow and take a look at that wastegate to downpipe return connection to be sure it is not restricted.
Flyin Brian
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- Jun 18, 2011
Well it was too rainy to test drive today but I did get a look at the wastegate pipe to downpipe return connection. Took an I-Phone and a flashlight and stuffed them down the pipe with the phone filming. The connection looked pretty good. No significant lip anywhere. Total area of the opening is definitely more than the area of the wastegate pipe cross section so I don't think it poses any real flow restriction. My wife can actually fit her hand in the downpipe and feel the opening where the wastegate pipe comes back in. Will try to do the test drive when the rain stops.
If you're looking to run lower boost you will need to open the waste gate bypass. If you decide to use an external pressure source with a boost controller you can use a light spring and the strategy i messaged you with . The simple fact is you can't have a wastegate that is adjustable over a wide range of mass flow without a lot of playing around and having good control over the pressure on the gate .The ex energy will be out of the wastegates controllable range if you are trying to run it to far from where it's really happy. That turbo will go over 70lbs/min on the right combo and will support about 150hp more than the old one. If you were to measure back pressure before and after the change you would find that what you have now has less back pressure even at higher pressure ratios. The compressor is biting off more air and it's taking less energy to drive the compressor because the wheels are fairly well balanced in flow. Therefore you actually have higher boost pressure and less backpressure . Perfect for making a lot of power .
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Flyin Brian
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- Jun 18, 2011
Well more power is of course what I want but my 80 lb injectors are at 100% duty cycle at 25 psi boost. I plan on upgrading to the 160 lb injectors next year. Just want to get the boost down to around 23 psi for now and go up to 28 or 30 psi when I get the bigger injectors. I will probably take the wastetegate hole up from 1.05 to 1.15 next week. My next buy is definitely going to be a torque converter though.
1fastcobra
Well-Known Member
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- Jan 24, 2012
Try a different boost gauge !!!
Just seems nomatter what u change u get basically the same readings. Just a thought
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Just seems nomatter what u change u get basically the same readings. Just a thought
Posted from the TurboBuick.Com mobile app
Flyin Brian
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- Jun 18, 2011
I thought about that but I am looking at the Powerlogger boost reading in the log file as well as looking at my mechanical boost gauge and they show the same. I do have another mechanical gauge laying around somewhere though that I could also try.
Flyin Brian
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- Jun 18, 2011
Yes, still 26 psi boost.
Flyin Brian
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- Jun 18, 2011
I have the dual 255 Racetronix setup. Since I have the SD chip I think I can jack up the base pressure and tune around it on the low end. Will have to try that if the weather ever dries up around here.
Phoneguy
Cometic HG stress tester
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- Aug 27, 2002
If you are still getting 26psi without the controller and a 7 lb spring, your wastegate is not able to handle the pressure correctly. What wastegate are you using?
Bryan
Flyin Brian
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- Jun 18, 2011
I have the knock off 46 mm wastegate that looks like a TIAL. I know it is not a good wastegate but I don't think it is the problem at this point. I think if I took the wastegate completely off that I would still get high boost because the hole in the turbine is physically too small to bypass enough of the exhaust gas to get the boost down below 25 psi. Of course I will not try this as it would be loud as hell and melt a bunch of stuff under the hood and maybe start a fire. I do plan on getting the real deal TIAL 46 mm gate someday as it will bolt right on my downpipe but I don't have 500 bucks burning a hole in my pocket right now so that will have to wait. I will open up wastegate hole in the housing to 1.15 and test again. It couldn't hurt right?
Phoneguy
Cometic HG stress tester
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- Aug 27, 2002
Try removing the wastegate from the downpipe and take a pic of both sides of the flanges...I would bet they are extremely small compared to the wastegate. I had severe issues with that downpipe and wastegate !! i removed it and went with Cottons downpipe and a Turbonetics wastegate...problem solved.
Bryan
Bryan
Flyin Brian
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- Jun 18, 2011
I do lament the day I chose this DP over a nice one like Cotton's. Fit up was not fun. You know the story. I will take some pics tomorrow night when I work on it again.
Flyin Brian
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- Jun 18, 2011
Ported the wastegate hole in the housing to 1.15". Took some pictures of the wastegate pipes etc. The bypass hole in the downpipe flange is 1.3". The bypass pipe ID at both wastegate flanges is at least 1.35". The wastegate hole in the housing is still the smallest point. Got it back together but did not get a chance to drive it yet. Still have the 7 lb spring in the gate and a hose direct from the turbo housing to the lower port on the gate no controller. Will try to do a test run this weekend.
