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Boost w no wastegate!?
https://www.slantsix.org/forum/viewtopic.php?t=56742		 Page 1 of 1
Author:  Ssg Pohlman [ Thu Dec 18, 2014 5:15 am ]
Post subject:  Boost w no wastegate!?
So last couple days I've been driving and tuning. Well it seems that even though my waste gate is free to do as it wants, I'm still managing to build boost! So I guess maybe I missed something? Any one else have this or know what went wrong?
Author:  Dart270 [ Thu Dec 18, 2014 6:04 am ]
Post subject: 
I'm not sure exactly what you are asking.

If you have no wastegate at all, you will build the maximum boost possible for your turbo setup. None of the exhaust gas is bypassing the turbo, so all of the exhaust gas goes to driving the turbine. If the wastegate valve is completely open (bypassing as much exhaust as it will flow), then you could still build boost if the flow rate through the WG circuit is not high enough to keep up with your exhaust output.

Hope this helps,

Lou
Author:  Ssg Pohlman [ Thu Dec 18, 2014 11:32 am ]
Post subject: 
Option B
The actuator is gone and in place is a rod/spring setup but not tight. It can do what it wants w no problem.
I did notice climbing a grade today that I could only build a cpl psi so maybe it just can't clear out enough when really matting it down.

10# for a brief second today! man what a blast!
Author:  Serj22 [ Thu Dec 18, 2014 2:34 pm ]
Post subject: 
Are you sure you don't have the wastegate set for say 12 or 14# and you've just never mashed on it that hard before?

I wish I had your issue. No matter how i adjust my wastegate I get 8 pounds. I've tried wiring it shut and it's close to 10. There's probably an exhaust leak somewhere...

What are you using to control your wastegate? A MBC vented to air? If so I've read stuff on the spring going out and it just vents a whole lot more than you intend it to.

Also - are you running your boost gauge to the intake, or the turbine?
Author:  Ssg Pohlman [ Thu Dec 18, 2014 5:35 pm ]
Post subject: 
There is zero wastegate control. I started to set it up w just the rod and spring but I set it up backwards.
So as I was driving home I wondered if I had it right since there was zero spring pressure. It would move all it wanted if I moved it by hand. So I said wth and tightened the nut down until the spring just barely held it up. What I thought was closed but turns out to be holding it open. When I had it tightened down all I could manage was about 5-6#. So I got back out and loosened the nut, letting the rod fall down all on it's own.Manet back to driving and over 5# I went. So basically my internal wastegate is only held shut by the weight of the rod, a tiny spring, a small metal sleeve, and a lock nut. It only has to build enough boost to lift the weight of all those. So now I need to redesign the wastegate situation. Makes me wonder how fast I'd build boost if my flapper was actually held shut. :oops:
Author:  Ssg Pohlman [ Fri Dec 19, 2014 4:30 am ]
Post subject: 
This part is more for serj22. I read I'm my build thread that you have 2-1/4 pipe exhaust? I'd recommend to open it up to at least 3" from turbo down a couple feet or so and then maybe reduce to 2.5 but not 2-1/4. I'd be willing to bet you would see a night and day diff w less restrictions. I could be wrong though.
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