Restrictor plate in BEGi exhaust - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 03-07-2015, 11:21 AM   #41
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Why is it that the same turbos on the engines they came on stock, like the sr20. The T25 turbine creep really seems to be a problem focused on mainly us and not so much on other cars. And its certainly not due to this motor being better than others. Are we like just better at tuning and running more spark advance than the other car?
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Old 03-07-2015, 11:48 AM   #42
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And 3" exhausts?

My TD04 runs 5psi at red line and WOT, with the waste gate wired full open. And that must not be uncommon because Vlad told me it would. I don't know how it responds in a WRX.
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Old 03-07-2015, 11:18 PM   #43
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I wonder if Corky will send me one of those?

I just wanted a ******* heat shield that fit or lacking that some stick on heat shield foil. In lieu of that I was offered a free A/O setup to make up for all the misery I went through with my S6 kit and it's boost creep issues.

Looks like the A/O is up for sale on the BEGi website. I haven't received the one I was promised, nor a phone call, nor an e-mail... not even a Christmas card.

Keith
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Old 03-07-2015, 11:41 PM   #44
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The only solution to boost creep is simply to run all of it.

weld waste gate shut = no boost creep (actually it just keeps creeping forever)
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Old 03-08-2015, 01:15 AM   #45
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BH2dKeith,

No A/O for you until the cast manifold is in my hands. The pattern has been at the foundry long enough to expect castings within a couple weeks.

Your turbo will need a few mods. You or me? If you do it, you will do it as I suggest.
I will be glad to fix it up, nc. What fuel system are you using? Need EGR?

Sorry about no Christmas card. It was just a bigger risk than I was willing to take.

Hang loose, you are at the top of the list. I'll need to figure out which list that was.

corky
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Old 03-08-2015, 07:00 AM   #46
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Seriously, why do we give a **** if we get 5psi of creep past peak torque?
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Old 03-08-2015, 11:08 AM   #47
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Quote:
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Seriously, why do we give a **** if we get 5psi of creep past peak torque?
because we understand how forces in engines work?

Last edited by Braineack; 03-08-2015 at 11:23 AM.
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Old 03-08-2015, 06:48 PM   #48
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If its past peak torque then its not putting any more stress on any components than peak torque already did. Which is why its called -peak- torque.
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Old 03-08-2015, 07:19 PM   #49
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Ebc on signal line to bov. Let it start trimming boost in the creep area.

Edit: peak wtq does not necessarily equal peak forces on components.
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Old 03-08-2015, 07:20 PM   #50
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Quote:
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Ebc on signal line to bov. Let it start trimming boost in the creep area.
Not bad. Would need a vacuum pump though. BOV needs vacuum to open.
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Old 03-08-2015, 07:24 PM   #51
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If the boost is removed from the signal line the charge will have enough pressure to open against the spring.
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Old 03-08-2015, 07:25 PM   #52
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Quote:
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If the boost is removed from the signal line the charge will have enough pressure to open against the spring.
Hmmm. Would be interesting.
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Old 03-08-2015, 07:26 PM   #53
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Wouldn't that make the turbo make a lot of hot air though? With an open intake line wouldn't it just spool through the roof, especially if it's already creeping?

I want a vac pump and a vac driven wastegate, mini cooper style. 0-allofit with no sweat.
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Old 03-08-2015, 07:48 PM   #54
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What can be used more reliably than peak wtq?

Hope our fueling map is good enough to use ve?
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Old 03-08-2015, 10:44 PM   #55
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Quote:
Originally Posted by deezums View Post
Wouldn't that make the turbo make a lot of hot air though? With an open intake line wouldn't it just spool through the roof, especially if it's already creeping?
Yes to both of your questions. High-flow, low pressure ratio regions of a compressor map typically correlate to shaft RPM of somewhere between "a lot" and "too much"
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Old 03-08-2015, 11:44 PM   #56
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Is super high shaft speeds an issue because of centripetal force on the compressor and turbine wheels or is the issue overheating bearings..?

I honestly dont know.
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Old 03-09-2015, 12:57 AM   #57
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"an issue because of centripetal force on the compressor and turbine wheels"

Having seen turbine blade passing through the housing and hood, yeah, the cf is probably the top speed issue for a sleeve brg.

Otherwise, I doubt a sleeve bearing gives ****. However, the ball bearing guys might find the ***** spewed out into low earth orbit.

The centripetal acceleration of the wheels is reasonably high. For some impressive fun, calc the C A and then use that number to calc how long it would take to travel 283,000 miles.

corky
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Old 03-09-2015, 08:21 AM   #58
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Quote:
Originally Posted by nitrodann View Post
If its past peak torque then its not putting any more stress on any components than peak torque already did. Which is why its called -peak- torque.
case and point.


Last edited by Braineack; 03-09-2015 at 08:38 AM.
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Old 03-09-2015, 02:02 PM   #59
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Quote:
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case and point.

Perhaps. Peak *power* is peak fuel flow though, so boost creep has the potential to outrun your injectors.

--Ian
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Old 03-09-2015, 06:16 PM   #60
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I thought it was clear that I was not including super basic reasons to hate creep past peak torque.

Come on then brain, explain it to me.
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