DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Yes another thread...sorry guys last one i promise (Boost intercooler realted)

Old 03-27-2010, 10:38 AM
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Default Yes another thread...sorry guys last one i promise (Boost intercooler realted)

Ok last one...So most of you know I just re-did my IC and pipes and if you didn't I went from a starion to a Cxracing one. OK so I took the car out for a ride and my boost gauge doesnt read 14psi any more it reads 12psi??? why is that? my boost/vacum to the MBC comes from the cold pipes before TB and after IC...sooo if the new IC had more Boost leak then my starion that wouldnt matter since I'm getting the boost/vac from after the IC so what's going on?
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Old 03-27-2010, 10:46 AM
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Is it warmer outside than the last time you adjust the MBC with the Starion?
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Old 03-27-2010, 10:51 AM
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Same temperature 40s
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Old 03-27-2010, 10:59 AM
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I'm guessing boost gauge line is on the manifold somewhere.

You will see more of a pressure drop with the larger intercooler, but not that much, and wastegate should still open at the same spot. I'm stumped, but at least this problem is easy to fix.

Unless it's a wastegate problem.
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Old 03-27-2010, 11:06 AM
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I doubt it's the wastegate, it's an upgraded one from a t28
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Old 03-27-2010, 11:11 AM
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Just dial it back up, blame it on the gremlins, and go burn some rubber. No technical explanation for it, but you did change a lot of your intake tract, are feeding the motor cooler air, and MBCs are subject to barometric, temperature, and humidity changes.
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Old 03-27-2010, 11:17 AM
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Yeah the good thing is that my AIT's dropped about 10deg on the same outside temps
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Old 03-27-2010, 06:00 PM
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The fix is just a twist away...perhaps you turned it down some by accident when pulling it off/apart.
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Old 03-27-2010, 06:13 PM
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you went from a tube and fin to bar and plate.... pressure drop.
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Old 03-27-2010, 07:03 PM
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Originally Posted by Braineack
you went from a tube and fin to bar and plate.... pressure drop.
But his reference point is after the intercooler...not on the compressor housing.
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Old 03-27-2010, 07:06 PM
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Originally Posted by gospeed81
but his reference point is after the intercooler...not on the compressor housing.
+1
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Old 03-27-2010, 07:12 PM
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Originally Posted by gospeed81
But his reference point is after the intercooler...not on the compressor housing.
Unless I am thinking something different, like brain said tube and fin to bar and plate, you said the reference was AFTER the intercooler so you change intercoolers which means pressure drop AFTER the intercooler.
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Old 03-27-2010, 08:06 PM
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Did you get larger charge pipes? That could account for pressure drop.
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Old 03-27-2010, 09:21 PM
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x3 for pressure drop

thread/
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Old 03-27-2010, 10:05 PM
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I don't think it could be pressure drop due to the fact his wastegate is receiving signal from after everything that would cause pressure drop. If there was an extra 2 psi being lost through the ic the wastegate would stay closed longer pressurizing the ic to 16psi (just pulling a number from my ***) on the hot side and after pressure drop he should see 14 psi on the cold side...unless the compressor can not put out enough psi to compensate for the pressure drop (hence only seeing 12psi). Do you have any way to get a pressure reading from the hot side and see how much drop there is? Not that you would necessarily learn anything from that but it may yield something useful...
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Old 03-28-2010, 12:02 AM
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I would have to move my boost gauge to my hot side... I think I should do a log tomorrow and see if it's my boost gauge or something else...
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Old 03-28-2010, 12:08 AM
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Originally Posted by miataspeed2005
I would have to move my boost gauge to my hot side... I think I should do a log tomorrow and see if it's my boost gauge or something else...
What you need to do is relax, realize that the only thing you changed was the intercooler and piping. After this change, your boost level changed. Just take a deep breath, turn your boost controller up a bit to get it back to 14psi, and enjoy the car.

I'm just saying, after the major panic attack in the last thread. You really need to take it easy.
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Old 03-28-2010, 12:23 AM
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Originally Posted by astroboy
I don't think it could be pressure drop due to the fact his wastegate is receiving signal from after everything that would cause pressure drop. If there was an extra 2 psi being lost through the ic the wastegate would stay closed longer pressurizing the ic to 16psi (just pulling a number from my ***) on the hot side and after pressure drop he should see 14 psi on the cold side...unless the compressor can not put out enough psi to compensate for the pressure drop (hence only seeing 12psi). Do you have any way to get a pressure reading from the hot side and see how much drop there is? Not that you would necessarily learn anything from that but it may yield something useful...
His wastegate actuator is probably getting its pressure signal from before the intercooler, hence the pressure drop AFTER the intercooler.
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Old 03-28-2010, 08:56 AM
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In his first post he said his wastegate is referenced before the tb and after the intercooler. It is an interesting situation but I think it can be remedied by turning the know bu another 1/2 turn or so.
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Old 03-28-2010, 09:26 AM
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A long shot.. didn't look to see what turbo he is using, but...

Your probably flowing alot more air lb's wise with the new bar and plate with pipes.
I would suggest seeing if you can actually make more than 12psi of boost. You may be maxing out that turbo.

Also check to see if your now lean, if so then your certainly just more efficient, forget about the temps.

Second don't forget the clamps both before and after. Make sure they are tight.
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