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wastegate porting question

Old Sep 3, 2010 | 11:14 PM
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TenthYear's Avatar
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wastegate porting question

hey guys, i'm knee deep in my s5 turbo rebuild and have a quick question.
i've ported the intake and exhaust, just a street port nothing huge. do i need to
port the wastegate to compensate? or is that only an s4 turbo thing to do?
i looked on aaroncake's page about porting it (very helpful by the way, thanks man!) but the s5 turbo looks like it already has double the wastegate as the s4.
Any suggestions are very helpful.
thanks.
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Old Sep 3, 2010 | 11:45 PM
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Nismo Convert86's Avatar
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Port the WG, and grind a relief in the backing plate to allow the door to open more, I did this, and I was unable to boost past 7psi, add a boost controller and you can have it will be rock steady to whatever you set it to.
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Old Sep 3, 2010 | 11:46 PM
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From: eureka
Why not port? Also exhaust flow is another consideration. There is a sharp angle the exhaust gases must go around after the holes in the wastegate and this angle can be shaved to help exhaust flow.

I have a stock s4 with an s5 turbo ported (by bluetII) ,RB 2.5 exhaust, custom tid and i still can boost creep in 4 th gear. Granted i live by the beach/sea level and cool weather.

Last edited by freemanrx7; Sep 3, 2010 at 11:49 PM.
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Old Sep 3, 2010 | 11:54 PM
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thanks for the input fellas. i'll check it out more tomorrow
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Old Sep 4, 2010 | 12:02 AM
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Black Knight RX7 FC3S's Avatar
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wastegate porting is always helpful both on the S4 and S5 turbos.

Just think of it like this.
More exhaust flow = better port that wastegate :P
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Old Sep 4, 2010 | 02:34 AM
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MaczPayne's Avatar
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Back-cut the runners also: you want to open up the passages all the way through, not just the opening at the flapper door.
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Old Sep 4, 2010 | 05:49 PM
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The S5 turbo has one opening that is smaller than the other. This one can be opened up around 5mm wider, while you can only do about 2-3 mm on the larger passage. Smooth it out all the way down and take a little off the backing plate as mentioned. I ported out my S5 turbo like this, and ended up with the equivalent area of a 35mm single wastegate. I don't have any boost creep problems either.
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Old Sep 12, 2010 | 10:52 PM
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ok i grinded the side down a bit to be able to open the flap, then i just started grinding away at the port holes to where the seat would still seat. it opened up quite a bit. here are some pics along the way too.
Attached Thumbnails wastegate porting question-img_20100903_211637.jpg   wastegate porting question-img_20100912_140608.jpg   wastegate porting question-img_20100912_142636.jpg   wastegate porting question-img_20100912_145831.jpg   wastegate porting question-img_20100912_165248.jpg  

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