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The single flapper vs. dual flappers on the 10.5...

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Old Jan 3, 2006, 11:26 AM
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The single flapper vs. dual flappers on the 10.5...

I hope to get a 10.5 housing.

Here's the single flapper;
http://linux.forcedperformance.net/m...05002_full.jpg

... and the actual ports (they look small to me);
http://linux.forcedperformance.net/m...05004_full.jpg

Here's the pic of the dual, but it really doesn't show the actual port.
http://linux.forcedperformance.net/m...O8001_full.jpg

Does any one have pics of the dual flapper WG ports, or know how they really compare?
Old Jan 3, 2006, 11:44 AM
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The dual flapper is the old design from the 9.8. When doing my own research a while ago, I was able to find several pics of old rusted 9.8s that had been taken off and photographed. It will take some searching, but they are in EvoM if you look hard enough. Also, I found a diagram of both flapper designs, which showed exactly how they were different, but in a drawing. The single-flapper design is the newer, better design.
Old Jan 3, 2006, 11:57 AM
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I hate to side step the obvious, but is the single flapper better SOLELY becuase it is larger and bypasses more exhaust? Does it control boost better?
Old Jan 3, 2006, 12:06 PM
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Originally Posted by Boosted AWD
I hate to side step the obvious, but is the single flapper better SOLELY becuase it is larger and bypasses more exhaust? Does it control boost better?
I wish I knew. I don't think it's an obvious question, but rather a good one. All it says on the Forced Performance website is:

"This is the same housing from the 2005 MR with the improved single flapper design that was updated from the 2003,4 models. "
Old Jan 3, 2006, 12:09 PM
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Yeh I believe this is my next mod along with "GASP" an eBay 02 housing and a ported exhaust manifold. Being that the Stock 16G flows over 600CFM's, I may just run that bad boy for a while. I guess that the 10.5 Hotside reallyt helps in teh torque department but does noting for peak whp?

How about porting the 10.5 side? Didn't this 10.5 hotside come on all 2005's?
Old Jan 3, 2006, 12:11 PM
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I have physically held both in my hands and compared the two. It actually looks like the old dual flapper design has larger ports that would flow more, but appearances can be decieving.

I believe the move to a single flapper helped not by increasing port side, but my unshrouding the ports. By moving to two half moon shaped ports that are closely placed next to each other rather than two round ports that are separated, the area around the flapper door was essentially increased. I believe this ultimately allows more exhaust gas to flow through the wastegate.

Also, the two closer ports might allow some sort of scavenging effect, but of course this is purely speculation.

- Steve
Old Jan 3, 2006, 12:13 PM
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Originally Posted by Boosted AWD
Yeh I believe this is my next mod along with "GASP" an eBay 02 housing and a ported exhaust manifold. Being that the Stock 16G flows over 600CFM's, I may just run that bad boy for a while. I guess that the 10.5 Hotside reallyt helps in teh torque department but does noting for peak whp?

How about porting the 10.5 side? Didn't this 10.5 hotside come on all 2005's?
If you do that, you will be mimicking my soon-to-be current setup (within 2 weeks). I will have the Buschur ported/coated 10.5 and stock exhaust mani, then an Ebay O2 that Dave is sending me to replace the stock ported/coated O2 that he already sent me. I'm going to test this combo with the Ebay O2, since Dave found awesome gains when testing.

Yes, that is the same 10.5 turbine housing that came on all 05s, and it is good to port it. Buschur doesn't just port it, but also port-matches it with the O2 housing and exhaust mani, then coats it all around if you get that service, too.
Old Jan 3, 2006, 12:26 PM
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Originally Posted by Warrtalon
If you do that, you will be mimicking my soon-to-be current setup (within 2 weeks).
No......You'll be copying my setup sir.
Old Jan 3, 2006, 12:27 PM
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i got my 10.5 from works. i wonder what 1 they use as i dident even no at the time there was 2 kinds. beter make a call
Old Jan 3, 2006, 12:35 PM
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Originally Posted by Boosted AWD
No......You'll be copying my setup sir.
Pfffft, I already have the parts in hand while waiting on the Forge WGA before installation!
Old Jan 3, 2006, 02:04 PM
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Originally Posted by evodan2004
i got my 10.5 from works. i wonder what 1 they use as i dident even no at the time there was 2 kinds. beter make a call
They use the newer style as stated by Jaime in this thread: https://www.evolutionm.net/forums/sh...d.php?t=169572
Old Jan 5, 2006, 10:52 PM
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My theory to the flapper change of design was for less surface but same air volume to allow a more tight seal, the lack of surface area on the exhaust pressure side will also keep it from cracking open on high loads.

My dummass went and bought the old 10.5 HS before knowing there were two lol
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