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Old 03-14-2006, 08:45 PM   #1
mranlet
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98 RWD BG Outback
...with R200 and ITBs ;)

Default Itbs?

Yeah, I'm almost done. Pictures are with only a single butterfly in place:





Synchronization will be handled by two of the same throttle wheel connected at a neutral point by an adjustable rose-jointed rod.

Idle control will be modulated by valves that are tapped into the walls of the throttle body below the throttle plates.

I will be running MAF with an intake plennium to see what sort of changes there are from the ITBs alone, and then be converting to MAP so that I may run exposed intake horns on track days.

The only big hurdle for this conversion on my car (98 Outback) is to adapt the Phase II style intake manifold bolt pattern to secure the bodies to my Phase I heads. I've thought about cutting just the flange off of a Phase II intake manifold and adding some tabs for the Ph I head pattern. This way, it would assemble by bolting my cut and welded flange on to my head and bolting the ITBs down via long studs that are permenently fastened to the adapter section. The Phase II intake ports are small, so any port matching that is needed (and there is a lot) can be done by shaving rather than adding material.

Any thoughts?
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Old 03-14-2006, 08:53 PM   #2
redwagon
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You make those out of WRX tumble valves?
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Old 03-14-2006, 08:56 PM   #3
mranlet
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...with R200 and ITBs ;)

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Yep. I've replaced the 3/4 butterfly with a full one that I cut down from a piece of flat stock galvanized. There is significant portwork to get the full throttle plate to pass by the low-tolerance passage wall.
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Old 03-14-2006, 09:06 PM   #4
Handsdown
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sick. super super sick.
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Old 03-14-2006, 09:13 PM   #5
djviper
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this might sound dumb but i dont know the back ground, what are you trying to achieve?
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Old 03-14-2006, 09:17 PM   #6
ballitch
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better throttle response.
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Old 03-14-2006, 09:25 PM   #7
mranlet
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...with R200 and ITBs ;)

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Individual throttles for each cylinder are the epitome of instantaneous response.

Just imagine a Subaru version of something like this:
http://video.google.com/videoplay?do...3082170&q=itbs
Or better yet, this:
http://www.youtube.com/watch?v=Ba8sT2BQ4uc&search=itbs

If you've ever driven an E30 M3 or Mercedes 190E Evolution, you will know that the connection between driver and engine is unsurpased with individual induction.
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Old 03-14-2006, 09:38 PM   #8
Kostamojen
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Oh snap!!! ITB's!!!

As for adapting them to the heads... Why not just run WRX heads? If you are going this far for ITB's, I presume you are doing something to bypass all the sensors and gizmos in the intake manifold region...
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Old 03-14-2006, 09:43 PM   #9
Rally_wgn
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Ahhh Yeah! subscribe!
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Old 03-14-2006, 09:44 PM   #10
djviper
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got ya!
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Old 03-14-2006, 09:46 PM   #11
Pakin
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I've always wondering why you had ITBs in your profile but only mentioned the aspect of the RWD BG.

-paK +1
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Old 03-14-2006, 10:42 PM   #12
DoctorNick
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wow
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Old 03-14-2006, 11:03 PM   #13
mranlet
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...with R200 and ITBs ;)

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Quote:
Originally Posted by Kostamojen
Oh snap!!! ITB's!!!

As for adapting them to the heads... Why not just run WRX heads? If you are going this far for ITB's, I presume you are doing something to bypass all the sensors and gizmos in the intake manifold region...
I'm trying to make them adaptable to the more popular NA platforms, and I'm partial to the DOHC Phase I heads because of their flow and tunability.

I'm going one step at a time; I've got to finish my setup before reproducing it for other people, but I think that eventually a set of these things will find their way on to a WRX
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Old 03-15-2006, 02:16 AM   #14
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I've been trying to figure out how to do this same thing, I had the same idea too , good job so far. I'm thinking the main problem is going to be the air after the throttle plates. For like the brake booster, vaccum lines, etc. How are you coping with these problems?
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Old 03-15-2006, 02:49 AM   #15
redwagon
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Quote:
Originally Posted by THAWA
For like the brake booster, vaccum lines, etc. How are you coping with these problems?
I think back to my old Alfa with two twin-choke Dellortos, that had small ports referencing below the venturis all connected with a small plenum box and then the brake vacuum hose etc. tapped to that. Just drill some counterbored holes under your throttle plates and tap some short bits of brass pipe to use for hose spigots.
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Old 03-15-2006, 02:49 AM   #16
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You can use a common pipe with small fittings in each throat to serve as a vacuum source for all of the necessary components.

I'm using a simple 4 port airchuck plenum fitted with the appropriate nipples and one large trunk line to the manifold. Although I'm not using ITBs, the single trunk line to a central vacuum distribution block seems to work just fine for me.

Jay Storm
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Old 03-15-2006, 04:13 AM   #17
JDMviola
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That is awesome, can't wait for the finished product
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Old 03-15-2006, 05:28 AM   #18
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*subscribes*
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Old 03-15-2006, 09:16 AM   #19
poruki
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I'll agree, ITB's make for GREAT throttle responce.
www.projectaerosol.com/porubi/
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Old 03-15-2006, 09:25 AM   #20
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Instead of changing the flanges, just finish it up and send them to me. I will put them on my car and just run open horns all the time with just some JDM filters (screen) over them.

Nice work, I've been thinking about this for a while, just wish nothing else was wrong with my car so that I could focus on that.
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Old 03-15-2006, 05:05 PM   #21
mranlet
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...with R200 and ITBs ;)

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Quote:
Originally Posted by poruki
I'll agree, ITB's make for GREAT throttle responce.
www.projectaerosol.com/porubi/
This looks awesome. I can see that you adapted the throttles using plates of aluminum, but how did you do the throttle linkages?
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Old 03-15-2006, 09:01 PM   #22
Kreeger
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Old 03-15-2006, 09:23 PM   #23
poruki
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The carbs are Weber 48 IDA's as used by the VW guys and that is where the linkage came from.
The intake manifolds are CNC machined from billet aluminum.
Stock 2001 EJ251 + Webers = 126.3 HP at the wheels.
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Old 03-15-2006, 10:09 PM   #24
Gator GT
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very very impressive. I can not wait to see (and hear) this final product!!!

GGT
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Old 03-15-2006, 10:16 PM   #25
PHATsuby
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to stock is a project too

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this is awesome!

great idea and awesome job implementing it! looks sick, cant wait to see it in action.

keep this updated with pics

Ben
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