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Intake Modification Concept for Ideola's Ultra Wide Body 931
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flosho  



Joined: 01 Jul 2004
Posts: 3155
Location: Eau Claire, Wisconsin

PostPosted: Tue Aug 28, 2007 12:49 pm    Post subject: Reply with quote

What if you did what you are describing but angle the TB more, and cut more of the original plenum away?
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ideola  



Joined: 01 Oct 2004
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Location: Spring Lake MI

PostPosted: Tue Aug 28, 2007 12:54 pm    Post subject: Reply with quote

Yeah, that's an option, particularly if the coolant reservoir can go (which in my case it is)...the big concern right now is the issue that Steve brought up. I just read the intake manifold chapter in Maximum Boost. Mr. Bell confirms that symmetrical is the best design for optimum flow. Less desirable would be the approach of tacking the TB on the front end of the intake. I think the best solution so far that retains the spirit of my original concept is to use the NA manifold and position the new TB runner exactly perpendicular to the plenum. It might not need to be a 90 degree bend...I'll have to take a look in the morning at the NA to see what kind of space is available...

This is freakin' awesome! We might actually come up with a design that works I'm pretty stoked. Thanks for the great insight, everyone!
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-nick  



Joined: 16 Nov 2002
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PostPosted: Tue Aug 28, 2007 1:48 pm    Post subject: Reply with quote

By the way - don't use a silicone elbow between the throttle body and the plenum. It will collapse under the vacuum without hesitation.
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ideola  



Joined: 01 Oct 2004
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Location: Spring Lake MI

PostPosted: Tue Aug 28, 2007 1:50 pm    Post subject: Reply with quote

that would suck!
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Min  



Joined: 04 Nov 2002
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Location: Vernon, British Columbia, Canada

PostPosted: Tue Aug 28, 2007 1:58 pm    Post subject: Reply with quote

-nick wrote:
By the way - don't use a silicone elbow between the throttle body and the plenum. It will collapse under the vacuum without hesitation.


If you go to your local large truck dealer, you can get reenforced silicon hosing that has metal wire in the hose to prevent this from occuring.

Also a nice place for inexpensive silicon hosing in general, just isn't as nice looking as the ricer stuff.

Min
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endwrench  



Joined: 07 Dec 2002
Posts: 1631
Location: Victor, Montana

PostPosted: Tue Aug 28, 2007 2:02 pm    Post subject: Reply with quote

Have you considered some sort of hybrid diffuser style intake? This would keep the clearance requirements to a minimum towards the back of the motor and would give you nice even distribution. It would take a little more fabrication and welding though I think.

Todd

Some photos: http://www.bufkinengineering.com/intake%20manifolds.htm
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Raceboy  



Joined: 01 Mar 2004
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Location: Estonia, Europe

PostPosted: Tue Aug 28, 2007 4:34 pm    Post subject: Reply with quote

I made this for my 931. It's complete now, with diffusor and shortened runners (brake booster clearance) but you'll get the idea. ITB's are from GSXR750. They cost me 80$, have EFI injector bungs, have TPS and are separable (different cylinder placement).




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endwrench  



Joined: 07 Dec 2002
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PostPosted: Wed Aug 29, 2007 2:11 am    Post subject: Reply with quote

Very nice Raceboy! I'd like to see it with the diffuser in place.

GSXR750, is that Suzuki? What size are the TB's?

Todd
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flosho  



Joined: 01 Jul 2004
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Location: Eau Claire, Wisconsin

PostPosted: Thu Aug 30, 2007 2:32 pm    Post subject: Reply with quote

endwrench wrote:
Have you considered some sort of hybrid diffuser style intake? This would keep the clearance requirements to a minimum towards the back of the motor and would give you nice even distribution. It would take a little more fabrication and welding though I think.

Todd

Some photos: http://www.bufkinengineering.com/intake%20manifolds.htm



Thats a very good link. The tapered manifold design seems to be a very popular design in the past and today. Many, many, cars use the same design, withouth diffusers. When I build a new intake manifold it will be something like you have mocked up dan, maybe angled a bit more. I think angling it more towards the front two cylinders would even out the flow.

Question: In a boosted application, can the flow rates really vary that much between cylinders, it would seem that the air being forced in would go where the least resistance is. Shouldn't the air in the intake manifold even out somewhat equally? I can see if the TB was aim directly at the rear two cylinder ports, or something that the front two might starve, but a tapered intake manifold design with a rather front mounted throttle body seems to work for most cars these days.
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ideola  



Joined: 01 Oct 2004
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Location: Spring Lake MI

PostPosted: Sun Sep 02, 2007 7:31 am    Post subject: Reply with quote

Great link, Todd, on the custom, two-piece manifold. This could be very do-able with our manifold setup. There is adequate space without having to move anything, and it would eliminate the 90 degree bend I am contemplating. It would allow me to stick with blocking off the original opening, and set up a tapered primary manifold, with the front-mounted TB. I understand the notion of the slot on the tapered portion of the primary, but how would you integrate the slot from the new, tapered manifold with the original manifold? Would you cut a slot all the way down its length, and simply have the two slots integrate between the primary (new) and secondary (original) plenums? Also, what about sizing? Would you start with 60mm (which is the inner diameter of the series II TB), and taper down to the size of a quarter or nickel, as indicated in the webpage that Todd linked to?
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endwrench  



Joined: 07 Dec 2002
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PostPosted: Sun Sep 02, 2007 8:28 am    Post subject: Reply with quote

I can't remember but I think it was Racing that turned me onto this concept in intake design. The diffuser acts as a distributor rather than a plenum. Your ideas on diffuser size seems sound. The slot between the plenum and diffuser needs to be a little bigger in "area" than the TB. You don't want to create a pressure differential.

Todd
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Raceboy  



Joined: 01 Mar 2004
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Location: Estonia, Europe

PostPosted: Sun Sep 02, 2007 3:04 pm    Post subject: Reply with quote

endwrench wrote:
Very nice Raceboy! I'd like to see it with the diffuser in place.

GSXR750, is that Suzuki? What size are the TB's?

Todd


I'll take few pics when I get my a$$ near my 931 (200 kms away from me).

Yes, Suzuki GSXR750. GSXR600, 1000 and 1300 (Hayabusa) suit also (1300 are 55mm inlet and 46mm outlet IIRC).

Those are tapered: 46mm inlet, 40mm outlet so basically what is needed for 931 38mm intake port.
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ideola  



Joined: 01 Oct 2004
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Location: Spring Lake MI

PostPosted: Mon Sep 03, 2007 6:44 am    Post subject: Reply with quote

endwrench wrote:
The slot between the plenum and diffuser needs to be a little bigger in "area" than the TB.

Todd, I think what you meant to say is the slot needs to be a little bigger in "volume" than the TB, correct? If so, then it should be a fairly simple matter to calculate the approximate volume of the TB by using its diameter and depth (of course, it is a somewhat more complex shape than a simple cylinder due to the tapers, but it should suffice for calculating the approximate volume). The slot would more or less amount to a simple cuboid.
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RC  



Joined: 25 Mar 2007
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PostPosted: Mon Sep 03, 2007 7:00 am    Post subject: Reply with quote

I`m quite sure that Todd is talking about the AREA of the slot. Perhaps if he said CROSS SECTIONAL AREA it may be more precise terminology.

I read this to refer to the relationship between the throttle body butterfly(s) and the size of the slot opening, Please correct me if this is misinterpreted Todd. After all the volume of a slot only takes into account the material thickness.

Oh yea, BTW Raceboy, that does look excellent!. Sure it will perform as well as it looks.

Roger
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ideola  



Joined: 01 Oct 2004
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PostPosted: Mon Sep 03, 2007 7:10 am    Post subject: Reply with quote

Ahhhh! OK...I'm nowhere near a car right now, so I'm guessing at the length of the intake manifold...but, using some approximate numbers, my Series II TB has a 60mm butterfly (I think), giving it a cross-sectional area of just over 2800 mm2; therefore, if the length of the intake manifold is about 300mm (give or take), the slot could be about 10mm high, accomplishing a larger cross-sectional area than the TB opening. Make sense???
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