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Old 09-21-2006, 03:46 PM   #1
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Default Restrictor for BEGi FMU

Anyone have the restrictor for the vacuum line that comes with a new BEGi unit? I threw mine on today but I couldn't lower it past a 9:1 rise. I'm looking for a 6:1-7:1 rise, so I need to throw one in.

On a sidenote: I tested my Vortech FMu today. I have the 6:1 disc installed (measurements confirmed). It acts just like a 8:1 disc. at 5psi it reaches 80psi of fuel and at 10psi it reaches 125psi of fuel. This is why when I calculated and installed a 8:1 disc I was overfueled on the dyno, dipping well below 10:1 AFR. I'm sure it was acting more like a 10:1 disc or something. Right now I'm reading pretty good AFRs, which makes sense, cuase I wanted a 8:1 rise to begin with.
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Old 09-21-2006, 03:52 PM   #2
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I had the same problem you are having. I used an inch of plastic hose off of a wd40 can. Worked perfectly.
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Old 09-21-2006, 03:56 PM   #3
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you smart son of a bitch! I gotta try that. Good thing this is an easy swap out.
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Old 09-21-2006, 04:39 PM   #4
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Also have it here in my BEGi pages: http://bellsouthpwp.net/P/o/PopVII/BEGi%20AFPR.htm
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Old 09-21-2006, 04:43 PM   #5
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Another example of me not reading very good. I've looked over your pages many a times.
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Old 09-21-2006, 04:46 PM   #6
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Now he's not going to think I'm a smart son of a bitch.
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Old 09-21-2006, 04:54 PM   #7
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6:1 ratio should take you to 80PSI at 5psi of boost shouldn't it?

50psi (base) + 30psi (5*6) = 80PSI

8:1 Would be 90PSI
10:1 would be 100PSI

Right?
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Old 09-21-2006, 05:09 PM   #8
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my base is 36psi (OEM). 8 x 5 + 36 = 76psi
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Old 09-21-2006, 05:11 PM   #9
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jayc72's calculation looks right, base is 36 psi, but that's at what..20 inches of vacuum? So you hit 0 vacuum/boost, you have 50 psi of fuel pressure, plus another 6*5 = 80 psi of fuel pressure. The Vortech doesn't do anything until you get on boost.
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Old 09-21-2006, 05:14 PM   #10
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yes, correct, i was at around 48psi at 0 ~hg. So it is working as advertised. silly me!
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Old 09-21-2006, 05:54 PM   #11
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Corky's sending me his restrictor along with one of those small fittings, but i'll try the spray tube trick in the meantime.
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Old 09-21-2006, 06:02 PM   #12
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I'm going to try using another needle valve since I'll have a spare when I get my rebuild kit. Should allow me to bleed off boost and slow the rate of rise.
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Old 09-21-2006, 09:51 PM   #13
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Quote:
Originally Posted by jayc72 View Post
6:1 ratio should take you to 80PSI at 5psi of boost shouldn't it? ... 50psi (base) + 30psi (5*6) = 80PSI ... Right?
Not unless you are using an adjustable afpr such as the BEGi or Vortech Super FMU which can raise the base pressure to 50 PSI at atmosphere and the ability to cap the pressure at desired top boost level. The Pierberg gives me the pressure I need and the BEGi permits me to adjust how much I wish to use.

FM suggests the base pressure of 50 PSI base for their systems, and nothing you can do about that if using the supplied Vortech. For my 8 PSI Greddy I prefer about 48 PSI base and capped at around 94 PSI using the stock 1.6 injectors. By seat of the pants tuning those pressures seem to give the best throttle response and crispness. Your pressures may vary and the Pierberg/BEGi combination permists tinkering for your optimal adjustments.

Everyone here is a smart SOB
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Old 09-21-2006, 11:13 PM   #14
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Weasel made a good point about me reading 36psi at 20 ~Hg. At 0 ~Hg. at the FPR i'm at 48psi which calculates out correctly, and makes a bit of sense.
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Old 09-22-2006, 12:24 AM   #15
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Quote:
Originally Posted by jayc72 View Post
I'm going to try using another needle valve since I'll have a spare when I get my rebuild kit. Should allow me to bleed off boost and slow the rate of rise.
Some needle valves are interchangeable, some are not. The thread size is 10-32.
Stephanie
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Old 09-22-2006, 12:34 AM   #16
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Thanks Stephanie, I'll make sure that I'm careful!
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