Carburetors Carb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.

not enough vacuum

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Old Jul 12, 2005 | 09:54 AM
  #1  
Nebu's Avatar
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From: Germany
Car: 91' Camaro
Engine: Carbed 305
Transmission: 5-Speed Manual
not enough vacuum

hi,

i have my pcv and brakebooster with a t-fitting at the back of my double pumper. but the brakes dont get enough vacuum to operate properly. when i remove the pcv it works good.

how can i fix this? pcv is new. normally i would connect the brakes to the manifold, but i dont have enough room because of the carb.

nebu.
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Old Jul 12, 2005 | 11:37 AM
  #2  
five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
You'll either have to move the carb up via a spacer, or find a way to get a fitting under the fuel bowl to the manifold.

This is exactly why many of us say not to T the PCV and brake booster together.
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Old Jul 12, 2005 | 04:00 PM
  #3  
Nebu's Avatar
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From: Germany
Car: 91' Camaro
Engine: Carbed 305
Transmission: 5-Speed Manual
i cant put a spacer on because i have no room left between the aircleaner and the hood and there is appr. 0.3" between the fuel bowl and manifold. i dont think there is 90° a fitting this small available.

is it possible to hook the pcv to the timed vacuum port?

Nebu.
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Old Jul 13, 2005 | 12:21 AM
  #4  
zNucleaRz's Avatar
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Joined: Mar 2002
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From: Newport News, Va
Car: 84 Z28
Engine: GMPP 350 HO
Transmission: 700R4 + Shift Kit
Axle/Gears: Auburn Posi; Richmond 3:73 Gears
If you have an Edelbrock intake these will help you.

Edelbrock Low-Profile Vacuum Fitting EDL-8096 9.95
Summit Straight Fittings 3/8 NPT to 3/8 Rubber Hose SUM-G3116 5.95

These are what I used I connect my brakes to this and the PCV to the carburetor.
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Old Jul 13, 2005 | 06:18 PM
  #5  
IROC-Z28_CAMARO's Avatar
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From: Toronto, Ontario
Car: 1988 IROC-Z, 95 Z-28
Engine: 357, 350 LT1
Transmission: Built 700-R4, 6-Speed
Axle/Gears: 2.73 Peg Leg, 3.42 Posi
I had the same problem. My cam is so radical it would not build up enough vaccum. I used one of those comp cams resovoirs and it works awsome.
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Old Jul 13, 2005 | 09:46 PM
  #6  
Fast355's Avatar
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From: Hurst, Texas
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
This is on a FWD GMC motorhome but you will get the idea. It is a GM electric vacuum pump that is used to boost vacuum to the power brakes. The 1992 donor van that I used had one under the battery box of all places. I relocated it under the evaporator box on my 1983. My power brakes work great. Alot better than they ever did off engine vacuum alone.

http://www.gmcmotorhome.com/tech/vacuum_pump/index.html
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