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Re: Weber DGV Carb Questions

To: "Bollinger, Bob D. (BODB)" <BODB@chevron.com>
Subject: Re: Weber DGV Carb Questions
From: Barry Schwartz <bschwart@pacbell.net>
Date: Fri, 19 Feb 1999 08:13:02 -0800
>- Will I notice significant performance improvement for the money?
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Yes, provided you set it up correctly (see below)
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>- Would I need anything else along with a new Weber DGV?
************************************************
The manifold, air cleaner, and new linkage to go with it
***********************************************
>- Is it fairly easy to install yourself?
**********************************************
As far as conversions go, yes
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>- After installation doesn't it need to be tuned and can I do it with one of
>           those Colortune spark plugs or should a mechanic do it?
**********************************************
This is what I meant above.  Properly setting up any carb NOT originally
intended for the vehicle it is being installed on requires quit a bit of
work, and simply setting it with a color tune will only set the mixture at
idle.  Color "tuning" is really only designed for checking the mixture with
a carb that is ALREADY calibrated for the engine/car combo it is on.
Carb's require settings for several distinct ranges of operation as well as
transitional areas of operation.  Basically, you need a calibration for
idle mixture, one for part throttle operation, another for cruise, and
another for full throttle operation.  In between these are the transitions,
that is from off idle to part throttle.  Part throttle to cruise, etc.  All
these must work in harmony or you will have driveability problems, or in a
worst case scenario, engine damage from a too lean condition.  There is
really no such thing as a "bolt on" carburetor other than a bone stock
replacement, because every vehicle is a little different and calibration
"corrects" for these differences. To calibrate a carb for anything more
than idle mixture really requires a fair bit of knowledge of the workings
of the various functions of the carb, a rolling dyno is great and really
the beat way for setting one up.  Years of seat of the pant's driving,
check the plugs for mixture type calibration, or now, installing an oxygen
sensor with air-fuel meter and testing under real world driving conditions
is another way to set it close enough for daily usage.
*********************************************
>- Would installing this new carb constitute "changing the emission system"
>           as the note in the catalog warns about (I'm in CA if that makes a
>difference).
********************************************
Unfortunately, you just answered your own question and made all the above a
mute point.  Yes, this would constitute an "unlawful" change to your
vehicles emission control system (unless the all the equipment has a CARB
certified sticker).  Therefore, you can't "legally" install this on any
1965 or newer car that had emission controls originally installed from the
factory, driven on public roads -, yes that includes 73 and older, you just
don't have to get those inspected. . .so. . . if you were to put one on. .
.well. . .;-)

Barry Schwartz (San Diego) bschwart@pacbell.net

72 V6 Spitfire (daily driver)
70 GT6+ (when I don't drive the Spit)
70 Spitfire (long term project)

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