I have triple webers on my 2.5L GT6 convertible (I assembled a car with
the features I wanted, not what the factory built). After 10 years of
tuning by the seat of the parts, I started tuning with an oxygen sensor.
I use a cheap narrow band, heated 3-wire O2 sensor/gage with a bung that I
welded on my header collector. In the future, I intend to buy a wide band
O2 sensor kit - with data logging capability! For about $250 to $400 there
a numerous wide band kits and several of them have data logging. For
older vehicles with out an O2 bung, it is not uncommon to clamp an O2
sensor into the tailpipe for temporary use.
I also have a slight stumble on very light acceleration in a slightly
narrower rpm band than you mention. I am fairly certain that I can tune
this out, primarily with idle jets - it is "good enough" for now and I have
too much going on in my free time right now to mess with it. There is
quite a bit of functional difference in idle jets once you play the
diameter of the fuel orifice against the dia of the air orifice. I
purchase idle jets off of eBay. Seller is in Italy and I presume that the
jets are not Weber brand in that they are marked slightly different than
the actual Weber jets that I have. From what I remember, cost is about
$2.50 per jet and you can get up to 14 jets for the same shipping price.
To cut my costs a bit more, I tend to buy my jets slightly on the smaller
size and open them up with very small drill bits (I have a drill press that
spins up to 8K rpm, ideal for drills that are frequently less than 1 mm in
diameter). I buy the 2 mismatched jets slightly larger and use them as
gages - to measure the hole diameters before drilling out others. BTW,
my fuel mileage has increased from 17 mpg to 26 mpg (up to 31 for all
freeway driving) and the carbs are still running from stoichometric (sp?)
to rich.
I have not bothered to give you my jetting since my chokes are 27mm and
that effects all other jetting.
Folks,
I need some help setting up my triple webers on my TR250.
I have a stumble in the mid rpm range, 1000 rpm to 2500
rpm. It idles good and it runs well above 2500 rpm. I
think I'm idling on the idle jets and not on the progression
circuits. It seems to me that the problem is with the progression
circuits or with the accelerator pumps. I'm thinking accelerator
pumps. Any idea on what to try?
Thanks,
David Brady
'68 TR250, CD8124L
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