Weber 32/36DGV verses the Weber 38DGES

Sarge
(carpal tunnel)
Sun Apr 03 2005
01:40 AM
Sarge
(carpal tunnel)
Fri Apr 08 2005
11:53 PM
Sarge
(carpal tunnel)
Sat Apr 09 2005
12:47 AM
making, so I gotta get back to my baseline and start over.
I've decided on setting my timing at 12* -- but NOTE!!! this is WITH the idle advance connected. I read in the FSM to set it to 0*
with the vacuum disconnected & plugged and that should give you 12* when you reconnect it. anyway, I'll drive it like this for a
while. if I can't get the timing right, there's no sense in wasting my time on jetting, because I'll never be happy with it.
Re: Weber 32/36DGV verses the Weber 38DGES
I would check for total advance @ 4,000 revs . With the idle advance hooked up you should be showing 32* or so , maybe down
as low as 28* at that rpm. The main switched vac advance should not be active at that rpm with no load on it . Most of the
Japanese mechanical vac systems are good for 8-10* of advance and most top out their ignition advance to a total of 34-36*
timing. So , if it reads 28* at 4k , you have a correct working system. Hope that makes sense, been a long day working on the
Suzuki's oil pump issues and trying to get time to tune the DCNF as well. Finally figured out the dumb main jets were too small
and the oil was overheating, gotta get a guage on this thing. The fittings to the remote filter were so hot it would burn you in less
than 1 second.
I never have really learned how to manipulate pixel size or orientation on computers. I was lucky to figure out how to post them
and that took some help. I tried to edit that post a week or so ago and the system wouldn't allow it . So far this DCNF is a killer,
tomorrow it gets it's high angle testing done and basically the snot beaten out of it . Throttle response is ticklish in almost a bad
way, breathe on the gas and the truck just launches . Monday I plan to spend most of the day trying to sweet talk the F tube
tables from the NY techs so I can figure out what tubes to run . The fuel curve right now is a bit weird and I'm sure that's what is
causing it . Hard telling, not too many guys alive that remember how to properly tune and set one these.
Sarge
Re: Weber 32/36DGV verses the Weber 38DGES
Ok, got some updates. Wheeled the DCNF pretty hard last weekend , with some less than desireable results. I had built into the
float chamber a vent tube and closed off the factory slot to keep fuel out of the idle air bleeds and main air jets . Either the tube
was getting into the edge of the float or the tube was unable to pass enough air to stabilize atmospheric pressure in the bowl .
Fought with it most of the day trying to keep fuel pressure steady and work on the hills. Downhill it wouldn't cooperate at all, just
had to keep shutting the fuel pump off . After it finally got to the point it wouldn't stay running I just bypassed the vent altogether
and went back to it's basic stock form. Even with the bowl in the rear it performed flawlessly, even at high downhill angles. That
carb has way more power than the 38DGAS any day of the week and will certainly kick it's butt offroad. Uphill is no issue at all
and it seems like side hills don't affect it as much as I would have originally thought. Basically, these can be run out of the box
offroad better than any other carb I've built to date. On top of all the probs, the dumb thing still does better on fuel mileage for the
last week in spite of running like crap on the trail the first day and being thrashed doing jet changes. Almost disgusting , really...
Sarge
Re: Weber 32/36DGV verses the Weber 38DGES
Got a pm from Yota concerning his jetting:
I'm considering taking off my choke plates for the summer.
on my jetting...
75/60
140/150
185/190
eh, it's so so, takes off when the main comes in, but I think with the air that big it's taking too long to come in. I think if I went to an
80 idle jet it would feel better. I'm gonna try that so I can keep the pulling feel at the top end without going into the secondary.
what do you think?
the secondary's still bleep. it just lays down if I'm in it at anything less than 4000rpm...
The comment about the secondary is pretty common really, most can get the primary jetted close enough to pull well but the
secondary just never seems to do it's job. Let's see what causes this....
For one thing, you must know what you are dealing with. Most progressives use a 3.5 auxilary venturi in the primary. This venturi
is where the fuel is actually delivered into the throat from the suction created by the smaller choke area in the throat's bore. Just
nothing more than a low pressure area to induce a pull through the main jets and emulsion tubes. The circuit control comes from
metering through the main jets, air blending via the emulsion tubes , and air induction controlled by the air jets. The 3.5 size of the
auxilary venturi dictates how much actual fuel/air mix can be sucked in from the main circuit. On most of these progressives, the
secondary not only has a larger bore but also a larger 4.5 auxilary venturi . Most common thinking is to use a larger fuel jet in the
secondary when in reality the larger venturi will draw more fuel from a jet the same size as the primary or even more. I set most
of the 32/36DGV's up with mains the same size in each side and a smaller air jet on the secondary. The smaller air jet keeps the
circuit from going lean at full velocity, fine tuning later will usually result in going a bit bigger in the air jet but I set them up that
way for safety's sake. So, if your secondary isn't responding as expected, take a look down the throats and see what size the
auxilaries are , might get surprised. BTW, 38DGAS and 40DFAV's use 4.5's in both sides out of the box . On DGV progressives,
you could use a 4.5 from a 38DGAS as a performance upgrade and slightly smaller main jets ....
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