Weber 32/36DGV verses the Weber 38DGES

(carpal tunnel)
Fri Apr 22 2005
04:11 AM
yodta
(pooh bah)
Fri Apr 22 2005
12:22 PM
Sarge
(carpal tunnel)
Sat Apr 23 2005
02:57 AM
yodta
(pooh bah)
Sat Apr 23 2005
04:36 AM
Sarge
(carpal tunnel)
Sat Apr 23 2005
11:39 AM
Cost factor, plain and simple. Everyone wants to go 200mph for $50 . Yeah, a few gallons of nitromethane will do just that , but
things don't last very long. What you want is a carb that has a selection of interchangeable venturis, auxilary venturis, jets and
such. Hmm, DCNF series comes to mind right quick. The 32/32, 32/36, 38/38/, and 40/40 DGV/DFV series all have cast-in
venturis that are not removable. You can change the auxilary venturis and change the main circuit's signal/flow but that is all.
Look at the book from Pierce again in the DCNF section, there are a lot of venturi's (chokes) available for those carbs. Only
drawback is a different bolt pattern, linkage and somewhat limited availablility of venturi's stocked here. I can get almost any size
from Europe, though. One other factor to keep in mind is signal vs. throttle response. The bigger venturi requires larger auxilaries
and more fuel, economy can disappear very quickly if you go too far. Power comes up at high revs but so does fuel demand.
Sarge
Re: Weber 32/36DGV verses the Weber 38DGES
I just hate that it took so long to get someone to look at it more closely and scratch his head and go, "yeah, that carb is pretty
small for that engine."
anyway, it should tune okay, just not optimally, but we'll see. if anything, like you said, I should get good fuel economy and pretty
good pickup since the vacuum response will be better.
maybe it won't really matter though given the torque curve of my engine.
yeah, I'm noticing the DCNF in more of my reading lately. it's pretty apparent to me that the DGEV/DGAS/DFAV series is exactly
what you said earlier - an economy OEM type replacement/build. seems if you want the ability to truely customize the carburetor,
you gotta spend the extra for the DCNF or DCOE. and yes, I understand better now how you prevent overcarburetion on smaller
engines now with these larger, more capable carbs you really can do just about anything with them.
I pulled out the old DFAV last night. it's got 28mm venturis in it, and I think 4.5 chokes, though I haven't had a chance to break
into it fully yet.
I'm gonna get the old manifold cleaned up and set this aside as the next project. now that I've got my timing issue sorted and a
better understanding of tuning, this carburetor may perform better.
here's a question for you though on setting the mixture screws on the synchronous carburetors. I've read two techniques on this:
1.) close one mixture screw and set lean best idle with just one screw first, then duplicate the setting on the other screw
2.) set them both at the same time
which is the best way to do it?
Re: Weber 32/36DGV verses the Weber 38DGES
I have my own set of tricks for balancing the idle screws on synch'd carbs. If you listen closely enough, you can hear each throat
just at lean drop, then just give that throat about 1/8 turn out . Most of the time equalizing the number of turns is close enough,
but some are more finicky about it . Try tuning it with your ear very close to the top of the carb with the air filter off once, you may
be able to hear the lean drop. It starts like a bit of a hiss just before killing off that throat's ability to run . I'd almost like a shot at
the original equipment manifold and the 40DFAV, see if there are some potential flow issues that can be corrected. Just depends
upon the amount of "meat" in the plenum. I really prefer a single common plenum with the DGV series carbs. In fact, there are a
lot of the same common plenum designs used on the DCNF series as well. The common plenum just gives a more smoothness
to the mix, less puddling and better overall atomization. That split design Offy works well but I wonder sometimes if they didn't go
too far.
Sarge
Re: Weber 32/36DGV verses the Weber 38DGES
I hear a hiss while adjusting the mix screw if I open it up too far. is this the hiss you're talking about? what causes that?
yeah, this Offy dual plane manifold is supposed to be designed for increasing low end torque and probably works really well with
the smaller primary barrel of the 32/36 in keeping the velocity high as it travels through the manifold, but it is pretty tight in there.
if I had it to do over again, I'd probably just go with the open plenum one which is the same basic open design as the Toyota one
and could be used with the other carburetor I have, as well, which I can't do with the Offy with the dual runners.
Re: Weber 32/36DGV verses the Weber 38DGES
No, there is almost a whistle when you hit the lean edge on a carb, hard to hear since it's pretty high in frequency. The hiss you
hear at rich idle mix is the fuel being sprayed out of the idle circuit, way too strong to be atomized so it just squirts.Just remember
to allow the plugs to clear up for a few seconds, helps a lot.
Sarge
Sarge Re: Weber 32/36DGV verses the Weber 38DGES
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