Lowtechprime
Retro Grouch
What are the differences in the sub model numbers, say like a 36-DCNVH-16-100 3D or a 36 DCNVH 26-100 4F ? Which would be appropriate for a Fiat 1500? Where can you get chokes for them?
FIAT 128 1971
- Thread starter SIMONE128
- Start date
fiatfactory
Steve Cecchele
Both of those models seem to be from Maserati Bi-turbo, no idea what the differences are between them, google is your friend.
I would guess that a carb made for a blow thru specific application may have a few differences in things like aux venturi, maybe pump cam, etc, but I have no data on either so I can't be sure, caveat emptor.
OD of the chokes is the same as 40dcnf, even though the butterflys are 36mm, a lot of the internal sizing is the same as a 40dcnf.... well thats the case with the DCA and DCNVA's I've used, not sure if applies across absolutely all models of the carb.
when you lop off the original stacks and choke flaps the opening is 40mm (plus a little from memory) so the 40dcnf bellmouths fit up with no step.
SteveC
I would guess that a carb made for a blow thru specific application may have a few differences in things like aux venturi, maybe pump cam, etc, but I have no data on either so I can't be sure, caveat emptor.
OD of the chokes is the same as 40dcnf, even though the butterflys are 36mm, a lot of the internal sizing is the same as a 40dcnf.... well thats the case with the DCA and DCNVA's I've used, not sure if applies across absolutely all models of the carb.
when you lop off the original stacks and choke flaps the opening is 40mm (plus a little from memory) so the 40dcnf bellmouths fit up with no step.
SteveC
Bjorn Nilson
True Classic
I couldn't resist to try Copilot on this one and here's the result:
The Weber 36-DCNVH-16-100 3D and the Weber 36 DCNVH 26-100 4F are both dual-barrel downdraft carburetors that were used in some models of Maserati BiturboAd12. They have the same bore size of 36 mm, but they differ in the following aspects:
The venturi size is 16 mm for the 3D and 26 mm for the 4F. This affects the airflow and fuel mixture ratio of the carburetor.
The choke type is manual for the 3D and automatic for the 4F. This affects the cold start and warm-up performance of the engine.
The emulsion tube is F16 for the 3D and F9 for the 4F. This affects the fuel atomization and distribution in the venturi.
The main jet is 115 for the 3D and 125 for the 4F. This affects the fuel delivery at high engine speeds.
The air corrector jet is 200 for the 3D and 180 for the 4F. This affects the fuel-air ratio at high altitudes and temperatures.
The idle jet is 50 for the 3D and 55 for the 4F. This affects the fuel delivery at low engine speeds.
The pump jet is 40 for the 3D and 45 for the 4F. This affects the fuel delivery during acceleration and deceleration.
These differences mean that the 3D and the 4F are not interchangeable and require different tuning and settings for optimal performance. The 3D is more suitable for turbocharged engines, while the 4F is more suitable for naturally aspirated engines3.
Impressive result from AI
The Weber 36-DCNVH-16-100 3D and the Weber 36 DCNVH 26-100 4F are both dual-barrel downdraft carburetors that were used in some models of Maserati BiturboAd12. They have the same bore size of 36 mm, but they differ in the following aspects:
The venturi size is 16 mm for the 3D and 26 mm for the 4F. This affects the airflow and fuel mixture ratio of the carburetor.
The choke type is manual for the 3D and automatic for the 4F. This affects the cold start and warm-up performance of the engine.
The emulsion tube is F16 for the 3D and F9 for the 4F. This affects the fuel atomization and distribution in the venturi.
The main jet is 115 for the 3D and 125 for the 4F. This affects the fuel delivery at high engine speeds.
The air corrector jet is 200 for the 3D and 180 for the 4F. This affects the fuel-air ratio at high altitudes and temperatures.
The idle jet is 50 for the 3D and 55 for the 4F. This affects the fuel delivery at low engine speeds.
The pump jet is 40 for the 3D and 45 for the 4F. This affects the fuel delivery during acceleration and deceleration.
These differences mean that the 3D and the 4F are not interchangeable and require different tuning and settings for optimal performance. The 3D is more suitable for turbocharged engines, while the 4F is more suitable for naturally aspirated engines3.
Impressive result from AI
fiatfactory
Steve Cecchele
mehhh, not that impressive.I couldn't resist to try Copilot on this one and here's the result:
The Weber 36-DCNVH-16-100 3D and the Weber 36 DCNVH 26-100 4F are both dual-barrel downdraft carburetors that were used in some models of Maserati BiturboAd12. They have the same bore size of 36 mm, but they differ in the following aspects:
The venturi size is 16 mm for the 3D and 26 mm for the 4F. This affects the airflow and fuel mixture ratio of the carburetor.
The choke type is manual for the 3D and automatic for the 4F. This affects the cold start and warm-up performance of the engine.
The emulsion tube is F16 for the 3D and F9 for the 4F. This affects the fuel atomization and distribution in the venturi.
The main jet is 115 for the 3D and 125 for the 4F. This affects the fuel delivery at high engine speeds.
The air corrector jet is 200 for the 3D and 180 for the 4F. This affects the fuel-air ratio at high altitudes and temperatures.
The idle jet is 50 for the 3D and 55 for the 4F. This affects the fuel delivery at low engine speeds.
The pump jet is 40 for the 3D and 45 for the 4F. This affects the fuel delivery during acceleration and deceleration.
These differences mean that the 3D and the 4F are not interchangeable and require different tuning and settings for optimal performance. The 3D is more suitable for turbocharged engines, while the 4F is more suitable for naturally aspirated engines3.
Impressive result from AI
for a start both have manually operated chokes, and both come from a turbocharged engine.
the last part of the number letter suffix I believe is a manufacture date, the number being a year and the letter being a month, so 3D is probably April 1983, and 4F is likely June 1984 ... my weber bible only ever lists a carby type (like 36DCNVH) and then a numbered suffix (like 16/100 and 26/100) and never lists a letter/number after that... I've run across plenty of carbs with the same model codes but differing number / letter at the end that were precisely the same carb, orr the same model, but made in different years, so I figure this is a manufacturer date code.
so they should be referred to as 36DCNVH16/100 and 36DCNVH26/100, which I'm sure is how you'd find them listed in a weber parts book
But mainly I doubt the veracity of one having 16mm venturis that just doesn't sound right to me, if it said one was 26 and one was 27 I could accept that, but one having 26 venturis and one with 16mm venturis, I 100% doubt that is correct.
the other differences it lists could well be correct, small idle jet / air corrector jet, etc makes sense... didn't a maserati bi-turbo come as a 2000 and a 2500 engine? ... likely the difference is related to engine size, or perhaps the market the car was sold in and emissions requirements..
SteveC
Steve Thomas
True Classic
ah, but you are using actual intelligence [AI] rather than the popular absent intelligence [AI]. Note that there is no Artificial Intelligence in existence. None whatsoever. The apps called AI are just good data moles.
ghostdancing
True Classic
hi simone, i'm from italy too (gulf of neaples) and own a red 72 coupe, there was a 128 forum in italy but it's gone a few years ago..
this space it's packed with lots of nice people and deep knowledge, so it's a wonderful resurce for us 128 owners from any country in the world
this space it's packed with lots of nice people and deep knowledge, so it's a wonderful resurce for us 128 owners from any country in the world
johnph
True Classic
Simone: To obtain a proper running engine, you should consider rephrasing your question from;
-will it fit my engine to 'what carburetor will give the most favorable results for my engine"(and its modifications from stock).
The original equipment (OE) carburetor was selected to maximize performance characteristics such and economy, torque and power.
It is possible to make your car perform worse than stock by fitting a carburetor that is too small or too large for your engine compression, camshaft and other components as well as your intended use.
I suggest that you read and understand a book which explains basic carburetor theory and tuning before making changes from stock like:
TUNING SOLEX CARBURETORS by R.C. Pack or WEBER CARBURETORS TUNING TIPS AND TECHNIQUES. These books can give you good guidance on carburetor selection including proper sizing of the throttle plates and choke (venturi) size. For street use, you may find that a two barrel downdraft carburetor that has progressive opening of the primary, then the secondary throttle plate with removable chokes may best suit your needs.
Hi, I have seen some forums in Italy but all the contents are old, as you told probably they are actually gone...
