34 DMSA or 32/36 DFEV?

[opus10583]

Hi,

In the vein of "in for a penny, in for Lire 2,500":

Having all but buttoned down a plan to add a 32/36DFEV to my early '78 CS1, I now wonder if I shouldn't rather go with the best carb FIAT ever gave the 1756; the 34 DMSA, available rebuilt for about 20% more than than the DFEV.

If I understand correctly, a longshot at best, the 32/36 should offer better around town performance and better overall power?

Advantages/disadvantages, comments, suggestions?

Thanks,
Mark

[So Cal Mark]

you can't always compare a rebuilt carb to a new one. There are parts that wear with time, and they don't get replaced during a rebuild. As for performance, I don't think there is that much difference between the two. It would be interesting to do a dyno comparison, but that only tells part of the story

[lanciahf]

Pretty sure a rebuilt Italian carb is years ahead of a new Chinese Weber.

[124ADDHE]

Not that it helps that much but I really did enjoy my old 34dmsa, removed the cold-start choke for better flow, it pulled really well on my 1800 right till just over 7000 rpm, even better @ the upper rpms than my solex c40's (cant match their torque though). The mechanical secondary is nice.

[opus10583]

Pretty sure a rebuilt Italian carb is years ahead of a new Chinese Weber.

Well, I'd normally be more than happy to be chauvinistic and all geopolitically self-righteous here, but Mark raises a point of legitimate concern.

But I'll ask again: Is there any engineering or production reason to justify the EMPI's 25% price premium?

Thanks,
Mark

[opus10583]

Not that it helps that much but I really did enjoy my old 34dmsa, removed the cold-start choke for better flow, it pulled really well on my 1800 right till just over 7000 rpm, even better @ the upper rpms than my solex c40's (cant match their torque though). The mechanical secondary is nice.

Hi,

Does the DFEV not have a mechanical secondary?

Thanks,
Mark

[124ADDHE]

No, just had a look, it has a mechanical secondary also

[So Cal Mark]

theoretically, the 32/36 should provide slightly better fuel mileage if you drive without opening the secondaries. So if you want to get optimum fuel mileage and drive accordingly, there could be an edge there. As for differences in design, I can tell you that Empi is/has done design improvements over the original design. Most of this development has been in the venturi booster area.
For example, compare the IDF carbs that Weber and Empi both offer. The newest version of the Empi has a new design venturi booster that eliminates that stumble off-idle that has plagued the Weber version.

[opus10583]

Thanks Mark!

theoretically, the 32/36 should provide slightly better fuel mileage if you drive without opening the secondaries. So if you want to get optimum fuel mileage and drive accordingly, there could be an edge there.

How would you compare "around town drivability" and then "absolute power increase" between the two.

As for differences in design, I can tell you that Empi is/has done design improvements over the original design. Most of this development has been in the venturi booster area.
For example, compare the IDF carbs that Weber and Empi both offer. The newest version of the Empi has a new design venturi booster that eliminates that stumble off-idle that has plagued the Weber version.

"Venturi booster area"? Is that the same as power valve/circuit? ...and then the Sesame Street version, if you will?

Thanks again,
Mark

[So Cal Mark]

the venturi is not the same as a power valve

[opus10583]

the venturi is not the same as a power valve

Indeed. What's a "venturi booster area" then?

Thanks,
Mark

[boogiedude]

the venturi is not the same as a power valve

Indeed. What's a "venturi booster area" then?

Thanks,
Mark

Accelerator pump

[So Cal Mark]

the venturi booster is part of the main discharge nozzle and plays a major role in the transition from the low speed circuit to the main circuit