Carb Swap

[sankyp]

I have a Suzuki Alto of 1993 in India. The car has a carb engine and its a dual barrel one. I want to swap it for a Constant Vacuum/Velocity carb with a single barrel from a smaller engine of a motorcycle. Current acceleration is a little more than needed. So I am sure can go with a little de-tuning. Shud I go ahead with the swap? What will be the single barrel equivalent of a 30mm dual barrel carb?

I am also interested in a final drive swap after some serious weight loss work on the car.

[drmiller100]

constant velocity generally are not as good as many of the two barrels.

if it were me, I'd use an EMPI or Weber version of this:

New 32/36 DGEV Weber Carburetor

there are a bunch of versions - basically there are mirror images of this one, and then various ways to run the choke.
For temperatures of 60 degrees and warmer, you can adjust the choke to where it never comes on.

These are easily tunable, and the very small primary means they are EASY to adjust, not tempermental at all, and very drivable.
Should get good gas mileage as well.

[Ryland]

The advantage of dual barrel carburetors is that they keep the air velocity up even at low engine speeds allowing them to work well at a wide range of engine RPM, a draw back of single barrel carburetors.
there are more and more companies offering after market fuel injection that you might look to go that route, with fuel injection you pretty much have to add an o2 sensor and with an o2 sensor your engine is getting the right amount of fuel for a complete burn no matter the engine speed so you should see a fuel savings and even a slight increase in peek power output.

[drmiller100]

to clarify my comments, the carb i specified is "progressive". This means one venturi is for idle, off idle, and part throttle. the venturi is relatively small, so exact metering of fuel to the air flow is easy for the carb to regulate.

when you want more power, the second venturi opens up which is setup richer to give more power and more air flow.

Constant velocity carbs are fairly notorious for being very clean, and make a lot of bad emissions. further, they do NOT get very good mileage in most applications.

Further, almost always the variable venturi carbs are side draft which makes them hard to mount to most automotive engines.

[sankyp]

I have decided not to go ahead with the swap.

Had a question abt 2-stroke engines. All this while I was told tht a 4-stroke is more efficient than a 2-stroke. However, some recent high efficiency engines use 2-stroke operation and claim to have nearly 60% efficiency. Bourke engine, the OPOC and Niama Reisser use 2 str0ke operation. Left me confused.