Hi, I was wondering what the differences between downdraft and sidedraft carbs were. I have a 2 piece racing beat intake manifold, but I've never seen anyone else with that setup. All the cars that I've seen have had the carb sitting up rather than having another intake manifold piece with it sitting sideway. I have the racing beat intake manifold, and have never seen another one of those either. Does anyone else have this setup? And could a side-draft carb be setup so it's sitting up and down?

 

I have the setup and no i really doubt that it can be setup and down do to the way it was designed. Why would you wanna do that anyway, it's what it was designed for.

 

Just out of pure curiosity.

 

My understanding is the longer the intake runners the more power you get. So by having it wrap out, up, and over you are getting a much longer intake length.

I could just be making that up, though, or maybe it was the swampy dog that told me...

 

the shorter the runner the higher the powerbrand is the longer the runner the lower the powerbrand is and you make more torque with the sidedraft that witgh the downdraft

 

Sidedraft carbs and downdraft carbs work the same, just that the throttle bores/venturis are situated differently. (I have no hard proof but do have a strong feeling that Weber IDFs are just downdraft DCOEs - enough parts interchange)

You can't convert one type of carb to the other. All the important bits (the float bowls and the layout inside) are dependent on which way gravity is facing. One reason why EFI is kinda popular with rockcrawlers - their rigs are typically *not* level with gravity

To answer your manifold question, the 2-piece manifold was borne with the advent of the GSL-SE. GSL-SEs are, of course, 6-port engines, and to keep the 6-port actuation operating you need to maintain the actuators hanging off the side of the manifold. Conveniently, Mazda used a multipiece manifold, so they just made an adapter to attach a sidedraft carb to the stock lower intake manifold (LIM). After that, they started making a LIM for the 12As that attaches to this adapter, so you can use the GSL-SE adapter (upper intake manifold) on a 12A. Just more options, say so if you have a carb setup from a GSL-SE, you can put it on a 12A if you get a different engine. That's all.

The best sidedraft carb setup is one-piece and situates the carb over the side of the engine, so the airflow doesn't have to make two 90 degree turns. These are available in single and double carb setups, the single carb manifold being known as the Lake Cities manifold.

 

I do believe that if you intake runners are a little longer that you do gain a little bottom end at of couse the price of losing some top end. Everything is a trade off in lafe *sigh*.

I Had the DCOE set up and it works great!

 

You need a shroud for your radiator, or an electric fan.

 

I've got the downdraft 48IDA... and I LOVE it. Because, by nature, I'm pretty hard on cars, I spend a lot of time in the upper rpm's, and this carb is perfect for it. It screams the whole way up to 10 if need be, and will keep going if you want it too.