Can someone give me an explanation of a Progressive Carb?

[Anonymous]

I am trying to decide which carb to mount on my Aussie 2v.

I am down to two possible candidates....

The 2300 350 cfm...
and Tom's 2305 350 cfm....

The only major difference between these two as I understand it is that the 2305 is progressive like the Weber or 5200....

Can someone tell me exactly what that means and in what ways each are better, worse, different.....?

I came across many different posts about the various two bbls but I found very little as to what they do differently and why one is better or not than the other....

Thanks


Jimbo

 

[CoupeBoy]

Jimbo,
I'll give this a try. On the 5200 I have here, when you operate the throttle linkage on it, only the primary will open until you get about 1/3rd of the way through the total movement (closed to WOT) during the last 2/3rds the secondary (larger) butterfly opens, the linkage is setup so that when WOT is reached BOTH primary and secondary are fully opened (darn near verticle). So at lower speeds/cruising when you are barely holding the throttle it will run off the smaller venturi.

On a NON-progressive carb, both butterflies are on the same throttle rod, or they are directly connected, and both open at the exact same time.

One other thing to consider is where the linkages come out. On my 5200 it comes out on the backside of the carb

on my 2100 (stock from my 289) it comes out on the side. This may not make any diff at all, but something to consider.

-ron

 

[Anonymous]

I understand the differences now between the two...

I even bought the haynes Holley manual which has been a great help... but I am wondering still...

Which of these carbs is better for the 250 2v I am running with a performance cam...

Seems like the 2300 would be great off the line, but would I get better economy with the 2305....? and would that be enough to run off of...

Maybe the best carb for my setup would be the 2305@500cfm, that way I get more flow and a progressive flow for the top end...?

And where are the throttle linkages for the 2300 series carbs, side or back? as I am running a cable throttle setup and right now it runs accross the intake to the rear of the carb.... best for me.