Carb linkage and velocity stack questions, Need opinions on CB performance recommendations Options

[Van]

I ordered a dual carb linkage kit and velocity stacks from CB performance for my 44 IDFs... 2 things surprised me - I called them, and was told, "don't worry about it - that's as good as you'll get." I'd like some other opinions...

#1: the air cleaner bases (there's a left and a right) have the same "offset" for the linkage bar - meaning the bar will be at an angle to the engine when it's installed. They said, "We don't have anything for the type 4 offset - don't worry, you'll be fine." I've seen pictures from searches, and it looks like many people have setups with a straight bar - what are they using?

#2: the velocity stacks have a bore which is a bit bigger than the top of the carburetor - like maybe 3/8" larger in diameter. (Actually, the air cleaner base plate has the same large bore, too.) Anyhow, it seems to me, that if one has that large a step transitioning from the velocity stack to the carb throat, any gain from the velocity stack will be eliminated from the turbulence. CB's response, "Don't worry - you'll never feel the difference."

Does anyone have any guidance for me? Should I try to get velocity stacks the right size? Should I modify the air cleaner base plates to make the bar perpendicular to the crankshaft?

[bobhasissues]

CB does sell an offset base kit, I have it on my car. I don't remember the part number for the base kit, and you'll need a shorter hex bar. I believe the offset bases were designed for a 356 and not a type IV, but it does straighten up the hex bar and eliminates the need for the offset spacer on one side. I think it's a bit of a better set-up, but will still switch to Jake's cable linkage when he releases it.

[jmill]

With no offset it won't be right. With the crossbar at an angle the distance the drop links travel will be different from side to side. One arm moves closer to the carb body while the other moves farther away.

As far as the velocity stacks go I bet they gave you 48 IDF stacks. The whole idea of the stack is to smooth out flow to increase its velocity. The turbulence at the step doesn't help. I don't know if the step will eliminate all the gain. I suspect it will eliminate some. I, personally, would want a smooth transition.

This looks like the hot ticket: http://www.914world.com/bbs2/index.php?showtopic=99851

[jmill]

I believe the offset bases were designed for a 356 and not a type IV, but it does straighten up the hex bar and eliminates the need for the offset spacer on one side.

You need the offset spacer on one side when you have offset bases. The spacer is what corrects the offset on the carb arm.

[bobhasissues]

I believe the offset bases were designed for a 356 and not a type IV, but it does straighten up the hex bar and eliminates the need for the offset spacer on one side.

You need the offset spacer on one side when you have offset bases. The spacer is what corrects the offset on the carb arm.

Isn't that what I said?
Stock bases require an offset spacer on each side.
Offset bases require a spacer on only one side.

[Van]

Thanks for the feedback, guys.

Jake's cable one looks fantastic!! I wonder if it's worth trying to make that from scratch... Or stick with the hex bar for now.

[McMark]

I'm not an airflow scientist, but I'd agree with your logic that a mismatch from the velocity stacks to the carb throats would negate the effect. In my experience, questions like that directed at a sales person over the phone will never get a real answer. Likely the guy/girl on the other end of the phone has never even touched that part, let alone put it on and engine.

[maf914]

#2: the velocity stacks have a bore which is a bit bigger than the top of the carburetor - like maybe 3/8" larger in diameter. (Actually, the air cleaner base plate has the same large bore, too.) Anyhow, it seems to me, that if one has that large a step transitioning from the velocity stack to the carb throat, any gain from the velocity stack will be eliminated from the turbulence. CB's response, "Don't worry - you'll never feel the difference."

Does anyone have any guidance for me? Should I try to get velocity stacks the right size?

Wow! Deja vu all over again!

Years ago, and I mean years ago, I bought a dual 40IDF kit from CB and it included oversized velocity stacks. I called them up and they agreed to exchange them for the correct size, which they did. But, apparently their quality control hasn't improved much since then, or the same guy has reached his level of incompetence and is still putting together the parts for their carb kits. (IMG:style_emoticons/default/laugh.gif)

They owe you the right size stacks. Give them an ear full! (IMG:style_emoticons/default/hissyfit.gif)

[Mark Henry]

CSP center pull linkage. wrong stacks.

[jmill]

Isn't that what I said?
Stock bases require an offset spacer on each side.
Offset bases require a spacer on only one side.

My bad. I didn't know the cockeyed linkage had spacers on both sides. I always went with the offset ones (IMG:style_emoticons/default/beerchug.gif)

[Jake Raby]

Thanks for the feedback, guys.

Jake's cable one looks fantastic!! I wonder if it's worth trying to make that from scratch... Or stick with the hex bar for now.

If you try to make ypour own set up you'll see just how complicated it can be and how critical wheel size and cable selections are.

The hex-bar set up isn't bad.. I have over 1,000 ngines out there running the set up. Its not optimum and thats why I have been developing bthe cable arrangement.

I have a mid-spring release date for the accu-link at this time.. I wanted to have it on the market already but the death of my Dad back in Octoiber and having to execute his Estate has taken priority and will for another 6 weeks or so.

[Van]

If you try to make ypour own set up you'll see just how complicated it can be and how critical wheel size and cable selections are.

The hex-bar set up isn't bad.. I have over 1,000 ngines out there running the set up. Its not optimum and thats why I have been developing bthe cable arrangement.

I have a mid-spring release date for the accu-link at this time.. I wanted to have it on the market already but the death of my Dad back in Octoiber and having to execute his Estate has taken priority and will for another 6 weeks or so.

I'm sure that if I make it, it won't be as good as yours... because I wouldn't spend that much time figuring it out. (IMG:style_emoticons/default/smile.gif)

I have the hex bar parts, but am not crazy about spending the time to get it all set up, then doing it again with your kit in 5 months. Of course, either way, I'll probably end up buying yours!

[jmill]

CSP center pull linkage.

Never used it but it sure looks like it'll work nice for around $120 bucks.

[Van]

CSP center pull linkage.

Never used it but it sure looks like it'll work nice for around $120 bucks.

But that can suffer from "engine expansion syndrome" right?

[bobhasissues]

CSP center pull linkage.

Never used it but it sure looks like it'll work nice for around $120 bucks.

Wow, I have searched for "weber linkage" all over the net for the past three years and never came across this one. I have seen (and even bought) type 1 center pullers with a different type of mounting base that would require modification or refabrication to mount on a type 4 case. Wish I had known about this and I would never had played with the CB stuff.

[craig downs]

I'm using that linkage now and it works pretty good. The center bellcrank uses 2 ball bearings and there's no slop. They sell one for the type 4.

[Van]

I'm reviving this to show off what I've done with the velocity stacks.

Short story: the first 2 sets CB Performance sent me were, in my opinion, too large. I got them to send me 40mm velocity stacks, which were a little small for the 44 IDFs, but I was able to modify them to my satisfaction.

http://www.ephotomotion.com/914engine/page41.html