Flange mount versus throat mount velocity stacks for weber dcoe

[Esc8p2NeverLand]

I've been looking for velocity stacks now and was recommended pierce manifolds. They have two styles available with two very different prices.

What are the pros and cons of flange mount versus the insert type? The one that mounts outside is almost half the price.

Flange Mount

Insert Mount

Thanks!

[ozconnection]

I like the slip in variety because of the smooth internal surface it provides. Anytime there is a mating point, there's the risk of an eddy creating step.

On the other hand, I like the idea of bolting the stack to the carb for secure fitment. And the chrome look is nice.

Do they come in different sizes? Are you looking to 'tune' your induction system at all? If you are, the slip in ones would be a snap to insert and remove quickly to find the best power and/or torque curve from your engine.

Have fun.

[Zs-ondabrain]

They were designed to run with the Insert style stacks. The insert secures the Aux Chokes and centers them. this hold the aux. in place and in return hold the stacks in place, then use the small tabs to hold them in the carb body.

[Ron Carter]

Although both designs work okay a fully rolled lip on the outside of the air horn will make a significant difference as well. This is race car stuff and not really something you would notice as much on the street.

We have seen crappy air horns create strange problems in the past that were simply solved by installing better air horns.

We have seen a difference of as much as 5 HP and the loss of dead spots in the power curve on the dyno with the TWM style (fully rolled) air horn.

http://www.twminduction.com/AirHorn/AirHorn-FR.html

[Esc8p2NeverLand]

Thanks all for the input.

As far as tuning, I'm just looking to have some sort of air horn. It seems that everyone recommends one rather than just a k&n filter (which the previous owner only had).

For it holding the aux venturi, my weber 45 dcoe seem to have two bolts underneath securing possibly both venturis? I need to take them off to get a better look. Can anyone chime in on that?

Edited June 22, 2010 by Esc8p2NeverLand