Recently we had a 912 come in to the shop for new fuel lines, vacuum lines, and tune up..etc, and I noticed that each intake runner had a vacuum line connecting first the two barrels of a carb together, and then connecting to the other carb. This got me thinking...how come I've never seen this on a 914?

Has anyone ever done this on a 914 engine? And what advantages would one see from doing this? Smoother idle, something along that line?

I was considering just drilling and tapping my intake manifolds for nipples to see what it would do. Any reason not to?

Wondering...

Were those Solex P 11's ?

I do believe they were.. I think..

i think those hose are used for balancing. i had a motorcycle that was set up the same way.... at least from what your describing. on the bike you unplugged one end of the hose and plugged it into the mercury stick. one column for each barrel. the barrel that was plugged was the one you used for reference. im just guessing from what you described.

After doing some research, I guess some 356's came with an "equalization pipe" to help smooth out the pulses at lower RPM's. Anyone have a good reason not to try this?

I have seen aftermarket type IV manifolds that have equalization tubes between each barrel and a plugged hose to run a line from one manifold to the other.
Go for it.
Bruce

not sure but I personally believe the dual solex carbs are a better design than the webers...especially the transition circuit, and they flow alot better.

I would say go for it, it may reduce the flat spot that webers so happily deliver.

rich

A balance pipe between the manifolds is used on single throat dual carbs like the stock ones that came on buses, type 1 or type 4 and with like weber 34 ict's.

Using a balance tube on dual barrel dual carbs, you lose the benefit of individual barrel carburation.

I have really old manifolds on my weber set up, and its got a port for each cylinder. I am running it hooked up, and it seems to run fine.

Click to view attachment

With the runners connected, though, adjustments from one side of the carb will inevitably affect the other cylinder, which negates the advantage of individual cylinder carburation.

Here's the thread on thesamba performance forum when I asked about this. -Bay window bus gets vacuum off the balance tube for the power brake booster, so it started as a discussion of which runner(s) to get vacuum from. The consensus from those who had tried it was not to go that route. I should add I haven't tried it, based on their advice.

http://www.thesamba.com/vw/forum/viewtopic...&highlight=