Here is a pic of the intake manifold on my engine,

 

I would like to install a vacuum manifold/balance tube so I can take advantage of the vacuum advance feature on the new dizzy.

Would 4 vacuum take offs from the 4 inner intake runners be enough to even out the pulses or should I take vacuum from all 6 ?

Thanks,

Chris

 

The vacuum advance is usually connected to ported vacuum and only needs to connected to one carb. The ports in your photo (not drilled on 4 of the 6 runners) are manifold vacuum and will result in full vacuum advance at idle.

The  123Ignition distributor that I installed in the spring is programable and I think it it is capable of ignoring

a vacuum signal at any rpm, idle in this case. I would just like to bring down the fuel consumption while cruising and the load is low.

Granny, you're on the right track. That 123dizzy can do it for you. Use as many cylinders as you can AND use a fuel jet or something similar to make a small orifice to further smooth the signal.

Chris ,

Look at my triple set up . I made a balance tune from a fuel rail.

The 123 ignition is using a map sensor if I understand correctly , so a strong vacuum signal would be best.

Thanks guys, I posted the same question on Hybridz and TonyD suggested that as long as there is a restrictor in the vacuum line, that I should only need to tap into one of the runners, so I'm a bit confused.

Maybe I should contact 123Ignition and find out from them the minimum vacuum signal the dizzy requires to work and then do some measuring of the vacuum from my engine.

Hi Grannyknot

Did you get any further with this? i am just installing triples with a very similar manifold, just bought the 123ignition module and am researching to head down the same road

7 hours ago, khughes said:

Hi Grannyknot

Did you get any further with this? i am just installing triples with a very similar manifold, just bought the 123ignition module and am researching to head down the same road

I did but never really got a chance to try and test it, shortly after this I decided to sell that engine and go with a bmw s38 engine. I was pulling vacuum from the back of the carbs. I know I have some pics of the finished set up but can't find them at the moment, I'll post them when I do.