240zip Posted October 8, 2011 Share Posted October 8, 2011 I have two Canon intakes for a triple Weber set-up. One has a single vacuum connector and a balance tube across the intakes. The second has three into one collector that has tubes running into the first three intake runners, then into a collector, and then to the vacuum advance. My question: Given there's a balance tube, would the amount of vacuum generated by both be equal? Or would the 3 into 1 generate 3x the vacuum? Quote Link to comment Share on other sites More sharing options...
240zip Posted October 8, 2011 Author Share Posted October 8, 2011 both intakes have balance tubes ... Quote Link to comment Share on other sites More sharing options...
Leon Posted October 9, 2011 Share Posted October 9, 2011 If both have balance tube, there shouldn't be much of a difference. What you refer to vacuum is simply pressure below atmospheric. Pascal says that pressure is equally distributed across all surfaces in a confined space, so no, there will not be 3 times less pressure if you have three separate taps. Running six individual lines to each intake tract may be slightly more accurate (more viscous damping, meaning cleaner signal) but for all intents and purposes both setups should be similar in their results. You can also use a small chamber with a restrictor at the inlet, if you want a cleaner signal. What are you trying to achieve, working vac advance? Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 9, 2011 Share Posted October 9, 2011 There is no difference, one runner, three runners, or six runners the pressure achieved will be the same. What will change is the volume available to do work. Like to run vacuum operated wipers, etc... Like Leon says, it all depends on what you want to do with it. If all else fails, put a small reservoir in. If there is not sufficient vacuum, install a Bullfrog Vacuum Pump from an 83 Turbo to MAKE more vacuum in your reservoir! Quote Link to comment Share on other sites More sharing options...
240zip Posted October 10, 2011 Author Share Posted October 10, 2011 yes, this is for the vacuum advance for the distributor. I guess that wasn't clear. I have what is termed a 'street' cam grind, triple Webers, and the stock distributor with Pertronix / MSD 6AL. Even with proper (meaning dyno-tuned) jetting, I'm getting a little bog around 2,000 RPM. Everything points to the timing advance. The right thing to do is likely an Electromotive crank fire set-up with coil-packs. I think there's a MegaSquirt equivalent there too. I was just hoping for a simple (and cheaper) fix. Quote Link to comment Share on other sites More sharing options...
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