ITB and Vacuum Lines Question

[YZFMax]

I'm n the process of converting my 260z (stock motor) from dual carbs to EFI ITB.  Started to collect the various parts and doing my homework. 

I have a good understanding on the conversion but still not clear on how the vacuum lines should be set up.  The ITB intake manifold I have has a single vacuum nipple which is used for the brake booster.  When I convert this to EFI:

1. Can I leverage the same vacuum line and add a T? 
2. Or is it better to tap into all the intakes and hook this up to a vacuum manifold? I will have to drill holes and tap into this if I take this route.

I thinking I will need the vacuum to connect to the following:

• Brake booster
• Fuel regulator
• MAP sensor
• HVAC controls (my car has factory AC)

Thanks!

[duffymahoney]

You will need to get a vac signal from each runner and combine somehow, either in a vac log or vac tank.  Then send that to the map signal and the fuel pressure.  Brake can run off the same spot on the manifold.  

 

My favorite new throttle bodies are the Borlas.  The fact that they have the vac on each runner is a huge plus.  

[YZFMax]

6 minutes ago, duffymahoney said:

You will need to get a vac signal from each runner and combine somehow, either in a vac log or vac tank.  Then send that to the map signal and the fuel pressure.  Brake can run off the same spot on the manifold.  

 

My favorite new throttle bodies are the Borlas.  The fact that they have the vac on each runner is a huge plus.  

Thank you!  This really helps.

[jonbill]

I think there are downsides to joining the TBs, and limitations to using MAP for load. 

on my engine, I've only got the brake booster on #6 vacuum tap. I'l use TPS for load and my regulator is a constant 46psi.

dunno about AC tho! 

[YZFMax]

54 minutes ago, jonbill said:

I think there are downsides to joining the TBs, and limitations to using MAP for load. 

on my engine, I've only got the brake booster on #6 vacuum tap. I'l use TPS for load and my regulator is a constant 46psi.

dunno about AC tho! 

Interesting, I've been getting conflicting information.  I plan on using Microsquirt as the ECU and one of the input it requires is MAP for load.  

I will also need a vacuum line for my HVAC as this controls the vents inside the car (has nothing to do with the ITB setup)

[jonbill]

what I read was that manifold pressure tends to atmospheric long before full throttle, so you get relatively poor resolution at higher throttle openings. I expect its less of a problem with smaller choke sizes and clearly many people have joined TBs and MAP etc working fine. 

I don't know microsquirt, I'm using Speeduino. If Microsquirt is MAP only, you might not have a  choice. 

[duffymahoney]

Tuners fight constantly about using TPS over map.  It's a very polar opinion.    

[YZFMax]

1 hour ago, jonbill said:

I'm using Speeduino.

Interesting, was not aware of Speeduino.  I'm reading up on it and very intrigued with it's simplicity, might be a good fit as I'm only looking to add EFI for drivability.  

Thanks for mentioning this.