Vacuum for brakes with Jenveys?

[dpetteng]

So I am putting an 87 3.2 in my vw van. The engine will have a brake booster but I need a vacuum from the engine. Where can I take one from when using ITB's from Jenvey?

[cgarr]

Might not get the vacuum you need? If not they make a nice electric vacuum pump that can be used for brake booster, we have one on ours.

[chris_seven]

Originally Posted by cgarr

Might not get the vacuum you need? If not they make a nice electric vacuum pump that can be used for brake booster, we have one on ours.

Craig,

I am interested to know why you can't get the vacuum. Is this because there aren't any bosses on the manifolds or is it more fundamental?

[cgarr]

With our webber setup using the Carrera brake booster in our track car we could never get the proper vacuum to operate the booster, most times running open throttle it never worked for us, the port on the 3.2 manifold is pretty large too, maybe for a reason. Not sure what type of booster they use on a VW Van? maybe that would work for this application?

[VFR750]

Originally Posted by cgarr

Might not get the vacuum you need? If not they make a nice electric vacuum pump that can be used for brake booster, we have one on ours.

Which one?

[Fly911]

I have a '87 Carrera with Jenvey ITB's, and my vacuum brake booster works perfect! On each intake runner (below the butterfly) there is a vacuum port, and each of the 6 vacuum lines are connected to a vacuum manifold, that in turn is connected to a non return valve on the vacuum line to the brake booster.

[dpetteng]

Fly, got any pics?

[timmy2]

Here is the one Rothsport uses for their Jevney installations.
Welcome to Rothsport Racing - Engine Products

[dpetteng]

that's awesome!

[jwasbury]

VW van with ITB 911 flat six = awesome

I have Jenveys on my 3.0l 911 race car. The rothsport set up per the link previously posted. No issues with vacuum for the brake booster

[robcf]

I'd say the cam choice (usually a reason to use ITB) and average engine speed would determine the available vacuum.

[Jeff Alton]

Not a problem to get enough vacuum even with big cams if you have a proper vacuum manifold.

Cheers

[JV911SYDNEY]

Originally Posted by dpetteng

So I am putting an 87 3.2 in my vw van. The engine will have a brake booster but I need a vacuum from the engine. Where can I take one from when using ITB's from Jenvey?

pics please!

[MetalDoc]

Here is a link and some pictures. Paul

Hole size for vacuum port on an intake manifold