Drill or Dont Drill (ITBs)

[luvndasun]

Hi All,

If I want to install the ITBs that I have, I'll have to drill and tap my intake manifolds in order to provide a place to monitor the intake perssure using a MAP sensor. The intake pressure port will have a tube routed to the MAP sensor manifold. You can see the MAP sensor manifold in the first picture. The second picture shows about where I think is the best place to drill the intake manifolds to pull the pressure signal from. (sorry about the pic quality). Before I make the irreversible modifications, I wanted to see if some of the ITB gurus out there would chime in and lemme know if I am on the right track or if there are any better alternatives. Thanks in advance for the advice. Oh yeah, the engine is a 3.0L.

[Trog]

My PMO ITB's locate their vacuum connection as shown below:



I'm confident it would work if you drilled/tapped the manifold flange.

Trog

[TimT]

No need to drill anything. Use whats provided on the throttle body

[Trog]

Originally Posted by TimT

No need to drill anything. Use whats provided on the throttle body

It would appear that he is missing the vacuum ports on the throttle bodies... at least I can't see them in the photo?

[Steve@Rennsport]

Those already have the vacuum ports below the throttle plates, as desired.

[TimT]

The TWM ITBs gang together the vacuum in the casting

[Steve@Rennsport]

Originally Posted by luvndasun

Hi All,

If I want to install the ITBs that I have, I'll have to drill and tap my intake manifolds in order to provide a place to monitor the intake perssure using a MAP sensor. The intake pressure port will have a tube routed to the MAP sensor manifold. You can see the MAP sensor manifold in the first picture. The second picture shows about where I think is the best place to drill the intake manifolds to pull the pressure signal from. (sorry about the pic quality). Before I make the irreversible modifications, I wanted to see if some of the ITB gurus out there would chime in and lemme know if I am on the right track or if there are any better alternatives. Thanks in advance for the advice. Oh yeah, the engine is a 3.0L.

Anywhere below the throttle plates will be fine; you are on the right track.

I've seen those TWM ports clog up with carbon, depending on what cams you use, so I like to install separate fittings to each cylinder runner.

[jpnovak]

I too have TWM throttle bodies. I could not get a clean MAP signal using the single port provided by TWM. It was so bad you could see the individual pulses of the center (#2 and #5) cylinder in the datalog. I sm not sure if this was due to the size of the port or the way it was connected across the runners.

I capped it and drilled one hole in each manifold runner. I then have six vacuum lines that Tee into a manifold similar to the one in the picture. I packed the manifold with open cell foam and have a rock-steady MAP at idle. I have not noticed any lag in response from the foam.

btw, I drilled small holes. I think bought brass hose connectors that are barbed on each side. I milled one side down in the lathe and then epoxied into the hole. On the back side I smoothed with a die-grinder. On my weber manifolds there are small circular flats midway on the height. They are on the outside of the manifold. This was my port location.

[luvndasun]

Thanks for the help, I feel better about doing this. I'll look into using smaller fittings. That PMO setup is sweet.
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