Tuesday, June 26, 2012

Butterflies > Butterfly. "ITBs"

Rocking some blurry shots tonight, my iPhone must not like the cold. Got out to the shed and actually got a bit done, it's times like these when I CBF doing much it's handy to have a full list of every little thing that needs to be done so I can go over it and look for something that interests me at any given time.

Drilled and tapped the holes for the blanking plate for my ITB setup. I'm going to be using the factory EF/L/AU manifold (I believe this one is from an AU, based on the injectors fitted; I honestly can't remember!) and the butterflies normally used for the short/long runner setup are going to become my throttle butterflies. They seal properly (tested) and the surface area is from memory somewhere between 30 and 60% larger than the standard throttle body on these (which is already relatively large). I'll be making a pair of blanking plates to cover the standard "long" runners.

Clamping and positioning this was a bit of a pain but I got there in the end.

The holes go straight through between the sets of runners. Plenty of meat to tap a thread into and zero chance of going through a wall.

Both sets of extra holes tapped.

Now I've run into a bit of a dilemma, this is where the main fabrication work is required. The factory TPS is as pictured below. I've got a couple of ways of trying to acheive the same activity. I can either cut down and make a blade as per the factory setup on the end of the butterflies, or I can cut down the factory throttle body and use that with a linkage to the end rod of the butterflies. I could also use it as a linkage to the center of the butterfly setup by welding on some form of linkage.

Pictured above is the factory BBM actuator cam, this is normally actuated by vacuum. I'm going to mount a spring here as a return, and use this as a full throttle/idle screw location. I have also thought about welding a throttle pull to this arm and attaching a cable bracket to the top of the arm. More thought required I think.

No comments:

Post a Comment