How to Make a Reverse Throttle Plenum (ecotec)

[Blakvsexec]

Take a standard ecotec intake plenum and mark out around the throttlebody where you want to cut.
Be mindful of the locations of the fuel rail attachment points.
Cut down the sides of the throttlebody with a hacksaw.


Next take a 4" angle grinder and using a 1mm micro cutter wheel cut at a 45 degree angle along the bottom of the throttlebody and remove.


You can see in these pics the angle and location(ignore the biro mark) required to cut along the bottom of the T/B



Sit the lid on the plenum and mark on it where you have cut the throttlebody out.
Turn The lid areoun 180 degrees and bolt on again with a couple of bolts and copy the marks you made on the lid to the plenum, This is where you will make your next cuts with a hacksaw and angle grinder.
I used the throttlebody to mark the approximate location of the bottom cut line.
Cut and remove.


Take the two pieces you have cut out and grind a 30 to 40 degree angle on the edges of them, Leave approx half the thickness unground, this will give you better penetration when you weld it all up.(sorry no pic of this step)

Bolt the throttlebody to the lid in the reversed position, make any adjustments if needed at this point.


If you have access to a Mig or Tig welder that is set up for aluminium you can use it to weld up, Alternatively you could take it to a welding shop and ask them to do it for you.
Weld in the throttlebody in its new location, sit the other piece in the other side(where the T/B used to be), and weld it in, be sure to close up the gap all the way round even on top, you can clean it up with a file later on. Be sure to weld inside and out.

Remove all Berries from the welding process and smooth over the welds unless you used a Tig then you wont have to.

There you go. You now have a reverse throttle plenum.

[Rhin0o8]

Nice work there . Pictures help out alot

What are the benefits of this? any proof of performance gains or better throttle response ?

[Blakvsexec]

Nice work there . Pictures help out alot

What are the benefits of this? any proof of performance gains or better throttle response ?

This is done for the purposes of adding a turbo and makes intercooler piping easier to run.

This was meant to go in the How to forum.