So I'm going to be taking my cyclone intake manifold and build a custom plenum for it. Going to go for a 4" tubular plenum with 8 velocity stacks. I'm using the wastegate mod to actuate the butterflies. Will be taking pictures once completed.

What were your reasons for the upgrade?

Attempt to make more power with the manifold while keeping the actuated runners. I picked up a sh*t load of torque down low with the cyclone and wastegate mod. The car was able to stall from 3200 to 4200 without spray with just this change. I would like to see if I can squeeze a bit more out of it upstairs.

I've contemplated the same thing, but I feel that you might end up reducing throttle response only. This will depend on the volume of the plenum, bit I think the runners are too small with to many transitions to gain a ton of top end. But I will be interested to see your results!

daplatano91 said:

Attempt to make more power with the manifold while keeping the actuated runners. I picked up a sh*t load of torque down low with the cyclone and wastegate mod. The car was able to stall from 3200 to 4200 without spray with just this change. I would like to see if I can squeeze a bit more out of it upstairs.

Click to expand...

I am curious to see how your results turn out as I'm running a modified cyclone manifold with a big turbo as well.

I have not come across any papers or testing that pointed to plenum volume having much effect with regard to turbo charged application. And if anything larger volume appeared to reduce response. There are many fruitful areas to address on a turbo application; the plenum in particular is not one of them. This is something critical in N/A applications. Btw, Dave Buschur experimented with a similar idea on the Evo (replaced stock plenum w/4” tube) and iirc lost power/curve. You can find pics, flow bench #’s and dyno #’s on the intake test page on his forum, from back in the day.