At its most basic a car’s engine is an air pump. Plain and simple.

The more air you get in and out of it the more fuel you burn.

The more fuel you can burn due to the larger amount of air means more power.

And lets be honest, that’s why you’re here.  You want more power, and quite frankly, we can’t blame you.

So… How to get more power?

Well, a there’s a few ways, but lets go back to the basics.  Bottom line you need more air, and more fuel.  In the case of the TGV we’re looking at more air.

The stock TGV is there to cause tumble for better air fuel mix.  Hence Tumble Generator Valve (or TGV), BUT in doing so it creates a problem for those of us seeking out more power.  It causes a restriction.  This held true on the older Subarus, and is even more prevalent on the new cars.

Here’s why –

Like we said an engine needs to move air, and in the case of the new 2.0DIT motor from Subaru a good bit of air that is trying to get into the cylinder is running into a huge blockage.  That blockage is the TGV.  Sure, they do open, BUT here’s what we found some interesting things. The rod for the actuator.  JUST the rod, we’re not counting the flapper or the screws or anything like that.  Just the rod, all by itself, TAKES UP ALMOST 30% of the port cross sectional area.  That is not good for letting the engine breathe.  We also found that the port size itself on the TGV assembly isn’t as big as it can be.

So…  We made a TGV replacement that eliminates the rod, the flapper, the screws, AND has bigger ports.  The outcome was brilliant.

With JUST the Cobb AP Stage 1 tune we picked up an immdiate increase of 30 lbs of torque on the bottom end, and a little more HP across the board.  AND that was on our super low ass reading, heart breaker Dyno Dynamics setup.

Once we did a custom tune for these we really started to see some gains.  Just this part with a Cobb Protune bumped Torque a peak of about 50 lbs in the mid-range and peak power increase 27 AWHP

Tune :

You will need a tune for these. There are a number of tuners out there, some are good, and many are very very bad. We strongly recommend using someone who has a good reputation from multiple people. Not just some dude who heard from this guy that saw a craigslist ad for this dude’s who has a cousin who just bought a laptop and can tune anything. Bro. (seriously, this actually happens)