TGV Deletes for Subaru WRX/STi

Are there any downsides to TGV Deletes? No. As long as you account for removing the associated TGV CELs, there are no known downsides to this mod. Depending on the user, some see a wandering idle on cold starts which isn’t so much a downside as it’s stated in case this should happen on your particular vehicle….it happens to some cars and not others, so you may or may not see this. Once the vehicle is warm, this goes away and most users report this for just the first few seconds of starting a cold car.

Is there anything to be careful about when buying TGV Deletes or using a TGV Delete service? WRX and STI TGVs are not interchangable, so you must state your year/model car with the Vendor to ensure you get the right kind as the JDM TGV varieties are complicated. For the US varieties:

2007+ STI are topfeed
2004-2006 STI are sidefeed
2002+ WRX are topfeed

Yes you can convert your car from top to sidefeed or vice versa, but unless you want the additional time/trouble/expense, it’s best to get the right TGVs in the first place. Top or side feed refers to the injector type/seating surface as they are different as are the associated fuel rails. So you must use all the components of either type if swapping TGV styles.

Where do I buy a TGV Delete? For purchasing, support your NASIOC Vendors. You have four options for TGV Deletes though:
1. Do it yourself
2. Use a TGV Delete service
3. Purchase APS, Zerolift (formerly known as MAW or Motive Autowerks), IAG billet TGV Deletes
4. Use a Japanese intake manifold/TGV assembly

So which route should I choose? It depends on many factors, but they are highlighted below:

DIY: Can be done while your car is down or with an extra set. Deleting can be accomplished in one afternoon with the proper tools (air tools and carbide bits) or over the course of a week with less than proper tools (Dremel). This is definitely the cheapest way to go and as long as you take your time, the quality and flow can/will match the best porting service.

TGV Delete Service: Probably the easiest solution as you can either send yours in for porting or most places offer a core charge service where you obtain $XXX back when you send in your OEM units. Most offer commercial grade painting and/or thermal dispersant coating.

APS TGV Deletes: These are a very expensive option as they were manufactured with a purpose built CEL fix as well as designed to accommodate extra fuel injectors. So if you plan on extra injectors, these may be the route to take first. Otherwise, they are a rather poor choice mainly due to their internal fit and finish as they are not port matched to the engine block and create a restriction at that junction compared to DIY/TGV Delete Service models. So yes, you can/should port the APS units for best flow. These are now near impossible to find unless used due to the dealer network in the US collapsing.

Zerolift (formerly known as MAW or Motive Autowerks) TGV Deletes: These are composite TGVs that are readily available and appeal to those that would like a near zero heat soak option due to the composite’s phenolic properties. On metal intake manifold cars, you’ll need to run a separate ground wire from the manifold to the block, since there will no longer be an electrical ground through the TGV housings. Additionally, on some cars, the inner bolt holes on the intake manifold will need to be slotted to line up with TGV housing.

IAG TGV Deletes: These are billet aluminum TGV deletes.