Installation of an external wastegate for your WRX or STi can seem difficult at first. How do you hook it up? Does it need to be tuned for? These an many other questions can arise when considering an EWG. So let's answer the basic questions. Does it need to be tuned for? Yes it does. You can use an open source tune or purchase a piggy back / stand alone engine management system like TurboXS UTEC, Cobb accessport, or other stand alone EMS. How do we hook it up? Basically, you run a line from your turbo vac port to your manual boost controller, and then to the side port of the Tial EWG. That is the easy part, actually installing it can be tricky.
First of all, you will need an aftermarket up pipe. I chose to go with Perrin's up pipe because it has a 44mm inner diameter, and is made of quality material that can be welded or modified. You can purchase up pipes that come with an EWG already welded in place, but what is the fun in that? I chose to install my EWG in a semi-hidden fashion that locates the majority of the equipment under the down pipe. Some say you can't run a divorced down pipe with an EWG, that is false. Using a custom welded up pipe, I was able to still use the Perrin divorced down pipe. So the rumor of "no divorced down pipe" is false if you run a custom welded up pipe. I took my up pipe to S&R performance of Tampa Bay for my custom welding. They are the best around!My hidden EWG under the divorced down pipe
Secondly, you will need a dump tube. You can get one custom fabricated, or you can purchase the ATP turbo flanged stainless dump tube for Tial 44mm. That's what I used, and it works perfectly. Good quality material, exceptional weld, and a perfect fitment! It also dumps nicely down the side of the transmission case in the middle of the vehicle for optimal sound and unique hidden location. See picture below for how the dump tube is setup on my vehicle.
Dump tube running down the tranny case
Make sure you pick a wastegate pressure spring that is about half of your goal PSI. I chose to go with a 10 psi spring because I want to run about 20 psi out of my turbo. The spring pressure determines where your wastegate will open along the boost. 10 psi spring will start opening at 10 psi. For the best flow, you want your wastegate to be approximately the same size as your up pipe. I chose the 44mm Tial wastegate because my Perrin up pipe is also 44 mm. This will in effect be a boost controlled exhaust cut out located between my turbo and exhaust manifold, releasing pressurized gas at 10 p.s.i. - It will be VERY loud and VERY effective in reducing spool time.
Additional modifications for running an EWG is you will need a turbo setup for external wastegating (is that even a word lol?). You can pick turbos that have no internal wastegate, or you can modify your turbo to run EWG by welding the old wastegate shut or using a wastegate bracket. The best is to weld it shut and remove the old wastegate. It's better in appearance and functionality, because brackets tend to lose tension torque over time as they are exposed to hot and cold heat changes. If you must use a bracket, use some kind of locking adhesive to lower the chance of pressure opening your stock internal wastegate. If it does leak or open, this can cause tuning headaches and rich conditions.
Overall, an EWG is an awesome modification but takes some preparation and supporting mods. It is not suggested for the average builder due to it's complexity during install. Also, adding a wastegate makes for even less room in the turbo area and creates a need for special tools during installation. I spent nearly three hours on the bottom bolt turning it 1/16 of a turn to get mine installed "hidden" under the down pipe. Worth it? Yes, to me at least. Check out a video of an external wastegate similar to my setup. I will post my own video once the build is complete (Jan or Feb of 2010)
Video content: WRX STi running 44mm Tial wastegate
Hear the "hiss" about half way through the RPM band? That's the EWG venting to atmosphere. PS- This is not street legal and should only be used for off road purposes. As you can see by the mud hidden inside of my car, I only drive mine off road and when I must drive it on road, I will swap turbos and up pipes to return to internal wastegating. ;-)
Make sure you pick a wastegate pressure spring that is about half of your goal PSI. I chose to go with a 10 psi spring because I want to run about 20 psi out of my turbo. The spring pressure determines where your wastegate will open along the boost. 10 psi spring will start opening at 10 psi. For the best flow, you want your wastegate to be approximately the same size as your up pipe. I chose the 44mm Tial wastegate because my Perrin up pipe is also 44 mm. This will in effect be a boost controlled exhaust cut out located between my turbo and exhaust manifold, releasing pressurized gas at 10 p.s.i. - It will be VERY loud and VERY effective in reducing spool time.
Additional modifications for running an EWG is you will need a turbo setup for external wastegating (is that even a word lol?). You can pick turbos that have no internal wastegate, or you can modify your turbo to run EWG by welding the old wastegate shut or using a wastegate bracket. The best is to weld it shut and remove the old wastegate. It's better in appearance and functionality, because brackets tend to lose tension torque over time as they are exposed to hot and cold heat changes. If you must use a bracket, use some kind of locking adhesive to lower the chance of pressure opening your stock internal wastegate. If it does leak or open, this can cause tuning headaches and rich conditions.
Overall, an EWG is an awesome modification but takes some preparation and supporting mods. It is not suggested for the average builder due to it's complexity during install. Also, adding a wastegate makes for even less room in the turbo area and creates a need for special tools during installation. I spent nearly three hours on the bottom bolt turning it 1/16 of a turn to get mine installed "hidden" under the down pipe. Worth it? Yes, to me at least. Check out a video of an external wastegate similar to my setup. I will post my own video once the build is complete (Jan or Feb of 2010)
Video content: WRX STi running 44mm Tial wastegate
Hear the "hiss" about half way through the RPM band? That's the EWG venting to atmosphere. PS- This is not street legal and should only be used for off road purposes. As you can see by the mud hidden inside of my car, I only drive mine off road and when I must drive it on road, I will swap turbos and up pipes to return to internal wastegating. ;-)
