Project Gen 3 STi – Impressions of the Turbosmart IWG75 and BPV

turbosmart BPV subaru STi impreza

Project Gen 3 STi – Impressions of the Turbosmart IWG75 and BPV

By Wes Dumalski 

(for this installment should be DumbASSki)


“Hey Bro, do you want to test some Turbosmart stuff?” The quoted text is from none other than Martin G from MotoIQ headquarters asking me if I would like to play with any Turbosmart products on our GR STi project. With this project still in the early and mild stages I first scratched my head wondering what I would be able to use and test. When I think of Turbosmart I envision huge external wastegates on race cars and e-boost setups. Initially I wondered exactly what I could even use on the STi… Not wanting to miss an opportunity I perused their site and used their vehicle specific search feature to see what they had available.

Of course I found the normal external wastegates and other race inspired items but what jumped out at me was their internal wastegate replacement actuator. The IWG75 is a replacement actuator for internally wastegated turbos and Turbosmart offers this wastegate in application specific as well as universal applications and their claim is that it improves turbo response by providing superior control of the wastegate flapper. In short the theory is that with their spring design it will hold the flapper closed longer thereby reaching the desired boost target more quickly and anything we can do to improve response and power in the area under the curve is what we here at MotoIQ are all about. In addition to the IWG75 I also found their STi application specific BPV. The goal here was to upgrade these components with the goal of improving low end power/torque as well as improving overall drivability. 

turbosmart IWG75 Subaru STi
The IWG75 is available for both application specific and universal applications. 

After collaborating with Martin and the brains at Turbosmart our order was placed and these juicy bits were soon on their way to the land of cheese where our GR STi project resides. To be honest I was very curious as to what, if anything, these items would actually do to this project. I mean the car already has an OEM wastegate and BPV, how much better could these be? I sold myself on the idea that even if they offered very little in measurable/quantifiable performance they would LOOK cool in the engine bay and I eagerly awaited their arrival. After a particularly stressful  day at my “real employ” I arrived at the homestead to find a box on the counter. It was in fine shape and the brown army must have known that some serious quality parts lied within. Rather than change out of my work clothes or start making dinner I snatched up the box and headed downstairs for some alone time with my new parts. It is clear Turbosmart takes pride in their products as the packaging is as first rate as the components themselves.

Turbosmart fully recirculating BPV BOV
We opted for the fully recirculating STi application specific BPV. If you want the best performance coupled with a QUIET bypass valve this is the option for you. Turbosmart offers 4 models of this BOV/BPV for your WRX or STi. 

Included with both the IWG75 and the BPV were CD ROM's containing installation instructions for all Turbosmart products as well as some stickers. I always like to play arbiter on packaging and in this case it was first rate! Printed glossy color boxes, perfectly cut foam protecting the delicate bits, yup real stuff here! After reviewing the instructions I packed them back up to await installation day.

Turbosmart IWG75 Subaru WRX STi universal
The STi specific kit (TS-0605-1072) has everything you need for a bolt in installation. Minor mechanical aptitude is required and not included! 


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