Improved Shifting, New Exhaust Note

The Mach V WRX is sometimes last in line for modifications, since we keep pretty busy modifying customer cars, but we were able to perform some more modifications since my last blog post. We installed a new Kartboy short shifter, Kartboy shifter stop, and and lovely Raceseng knob to top everything off.

The Kartboy short shifter is an interesting part. As you probably know, the WRX uses a cable shifter mechanism, which is a departure from the old lever-actuated shifters in previous WRX models. The shift lever operates a counterweighted pivot on the underside of the car, and the Kartboy shifter is a shorter version of that pivot. Unlike some of the competing short shifters, the Kartboy unit is itself counterweighted, which gives a nice feel and sense of mass to the shift motion. And since you asked, it IS compatible with the OEM Subaru short shifter available from the dealer.

Up on the inside of the car we installed a brand new Kartboy shifter lock, which limits the left-right travel of the shift lever, further tightening up the throws on the shift lever. There are other versions of this kind of part on the market, but most are made of metal, which can lead to some noise when the shift lever contacts the stop. The Kartboy unit is made of a high-strength glass-filled nylon, which is almost completely silent when the shifter contacts it. (Kartboy banged on it with a hammer to test its impact strength. It survived.) Our prototype part was black, but production parts will be yellow.

Finally, with all these improvements in the shifter action, we thought the top of the lever deserved an upgrade in the form of a nice shift knob. We chose the Raceseng Topologi, which has a massive stainless steel core with an outer layer of Delrin. We installed the red Delrin sheath for now, but might switch colors later -- the parts just thread together, so we can swap out whenever we want.

Shifter feel after these changes is light years from the feel of a stock car. The throws are short and weighty, and you can feel click-click when the lever is going from gear to gear. It takes a bit more effort to push the lever around, but it's a welcome trade-off for the improved feel.

One final modification we made to our WRX lately is to install a Cobb cat-back exhaust. I can't say enough good about this system. It fit up perfect to the factory J-pipe, it looks great, and it sounds terrific -- it's got a good growl under acceleration, but at idle it is just a pleasant murmur. It took us a while to get one for our own car, though, since demand for the new system outstripped Cobb's manufacturing capabilities at first. The supply situation has finally improved, so the systems are readily available now.

Parts referenced in this post: Kartboy 2015+ WRX short shifter, Kartboy 2015+ WRX shifter lock, Raceseng Topologi shift knob, Cobb 2015+ WRX/STI cat-back exhaust.