I (little) big turbo’d my Mazdaspeed3.

That pic is about mid way through so it’s not all hooked up in its final form. The kinked coolant line got replaced.

It took me, a mechanic from work who hasn’t worked on anything but American v8’s and Indycars, and a Mazda tech who swaps out the turbos on CX-7’s (basically the same motor as the speed3) about 10.5 hours across 2 days to do everything. While I was in there I also installed a 3.5” intake, downpipe, 3 bar map sensor, EGR valve delete, and a 3 port electronic boost control solenoid.

The turbo is made by a company called Corksport, and is basically a Mitsubishi 18g in a td05 housing modified to fit the stock exhaust flange. They make some awesome Mazdaspeed products, and most of their stuff is tailored to getting more power out of the stock motor. This turbo is still well within the limitations of the stock block, but makes up for where the stock k04 falls on its face.

This was a pretty big project for me, I’m an IT guy by trade and don’t have as much wrench time as a lot of you guys. Because of this, I rounded off a couple bolts that were super torqued by Mazda and made it a bit of a pain in the ass to get completely done, but we got there. The downpipe was what I was dreading most, as I’ve heard horror stories of it taking people hours longer to install than the whole install took me to get it off. O2 sensors were what I was most worried about, so I soaked those in PB blaster many times in the days before we started.

Advertisement

The turbo on these cars wedged between the firewall and the motor, so there’s not much clearance in there. Most people who put huge turbos on these cars get exhaust manifolds that sort of flip upside down and mount the turbo where it’s much easier to access with a lot more room. Getting the old one out and the new one in only took about two hours. The hard part was fitting everything back in together. I had to relocate the ECU to fit the 3.5” intake because it sits on the side of the battery box, and there’s not enough clearance to have both a big intake and the ECU in stock location.

As for power, I was previously at around 280 to the wheels with a 21 psi tune and supporting mods, plus a couple power mods. With everything the way it is now, I should be at around 340-360 to the wheels. I contacted a tuner (Freektune) and they sent me over a base map tailored to my mods. I’m currently set at wastegate spring pressure, around 18psi. Just with a base tune and no power added to it, the turbo really shines. It screams all the way up to redline, whereas the stock k04 fell on its face at 5500 rpm. I’ll update you guys on some info as I continue tuning and shaking it down.

as always, inb4 tq steerlololo