Tomioka Racing Exhaust System for Mitsubishi Evolution X

This month we tested Tomioka Racing full line of exhaust products for the Mitsubishi Evolution X. We had the cat-back, exhaust manifold, downpipe and test pipe for our lucky 2008 Mitsubishi Evolution X MR. This stock 2008 Evolution X had a base power of 227 whp and 258 lb/ft of torque on our dynapack dyno. This Evolution X was ready for its exhaust makeover.

At first glance, the Tomioka Racing dual-tip cat back resembled a polished factory catback. In fact, it was more than a mirror finish look. The Tomioka Racing dual- tip cat back is constructed from stainless steel 304 materials with 3-inch piping throughout the pipe. The catback is TIG welded and it comes with a resonator on the mid-pipe. Inside the muffler chamber, Tomioka cat-back has an internal core mesh design that balances the cat-back sound and performance. For those customers who like to keep the sound down, the cat-back comes with pair of silencers.

The Tomioka Racing tubular exhaust manifold for the Evo X styles the same characteristics as the catback. Constructed from stainless steel 304 materials with larger piping, the exhaust manifold is guaranteed to increase the exhaust flow efficiency of the 4B11 engine. The bolt-on exhaust manifold comes complete with gasket for easy installation. The mirror finish of the Tomioka exhaust manifold adds a stylish upgrade from the cast iron factory exhaust manifold.

Exhaust system upgrade is not complete without the addition of downpipe. The Tomioka exhaust manifold will need a match to meet its increased exhaust flow.   The Tomioka Racing downpipe replaces both the factory housing and downpipe. The downpipe styles a wide-mouth opening bolted to the turbo exhaust housing and a 3-inch piping connected to the factory test pipe. In Tomioka style, the downpipe is constructed from stainless steel 304 materials and mirror finish that exhibit quality and top-notch craftsmanship. The downpipe comes complete with gaskets and hardware to bolt-on to factory Evolution X.

When all the pieces were installed on the car, it was ready for the second round of dyno runs.  During the initial dyno pulls, the car ECU was definitely not used to the increased exhaust flow.

It barely registered an increase of power, about 5 whp and 5 lb/ft of torque, although the car did register a better performance overall especially after 3000 RPM. But more work needed to be done to match the increased exhaust flow. After tuning and matching the ECU parameter we saw real improvements in performance. The Evo X achieved a peak power of 298 whp and torque of 317 lb/ft plus better performance across engine RPM.

With all the excitements of the power performance gain, we actually had forgotten about the last piece in exhaust upgrade, the test pipe. Tomioka test pipe for the Evo X is a straight through design constructed from stainless steel 304 materials. As in Tomioka tradition, the test pipe is bolt-on and comes with all hardware necessary for installation. Once the test pipe was installed, we saw more gain to the Evo X. The final number achieved was 314 whp with peak torque 316 lb/ft. Once again, the power was improved across all engine RPM.

After all the exhaust upgrade, the Evo X was not as loud as everyone was expecting.

The driving experience was definitely different than before. In the words of the owner of the Evo X,Dino, who happens to be the owner of Socalevo forum, “  The exhaust is actually quite stealthy at idle.  The volume is close to stock except for a deeper rumble, but once you start opening up the gas the car produces a totally different tune from the stock exhaust and the turbo sound is much more pronounced with the Tomioka exhaust manifold in place.” You can check out the catback sound clip here and here with the silencer.

We will be testing the Tomioka Racing Fuel Rail, Fuel Pressure Regulator and the soon-to-be released Tomioka Racing turbocharger for the Mitsubishi Evolution X. Stay tuned for its progress!