With respectable baseline numbers, it was time to see where all the power was hiding. The most basic and cost-effective modification is a new filter element. It is cheap and simple to install. A $45 K&N air filter was installed and after ample cooling time, the dyno was once again spinning. Big dividends were paid; output skyrocketed by 11.2 hp to 201.8 and torque jumped to 220.3 lbs-ft, 22.1 lbs-ft to the good.
Following the filter was a Doug's Dynopower (DDP) cat-back exhaust. The stock system makes the 4G63 exhale though a straw, so there should be some big-time ponies let loose with this addition. True to form, the 2.5-inch system made a healthy difference as peak power was bumped to 215.5, a 13.7-pony increase. Torque was the big winner on this modification, seeing an increase of 23.3 lbs-ft to 243.3.
Always a gateway to power, the stock downpipe of most any factory turbocharged engine is a prime candidate for replacement. On the Galant, we elected to go with a 2.5-inch mandrel-bent DDP unit. Still using the stock cat converter, decent power gains across the range were made just by freeing the rest of the exhaust system. Again, torque was the main benefactor jumping 10.5 lbs-ft to 254.1. On the horsepower side, a modest 5.2-hp improvement was noted. All tallied this was a hard-hitting trio of bolt-ons, generating an impressive 30.1 hp and whopping 55.9 lbs-ft of torque.
Phase two is on tap for the Galant-consisting of a boost controller, front-mount intercooler and an upgraded turbocharger. Later on, a fuel computer, camshafts and other power adders will be unleashed on the Galant. An eager 400 hp at the wheels in a four-door is going to be very interesting-so sheep beware.
| POWER REALIZATION CHART |
| | HP | TQ | GAIN HP | GAIN TQ |
| Baseline | 190.6 | 198.2 | -- | -- |
| K&N Filter | 201.8 | 220.3 | 11.2 | 22.1 |
| DDP Exhaust | 215.5 | 243.6 | 13.7 | 23.3 |
| DDP Downpipe | 220.7 | 254.1 | 5.2 | 10.5 |
| Total Gain | -- | -- | 30.1 | 55.9 |

DDP Exhaust Bolting on a...

DDP Exhaust
Bolting on a Doug's Dynopower cat-back exhaust system netted more impressive numbers. We added another 13.7 hp to the 4G63 and substantially more low-end grunt with 23.3 extra lbs-ft of torque

DDP Downpipe The big numbers...

DDP Downpipe
The big numbers continued to flow from the Mitsubishi sleeper; a 2.5-inch downpipe produced 5.2 ponies and 10.5 lbs-ft of torque. The final tally shows 30.1 hp and 55.9 lbs-ft of torque.