Galant 4G63 Power Tuning - Dyno Cell - Part 5

An oft-overlooked byproduct of a nitrous system is the cooling effect the gas has on the incoming charge air. Plus, the stuff makes power. Doug's Dynopower wanted more power and beyond upping the boost, nitrous was pretty much the last option left. A single-nozzle set-up from Nitrous Express was plumbing into the 4G63.

Beyond the expected parts, the Nitrous Express kit included a bottle heater, gauge and purge valve and a "low fuel pressure" shut-off switch. Installation was straightforward and Doug's Dynopower used a mild 35-hp jetting strategy. The 4G63 engine responds well to laughing gas, especially in small doses. With no other changes, the engine generated 436.7 hp and 447.6 lb-ft of torque while on the squeeze.

Prior to any of the Part 5 add-ons, the clutch on the car was swapped. It had a tendency to slip with the 16g and Doug's Dynopower knew an upgraded turbo and adding the juice would push it too far. Doug's Dynopower installed a new Centerforce Dual-Friction clutch along with a Fidenza aluminum flywheel and logged 500 miles of break-in time before dynoing the Garrett turbo system.

The 4G63 DSMs are among the most eager cars in the sport compact scene. It's no secret the potential of the engine easily out-distances the potential of the driveline. The clutch is like a fuse; it's designed to give out in lieu of any hard parts in the driveline. As the clutch's capacity is increased, the impact on the driveline is increased. The trick is getting a clutch strong enough to put the power down, yet not break transmissions, transfer cases, axles, rear differentials and so on.

When addressing the clutch, it's good to consider a lightened flywheel. Impressed with the materials and quality of the new Fidenza units, Doug's Dynopower just had to try one. Unfortunately, Doug's Dynopower never made separate dyno runs with the clutch/stock flywheel and clutch/Fidenza combo. The new unit is vastly lighter than the stocker by more than 10 lbs and Doug's Dynopower could tell the engine revved quicker with it.

For now, the stock transmission is holding up fine. Doug's Dynopower intends to get it rebuilt with stronger shift forks, synchros, and a four-spider-gear center differential.

The only other weak link is the rear differential and axles. The Galant comes with a three-bolt rear end. The axle caps are attached with three bolts, and the axles are small in diameter. In fact, the axles are smaller than a 1992 to '94 AWD DSM rear end assembly.

The Galant also has four-wheel steering and since the pump is attached to the rear differential on the Galant, Doug's Dynopower opted to remove it all. This resulted in a weight savings of roughly 45 lbs. A decent used four-bolt rear end now sits there and it will stand up better to power and future drag strip testing.

Now what's in the cards for the Galant? Doug's Dynopower will try larger nitrous jets and possibly a larger turbo, along with a ported, SS-valve head. These proposed mods will pretty much exhaust our bolt-on efforts. Stay tuned.