Making 500 Horsepower
Achieving 500 horsepower is pretty easy to do with a Duramax but there are a few supporting components that cannot handle the additional power. The 300 horsepower factory-rated engine and powertrain were not designed for 500 horsepower. So, as soon as the horses start increasing, the Allison transmission starts having issues.
"At the 450 to 500 horsepower mark, if the transmission is holding up, it won't for very long. Having the entire transmission rebuilt with upgraded clutches, valve body and torque converter will ensure that the power gets to the ground and not the pocket book," says Jim Jones, owner of Texas Performance Diesel.
Not having to worry about powertrain issues, the builder can focus on engine. Intakes and exhaust systems are a must. The factory didn't design the engine with this much horsepower, so the factory intake must be replaced with a good breathing intake and the exhaust needs to be upgraded to a 4-inch system.
To get the fuel into the engine doesn't require major overhaul, thanks to the common rail injection system. So it is a matter of programming and tuning to get the power or rather the fuel into it. A good EFI Live custom tune, PPE Hot Plus 2 or the TTS Extreme programmers can be tweeked to get 500 horsepower to the ground. To keep the CP3 (the high pressure fuel pump) fueled, an upgraded lift pump (the low pressure fuel pump) needs to be upgraded to flow the required volume.
For a daily-driven 500 horsepower road warrior, the turbo charger needs to be upgraded to a GT4088R or a GT4094R which is somewhere between a 64 to a 68 mm charger. This will supply the required air and keep the backpressure in check.