Since you read Diesel Power, you are already on the right path to becoming a trailer-towing master. You know that an oil-burner is the best type of engine for towing and that it has tremendous potential for upgrades. Now, let's look at ways to maximize the trailer-towing capacity of your truck through performance increases, safety improvements, and truck-buying tips.
1. Lower Axle GearsLower gears, shorter gears, whatever you want to call them, they will result in your tires spinning fewer revolutions for each turn of the driveshaft. That means more of your engine's torque will reach the ground, giving you extra power for acceleration and pulling grades. If you are running 3.73 gears and they aren't giving you the leverage to pull with confidence, then you should consider swapping in 4.10 or 4.30 gears. Since the axle will need to be cracked open, this will give you the chance to add a limited-slip or locking differential for improved traction. If you own a four-wheel-drive truck, make sure to upgrade the front gears to the same ratio as the rear to prevent drivetrain binding when both axles are engaged.
2. Engine ProgrammingMild engine calibration changes can tailor your engine performance to your towing needs. Many aftermarket programmers and chips include tow settings that will limit engine revolutions, monitor and limit boost levels, and adjust the shift points of the transmission. The computer can also be set to de-fuel the engine to reduce EGT (exhaust gas temperature) and prevent heat-related damage to the engine. That allows you to concentrate on the road ahead, instead of worrying about gremlins sabotaging your drivetrain.
3. Turbo UpgradesReplacing your stock compressor will give you more air power, but bigger is not necessarily better. A giant turbo will produce gobs of boost, but it may take longer than your stock unit to spool up. This can result in power reduction at low engine speeds, which is fine at the drag strip, but would not be good for towing. Turbos with ball bearings in the center cartridge spool up about 25 percent faster than standard journal bearing units, reducing the time lag before boost delivery. Twin-turbo setups combine the fast spool-up of a small turbo with the high boost pressure created by both the large and small compressors.
4. EGT GaugeIf you don't know how hot your combustion chambers are running while you are towing, then you are asking for trouble. Your EGT should not exceed 1,250 degrees Fahrenheit for extended periods or you are risking serious damage to your engine and turbo. To get an accurate reading of the conditions being experienced by your engine, the temperature probe should be placed before the turbo, in the exhaust manifold. Once you have installed an EGT gauge, you need to keep an eye on the readings and adjust your driving habits. As mentioned earlier, a programmer can de-fuel your engine when the EGT gets into the dangerous range.
5. Water/Methanol InjectionSometimes called "chemical intercooling," a water/methanol injection system allows more air to be crammed into the engine, plus the methanol acts as additional fuel in the combustion chamber. As an added benefit, even with power gains of more than 50 hp at the rear wheels, your EGT will be lowered by about 200 degrees Fahrenheit. To make sure you don't run out of chemicals while on a long haul, companies offer large reserve tanks to hold several gallons of drugs. In many states-sorry California-you can buy inexpensive window washing fluid that is a 50/50 mix of water/methanol to fill your tank.
6. Free-Flowing ExhaustYou don't have to install vertical exhaust stacks on your truck to reap the benefits of a free-flowing exhaust system. Many companies offer 4- and even 5-inch-diameter exhaust pipes that will fit under your diesel truck. By allowing exhaust gases to escape with little resistance, your engine and turbo will have the freedom to produce more power. While towing, the main benefit of a large-bore exhaust system is lower EGT, which will allow you to pull harder without risking damage to your powerplant. Be sure to consider the exit path of your exhaust when having an upgrade installed, to prevent it from blowing soot all over your trailer. Turn-down tips that point at the street or side outlets are conventional alternatives to semi-truck-style stacks.