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 Gears
Lower 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 Programming
Mild 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 Upgrades
Replacing 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 Gauge
If 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 Injection
Sometimes 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 Exhaust
You 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.
7. Transmission Upgrades
With more power on tap, you will need to protect your transmission from the stress of pulling a trailer. High temperatures, combined with heavy loads, are the number one cause of transmission failures, and nothing ruins a trip quicker than metal shavings in the transmission pan. Upgrading to a multi-disc torque converter will reduce slippage between the engine and transmission, and help keep your automatic operating in the safe zone (less than 200 degrees Fahrenheit). A heavy-duty rebuild will often include a torque converter upgrade, along with stronger gears and shafts, better seals, high-performance pumps, new bearings, Kevlar bands, and a larger capacity oil pan with fins to aid cooling.
8. Transmission Temperature Gauge and Auxiliary Cooler
Just like EGT, the operating temperature of your transmission should always be on your mind while towing. Any more than 200 degrees Fahrenheit for extended periods of time can make your slushbox vulnerable to failure, especially when you are pulling a heavy load. HD trucks may include a factory transmission temperature gauge, but if you don't have a way to monitor your transmission, then you need one. Some companies sell in-line transmission oil filters (for added safety) that include a temperature gauge. If your readings are constantly pushing the limits, it's time to start shopping for auxiliary oil cooler. These units will lower the operating temperature of your automatic in all conditions, which is great, because a 20 degree reduction is said to double the life of a transmission.
9. Brake Upgrades
Stock four-wheel disc brakes are great but can quickly be overwhelmed when asked to slow more than 10 tons of truck and trailer. Aftermarket brakes offer advantages such as larger discs, six-piston calipers that are better at clamping, and slotted and drilled disc rotors designed to funnel warmth into the ventilation vanes and out of the brakes. Upgrade brake pads are built with high-friction compounds for quick deceleration and extended fade resistance. When ordering, make sure the new brake kit is designed to work with your truck's antilock programming.
10. Exhaust Brake
You've probably heard semi-trucks engaging their exhaust brakes on downgrades, and you can use the same technology. Gasoline engines can slow a truck after a downshift because the engine is trying to pull air through a closed throttle. Since diesel powerplants have unrestricted access to air inside the intake, downshifts will not do much to slow your truck. An exhaust brake is a valve installed in the exhaust system that will restrict the exit of gases and provide resistance to revolutions in the drivetrain. This provides a way to slow your truck by as much as 50 percent without constantly using the wheel brakes, which can overheat and fail.
11. Trailer Brake Controller
A Trailer Brake Controller (TBC) is a great way to increase your ability to safely tow a heavy load. It works by synchronizing the truck brakes and the trailer brakes, and allows the driver to adjust the output and gain to compensate for the load being carried. Trailer brake controllers are a factory option for some heavy-duty trucks and are available from many aftermarket companies. This is another one of the "if you don't have it, you need it" towing upgrades.
12. Aluminum Differential Cover
Not only does it look cool, but an aluminum differential cover can keep your gears from turning into an axle grenade. Towing puts tremendous strain on the entire drivetrain, but a stock rear differential can have trouble dispersing the heat that is created. Aftermarket covers have more gear oil capacity and include heat-sink fins to help diffuse heat created by the gears' movement inside the differential.
"You are on the right path to becoming a trailer-towing master."