How to Get More Power in My Toyota Motorhomeby Eli Laurens
Toyota Motorhomes were a C-class recreational vehicle manufactured from a Toyota truck chassis from 1970 to 1996. The simple design of the early models led to behemoth motorhomes with full kitchens and showers, still driven by the anemic four cylinder engines until 1986. Power was greatly improved by the addition of the V-6 engine, but the style was discontinued due to the inherent instability of using a mini-truck chassis to pull an 8,000 pound motorhome. Improving the power on these RV's can be accomplished by the average backyard mechanic in about 2 hours.
Remove as much weight as possible from the rear of the motorhome to reduce the amount that the small engine has to haul. This will have the largest impact on speed and economy. All of the water tanks should be emptied before travel, both fresh water and black water tanks. On a normal motorhome, this is usually not a concern, but here it can mean the difference of a few hundred pounds. Interior appliances that are not used can be removed, such as the refrigerator, stove and cabinetry. Chairs and tables that are not needed can go, too. With the rear as light as possible, the Toyota can gain maximum speed and save gasoline with higher mileage. Some mid-80s models are known for being the heaviest of the bunch, with the four cylinder engines standard. These were also the most lavish of the series. Many extraneous items can be removed and actually increase comfort.
Replace the spark plugs with units with a higher hear range rating. Remove the old plug with a long socket by turning it counterclockwise, then replace it with the new plug in a clockwise direction. Most manufacturers will pre-gap the plugs, but experts will at least double check it with a gap tool. The higher heat value of the plug gives more power to the cylinder ignition, and will be around a five rating. Stock Toyota plugs for most engines rate about three.
Replace the ignition wires with 8mm models by pulling each plug wire and replacing it individually. The wider core plus better insulation means that there is less resistance for the energy to go from the coil to the plug. This results in more power. They can even be purchased in a variety of colors. Do not pull all wires and replace them en masse; this can cause misfiring if they are not replaced in exactly the same position.
Replace the stock Toyota air box with an open element air cleaner. Take the old air box off by turning the mount bolts counterclockwise, then removing the hose clamp and hoses connecting the box to the intake. The open element air filter kits install easier on older models, but they are relatively easy to install regardless. Position the new air cleaner and connect it to the hoses with clamps. Most open element cleaners will have one or two mount arms that can be secured with bolts turned clockwise. This lowers air restrictions and allows more power because the engine doesn't have to fight the air box opening for oxygen.
- Consider a manual shift transmission over an automatic in a Toyota motorhome, the manuals have better power and break down less often.
Things You'll Need
- Socket set
- Spark plugs (higher heat range)
- 8mm ignition wires
- Open element air filter
- Gap tool
- Use extreme caution when working on a vehicle.
Eli Laurens is a ninth-grade physics teacher as well as a computer programmer and writer. He studied electrical engineering and architecture at Southern Polytechnic University in Marietta, Ga., and now lives in Colorado.