Advice: How to get better RV engine performance

Since 1972 Eric Davis has addressed engine performance and handling problems for motorhomes and trucks used for towing heavy 5th wheel trailers. Send him your questions and will answer as many as he can in this space.

Dear Eric,
I have a 1996, 33-foot Holiday Rambler motorhome with a Ford F-53 chassis. It has always lacked good power and has overheating issues in warm weather — the fan clutch runs a lot of the time. I have changed to a large muffler and K&N air filter and the engine is in good tune. What do you suggest for more performance?

Eric: Changing the muffler was a good choice, but most of the problem is with the exhaust manifold design on the Ford 460: it simply does not flow very well, restricting the exhaust from leaving the engine. This in turn causes the combustion temperatures to climb, raising the water temperature, resulting in the fan clutch to run more.

Another problem is the cast iron manifold expands and shrinks with the exhaust temps causing the manifolds to break bolts, and sometime worse — the cylinder heads where the bolts are, which is very expensive to repair besides being a nuisance and hazard.

I recommend installing a Bank Power PAC, which consists of an improved air intake design called Ram Air, Torque Tube headers. These are made with 5/8” thick exhaust flanges and long free flowing tubes that will breathe much better than the stock manifold and run cooler, thus will not have a chance break bolts and heads. Along with the monster exhaust you will gain about a gear higher up hill, much improved acceleration and hopefully better fuel mileage.

Please note that it is important to have the fuel pump pressure checked from time to time and change the fuel filter often (like 8000 miles or so). When having the fuel pressure checked ask for the technician to do a road test with the text gauge and test for at least a block. At wide open throttle for good performance you need to reach 40 psi. If less, it needs to have the fuel pump replaced: this has been a long standing problem with Ford F-53/460’s from 1990-1997. Many have already experienced this problem and have had the pump and wiring harness kit replaced..

When you get all the eggs in a row this will perform very well and run much cooler.

Eric Davis, an avid RVer, is recognized by many old timers in the RV industry as the creator of the term “RV Performance.” Since 1972 he has addressed engine performance and handling problems for motorhomes and trucks used for towing heavy 5th wheel trailers. He has been an innovator in the RV industry, inventing and creating solutions and products. His business, Eric’s RV Performance, is headquartered in Sequim, Wash., and also operates each winter season in Quartzsite, Ariz. The company performs all major service and maintenance. Davis is also a popular lecturer at RV conferences and seminars. He can be reached at eric@ericsrv.com .