Can you make a giant gas-powered RV better with an engine and transmission tune? We take this 38-foot Allegro Open Road motor home to a drag strip at sea level, put it on a dyno, and take it on the Ike Gauntlet – world’s toughest truck test to see what’s it made of.
If you are interested in getting more performance from your new or used motor home / RV – you can go directly to 5 Star Tuning here for pricing. 5 Star tunes RVs produced after 1996.
Stock Engine & Transmission
The engine in question here is Ford’s 6.8L V10. The most recent rating is 320 horsepower and 460 lb-ft of torque at the crank. It’s mated to a heavy duty 6-speed automatic transmission, just like in this 2016 Allegro motor coach.
After putting it on a dyno, we quickly learned that there is a giant power loss in the driveline of this Ford F53 chassis. The engine has to deal with a heavy transmission, many sections of driveshafts, and a big rear differential.
It is time to do something we have not done before, put the Class A RV on a drag strip in North Carolina. The 23,000 lbs behemoth needed over 30 seconds and nearly an entire 1/4-mile runway to reach 60 mph from a dead stop.
Ike Gauntlet: Extreme Test
Next, we put the RV on our Ike Gauntlet in the Colorado Rocky Mountains. We wanted to see how the RV performs in the real-world and this extreme environment. The Eisenhower/Johnson tunnels are located at an elevation of 11,158 feet above sea level. The Ike Gauntlet is an 8-mile stretch of I-70 with a 7% grade.
We top off the 80-gallon fuel tank with 87-octane fuel in order to measure fuel economy, and set off for the extreme run.
We measure the downhill performance by counting brake applications needed in order to keep this house on wheels between 50 – 60 MPH. This stretch of the interstate has a 60 MPH speed limit.
On the way up, we time the run and use wide open throttle (WOT) to keep the speed.
5 Star Tune
The guys at 5 Star Tuning have been working with these big RV engines and transmissions for over 12 years. They saw an opportunity to unlock the additional power left in the 6.8L V10 engine and improve how the transmission helps the driver manage difficult terrain. Making the big RV quicker off the line make it safer while merging into traffic and more confidence inspiring in mountainous terrain.
The result is approximately a big 100 lb-ft of torque gain at the wheels in the middle of the RPM ranger.
There is another benefit to tuning this engine and transmission. 5 Star guys estimate an 8% improvement in fuel economy when using their 87-octane performance tune.
The tuning process is very straight forward. Connect the SCT 5-Star device to the OBD-II diagnostics port, select the tune, and you can be back on the road in a matter of 5-10 minutes.
Once the tune was loaded, we put the RV back on the drag strip. Since the majority of the power increase comes between 2,000 – 4,000 rpm, you can feel the acceleration difference right away. The 0-60 MPH time was a whole 3 seconds quicker. This is roughly a 10% acceleration improvement for a vehicle that weighs around 23,000 lbs.
Switching back to the Ike Gauntlet, we tuned the RV back to the 87-octane performance program, topped off the tank, and went back up the and down the highest-elevation interstate in the country.
While we did not see a dramatic improvement in total speed up the mountain or brake applications on the way down, you can feel the additional power while merging onto the highway. The 6-speed automatic transmission is more eager to downshift when acceleration is needed to help gain speed. It also downshifts while starting a downhill without the need to touch the brakes.
The overall drivability is improved as the engine and transmission are more responsive. We also saw a 5% fuel economy improvement while completing the Ike Gauntlet driving loop.
While you may not be driving across the Rocky Mountains on every trip, you are likely to face head winds across the country. Having the extra power is always welcomed to overcome winds, maintain speed up the hill, keep the engine rpm lower, and the cabin a little more quiet as well.
Take a look at all of our testing in the video below.