Any van operator would welcome a 25% increase in fuel economy, especially if there was a low-cost way of achieving the improvement.
The solution comes in the form of rev limiters that allow normal use of a van, but restrict its engine revs and, consequently, its maximum speed.
A trial by Autokontrol, one of the UK’s leading suppliers of aftermarket limiters, showed a 24.7% improvement in economy, corresponding to a similar reduction in CO2 emissions.
One utility company in north-west England fitted limiters to 19 vehicles, including Ford Transit, Land Rover Defender, Toyota Hilux and Vauxhall Movano.
The average improvement to economy across the range of vehicles was 4.42mpg to give an average consumption of 22.31mpg.
The company has now ordered rev limiters for its entire fleet.
Gerry Leggat, product manager of Autokontrol, said:”This trial ran for six months and we saw improvements of as much as 13mpg for some vehicles.
"Even with vehicles that already had a factory-fitted speed limiter, we witnessed worthwhile economy gains.”
The cost of fitting an aftermarket limiter can be spread even further than its use on the original vehicle.
Leggat says: “A rev limiter is simple to install, which means very little downtime for the vehicle, and the approximate £300 plus VAT cost is easily returned in fuel savings.
"The limiter can be removed from the original vehicle and fitted to a replacement van for around £90.”
The amount of fuel saved using a rev limiter worked out at 5mpg for a Ford Transit 350 medium wheelbase, lifting it to 22mpg.
This van would cost £23,734 in fuel at current prices over a typical 36-month/60,000-mile period with no rev limiter. Fit the limiter and the fuel bill drops to £18,340, saving £5,394.
Richard Wiggins, head of technical fleet for Royal Mail, has fitted speed limiters on all the fleet and rev limiters on urbam-based vans.
“We recognised our light fleet was capable of performance that exceeded our needs, so we adopted a policy of fitting limiters prior to the vehicle entering service,” he said.
“Every LCV we purchase is limited to 70mph, as well as coming with reversing sensors and seatbelt warning devices.
"We have seen a small benefit in fuel economy, but just as importantly it has helped set a standard for driver behaviour.”
He added: “If purchased as an option on a new vehicle, the costs is commercially viable across the life of the asset for Royal Mail.
For retrospective fitting of a rev limiter, it should be undertaken as part of a scheduled service visit and is a small job for most vehicles without attracting vehicle downtime.”