Volvo FH 460 I-Save 6x2 truck review

In recent years, we’ve made a conscious effort to downplay fuel consumption figures. It’s not that they aren’t of great significance, but they are only one of the many factors that go towards making a good all-round truck. This doesn’t mean we’ve compromised our efforts to obtain the best consumption possible while driving in real world conditions, though.

For this truck review, however, we’ve set aside our usual policy and put our focus firmly on economy. After all, after seven years on the market, we’ve written most of what there is to write about the fourth generation Volvo FH – and judging by sales figures, many operators are happy with its overall capabilities. And this time, Volvo has introduced technology with bold claims of major fuel economy gains, so it seemed only right for us to alter our focus slightly.

The truck under review is an Volvo FH 460 6x2 equipped with a package of technology collectively known as I-Save, significant enough that it effectively creates a model in its own right. The FH under review is uncompromisingly aimed at ultimate economy, from its lower roof Globetrotter cab to the longest final drive ratio in Volvo’s current armoury.

Cab interior: seats and infotainment

Because this review is concentrating on the dynamic properties of Volvo's I-Save package, we’ll refrain from telling you once again how many cup-holders the now familiar FH cab has. Apart from some nice leather seats, the review truck is a standard fleet spec FH, but that doesn’t make it a bad place to work, with essential luxuries such as an underbunk fridge still included. The infotainment system fitted in the cab goes by the full title of Secondary Information System – High. This means that it’s the highest level unit, and includes access to the Dynafleet management system.

Gear shifting is courtesy of the dashboard push-button alternative to the familiar floor-mounted quadrant. This is becoming increasingly popular, particularly among larger fleets. From a driver’s perspective, it provides easier movement around the cab, but for the operator, it reduces the temptation for the driver to intervene in the carefully designed gear-changing strategy. While it is available on all driving software packages, it doesn’t include a Performance mode. And apparently, the old quadrant was rather prone to having coffee spilled in its innards, doing it no good.

I-Save engine options

At the time of our reivew, the Volvo I-Save package was only available in fleet-focused 460hp and 500hp ratings of the familiar 12.8-litre D13K engine family. Interestingly, Volvo carried out some preliminary runs around our route with both versions of the engine and found little difference in fuel consumption between them.

Volvo turbo-compound technology

The I-Save package basically consists of the latest I-See predictive cruise control and, more significantly, the turbo-compound unit.

Traditionally, when exhaust gas leaves the cylinders it powers the turbocharger to increase air flow into the engine, then exits to the atmosphere via the emissions after-treatment systems. With turbo-compounding, the gas powers another turbine just beyond the turbocharger. The energy recovered from this is fed directly back into the engine flywheel via a small fluid coupling that damps out any combustion pulses.

I-Save engine power and torque

While turbo-compounding has been seen before on engines from both Volvo and Scania, it has previously been used as a power enhancer. This is the first time it has been engineered as an economy aid, however, and Volvo claims an improvement in the order of 3.5% over the already enhanced Euro-6d engine. It has the additional benefit of increasing torque by 300Nm on both versions, so a 500 with I-Save now has the same torque as the lowest rated FH16, the 550.

The compound turbo technology has been used in Volvo’s US market trucks for a couple of years so is well developed. A key figure is that it raises the engine’s brake thermal efficiency from 43% to 47%, with around 55% expected to be achievable in time. Just using turbo-compounding has shown fuel savings of around 3% over there.

I-Save can be mated to either conventional I-Shift or Dual Clutch transmissions, Volvo saying there is at best a marginal difference between the consumption of either application.

FH 460 acceleration

A significant feature of the I-Save package is that it does away with the Performance mode generally fitted, so the on-track acceleration figures may look a little tame compared with rivals tested in the fastest mode available.

In the real world, though, journey times don’t suffer. Average speed around our Scottish review route was in the faster half of recorded times, and interestingly exactly the same as the last FH16 750 we reviewed.

Volvo driver assistance systems

The truck supplied for our review has the latest version of Volvo Direct Steering (VDS) with the personal settings facility. Having always felt that VDS was a bit over-assisted at higher speeds, we now like to select the STABLE option and leave it there, getting what we feel is the best all-round compromise of ease of use and good road feel.

We’re quickly getting accustomed to the gentle intervention of Volvo's Lane Keep Assist system, particularly through the seemingly interminable roadworks on the M6. What is harder to get used to is the car horn sound of the blind spot assist, which invariably has you looking round to see who you’ve upset.

I-See predictive cruise control

The latest I-See predictive cruise control is greatly improved, based on a more reliable communication platform. It reads the road 2km ahead, and while it uses over-the-air mapping data, it also has an on-board backup system. A notable enhancement is the increased use of in-gear over-running when appropriate, which uses no fuel at all, instead of coasting in neutral, which uses an admittedly small amount.

In some ways, the Volvo I-See system seems rather unintuitive to an experienced driver, such as coming off the power before the crest of a hill. It’s best to just go with the flow and trust it. We had it set to the highest Eco level which, giving a maximum overspeed of 5kph and under by 7kph, has the widest variation but the best efficiency.

As always, we were driving for best economy but without wasting time. That means making maximum use of the normal cruise control, really only coming off for safety at roundabouts, in heavy traffic and on tricky hill descents. Adaptive cruise control was kept for situations where you have no choice but to follow the traffic, such as in those roadworks. Otherwise you run the risk of not noticing that you’re losing valuable momentum behind a slowing truck in front. As we have done for years, we maintain 85kph on motorways to avoid getting into elephant racing situations. The biggest downside of adaptive cruise control systems from all manufacturers is the frustrating interaction with other trucks. Maybe things will get better when everyone is using it.

FH 460 ride and handling

The FH 6x2’s on-road behaviour is almost impeccable, but once again, the experience is let down by over-firm front suspension that struggles to cope with the worst of neglected UK road surfaces.

Volvo FH 460 I-Save fuel consumption: mpg performance

And so to fuel consumption. Truck launch claims are one thing, but proving those claims under known conditions is another. Having said that, we were expecting a good result after Volvo reported back from a trial run with the FH 460 I-Save around our review route. On the run back south, we traditionally have a short break at Barnsdale Bar services on the A1. When we’re there, we always take on 200 litres of fuel, not least because it’s significantly cheaper than our end-of-review-route location. This time, we were told the Volvo driver couldn’t get more than 190 litres into the FH 460 – something that has never happened before.

Things looked good on the run up the A5 and M6 to our overnight stop just over the Scottish border. Weather was warm and still, every light seemed green and there were no significant traffic delays. Luck was definitely on our side – we were even one of the last two vehicles through before a police road block near Lancaster. By the time we could smell the haggis, the FH460 I-Save's on-board trip computer had us at just over 10.1mpg.

Incidentally, for the benefit of those who doubt the veracity of modern trucks’ fuel meters, the difference between the reported fuel consumed and the amount actually added after 763km was just 350ml. That’s just about one coffee mug – we’ll call that accurate.

Back at Barnsdale Bar on the real run for the usual 200-litre top-up, the FH 6x2's tank wouldn’t take more than 189 litres, and at the final fill back in Warwickshire the calculations were done. And then they were redone a few times because frankly, the result was verging on unbelievable. But still the overall figure for the I-Save equipped 6x2 came out the same and was backed up by the FH trip computer.

Not only did our FH 460 pass the previous 8.65mpg record, it broke the 9.0mpg barrier. In fact, the final figure of 9.49mpg didn’t just match Volvo’s claims, it exceeded them by a healthy margin, while AdBlue consumption of 7.7% was in the expected range.

Review verdict: 88%

In September 1978, a Volvo F10 became the first 32-ton artic to break through the 8mpg barrier [ADD LINK TO F10 TEST?]. Then in August 1994, a Volvo FH12.420 [ADD LINK TO FH12.420 TEST?] raised the bar for a 38-tonner to 8.39mpg. Since then, of course, maximum weights have increased to 44 tonnes, speed limits have increased and perhaps most significantly, emissions have been reduced to levels unimaginable four decades ago. We never tire of paying tribute to the engineers who have achieved this progress while keeping fuel consumption somewhere in between those two old benchmarks.

Before the 1994 review results were published, the leap was such that we went to the effort of checking the truck more closely in case it was running with trick tyres, exotic lubricants or any other unconventional benefit, but all was found to be legitimate. These days, fuel saving has become such a key issue that ultra-low rolling resistance tyres and economy-optimised lubricants are just part of the specification that any switched-on operator takes for granted.

The Volvo I-Save package will add around £4,000 to the purchase price of an FH, but some easy calculations using your own operating circumstances will tell you how long this will take to be recouped. In the first month of trucks fitted with the I-Save being on sale, 75 found buyers – all in predominantly larger fleets.

This long tradition of Volvos raising the bar has been repeated to an extent that will now take some beating. Short of some currently unknown technological advance, the laws of physics suggest the fuel consumption performance recorded in our review of the FH 460 I-Save 6x2 is unlikely to be matched easily by any manufacturer that allows recoverable energy to be thrown away down the exhaust pipe.

Images: Tom Cunningham