The Grunt Factor: Measuring the heart of the beast

NOT BAD AT ALL: The Mack MP10 has claimed the top spot of Mr Grunt from the mix of modern, road ready engines.
NOT BAD AT ALL: The Mack MP10 has claimed the top spot of Mr Grunt from the mix of modern, road ready engines. unknown

WALK into a truck stop, grab a cuppa and a feed and listen. An outsider might expect a high level of bragging and pride about the power of a driver's truck.

With a few exceptions, this is not the case. It is more likely that a driver will be whining about not enough power, "needs a new filter", the boss has cut the power riding back, "bloody emission gear" and so forth.

Even with the complaints of lack of power, most of these drivers wander out to their trucks and drive away with a powerful growl and a smile on their face.

Most know that a truck driver today has more power to play with than they did 10 years ago and certainly a lot more of the old blokes talk about when they are remembering the "bad old days".

The exceptions are when an owner driver has got his engine tuned to the hilt, and he or she has absolute confidence in the power and they're quite happy to talk about it.

So we all look at the specifications for various engines, we talk to blokes on the road, and most importantly the moment we take on a long hill and another truck loaded as heavy as we are, pulls out and passes us and we think "bloody hell".

All the spec sheets in the world tell us only so much about the power of a truck engine, there are so many variables from how the diffs are set up through to the ratings set on the engine and those settings these days are almost infinitely variable with computer management of engines. And of course there is an actual variability in the same spec of engine from a manufacturer.

We've all heard of the dreaded lemon through to the occasional engine that just seems to fire under all conditions.

So to attempt a comparison of engines through power, torque and driveability is not a chore for the faint-hearted.

In this Drive Line feature in Big Rigs it seemed appropriate to begin the drive line where the power begins - in the engine.

We have picked the grunty end of engine specs from half a dozen manufacturers, taken to account the horsepower, the torque peak, the range or plateau of the torque holding through the driving range and created an algorithm to make the comparison for us.

As part of this algorithm, the data is fed through a filter of driver feedback and on road performance.

Not for a second are we claiming this comparison is the be all and end all of scientific assessment but we do say it is a lot more relevant than just looking at spec sheets.

So we took top of the line engines with the highest normally available horse power ratings, out of the yard horsepower ratings and ran them through this algorithm. Manufacturers represented are Mack, Volvo, Mercedes-Benz, Cummins, Scania, Detroit and Caterpillar.

A reasonable representation of the engines out there doing it hard today.

Interestingly enough, the comparative ratings through this assessment do not necessarily follow these simple horsepower multiplied by torque index often used.

Time to make the call and we'll talk through the competition from the winner to the also-rans.

No 1: Mack MP10

What the MP10 has done over the past five years is no news to anyone who spends a bit of time on the road. From the earliest days in road train work, these engines either in a Super-Liner or a Titan have made a name for themselves on every hard pull in the country.

Yes, as with every engine there have been some issues that have been for the most part sorted out reasonably quickly. One of the early hurdles with the MP 10 was that it was only available with the automated MDrive transmission.

While some have escaped the coop and gone out on the road with a Road Ranger, Mack Trucks has largely held to its guns and the vast majority have the automated transmission and drivers are getting used to them.

This is a transmission that can handle the hefty 3150 Nm of torque (for comparison sake we have converted all lb/ft torque measurements to Newton metres).

The MP10 in its highest form is rated at 685 hp, and is a 16 litre in-line six cylinder block, with Euro 5 (ADR80-03) emission standards.

The Big Rigs algorithm gives this engine the top rating of 21.6.

No 2: Scania DC16730

The big V8 from Scania on paper is all grunt and power, and the algorithm has served the big Swede well. The DC16730 is a 16 litre V8 rated at 730 hp with 3500 Nm of Torque (Euro 5 version).

The Big Rigs algorithm returned rating of 20.444 for the big Scania.

No 3: Cummins X15

While the power ratings of the Cummins engine were based on the new X15, road feedback took into consideration the running of the previous 15 litre ISXe5, as they are both pretty much the same engine with the X15 being adapted for more sophisticated electronic management and integration with electronic transmissions.

The X15 uses SCR emission technology and will not go back to EGR to meet the Euro 6 requirements.

The highest horsepower rating available is now 600 hp with a torque peak of 2780 Nm.

The Cummins X 15 scored 19.5 on the Big Rig 's scale.


The Cummins SCR X15 and its immediate predecessor the ISXe5 scored well.
The Cummins SCR X15 and its immediate predecessor the ISXe5 scored well.

No 4: Caterpillar

The 15 litre Acert Cat engine has a long history, working in linehaul and road train applications.

The in-line six cylinder engine has a top rating of 550 hp at 1800 rpm with a torque peak of 2780 Nm. The strength of this engine lies in the flat torque plateau that runs from 1000-1500 rpm.

The algorithm gave the Caterpillar engine a score of 19.0.

No 5: Volvo D16G700

The fact that the Volvo more than compares favourably with its close relative the Mac MP10, delivers a result that is a little counter-intuitive. No accounting for these algorithms as they crunch data.

With a high 700 hp output with the power of 3150 Nm of torque, the top-of-the-line Volvo is no doubt a grunt machine.

It scored 17.6 on the Big Rigs scale.

No 6: Mercedes-Benz OM3358

This is one powerful engine from the Mercedes-Benz stable but it has a ways to go for on-road acceptance. We are seeing the revitalisation of this brand going on at present.

The OM3358 presents well on paper with the 15.6 litre block pumping out 625 hp with a 3000 Nm torque peak and a lot of hanging on power.

But algorithmic ratings are what they are and this engine has a Big Rigs rating of 15.

No 7: Detroit

It could be argued that the 560 hp, 14.8 litre engine be included in this round-up of the big blocks.

Even the people from Mercedes-Benz made it very clear that the Freightliner is available with the Cummins option.

But the in-line six cylinder Detroit is a little battler, has good pulling power down to 1100 rpm and still pumping out 90% of torque at the horsepower peak of 1800 rpm.

The Big Rigs rating for this engine was 15.4.


Looking into the future - will the Cummins powered International ProStar perform through 2018?
Looking into the future - will the Cummins powered International ProStar perform through 2018?

Topics:  detroit emissions engine mack mercededes-benz scania

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