Harrop Supercharged Ram 1500 Express Review
Harrop has been tuning performance cars and 4x4s for years, and one of its latest projects is a supercharged Ram 1500 Express making 407kW and 778Nm. We sent Robert Pepper along to take a closer look at it.
Words and Images Robert Pepper: What we have here is a Ram 1500 Express, not quite as large as the big-brother 2500 or a Ford F250, but still larger than our usual dual-cab pick-ups, like the Ford Ranger.
The 1500 starts off well, with a 5.7L V8 petrol that’s good for 291kW and 556Nm delivered through a pretty smooth and intelligent eight-speed automatic. That’s a lot more kW and nearly as much torque as a diesel LC200 of about the same weight, and the 200 has only six gears, so, stock-standard the 1500 is ahead. But what if you added a supercharger from performance specialists Harrop?
What is a supercharger? A supercharger increases the power and torque of an engine by forcing more air into the cylinders. The engine drives a belt which powers an air pump which pushes more air into the cylinder than the engine would otherwise be able to draw in. The greater volume of air in the cylinder means an increase in air density, so the more fuel can be injected to keep the air-fuel ratio correct. And the more fuel injected, the bigger the resulting ‘controlled explosion’…which means more power and more torque.
The particular design of supercharger used by Harrop is the Roots-style positive displacement blower. This means it delivers a near-constant amount of extra air to the engine, as distinct from varying it with engine speed, so there’s more of an improvement in power and torque at lower revs compared to superchargers which increase the air volume with revs.
The end result is a power and torque improvement of around 46% and 36%, respectively. Take a look at the dyno graph, it’s a meaty improvement all the way from 2000rpm, particularly up to 4600rpm for torque, and there’s no fall-off in power above 5400rpm either, good for feeling that grunty surge. The supercharger transforms the 1500 into an amazing drive. How about 0-100km/h in less than 5.5 seconds, on 35-inch mud tyres? Yes, this is a very rapid vehicle indeed. To try and stress the Ram, I loaded my Forester onto a large car trailer, added some extra weights and had myself a three-tonne load to pull.
The Ram pulled it quicker with more control than my Ranger pulls my racecar on the same trailer which totals about 2200kg. And, I deliberately didn’t load the Forester perfectly to try and replicate the poor weight distribution of the average large caravan. To be honest, I think the Forester’s 0-100km/h time is improved when it’s being pulled by the Ram.
The supercharger kit costs around $15,000 fitted and while it isn’t strictly necessary, the fun-factor is immense and who doesn’t need more power? And there’s coil springs all round with disc brakes too.
But the 1500 isn’t perfect. I’m disappointed in the lack of a standard-fit reversing camera for the price but this isn’t anything to do with Harrop, and the mirrors are too small for this size vehicle. I’d like to see proper towing mirrors as standard. And I think the rear springs are a little soft, so while the around-town ride unloaded is surprisingly limo-like, certainly better than any leaf-sprung ute, there’s a bit too much sag when towing, so a set of helper airbags wouldn’t go amiss. The Express interior is a bit basic too, can’t control the volume from the steering wheel, no mirror on the passenger sunvisor, no real luxuries at all to speak of. And the park-brake is annoyingly foot-operated.
I did take the 1500 off-road and it is a bit ordinary. Probably a bit large for our tighter tracks, poor engine braking, lack of control over the gears, and indifferent, jerky traction control. It isn’t a vehicle I’d choose for off-road work, and the 800kg payload is small for its size, even less than a Ranger, so you can’t put many accessories on it. The lack of payload also counts against it when towing – while Ram claim the truck can tow 4500kg and it can but, realistically, if you’ve got a trailer that heavy then go out and buy the larger, heavier-duty 2500 instead.
The 1500 is, in my view, ideally suited to towing loads of up to 3500kg, and adding the supercharger just makes the truck better whether it is as a daily driver or tower. Never met a kilowatt I didn’t like, and spending time with a supercharged 1500 has just reinforced that view.