Porsche Cayenne E-Hybrid 2020 Tow Test

While the turbo-diesel slowly clatters itself towards a grave dug by emissions regulations, many are left wondering what will replace this powerplant if they want an SUV to tow a heavy trailer.

Yes, you can cut to the chase and buy the all-electric Tesla Model X for towing duties, but you’re limited to towing a maximum of 2280kg and EV issues of range anxiety and recharge time are magnified when lugging a heavy trailer across the country.

This leaves us with the petrol-electric plug-in hybrid vehicle (PHEV), of which there are a growing number that can tow trailers, such as the 2020 Porsche Cayenne E-Hybrid.

Introduced in 2018, the 2020 Porsche Cayenne E-Hybrid is the only hybrid PHEV on sale that’ll tow a maximum (braked) 3500kg.

The only other ‘heavy-duty’ hybrid SUV alternatives are the BMW X5 45e (2700kg), the Range Rover Vogue P400e PHEV and the Range Rover Sport 2.0 Si4 SE PHEV (each able to tow up to 2500kg). Then it’s down to the likes of the Lexus RX450h, with a 1500kg towing capacity.

While the Porsche’s maximum towing capacity is 3500kg, tow ball download is restricted to 280kg (not the 10 per cent TBM – 350kg – that some might expect).

However, the 2020 Porsche Cayenne E-Hybrid has a GVM of 3030kg and a GCM of 6530kg, meaning it’ll tow its 3500kg maximum while at its fully loaded (GVM) weight.

Payload is potentially an issue though, because the kerb weight is in the range of 2295kg-2605kg depending on equipment. If your Cayenne E-Hybrid is fully loaded with options and weighs 2605kg and assuming you’ve loaded the maximum you can on the tow ball (280kg) then you have just 145kg left for payload in the vehicle.

If the Cayenne and the other prestige hybrid SUVs seem irrelevant to the average tow-vehicle buyer, don’t forget that even Toyota is to ditch diesel in favour of V6 petrol and petrol-electric powertrains for not only the replacement for the darling of the towing set, the LandCruiser 200 Series, but has also promised electrification for every Toyota model by 2025.

The latest hybrid tow vehicle tech doesn’t come cheap. The Cayenne E-Hybrid starts at $136,700 (plus on-road costs) and as tested with options was $162,790 (plus towbar fitting and on-road costs).

Fitted to the test vehicle were a towbar kit ($1850, plus fitting), LED matrix headlights with dynamic (adaptive) lighting system ($4380), sunroof ($4490), adaptive cruise control with autonomous emergency braking ($3790), 20-inch wheels ($3130), Bose surround sound ($2470), metallic paint ($2190), two-tone leather interior with Porsche crest embossed on head restraints ($1860), aluminium roof rails ($1390), heated front seats ($990) and power steering plus ($650).

The teardrop shape of the Cayenne’s side mirrors don’t make fitting clip-on towing mirrors easy, and the 13-pin Euro trailer electric plug requires (as many such Euro set-ups do) an adapter to plug into most Australian trailer plugs – adding another potential failure point for trailer electrics.

We hitched up a Millard van weighing 2600kg from RV Connection at St Marys and with 22km of electric range remaining, headed about 2km down the road for some photos.

The strange sensation of driving a vehicle without a combustion engine running was revisited with the Porsche – because it feels odd to be towing a large caravan without an engine thrumming away.

Yet the Cayenne was responsive and didn’t feel sluggish in EV mode with a 2600kg trailer behind (with a 205kg tow ball download). Not too surprising when you remember that the electric motor has 400Nm on tap from the moment it begins to spin.

By the time we headed past RV Connection (a total of 5km all up) the E-range (electric only) had depleted from 22km to zero. Clearly the Cayenne’s (44km maximum) electric-only range is seriously curbed with a heavy trailer hitched up.

Once beyond the on-ramp’s sharp, 30km/h corner and onto the straight to merge onto the freeway, the Porsche Cayenne E-Hybrid got up to 100km/h incredibly easily using full throttle.

In fact, it was a matter of backing off and rolling onto the freeway merge point, because the Cayenne had got up to speed well before then. There’s no worry about trying to build up enough steam to safely merge with freeway traffic here.

As the E-Hybrid system had been depleted of its electric-only motivation, we were down to towing on the bi-turbo petrol V6 and whatever fuel-saving we could manage while the Cayenne coasted downhill (with engine automatically shut off).

At 100km/h, the Porsche settled into an easy cruise with transmission swapping cogs mostly between seventh and top (eighth) gear with revs sitting around 1500-2000rpm, depending on the (mostly flat) terrain. On a mild incline and it was back to fifth or sixth gear.

While the tail of the Porsche Cayenne E-Hybrid dropped 55mm and the front rose 5mm with the van on the back, stability was remarkable good.

It was only on rough, undulating secondary roads where the Cayenne began to pitch a little. At no time did it feel like yawing, so it would appear that this is a fairly stable towing platform.

What was surprising about the Cayenne is not that it climbed the steep test hill at the posted 90km/h limit -- but just how easily it did it. About one-fifth of pedal travel kept it at the posted limit and it felt as though it could have easily increased speed by a fair margin.

We treated the E-Hybrid as with any other tow-test vehicle on steep hill descents, employing engine braking to help peg back descent speed. Despite being a free-revving petrol V6, the Cayenne’s petrol engine did a pretty good job, only requiring a few dabs at the brakes on the test hill to peg the rig at the 70km/h speed limit.

Speaking of the brakes, while they performed well and were predictable in most towing scenarios, when driving solo – especially at slower speeds – under moderate braking pedal feel was inconsistent.

Towing fuel consumption is always the area where you might assume that a petrol-electric hybrid would be slammed. Yet, just as with the Toyota RAV-4 Hybrid we tow-tested a few months ago, the Cayenne returned a fuel consumption figure not far off that of an equivalent diesel SUV towing a similar weight – 16.8L/100km.

The only downsides with the figure we achieved were fuel range – the E-Hybrid has a 75-litre capacity fuel tank (giving a relatively poor 396km touring range with a 50km safety margin) and the relative expense of feeding it with the recommended 98 RON fuel.

The minimal extra fuel cost the Porsche Cayenne E-Hybrid adds over a diesel when towing is countered in the kind of use most of subject our vehicles to when not towing: the daily commute.

If you plug in the Cayenne you can see up to 44km of range, during which no petrol is consumed. Without the van attached and with 40km of electric reserve showing at the start, we saw a fuel figure of just 3.1L/100km over a 150km trip – just astounding.

The Porsche Cayenne E-Hybrid is not the solution for everyone’s heavy tow-hauling needs. It’s expensive (although its starting price is not all that much more than a 200 Series), doesn’t have an especially long towing fuel range and, if you have a breakdown in Tibooburra, you probably won’t get parts or repairs done quite as quickly as you might with a LandCruiser.

But much of that is missing the point. In the role of a heavy-duty tow vehicle, the Cayenne hybrid offers good stability, great performance and is not by any means thirsty.

For those who want a large, luxury/performance SUV tow vehicle, those achievements tick more than enough boxes.

How much does the 2020 Porsche Cayenne E-Hybrid cost?
Price: $162,790 (As tested, plus towbar fitting and plus on-road costs)
Engine: 3.0-litre turbo V6 petrol/electric
Output: 250kW/450Nm (V6), 100kW/400Nm (electric motor), 340kW (combined)
Transmission: Eight-speed automatic
Fuel: 3.4L/100km (Euro 6/WLTP Combined)
CO2: 78g/km (Euro 6/WLTP Combined)
Safety rating: TBC

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