Test, Audi Quattro: all the differentials compared on the track in Vairano

Test, Audi Quattro: all the differentials compared on the track in Vairano

Test, Audi Quattro

On the historic test circuit of Vairano, a few days ago, we were invited by Audi to try the 7 types of differentials whose development began in the 1970s, with the historic Quattro brand that we still know today.

It was in fact starting from an off-road vehicle that, in 1976, Audi developed its first light, compact and reliable four-wheel drive system, which in the space of a decade was gradually improved and successfully used in road and racing cars. Audi was in fact the first European 4WD car and the first 4WD car used in rallies. - th_motorlabs_d_mh2_1 slot id: th_motorlabs_d_mh2 "); }
Since 1980, 12.2 million Audi all-wheel drive cars have been sold and still today is 35% of the German manufacturer's registration. Let's go below to analyze, summarizing without too many technicalities, the differences of the 7 types of differential marketed by Audi, and below you will also find our experiences on the track.

Permanent integral with self-locking center differential: used in the longitudinal front engines, it has a standard 40:60 torque distribution with up to 70% thrust on the front and up to 85% at the rear. This is the case, for example, of the RS 7; Quattro with ultra technology: although this system is also used in the front longitudinal engines, in this case the torque distribution to the rear occurs only when necessary, for maximum efficiency and traction in line with the permanent systems; Permanent integral with electro-hydraulic multi-plate clutch on transverse front engine: it has a totally variable torque distribution between the axles which guarantees immediate adaptation to the conditions of the road surface and driving style; Permanent integral with electro-hydraulic multi-plate clutch on central engine: in this case the clutch is integrated in the front differential and the distribution of torque between the axles is totally variable. This configuration favors the distribution of the thrust to the rear, reacting in a few milliseconds, guaranteeing a very high performance in terms of performance. This is the case, for example, of the R8; RS Torque Splitter: used in the transverse front engines, it uses two electro-hydraulic multi-plate clutches and the distribution of torque between the rear wheels is active and totally variable. This type of technology guarantees a radical reduction in understeer and increases oversteer as in the case of the RS3. Turning instead to the electric differentials we then have:

Integrale Quattro electric: this is the case of the RS e-tron GT, with two engines, where the distribution of the torque between the axles is active and totally variable and creates a possible decoupling an axis. This system is up to 5 times faster than a traditional 4WD and has a predictive distribution of thrust; Electric quattro integral with electric torque vectoring: used for example in the e-tron S with 3 electric motors, it has a totally variable distribution of torque between the axles and an active distribution of thrust between the rear wheels. This system is up to 4 times faster than a mechanical rear differential and tends to oversteer a bit. | ); }

Our track test

The first tests were done on dirt with Audi Q3, Q5 and Q8 on ramps with gradients up to 70%. I state that before getting into these cars, looking at the slopes, I was a bit skeptical; I never really thought they could tackle this kind of off road testing with stock road tires.

I started with the Q5, I wanted to test them in the exact order but it wasn't possible. I had no difficulty with this car, it uses the Quattro differential with Ultra technology and on the climbs I did not notice any uncertainty, as well as on the descents where the automatic braking was very intrusive and even led me to accelerate in order to unlock the braking system. Even without taking a run-up she behaved in an impeccable way that left me amazed.

The second I tested was the permanent integral Audi Q8 with self-locking center differential system. I did not find this car very different from the Q5 in terms of sensation, except in the interior finishes and various accessories such as the front camera, very useful in these types of situations because, unlike the Q5, it allowed me to see what was in front of me. Also in this case no uncertainty and the test took place in the best conditions.

I finished this off road test with the Q3. The first thing that catches the eye going up are the finishes, very good but not comparable to either the Q5 or the Q8. My impression is that this applies to practically everything, suspensions, brakes and certainly also the differential that uses the permanent integral one with electro-hydraulic multi-plate clutch.

As soon as I left, it immediately gave me a feeling of lightness compared to the other two and, absurdly, more rigid than suspensions. Without major problems I tackled all the routes even with this one but the difficulties in facing them were certainly more evident than the other two solutions. Probably if I had started with this, my judgment would have been better but trying it after Q8 made me a bit more severe. Despite everything, however, it proved to be unexpectedly effective.

The only curiosity that remains for me concerns the effectiveness of these systems even in the case of damp or completely wet soils; in any case, we must nevertheless remember that these are not “real” off-road vehicles, therefore any performance on dirt roads is to be considered commendable from all points of view.

After the off road tests, I passed the test of the other cars on the track with a rather welcome surprise: part of the test was on wet asphalt and it proved to be one of the best ways to test the behavior of these different types of differential.

The track tests began with the e-tron S Sportback, a full-face electric with electric torque vectoring. Speaking of SUVs in this case is an understatement, this car is a concentrate of many things, technology, power, control; we are talking about a car with 503 electric hp and a crazy torque.

Weight is something that you notice immediately and that I personally don't appreciate but we know that by now the market trend is to make cars extremely safe, soundproofed and therefore also heavy. By pressing hard on the power released, the mass of the car is sensibly perceived but I would never think of a power of 500 horsepower precisely because of the weight. What you immediately notice by pressing hard on the wet asphalt is that the differential does an impeccable job, the car tends to oversteer but in a controlled manner, I would dare to call it a good giant because in any case it manages to convey what is happening and works for the driver to keep the car where it needs to go.

For the first time I also tried the electronic mirrors with camera and unfortunately, due to the positioning of the displays below the eye line, I did not find them particularly practical. If you are curious about the operating system, we have published an in-depth study about it.

The test continued with the RS e-tron GT. I believe this flagship is the synthesis of all the technology put in place by Audi. Also in this case the weight is very high but coming from the e-tron S it looks almost like a featherweight. Maybe I was fooled by the 646 HP and 630 Nm of torque, numbers that until a few years ago were only the prerogative of supercars, but also the lower center of gravity compared to the S has helped to make it look much more effective in the corners. It is understood that we certainly cannot consider it as a track car but as a comfortable and very fast travel car. Also in this case the differential works perfectly and allows errors which he thinks to correct by intervening in an "elegant" and never invasive way.

The thing that surprised me is the standing start; since the numbers speak for themselves, I thought I'd relax before putting my foot on the accelerator: the thrust is constant and full-bodied. At this point I then switched to the RS3. I confess that it is the car that perhaps most of all I was curious to try, this is because on paper it promises many beautiful things that I wanted to verify.

The thing that immediately struck me was the larger size of the front rims and tires compared to the rear ones, in the previous version they complained of a bit of understeer so I suppose that is the reason. The second thing that struck me, in relation to the band of the car, were the carbon ceramic brakes. So anxious I get behind the wheel of this 400 HP monster and the first thing I do is accelerate moderately in the wet area of ​​the track to check how the differential works. Disappointed, or rather, pleasantly surprised by the lack of reactions, I continue the lap on the dry track to better understand the car and I immediately realize that the power is the right one, I wouldn't want more because it is perfectly managed by the differential.

The car goes fast, indeed very strong, I find it light, balanced, communicative and it makes me think of a car with which I can go shopping and ride fast on the track with all the comforts at a reasonable price. It goes without saying that the braking is crazy, it's like throwing an anchor out of the window without the car making a wrinkle. At this point I go over the wet asphalt part and with more conviction I sink without uncertainty on the accelerator and the car enters a strong oversteer that is handled very naturally by the car and makes me look like I was an expert drift driver. With a smile on my face I do another couple of laps and the first thing that comes to mind is that I would like to go and buy it right away. I fell in love because it allows you to go fast and precise without getting upset but if you want it also allows you to have fun in spectacular oversteering without your heart ending up in your throat.

As a last test I kept the "heavy weapons" the R8 CoupĂ© V10 performance quattro. This Audi engine is also used by Lamborghini. The car has 610hp, accelerates from 0 to 100 km / h in 3.1 sec. and reaches 331 km / h top speed with a weight of 1,670 kg. It is evidently the most performing car from Audi, I tested it by removing the traction controls only partially because the over € 200,000 cost forced me psychologically to maintain a respectful attitude towards him.

Having understood the goodness of these differentials I immediately felt safe in accelerating everything in the wet corner, the car slipped into a more exuberant oversteer than the others, but it was what I expected. Attention, I do not consider it a defect because a car of this type must convey a feeling of power that can go beyond the control of an inexperienced driver, but all in all with a hard and pure supercar I would have immediately found myself in the head of the queue after a maneuver. of this type, however, the R8 only made me understand its intentions. | with a comfort that is not normally found on this type of vehicle. If I had to find a flaw I would have preferred it to be lighter, but probably at that point we should move on to other solutions.

In conclusion, we would like to thank Audi for a wonderful day on the track aboard its most sophisticated cars.

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