Why Hyundai’s top speed in Sweden should be no surprise

After a disastrous winter break and a dismal Rally Monte-Carlo, Hyundai Motorsport was in desperate need of positive headlines on Rally Sweden. Thankfully for Hyundai, I believe it will receive a few of those after its hopeful performance on the second round of the World Rally Championship’s Rally1 era.

Top speed was a clear strength for the Hyundai i20 Rally1 car in Sweden. The Umea based snow event was as fast as they come and Hyundai’s three drivers clearly benefitted from this characteristic on the rally’s fastest sections.

At one flat-out section on Rally Sweden’s 10th stage, Langed 1, the i20 was topping out at 192 kph, 10 kph more than rivals Toyota, and approximately 12 kph more than M-Sport’s Ford Puma.

So what does this actually mean when it comes to stage times? To calculate the effect of this top speed differential you need to estimate how long the car is at that top speed for.

Looking at Ott Tanak’s Power Stage winning onboard, he was hitting his highest speeds for around 40 to 45 seconds of this six and a half minute stage.

When you do the numbers, if he was going 10 kph quicker than his rivals in their Yaris and Puma equivalents, then he saved over two seconds thanks to his top speed alone.

Rally winner Kalle Rovanpera finished 1.9 seconds behind Tanak on the Power Stage.

How is Hyundai doing this, you say?

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When it comes to achieving maximum top speeds there are three things we can talk about:

  1. Engine performance
  2. Drivetrain ratios
  3. Aerodynamic efficiency

The first two, I can’t explain as without being an engineer for one of WRC’s leading teams there is no way of knowing a) the exact power of their engine, and b) what gear ratios they run.

Even if I was an engineer for one team, I doubt I would be given the information for one of the other teams to compare anyway!

The impact of engine performance and power on top speed is easy to understand. Drivetrains may cause a few questions, however. Simply put, teams with a shorter gear ratio will have better acceleration but will top out at a lower top speed, and vice-versa. That decision is a perfect example of an engineering compromise.

Hyundai’s aerodynamic performance is the only point that I can directly comment on, as it is the only one which is visible to the outside world.

The location and size of Hyundai’s battery cooling inlets is different to both Toyota and M-Sport. The i20’s slim inlets along its side windows are much more discreet than its rival’s more bulbous designs.

The smaller, more streamlined inlet designed by Hyundai will create much less drag; it catches less air and as a result pierces through the air easier. This effect is magnified at top speeds as resistance from the air and surface stops the car from going any faster.

Is this what allowed Hyundai to go that bit faster in Sweden’s flat-out sections? It would have helped for sure but you cannot totally rule out the effect that engine performance and gear ratios might have had.

Perhaps the obvious question is why M-Sport and Toyota didn’t design small inlets like Hyundai?

So far WRC has ticked off two cold winter rallies: Monte-Carlo and Sweden. Cooling is less of an issue in these climates.

When the teams travel to the championship’s hot summer events, then we might witness why a larger cooling inlet is needed. If Hyundai’s i20 doesn’t take in enough air through those critical side window ducts, it will have to say goodbye to its extra hybrid boosts.

Air might have been the enemy on Sweden’s fifth-gear straights, but come Portugal, Italy, and Kenya, it will certainly be a much desired friend for WRC’s Rally1 challengers.

Photos courtesy of Red Bull Content Pool

Adam Hall

Brought up in the Irish countryside, Adam was never far away from the world of rallying. From following local events like the Circuit of Ireland and the Ulster Rally, Adam now puts the stories from stages all around the world into words through his website Rally Insight.

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