A new dawn has approached the World of Formula 1. As a result of again a new breed of technology evolves. What grabbed us all in Jerez and Barcelona testing was the sheer power of the Honda power unit (PU) but also the reliability of the Mercedes engine. Furthermore, Renault and Ferrari seemed to have closed the gap, with paddock talk of an extra 80BHP for them both. Could this be the closed season in Formula 1? No. 
Mercedes ran on rails all through the tests they committed. It became worryingly clear that Mercedes in qualifying mode was one second quicker to the next car, on any tyre it ran. Not even Honda, with the immense power could rival them. Ferrari and Renault look a world behind Mercedes, and still haven’t fully closed the gap.
So what have the teams been up to? What are the secrets? With Honda behind in development, their PU is not 100% optimised yet. They have taken the route of pacing the turbo at the rear of the engine mounted onto a shaft which has the MGU-H (motor-generator unit – heat) mounted amongst it, which eventually lead to the compressor.
What made the Mercedes W05 so quick was the split turbo philosophy between the front and rear of the 90° “V2 mounted engine block, which has the MGU-H working on the same shaft which connect them. This therefore allowed Mercedes to run an even bigger compressor than usual, while keeping the turbo blade spinning and keeping heat away from the exhaust, which also minimised the collector housing and turbo speeds.
Meanwhile Ferrari and Renault mounted their turbo more conventionally by placing it behind the engine, with Ferrari splitting the turbo with the MGU-H. This is a simple but effective concept to engineer, and is pretty straightforward.
Over the winter, when we had tests and car reveals, it became adamant that not all had followed the Mercedes “log style” concept, something that caught as all be surprise. It soon became clear that Mercedes did not go for the “log style”, but a tubular ceramic housing which covered the manifold. It’s still unclear what design the Mercedes PU has, but looks to be a step on from the effective “log style”.
This became clear when Lotus had their sidepod cover removed. It does show a large radiator in the left sidepod, with basin steel pipe work exiting it. They are more steeply raised, but have a low profile thanks to the positioning when mounted on the cars floor. This does help the cars cooling requirements as the sidepod can be as small as the radiators are. This helps the car aerodynamically, creating a clean flow to the rear of the car.
On the Renault it’s clear to see the tiny sidepods and the huge airbox. The reason behind this is that Renault powered cars will be using the role hoop inlet more than others, as more air will be fed in via this inlet and to the water and oil coolers mounted on the far side of the engine. This then leaves the sidepod radiators to cooler the power unit and turbo, and nothing else, therefore creating a smooth profile at the rear.
This will help the rear aerodynamics on Renault powered cars, as less bulk from the sidepods helps to aid flow, and therefore downforce at the rear. Which is why Red Bull ran a “camo” livery on the RB11, so other teams couldn’t see the profile of the sidepods.
Ferrari were the busiest team over the winter, with a much improved PU from 2014, over 25% has been gained. Likewise to Renault and Mercedes, they seem to have a collector that merges into one, and then to the rear turbo. They also have to feeders from the roll hoop, which look like they feed the high-mounted oil and low mounted water coolers in the car.
This then allows the sidepods to cooler the engine internals and turbo. This again helps the rear aerodynamics and stability.
Honda are back in Formula 1 and with the loudest engine at present. Their new V6 engine is also very advanced. What McLaren Honda have done is create a fantastically aerodynamic car at the rear, which they call the “size zero”. The engineering behind this is a great way to get around this is very impressive.
What they have done is mounted a radiator on top of the engine, this is for cooling the ERS (energy recovery system). This then frees more space in the left and right sidepod, which houses one intercooler in the right hand side, then engine and electrical internals in the left one.
The airbox on the McLaren is large and is split in half, feeding coolers. The engine cover is normally thinned to make a slim profile but McLaren’s is rounded all the way down, due to the side spear radiator up top.
Honda have gone for a split-turbo across the ICE (internal combustion engine) like Mercedes have done, dividing the compressor and exhaust driven sides of the turbine with the MGU-H along a long shaft, similar approach to the 2014 Mercedes.
Like the Mercedes PU a duct feeds a water-jacketed intercooler which is situated behind the rear bulkhead of the chassis, through a pair of plenums and into the combustion chamber of the V6.
The radiator mounted above the PU is used to cool the water for the jacket cooling concept. The problem is that having a water system at that height above the ground can’t be good for centre of gravity. With lots a weight high up, and sloshing around, it can’t be good for balance, but McLaren Honda have seen through this, and still have it implemented.
For all engine creators, it early days, so not everything is optimized, as we saw Honda have several MGU-K seals going, and Ferrari having some teething ICE troubles. As the season progresses the more we will hear the fantastically sounding yet reliable V6 power plants. But unfortunately still looks clear that the factory Mercedes cars are going to be dominant, it’s a question on which team can close the engine battle the most over 2015, and stop all the glory going back to Brackly.
