What's really going on at Jerez

Day two of 2014 Formula 1 testing on Wednesday started fairly slowly, with the decision made to capitalise on overnight rain to make this a wet day of running. That meant wetting it further, and not particularly effectively, with a tractor!

But the rain didn't return and the track had completely dried by midday, so the teams were able to get some preliminary running done in the morning, and then things got much more serious in the afternoon.

That gave us the first clear indications of where the field stands at the moment - and it's bad news for some.

RENAULT HITTING TROUBLE

The big story was that the Mercedes-engined cars (average 53 laps per car) seem to be the least problematic, with Ferrari (50 laps per car) not too far behind.

Renault, by contrast, is having difficulties, and only averaged six laps per car. While the problems could be down to the teams, they do appear to be engine-related.

This is not a good situation for Renault. Its three teams completed only 19 laps between them today, with Toro Rosso not running at all.

That 19-lap tally was the same as Renault's for Tuesday, so it appears there could be an issue with getting the engine systems working together. The energy store appears to be at the heart of the problem.

It's now the end of day two, and these sorts of problems shouldn't be happening.

There seem to be some engine mapping difficulties. Listening to the Caterham trackside, it just won't run cleanly, with a lot of misfiring and noise coming through the turbo.

It's difficult to understand why this is happening given the tools, and the transient dynos, that Renault has available.

This doesn't mean it's a crisis for the engine manufacturer and these problems should be fixable. Renault has now said it's a problem in the energy store that can be repaired overnight.

All the batteries are inside the energy storage unit. There could be 50-60 or more batteries all linked together and if the coupling is not of the correct sizing, it will get hot and you lose energy.

It will be like running an electrical fire through a small wire, so you can't get energy into the storage system or they cannot get it out.

That's putting in simple terms a way that the problem could be manifesting itself. Caterham might not have got to the point of charging the batteries so much or dissipating energy so much.

It appears Red Bull has also had some kind of problem with the turbo, although that seems to be unique to its RB10 rather than a problem for all Renault teams.

Even if all of this is fixed quickly, the time lost already is a problem with only 10 days of running remaining pre-Melbourne.

Looking at the other engines, surprisingly there's a lot of variation between the teams running Mercedes power. The Williams sounds the cleanest and the crispest, with a pleasing, deep noise.

The works Mercedes comes next, although you can hear some spluttering out of the corners either because the team is using the throttle differently or not getting as clean a throttle application on exit.

The McLaren is one step beyond this and sounds quite rough. It's not misfiring, but it certainly burbles.

Coming into the test, you would have expected the engine companies to have a major input into the way their V6s were running, but there do seem to be differences between Mercedes, McLaren and Williams. It will be interesting to see how the engine mapping evolves for each team.

VIEW FROM TRACKSIDE

With so many short runs and big gaps between cars going out, it's difficult to build a comprehensive picture of how they're behaving. But there are a few things that stand out.

Although not everyone was out for longer runs at the right time for me to get a clear impression when I was trackside, it was possible to pick up a few traits.

The Williams looks to have a very positive front end. It turns in well and looked excellent through the right/left/right chicane near the end of the lap. This doesn't seem to come at the expense of the rear, which appears stable.

The Mercedes appears a bit lazier and doesn't have the same bite. That's not necessarily a bad thing, but it looks less lively.

The Ferrari looks very similar to how it was in previous years. If anything gives up, it's the rear end that's losing out on corner entry and exit, which is not a good characteristic.

PERFORMANCE

We've not seen anything approaching a serious flat-out performance run so far. But the fastest time of 1m24.165s by Jenson Button is three seconds quicker than Kimi Raikkonen's fastest time on Tuesday.

Based on yesterday's pace, it looked like a 1m23s might end up being the fastest time of the week, but now it looks like it'll be quicker, probably down into the low 1m20s bracket.

It's difficult to draw any conclusions from the lap times given the varied work being done by the teams, not to mention the different tyres used, including Pirelli's Jerez-specific rubber, so it's important not to read too much into that.

WHAT EXACTLY ARE THE TEAMS DOING?

After a stuttering start on the first day of testing, when the eight cars that ran managed a grand total of 93 laps between them, a lot more work was done on track at Jerez on Wednesday, with 331 laps logged.

This is a test unlike any other in F1 history, with every team running completely new cars and brand new 1.6-litre turbocharged V6 powerplants. But as well as troubleshooting, there's a huge amount still to understand about how to run these engines.

Last year, with a well-proven 2.4-litre V8, you'd go out early in testing, perhaps not with maximum revs, but lean fairly heavily on the car at first to get a feel of its vices and get into set-up work relatively quickly.

You'd closely monitor the data to ensure there were no glitches and check basic things like cooling, but that could be done relatively quickly.

The 2014 regulations are completely different because there are so many systems feeding into the power you get at the rear wheels. The 1600cc internal combustion engine itself produces a certain amount of power, then the turbocharger increases that.

In addition, you have the 160bhp electric motor, which is similar to the old KERS package, which can charge the battery.

You also have an electric motor on the back of the turbo which can charge the battery. That battery can be discharged to produce extra power, but the combined total of this power is only accessible through the throttle pedal rather than the push-button system we had with KERS last year.

The turbo engine itself will put out maybe 620-640bhp, with the extra 160bhp from the ERS on top. But there's so much work to be done in using this system.

After missing all of Tuesday, McLaren got down to business on Wednesday © LAT

Even the charging system is complex. When first running, the teams will generally have started out using only the engine and turbo before looking more deeply at the ERS and how you go about harvesting and deploying that power.

This takes a lot of work to master, and there are many pitfalls. If you've ever recharged an AA battery, you'll feel how hot it gets. Here, you're getting that temperature build at every corner as you brake.

The batteries are having energy shoved in and out maybe 10 times a lap, and it will be easy for the temperature to exceed the system's ability to cool - a thermal runaway - so you have to stop or suffer a failure.

During Tuesday's initial running, teams would charge the battery a bit, perhaps to 10 per cent, then use it out of the corner and gradually build that up as running time increased.

The teams will gradually see how the system reacts and ensure it works correctly. Then they'll start being more clever with where they use it, deploying the power in different places.

The boost pressure isn't specifically limited, but it effectively is by the 100kg/hour fuel rate. That will limit the power of the turbo engine. The turbo speed will be altered to manage that using the electric motor mounted at the back.

On top of that, you've only got 100kg of fuel, so it's just not practical to run high boost pressures all the time. You might be looking at an average of around 1.7 bar. It won't be until the last day that people really turn up the wick here.

This test is all about poking around in the dark to accumulate knowledge, not to mention the necessary data to build your simulations for the very complex challenge of mapping the engines properly.

As Adrian Newey underlined to me yesterday, when you get a new hybrid car on the road, it has five years of testing and development behind it. These are brand new cars that will only have a maximum of 12 days of testing, which is a very small timespan for something so complicated. And these are 20 times more complicated than the most complicated road car.

I'd say that any team will be very happy if on Friday it could do 80+ laps with the current best engine and electrical power management in place for Jerez. That would be a major achievement and allow them to go to the Bahrain tests and work on details.

Mercedes managed nearly 100 laps today with Nico Rosberg, probably not with a refined engine map. So despite yesterday's front-wing failure, I'd say it's been a very positive two days for the Silver Arrows.