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I'm Matthew Somerfield, a freelance journalist focused on the technical elements of Formula One. It has been a pleasure to provide content via this site for the last 5 years, which has led me to several paid freelancing jobs along the way. I'm currently plying my trade with and working alongside the legend that is Giorgio Piola.

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19 Mar 2015

2014 provided the backdrop for the most technologically advanced 'powerunit' ever to race in Formula One, it might be suggested that 2015 should be a walk in the park then.  That assumption would be incorrect though and rather than be locked into frozen development/homologation rules like the previous V8 era, the V6T's have much more scope in terms of development.  Firstly we must realise that both Ferrari and Red Bull (Renault) are responsible for a shift in the original homologation framework, as they clearly languished behind Mercedes in 2014 and decided to move the lines in the sand to try and close the deficit.  The original intention was that 2015's PU's would be homologated after pre-season testing just as they had been in 2014, with the manufacturers able to spend up to 32 'tokens' improving their powerunit from the 2014 iteration.  Ferrari and Renault argued as there was no date in the regulations pertaining to a 2015 homologation that they should be allowed to spend these tokens thoughout the season too.  With the date missing the FIA had no alternative but to agree, so now we find ourselves back in a situation where in-season development is acceptable (within the scope of the token system).

"I don't understand what is meant by a token system"

A powerunit is made up of 100's of components, but in order to simplify the homologation process a matrix was drawn up, which combined this to 42 more manageable components that act together to perform each function.  These 42 components were then 'weighted' from 1-3 based on their importance within the powerunits infrastructure, giving a total of 66 weightable items.  5 of these were immediately frozen upon homologation:

Upper/lower crankcase - Cylinder bore spacing, deck height, bank stagger - 2
Crankshaft - Crank throw, main bearing journal diameter, rod bearing journal - 2
Air valve system - Including compressor, air pressure regulation devices - 1

Of the remaining 61 weightable items the manufacturers were allowed to change up to 32 of these (48%) for 2015 (now more formally known as tokens).  As Ferrari and Renault argued that there was no set homologation date in the 2015 regulations these changes were allowed to be made throughout the course of the whole 2015 season.  This would allow manufacturers the opportunity to continue R&D and affect changes that would otherwise have to wait until 2016.  Honda entered the fray with a new powerunit for 2015 and so it was agreed the intended homologation date would be retained for them, with them allocated an average (rounded down) of any 'tokens' that the other manufacturers hadn't spent when the season started in Melbourne.

The FIA issued the list of tokens spent by the teams in Melbourne, clarifying Honda's position too:

Ferrari 22 of 32 tokens
Mercedes 25 of 32 tokens
Renault 20 of 32 tokens

As a new power unit manufacturer for the 2015 season, Honda has been granted an allowance of nine tokens for in-season development. This is based on the average of those available to the 2014 power unit manufacturers. The following residuals are therefore available for use in-season:

Ferrari 10 tokens
Honda 9 tokens
Mercedes 7 tokens
Renault 12 tokens

I think it is also important at this juncture to talk about variable length intake trumpets (VLIT) which was prohibited for 2014 but returns to the sport in 2014:

5.9.3 Variable length intake trumpets are forbidden in 2014 only.

I raise this point here as many questioned why Honda couldn't be given the full 'token' allocation of 32, to be spent throughout 2015.  Ferrari, Mercedes and Renault all competed in 2014 with standard tuned inlet lengths, meaning they would have to spend in the order of at least 3 tokens (inlet system) to change to VLIT's.  However, in reality if they adopted them they'd need to spend far more tokens on other components in order to maximise/extract performance.  When we consider VLIT inline with turbocharging conventional wisdom would suggest their wouldn't be huge gains. However, we must remember that the current regulations put a huge emphasis on efficiency, and whilst the MGU-H infills the blanks, keeping the turbo spooled, the way in which air is fed around the system may still be improved further by the use of VLIT's, if co-ordinated correctly.

Honda have re-entered the sport with the opportunity to use VLIT's as part of their base design, as such they had the opportunity to integrate it into their concept, rather than having to retrospectively change parts, using up tokens in the process.  This alone is evidence enough for me to suggest that the FIA made the right decision in allowing Honda only an average of tokens to spend throughout the season.

Let's now take some time to evaluate some of the visual changes that have been made for 2015.


(W05 left, W06 right)

One of the standout features of the PU106a was Mercedes HPP's adoption of a log style manifold (yellow), this has been changed for 2015 with an enlarged, tuned version taking its place (1 token).  Heat protection is still being used and prevents us from seeing the inner layout at this stage of the season.  You'll note, that albeit a small change, the team have opted to make amendments to their radiators (highlighted in blue).
It's clear to see that Mercedes HPP have also made changes to their inlet (Green), undoubtedly taking the opportunity to run VLIT's (3 tokens).
Incidentally Mercedes have retained their air-liquid-air cooling solution like the W06's predecessor, although I'm sure it has seen some refinement (Not highlighted in the images as it's sandwiched between the fuel cell and front face of the engine).

As we can see below the other Mercedes powered cars are running standard air-air coolers.  In the case of Williams, one sidepod is responsible for charge(inter)cooling (red), whilst the other houses a radiator (as an aside the green cooler shown is an oil cooler)
Above: Williams FW37 (image: left, right AMuS)
Above: Force India VJM08 (image early indications point at the team running the same configuration as in 2014 and as Williams above.
Above: Lotus E23 (image Race Engine Technology / Lawrence Butcher) early indications point at the team running the same configuration as Williams above.

Exposed images of the E23 and VJM08 are still thin on the ground at the moment but I'll add them as they become available.


Having parted ways with their long term partner and previous 'works' team Renault now only supply the two Red Bull teams.  This was a conscious decision by both Renault and Red Bull as they were eager to reinforce their relationship, with the pair making a concerted effort to align their development paths.  2014 was not what either party had hoped for with the powerunit demonstrably down on power when compared with Mercedes.  In an effort to turn around their fortunes ahead of the 2015 season, Renault restructured their workforce at Viry, re-signing Cyril Abiteboul from Caterham.  No sooner had Lotus signed off on its Mercedes deal, Red Bull started hiring their own staff to work alongside those at Viry in an attempt to create a more unified front.  Toward the end of the 2014 campaign it became clear that Red Bull had also approached Mario Illien of Ilmor Engineering to assess the problems that they and Renault faced.  Mercedes HPP is the descendant of Ilmor Engineering and so it is obvious that they have the capability to build race winning F1 engines, we await to see just how much of a hand Mario and his team have in a Renault resurgance.  Having had another anonymous pre-season test Red Bull were disenchanted with Renault heading to Australia.  However, the fact that 3 of their drivers (Ricciardo, Kvyat and Verstappen) have already lost at least an I.C.E from their allocation, led to a scathing attack from Christian Horner and Helmut Marko.  Driveability was also earmarked as being a problematic area for the Renault powered teams, compromising corner entry, apex speed and VMax.

Remi Taffin - "The biggest issue has been the driveability, which has made it hard for all the drivers to feel comfortable in the cars. It affects pedal application and confidence in the corners so has cost lap time and points this weekend. It’s related to the maps, or the way the Power Unit is configured, so while it’s definitely not an easy fix, it does not require a complete redesign."

Cyril Abiteboul - "The weekend has been very frustrating. We know that we made genuine progress over the winter but we could not show it here and in fact we would even seem to have moved backwards. Given the pace at which we conducted our development programme towards the last few weeks of the winter, there may not be lots to change to be able to access these improvements. Now, we need to react, but not overreact, and get back to some basic common sense that has always driven our approach in all these years of F1 engine development."

Renault clearly understand the issues at hand, and as Cyril points out the powerunit has seen significant change before the first event in Australia.  As I understand it, the specification used in Australia actually differed from the one used in pre-season, in order to maximise their token spend.  The problem with doing this is the lack of data, with dyno work and simulations providing the backdrop for the maps being used during the weekend.  As we know there is difference between the way a driver applies the controls than how it is simulated by software or on the dyno.  This is important when we consider how may components have to work in unison with these powerunits in order to extract performance.  Red Bull have already stated that they'll utilise the AVL facility, as Toro Rosso did last season in order to understand these issues.  AVL's chassis dynamometer will offer a set of results with a more tangible connection to those seen on the track, than the standard dynamometer's that Renault use at Viry.
Above: RB10 (left, AMuS) vs RB11 (right, AMuS)

In terms of architecture we can see that Red Bull have made significant changes to their cooling package, accommodating the change in position and dimensions of the exhaust (yellow, 1 token).  As we can see the radiators (blue) and air-air coolers have been stood up more vertically, leaving more space in behind.
As we can see in the image above it's difficult to ascertain whether Renault have made the switch to VLIT's, as their inlet was large in the first place (RB10 on the left AMuS) and (RB11 on the right, Race Technology / Lawrence Butcher).  However, Rob White did suggest they would make the switch in a pre-season press release (3 tokens).
Above: AMuS

Renault have also made changes to their turbocharger, with Rob keen to highlight a more efficient compressor will be in use.  The turbine appeared to have two inlets on the 2014 variant however it seems that for 2015 this has been reduced to a single inlet that will be shared by both exhaust banks (5 tokens).

Above: STR10 (left, RB11 (right, AMuS)

As we can see both Red Bull and Toro Rosso are running very similar setups in 2015, the differences being the large oil cooler (green) mounted across the car, which also forces Toro Rosso to mount their compressor outlet to intercooler boost pipe (purple) differently.  Red Bull's higher mounting of this pipe keeps it further from the exhaust, reducing the chance of heat soak.


Ferrari seemingly made several errors associated with the turbo and its ancillaries in 2014.  They opted for a complex wastegate solution and suffered from what seemed like an incorrect sizing of the turbocharger itself (as noted here last year: These mistakes often led to the team being underpowered and heavily reliant on the ERS to infill the gaps, however, when that was depleted it left them exposed.  This has an impact on fuel efficiency too, meaning they were always fighting one ailment or another.
Above: Marussia MR03 (left, Racecar Engineering) Sauber C34 (right Race Engine Technology / Lawrence Butcher)

As exposed shots of the Ferrari are always thin on the ground early in the season, I've opted to use the Sauber as a comparison to last years Marussia.  As we can see Ferrari have made changes to their exhaust layout, shortening the primaries, entwining them into a more compact design (1 token).  This has been achieved by a change in their turbo and wastegate design with the turbine inlet seemingly moved to the lowest position, rather than the highest (5 tokens).  I for one could never understand their logic when it came to last years exhaust manifold, as the design seemed more akin to a naturally aspirated engine.  Furthermore, I still find it puzzling that they have opted to leave the manifold exposed, especially when Marrusia reported an uplift in performance when they wrapped theirs last year.  There doesn't appear to be a change in philosophy when it comes to their inlet and so I'd suggest they have retained their chargecooler in the V configuration (see below) and not moved to VLIT's (we shall have to see if this is the case later in the season).

Much has been said since Melbourne of the increase in performance seen by both Ferrari and Sauber when compared with 2014.  I'd propose these wholesale gains are only proportional to the rectification of last seasons inefficiencies though.  Both teams will openly admit that they not only suffered from problems with their powerunits but also intrinsic aerodynamic and mechanical mistakes that they have also rectified for 2015.  Whilst Ferrari were able to marginalise the PU's inefficiencies through more aggressive maps it didn't leave them strategically hamstrung, something they should be better equipped for with the changes made to the PU this season.  Driveability will most certainly have been improved, with the new architectural approach improving turbo performance and reducing the ERS need to infill the power gaps, allowing better power distribution throughout.

Leftover tokens?

You'll note that the token spend mentioned for each manufacturer so far is somewhat adrift of their overall spend, that's because there isn't a published list to work from and there are certain areas all of the manufacturers will have made improvements.  These range from changes to the fuel injection system (2 tokens) to the Energy Store, which will almost certainly see changes made to improve its efficiency (Cells - 2 tokens and BMS (Battery Management System) - 2 tokens).  Furthermore the following areas are frozen from development after 2015 and as such will likely have seen further improvements should the manufacturers have made mistakes initially:

Upper/lower crankcase - All dimensions including Cylinder bore position relative to legality volume, water core. - 3 tokens
Valve drive - Camshafts - From camshaft lobe to gear train. Geometry except lift profile. Includes
damping systems linked to camshaft. Exhaust and Inlet - 1 token
Valve drive - Gear train down to crankshaft gear included. Position and Geometry. Includes dampers - 2 tokens
Covers - Covers closing the areas in contact with engine oil Cam covers, Cam-timing covers - 1 token
Ancillaries drive - From ancillary to power source. Includes position of the ancillaries as far as drive is concerned - 3 tokens


As Honda enter the fray in 2015 their baseline starts here, meaning I have nothing to compare them against.  Furthermore the secretive nature of F1 allied to their low running through pre-season testing has meant exposed images of the Honda powerunit and McLaren architecture are slim.  I will add images as and when they become available but thus far we only have the following:

Above: AMuS

In the upper image I've highlighted the saddle cooler in yellow, which is believed to be tasked with keeping elements of the ERS cooled.  I believe the left hand sidepod is home for a regular radiator, whilst the right hand one is occupied by an air-air intercooler, which cools the Mercedes-esque split turbo configuration (ie compressor at the front and turbine at the rear with the MGU-H running through the I.C.E's V).  This is contrary to what Giorgio Piola has suggested on but what I believe to be the true configuration.

[EDIT 25/03/15 12:30]
Above: AMuS have taken this image of the MP4-30 during the build up at the Malaysian GP, it appears to show the use of an intercooler in the right hand sidepod as I've already suggested. [/EDIT]


Renault and Red Bulls poor performance in Australia had Christian Horner grabbing at straws already, suggesting that this year will be a borefest as both the Mercedes drivers duke it out for the title and the rest scrabble for the scraps.  In reality he's not wrong, Mercedes are clearly the strongest team and by some margin, but as he perpetuated a line about equalising the engines I couldn't help thinking isn't this just a bit of history repeating? The last request by Red Bull to equalise engine performance was in 2010 (Autosport - 2010) when Horner bemoaned a roughly 50bhp defecit, whilst he now claims that their Renault PU is around 100bhp in the hole when compared to Mercedes. 

There are several angles to the argument, first of which is that Mercedes HPP provide 3 other teams (Force India, Lotus and Williams), with Williams the only ones thus far to have challenged Mercedes and even then not on a regular basis.  This suggests that the powerunit is not the only story but the way it is integrated and operated being a key factor in Mercedes dominance.  We must also realise that the Annual Powerunit Homologation was introduced so that an advantage wasn't "baked in", with improvements made by the ailing manufacturers year on year, as the number of changes that could be made were reduced.  Red Bull and Ferrari have already taken a chunk out of this, buying time for R&D and allowing in-season development.  I guess they (Renault) wouldn't have had 12 tokens spare at the start of the season if this loophole hadn't been found.

The problem for Red Bull is that Mercedes HPP have continued to refine their product whilst Renault are still working on recovering the deficit, leading to chances being taken by Red Bull in order to extract additional performance.  Although Red Bull classify themselves as Renualt's 'works' team there is still an air of hesitancy about the relationship, as if one doesn't fully trust the other.  The biggest issue with this is that decisions about the architecture of the PU can have a large bearing on the chassis design and/or development can be sent in certain directions.  An example of this would be EBD/Off throttle blowing which was Renault developed, through map settings and passed down the chain to Red Bull.  This required the "baked in" advantage Renault powered cars had, as Mercedes and Ferrari never fully exploited it to their level. 

I struggle to see how equalisation would work unless Ferrari, Honda and Red Bull were given carte blanche by the FIA to improve their PU's whilst Mercedes specification was frozen.  As already discussed though this doesn't only have a bearing on the 'works' teams but also the teams that Mercedes HPP supply.

In any case I find the call for equalisation to be inequitable given the homologation process has already seen the goal posts moved to favour Renault and Ferrari.  The consequence of the redefined homologation/token process also brings up some quandaries for the manufacturers themselves.  As previously they could only have one specification of powerunit available:

Excerpt from the Sporting Regulations (Appendix 4)
2. A manufacturer may homologate no more than one specification of power unit.

The fact that the homologation period has been broken by the in-season token spend means this can no longer apply as each driver is now on his own schedule, based around the 4 PU's per season rule. To understand this quandry let's take the Mercedes HPP as an example.  If a driver were to work to the schedule of 20 races without any failures you would use each PU for 5 racesThe problem lies in the fact that you will get failures, it's inevitable, throw in the fact that the manufacturer can also introduce updates through the token system and you suddenly end up with drivers with PU's all in different states of tune.

So let's say bad luck struck Lewis in China (3rd round) and he destroyed his I.C.E, Turbo and MGU-H but continued to use the CE (control electronics) and MGU-K from the first allocation.  You might rightly point out that this happened throughout 2014, but what if Mercedes HPP were targeting an update to their MGU-H for Monaco, by rights this would be the right time for a driver to take a new unit.  However, as Lewis has already lost of his allocation, to take the new updated unit means extending the lifespan of his remaining MGU-H allocation or bearing the pain of using the older specification again at some point later in the season.

The plot thickens when you think about supply from the manufacturer to other teams too, let's use the same example; Mercedes HPP are preparing an MGU-H upgrade (token spend) for Monaco, however this new unit doesn't fall inline with what Williams wants, they can choose to continue to use the older specification.  It doesn't work the other way though, a manufacturer cannot hold back an upgrade from those they supply to benefit their works team.  The cynic in me though suggests that a development path could be taken by the manufacturer/works team that they know will suit their own design cycle and scupper the customer team.  You see what you have done Red Bull/Renault and Ferrari? You've made things even more complicated!....

In response to Christian Horner's equalisation and quit threats in Australia I'd suggest some perspective, yes it's problematic in terms of losing PU's, yes you aren't where you believed you'd be, yes you have driveability issues.  However, most of these issues can be rectified quite quickly and in reality Red Bull are still at least in Williams and Ferrari's ball park once driveability is restored.  Lest we forget these powerunits are complex, with each sub-system reliant on the next to create performance. Lean on one too much and it'll compromise another just as 'turning down' one will also be to the detriment of the other, it needs to be a harmonious relationship just as a manufacturers should be with a teams.


  1. Excellent article! Made me realize that it will get so complicated once they start to change parts!

  2. Well written and a joy to read. The complications are mind boggling!

  3. Thank you for this great article

  4. These "powerplants" are gonna destroy F1. Just try to explain the "powerplants" to someone unfamiliar with F1, but familiar to conventional motorsports. And this token concept makes it even more of a PIA to understand.

    The typical motorsports fan understands conventional engines pretty well .. even my wife understands them, and trust me, she's no motorsports fan. (She does think Alonso is cute though)

    All this "powerplant" stuff? It's complicated, and your typical motorsports fan doesn't care to take the time to understand it, and to what end? And the runaway dominance of Mercedes isn't helping, though it's not directly related to just the powerplant. These are the bulk of F1 fans, and they don't care about powerplants, they care about the racing. Plus it's just a big money eater. We just witnessed our first F1 race with only 16 cars or so in it since the 60's! And many of those failed to finish.

    You will NEVER find a fan overhanging a snow fence saying "great move on spending those tokens Honda!" .. it just alienates the normal motorsports fan.

    We're gonna look back on this and see it as the back breaking event of F1. Certainly I don't care all that much these days as well, and I've followed F1 since the 80's. Bernie is right .. something has to happen soon or F1 will have a shrinking market for a number of years. It might even return F1 to a Europe only series again, due to nobody giving a crap anymore.

    I love your blog .. I HATE this "green" powerplants in F1. Let's bring back real racing.

    1. Although I agree with you on some of your points I think we must remember that Formula One has always been the pinnacle in terms of engineering owing to the teams trying to work around regulations. It would be interesting to see the type of car that might be designed now if we used say the 1988 regulations that had only 10 pages...

      I appreciate that not everyone wants to understand the technical nuances of the sport BUT I think if you watch F1 regularly you actually need to have a basic understanding. The problem arises from poor technical coverage from the mainstream media and broadcasters. BBC tried and failed with Gary Anderson because they didn't have the airtime to do it right and cover all the political guff that follows F1 around. Sky try to do it with Ted Kravitz but it loses all credibility to me when he uses a banana to explain the nose regs etc.. Sky have the perfect platform in terms of a dedicated channel but seem reluctant to produce content for it.
      That leaves you with people like me and Craig (Scarbs) and in fairness we only have very limited budgets (unless people buy our work) and limited time.

      Maybe one day I can make enough money to support a studio setting, cameras etc and do a proper Tech show each GP, until then you've got my blog.

    2. Although I agree with you on some of your points I think we must remember that Formula One has always been the pinnacle in terms of engineering owing to the teams trying to work around regulations. It would be interesting to see the type of car that might be designed now if we used say the 1988 regulations that had only 10 pages...

      I appreciate that not everyone wants to understand the technical nuances of the sport BUT I think if you watch F1 regularly you actually need to have a basic understanding. The problem arises from poor technical coverage from the mainstream media and broadcasters. BBC tried and failed with Gary Anderson because they didn't have the airtime to do it right and cover all the political guff that follows F1 around. Sky try to do it with Ted Kravitz but it loses all credibility to me when he uses a banana to explain the nose regs etc.. Sky have the perfect platform in terms of a dedicated channel but seem reluctant to produce content for it.
      That leaves you with people like me and Craig (Scarbs) and in fairness we only have very limited budgets (unless people buy our work) and limited time.

      Maybe one day I can make enough money to support a studio setting, cameras etc and do a proper Tech show each GP, until then you've got my blog.

  5. I'm glad that I waited until now to read this in one go - continuity of thought. Great seeing the evolution from 2014. Lots of changes with some unexpected results in Melborne. Bring it on! However, I'm disappointed at there being no race in Germany.

    1. Yea I imagine trying to dissect it into smaller reading fragments could be a problem and that's why I wrote it that way too. I'm disappointed about the German GP too, however I must say it's never a classic so will we really miss it?...

    2. Yea I imagine trying to dissect it into smaller reading fragments could be a problem and that's why I wrote it that way too. I'm disappointed about the German GP too, however I must say it's never a classic so will we really miss it?...

  6. Great work, especially with the pictures. I am interested how the exhaust manifold from Renault reach their Turbine. For me is this in-season development not complicated, you just have to count each component for each driver. On some point of the season drivers of one manufacturer have different engines, but this will be a result of a malfunction, or chosen by themself.

  7. Such joy to read. Awesome article. Not many people have patience for these kind of things, but this is by far the most interesting thing you can read about F1!

    Thank you for making these!

  8. Excellent article, for me, a regular F1 fan this explain a lot of things that most of the people can not see. It clearly show the inside problems motorists are confronting. The enginnering race!

  9. I am quite dissapointed to read that F1 fans have no idea about these tokens since... there's a whole section in the official regulations. So either the F1 fans have no idea what they are looking at or they don't care about regulations which means... why the hell are you even watching the F1 races people?

    From my point of view, when I watch a sport (any), I 1st go and read about it, to understand what I am watching at. I read the rules, even at the basic level just to get a basic understanding of how a sport works, but seeing that most of the people that follow this site, are interested only in news about McLaren and mostly just those about McLaren having a nice advantage, while the news about them having problems... hell who wants to read about it right?

    In the F1 technical regulations, on the official site, there's a lot of information to read, including a lot about the new powerplants which from my point of view are quite interesting for an engineer. But... the fan has a duty to read about the regulations, hell it's about understanding how a sport works... why bother watching a race if one doesn't even understand the regulations.

    To be honest, the article is nice to read, I knew everything presented since like 2013, when the regulations were presented but seeing how many fans... are ignorant about the rules and regulations... I would have never expected that. It's quite dissapointing to find it out...

  10. Today i discovered your website. This was the first article i read.

    Congratulations for your excellent work. Just wanted you to know that you earned yourself a new regular reader.

  11. I'm really amazed by the fact how interestingly you explain all these details. And even if english is not my mother language I'll do my best to understand all content. Great job Matt!

  12. Following this average value of manufacturer tokens allowed for Honda to change, shouldn't that be 10 tokens instead of 9, since arithmetic mean is 9.6666...?

  13. Hi Mike,
    I've only recently found your site, and am enjoying stretching my mind by working through some of the articles. This one on Tokens is fantastic, it takes a bit of work and concentration to get through, but certainly unpacks alot of the considerations and complications of packaging and improving these new power units.
    How will the relaxation on component numbers (before penalties) and the proposed revamp of the token system affect things? These seem like more decisions designed to 'normalise' the performance of the p.u's as quickly as possible - it looks like Renault and Honda need all the help they can get.


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