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Author: Ian Bamsey

Source: Race Engine Technology

Publication Date: 21^st November 2007

Renault’s RS26 engine of 2006 powered the first ever World Championship winning, naturally aspirated 2.4 litre V8 Formula One car. It was modified rather than replaced to create the RS27 engine for 2007, in view of the limited timescale and scope for change imposed by the FIA, which governs Formula One. On September 18 2006 the FIA confirmed that effectively unrestricted engine development would no longer be permitted. In 2007 the 2.4 litre V8 engines would be subject to a 19,000 rpm rev limit and a freeze on specification from that homologated prior to the season.

Significant scope was permitted to change the existing engines from their 2006 specification but the 2007 specification had to be confirmed by the manufacturer to the FIA in writing by December 15, prior to submission of an actual engine for homologation by March 1, thus before the first race of 2007. The upshot was that the RS27 design team at Renault F1’s Viry Chatillon, Paris base led by Axel Plasse had to completely change direction on that day in September.

Under the technical direction of Rob White, Plasse led the team that designed the 2005 World Championship winning, RS25 3.0 litre V10, then turned its attention to 2007 while a parallel team was designing and developing the RS26. Normally the engine for 2007 would have been "95%" new, according to White, whereas in the circumstances, compared to the RS26 the RS27 was only "10%" new. This was the first time since its return to the sport in 2001 that Renault had not made what could be termed a "new" engine for the following season.

Also for 2007 came a change of the Friday to a test day rather than part of the Grand Prix meeting itself, slightly reducing the mileage requirement over the mandatory two race meetings each engine has to cover. There was also the introduction of a single tyre supplier but in effect a consequent reduction in tyre grip was offset by improved aero performance. However engine duty cycle was further affected by the 19,000 rpm limit. Given that this was below the limit to which the RS26 had been designed Renault sought to run the RS27 at or near the new limit for a greater proportion of time, increasing the severity of the duty cycle.

Against this background, I spoke to White at the 2007 Santander British Grand Prix, Silverstone in early July 2007. White has headed Renault F1’s engine technical operations since he joined the team in 2004. This year he has been promoted from Technical Director (Engines) to Deputy Managing Director (Engines). Silverstone was round nine of 17 World Championship events, consequently the precise mid point of the first season of frozen engines.

I commenced by asking White: What is your view on the current Formula One engine rules?

"The priority is the show. We need to look after the show; to improve the show not put it at risk.

"It remains the case that Formula One is a very expensive activity. At the same time it creates a lot of interest and that is one thing that we want in any future version of Formula One. However, we don’t want a ‘techno-fest’, an arms war in which the costs spiral out of control. It is important to us that the cost of participating does not increase and that overall the cost-effectiveness of the sport is improved."

It would seem that this year, the 19,000 rpm rev limit and the engine homologation requirement on top of the previous two-race rule have capped horsepower, I remarked. I believe that the horsepower levels seen here mid season at the British Grand Prix are around the same as at the same event one year ago - and are within a surprisingly narrow band?

"I think that is pretty true".

I think last year the horsepower level across the paddock here at Silverstone was about 755 bhp, plus or minus 10 bhp and I cannot see a lot of difference this year. Some knowledgeable insiders to whom I speak think 740 bhp is about the level; most think that 770 bhp is over the top...

"I am reassured that most think that 770 bhp is over the top!

"Of course, none of us truly know how much the other guy’s engine is making and we only know how much we are making within reasonable limits of precision.

"Last year was the first year of the current 2.4 litre V8s. It was a peculiarity last year that everybody had to produce a brand new engine. Everybody had approximately the same start date for their V8 programme and exactly the same first race date.

"Most people have different philosophies going into a new engine programme. Peoples’ approach to the development of the V8 during last year and beyond meant significant differences early on. The differences between engines tend to be relatively significant early on, then there is normally a period of convergence as people who are in trouble at the beginning catch up. Others who have not been in trouble early on have got onto the development path a little bit sooner and then you get into the way that people see the future, which can lead to divergence as development proceeds.

"One thing that was different last year was that people had different future objectives; different thoughts about how they would operate their engine, how they would manage the race weekend on so on. So towards the end of last year there was convergence due to people learning about the new V8 engines and perhaps not yet a very divergent path so far as on-going development is concerned.

"This year, clearly with the homologation requirement, to have had to declare to the FIA what you were going to do by mid December, and having had imposed upon us a 19,000 rpm rev limit and changes to the race weekend format, then diverging future objectives all get rubbed out. Everybody gets to have the same objectives and inevitably the performance converges. I think the purpose of the homologation requirement was to save money but to do so in a way such that the performance difference between the engines was minimised.

"Of course like all Formula One engineers I have mixed feelings about the new rules. I think we have to acknowledge that the differences in car performance due to engines are probably reduced as a result of these rules."

What reliability issues did you face last year with the RS26?

"We had one engine that failed rather spectacularly in the race, which we would rather had not happened!

"That was a problem in the bottom end of the engine. It was something that as we pushed to improve performance, we had a way of using the engine that made the engine break, which slipped through the net of the validation procedure."

So (following that failure of Alonso’s engine in the 2006 Italian Grand Prix) you had to redesign a component?

"Yes".

Aside from that?

"Life is never completely tranquil. At the beginning we had a lot of little things that we were worried about. We made good progress during the year. Inevitably as you make progress, you balance performance progress with reliability progress, the idea being to have zero defects while making performance gains.

"I would say we didn’t have anything out of the ordinary as a consequence of 2006 being the first year of the V8s. We brought everything we had learned on previous engine projects to this one and on the whole it was pretty good."

Development Of The RS27

At Silverstone I asked White: Last year, how much progress did you make in the performance of the RS26 and what peak power speed did you reach by the end of the year?

"At the end of the year we were running near to 20,000 rpm and I think our engine performance was well noted in the pitlane throughout the season."

It sounds as if, along with other engine manufacturers you were over 19,000 rpm in terms of peak power speed at least by the end of last year, so the 19,000 rpm cap for this year must have hit you in terms of peak power?

"I think the thing that was odd about the rules for 2007 was that there was the principle of freezing the spec to prevent development activity and then there was a rev limit imposed that was not consistent with the operating conditions of most of the engines at the time, which in turn created the legitimate demand for what became known as the ‘retuning list’...

"We had the scope on certain limited changes to re-optimise the engine to 19,000 rpm. We were able to modify the engine we had to take account of the reduced rev limit but it was a quirky thing to have to do, to have to change the rev limit from the one we were running at."

In fact, in practice you had a lot of scope to change the engine, provided you had your papers detailing the 2007 design into the FIA by December 15?

"Yes."

How much change did you actually make to your 2006 RS26 engine?

"The list of things you could change is widely known and those are the things you need to change to readapt to a different engine speed. Those are the things we changed. Like everyone else we tried to organise our time to make best use of the scope between the mid September decision date and the mid December paper homologation and the beginning of March physical homologation. We had to get our retuning activity figured out and acted upon."

It does appear that people managed to retain power levels, at least compared to 2006 mid season in spite of the rev cut, through that retuning work.

"The way we attacked it, we looked at the planned development activity, we eliminated the things that were not permitted in the new rules, eliminated the things connected with making more revs and then we re-jigged the list a little bit to get the best performance we knew how in the time available given the scope provided by the permitted modifications.

"The use of a homologated, 19,000 rpm engine was actually agreed upon on September 18 2006 and by that stage we were already well advanced with the development of our engine for 2007, design of which had begun in late 2005. In the circumstances we were pleased to recover most of the performance loss associated with a substantial reduction in engine speed."

Formula One engine development has seen over the years the revs keep on increasing and with that power output. However, it is almost certain that if the revs had been capped at any point, more power would have been found through optimisation at that particular set level.

"I disagree that all the performance comes from revs. Of course, revs mean air and air means opportunity to make power but I disagree that power only came from revs."

No, what I am saying is that if the FIA had, for example forced everyone to stop at 15,000 rpm, without otherwise freezing development, over time more performance would have been found at that level than was ever found back at that time, when in reality the focus was on ever higher revs...

"There would have been some more performance found at 15,000 rpm than was seen at the time, for sure."

So now, if there wasn’t an engine development freeze as well as the 19,000 rpm limit, power outputs would continue to increase, albeit not at the rate to which we have become accustomed...

"Yes, but there is a law of diminishing returns..."

And in any case we do have the freeze - on the face of it to be maintained until brand new engines come along, provisionally in 2011. Are you anticipating any further scope for development in the meantime?

"There is nothing explicitly stated."

So, as far as you know, the engines will be frozen in their current specification until the end of 2010?

"There is nothing anywhere in the rules that says anything different to that."

And given that the six current engines appear to be grouped closely in performance, there is not the pressure for change that there might otherwise have been!

"Outside of the engine, we are anticipating Kinetic Energy Recovery Systems in 2009 and we are expecting a change to the fuel in 2008, when there will also be a standard ecu."

What will be the impact of the standard ecu?

"The physical changes will be modest as the rules are not substantially different. Minor modifications will be needed to adapt the engine sensors to the standard ecu but the major workload comes from learning the new control systems and how to calibrate the engine."

What impact will the fuel change have?

"From 2008 a minimum of 5.75% of oxygenates has by obligation to be derived from biological sources. That will only mean a remapping. It is interesting work in which we are cooperating with our supplier, Elf. Like every fuel evolution, we will be seeking to make the best possible car performance choice from the opportunity it presents. But it is not expected to be a major thing."

The KERS side of things, with the anticipated 2009 systems effectively an extension of the transmission is a chassis rather than an engine project so far as Renault is concerned?

"Yes, the way the rules are written, it is more chassis side than engine side. Of course, at the end of the day we design and build the racing car together as a team."

With this year’s 19,000 rpm RS27 engine, were you able to make improvement to the shape of the power curve or driveability?

"The task is to make the racing car go as quickly as possible. The goal is always the best overall car performance. Therefore the performance indicators that we use try to take that into account."

You can still develop the car outside of the seals - what sort of work are you doing in this respect?

"Inevitably we had to prioritise our work to ensure the stuff we couldn’t touch after homologation was finished in time. But in the accessories - the pumps, the alternator, the exhaust, the inlet system - there is really only modest potential to improve performance. We must leave no stone unturned in our effort to harvest performance from those areas but we also need to be realistic - the potential is very limited."

The intake and exhaust are still free. Can you still change the firing order?

"I would say ‘no, you cannot’. The engine has to be identical to the engine we homologated, so we couldn’t change the firing order down one bank, as that would imply different camshafts. Could you change the phasing of the banks to one another? I would say ‘no’. That is not written down anywhere and if anyone was unclear about it they should ask Charlie (Whiting of the FIA) for a clarification..."

So there are now a lot less people working on development of the Renault engine than there were a year ago?

"The object of the new rules was to save money and to bring the performance of the engines closer together. That has led to us being able to do less development, so we need less development engines..."

So you have had to let staff go or have they been reassigned?

"Clearly one of the big things concerning our situation is that we are located close to the parent company, so we were able to move people from the racing programme to benefit other programmes from the experience of racing they have acquired over the years.

"However, this is the first year we have supplied a second team. Supplying engines to the Red Bull team has compensated for the reduction in development activity."

Notes:

Ian Bamsey interviewed Rob White, Deputy Managing Director (Engines) for the ING Renault F1 team at the 2007 Santander British Grand Prix, Silverstone, July 4-6.

In 2007 the ING Renault team failed to match the competitiveness level of its previous two World Championship winning seasons. In a season when engines were close on performance across the board this was clearly an overall car performance issue rather than any lack on the part of the RS27 V8.

In September 2007, as the season drew towards its conclusion Rob White was asked: Has the performance of the RS27 lived up to your expectations?

"We were satisfied with the RS27 when we first tested it during the winter. We’ve tried to develop it in the areas still allowed by the regulations. So we have done a lot of work with Elf on fuel and lubricants. We’ve also revised some of the accessories outside of the frozen parameter."

Have you made big gains?

"We wouldn’t have made the modifications if they hadn’t been beneficial! On the other hand, the gains have been much smaller than when development was unrestricted."

Added to the database on 21^st November 2007