Work continues behind the scenes at Honda Performance Development's Southern California base as the manufacturer readies its new turbocharged customer P1 engine.
With a fundamental change to the regulations that govern energy consumption and usage within the ACO's top prototype class, major entrants like Audi and Porsche have embarked upon costly P1 projects that involve hybrid-assisted combustion engines and standalone electric motors, yet powertrain options for P1 privateers have been relatively limited.
HPD's IndyCar-based turbocharged V6 is one of the most interesting solutions for non-works programs to consider, and with a hybrid system coming for 2015, the Japanese brand could have one of the few turnkey answers for those who want to challenge the factories. With all of the changes in mind, developing that engine, as HPD technical director Roger Griffiths revealed in a RACER exclusive, has been rather educational for his team.
“As far as the engine goes, there's quite a bit of running on the dyno and we're extremely pleased with the way it's going,” he said. “Straight out of the box it was thereabouts where we thought it would be, where the ACO thought it needed to be, so we thought that was pretty good. Now we can start developing. To be where we're at this early in the program we're actually very pleased with the way it's going. That's off to a really good start.
“But figuring out the fundamental change on giving manufacturers a set limit of fuel flow to work with has, as I'm sure it's been for others, been quite revealing. There's been a lot to digest. When you look at the shape of the power curves and the torque curve, it's very interesting because you run up against the fuel flow restriction. And I just don't know what it's going to be like to drive. It's going to be really interesting. I've never seen a power curve quite like it.”
Without delving too far into the minutia involved with the 2014 P1 engine rules, the ACO has, in basic terms, allowed engine manufacturers an immense degree of freedom. The previous convention of limiting displacement, the number of cylinders, and other design elements ended up painting designers into a fairly tight box. And while some of those restrictions are still in place, design creativity has been greatly increased.
By using a mandated fuel flow rate as most significant performance governor, the ACO has forced HPD and the other manufacturers using gasoline to find a way to make power without revving their engines to familiar limits.
"It's very early days but you run up against this point where you can't get any more fuel in there,” Griffiths explained. “And so you're trying to maintain an air/fuel ratio. Yes, you can keep revving the engine harder and harder and you're making it a little more power but that's kind of offset by the increased friction you get, so the gains become minimal. Right now it's certainly a uniform amount of power over quite a large rev range. Thousands of RPMs.
“You aren't seeing the normal rise in power with RPMs beyond a certain range, essentially. When you look at the shape of the torque curve, from pretty low the torque builds extremely quickly.
Griffiths equated what he's seen on the dyno with the derivation of HPD's 2.2-liter open-wheel mill as having a diesel-like power curve.
“Yes, yes that's almost what you're up against,” he continued. “And we've sat down and we looked at it because we weren't really sure quite how fast we were going to run this engine. And I think now that we've seen the shape of the curve it gives quite a lot of opportunities to... it gives me more opportunities to really, say, 'OK, due to the shape of the curve, I could maybe configure this differently for different tracks.'
"And with the engine being based around the IndyCar one, it was designed to run to 12,000 RPM. We knew that we weren't going to be running it that high regardless, because at that high RPM friction starts to become such a dominating factor with the ACO's efficiency formula. That was working against us. So we knew the operating range of the engine would be a lot lower. I think you could almost take an RPM point anywhere between 8,000 and 10,000 RPMs and say 'OK, where are we going to run?' Obviously, that then helps durability considerably.”
HPD and electronics partner Magneti Marelli have been developing a new, multi-purpose energy recovery system (ERS) for its P1 engine package that could also be used in IndyCar and any of its other motorsports applications.
Initial talks had the P1 ERS unit coming online in 2014, but Griffiths confirmed it has been moved back one year. Preparing the non-hybrid solution and signing a team to use its P1 engine, rather than concentrating on the engine's bells and whistles, has now become the overriding priority.
“Assuming that we find a home for the engine for 2014, our plan is to run it non-hybrid and for 2015 to run it as a hybrid,” said Griffiths. “Right now we're focusing on a lot of the [ERS] mathematical modeling. We've got a lot of work done, we're planning out for testing, we've redesigned the battery packs, we've got solutions there.
“We're looking at a lot of rig testing, modeling how the energy recovery system is going to work. We're focusing a little bit more on running the mechanics of the engine first rather than getting too deep into the hybrid system.”
HPD and Wirth Research have a 2014-spec P1 coupe chassis to house the new engine, and in a recent development, rather than offer a complete solution to customers as it does with the ARX-03b and 03c, examples of the new car will not be built until specific commissions are placed.
“We've looked at it very hard,” Griffiths noted. “And we have quite an advanced design. Whether that ultimately ends up getting built is another matter. Certainly, if it was built it would be a customer program, not a factory program. So we need to find the right partner to work with. If somebody turned up and said, yes, we'd like to move forward, there's a possibility you could see a car in 2014.”
Former ALMS champion David Brabham, who drove a Highcroft Racing-prepared HPD to the P1 title in 2010, has been mentioned as one of a few people interested in putting HPD's new P1 chassis and engine on the WEC grid next year, and Griffiths hopes to see both of its products in action.
“We've had quite substantial conversations with several people including the chap you mentioned,” he acknowledged. “Everybody wants to do it. But wanting to do it and being able to do it are two different things. If you're a team stepping up from running a P2 car or you're a team that may be coming in at it in the new program, it is quite an undertaking. It's not an inexpensive car to purchase and to run. But if you look on the dollars curve and performance lap time, it's a very cost-effective car for what we believe the performance of the car will be.
“Nick [Wirth] has had a design for a couple of years that he's been kicking around and trying to convince us to do. So this car had a lot of thought put into it but we're not at the point we're ready to say we're going to build it. We all would really like to but it has to be done for the right reason.”