LOTUS INDYCAR ENGINE
Despite the 18-22psi boost range, Judd has noticed engine wear in 700bhp road course configuration, and admitted there is more work to do
on our engine at the start of this season, let’s put it like that.’ In the interest of cost savings, IndyCar made an effort to keep exotic metals out of the engine, which Judd took no issue with. ‘For cranks and pistons, as I tell people, if you go and dig a World War II fighter out of the ground, you could probably make them of the same material. Nothing has changed. Rolls Royce made all those things years ago. The basic crank material is what in the UK used to be called N40. It’s all still pretty much the same thing. As far as I know, that is what’s generally used. You can pay different prices for various degrees of purity and keep the inclusion sizes down, but it’s basically a nitrided steel. Nitride for 80 hours and that’s the business. Pistons are mostly aluminium 2618, which is just an international version of what used to be called RR58, Rolls Royce 58. I can’t say everybody uses that, but it’s pretty common.’
LEADING LIGHT Of the off-track races taking place between IndyCar’s manufacturers, EDL emerged as
the leader in lightness – a fitting category to win with its Lotus affiliation in mind – as the DC was rumoured to be as much as 20kg below the initial 100kg minimum the manufacturers agreed to. But when one of them came in well above the 100kg target, the series moved the minimum to 112.5kg, requiring heavy ballasting of the DC to meet the new limit.
In the first two months of
track testing, EDL tried as many different exhaust configurations as made sense with the homologation deadline and the list of development priorities in mind. ‘We’ve gone through a couple of iterations but, once you decide where the turbos are going, you pretty much decide on your headers. Again, it responds to length the same as a normally
“It was actually our intention to design the main structural parts in a conservative manner”
‘One has come in really heavy,’ Judd said with a laugh. ‘We did not particularly set out to make it light. We said, let’s do what we normally do and make sure that the bits that need to be strong are stronger than usual. It was actually our intention to design the main structural parts in a conservative manner. We haven’t got enough miles on any engine yet to know whether they really are conservative or not, but we’ll find out pretty soon.’
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www.racecar-engineering.com • May 2012
aspirated engine [but] that trade off between the closeness of the turbo exhaust port, the better the response, may not be the best thing for maximum power.’ Lotus encountered issues
when attempting to run its test engines on high boost in testing, but overcame the problem with its post-homologation powerplants. Despite the relatively low 18-22psi boost range, Judd says the DC’s internals show signs of wear
when the engine has been run in 700bhp road course configuration: ‘We can sense the difference in engines between low and high boost. We can see the difference, and we have some work to do in regard to that. On the face of it, [22.4psi] is not huge pressure. In fact, it’s lower than what we had on the old Champ Car engines years ago. [But] it’s a different engine.’ The final change of note
for Judd and the rest of the manufacturers came with a slight reduction in expected mileage for each engine. The 2000-mile minimum between rebuilds was reduced to 1850 shortly before the first round, which helped ease some of Judd’s concerns slightly. ‘It shouldn’t be scary, and we are working towards it, but we’re not there yet,’ he conceded. With its engines running just
over one second off the fastest times set in pre-season testing at Sebring, the DC showed that Judd’s approach to IndyCar’s new formula is not only sound, but could eventually measure up to the giants at Chevrolet and Honda once the 2012 season hits the home stretch.
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