IRL INDY CAR ENGINES
by Larry Roberts
May 9, 1997
The Indianapolis 500 has undergone a multitude of changes during its 86 years of existence. It survived two world wars, the Great Depression, several ownerships and a dozen different formulas.
This year the Indy 500 will be undergoing another change. Tony George, owner of the Indianapolis Motor Speedway, elected to take the 500 back to simpler days and restricted the event to simpler cars and engines. In order to implement the changes, he formed a new sanctioning body, the Indy Racing League (IRL), and formulated an entirely new set of technical specifications. The ultra high-tech engines and chassis of the past are still in existence and racing in the CART championship series, but they're not eligible for the 500.
Technically, the most interesting facet of the new Indy car formula is the engine restriction. The engines that can run in any IRL race (and this includes the Indy 500) must be based on a 4.0 liter production car engine and there are many technical restrictions. The engines must be V8s and the cylinder bank spread must be 90 degrees. They must have twin overhead camshaft heads, four valves per cylinder and the cams must be chain-driven. I assume this eliminates the use of high-tech and very expensive gear-drives that are common in CART and Formula One engines.
Turbochargers aren't allowed, the engines can turn no higher than 10,500 RPM and they must burn methanol. The IRL rules committee has guaranteed the participating teams that these engine rules (as well as chassis and tire restrictions) will be in effect until 1998.
The only two engines that have been authorized for this year's Indy 500 race are built by Oldsmobile and Nissan, and both have been listed as producing around 650 horsepower. The Oldsmobile unit is based on its successful Aurora sedan and the company had a big advantage in that it has been developing the race engine for several years. It has been used for a couple of seasons in IMSA prototype sports car racing and most of its changes for the IRL come from the fact that it now must run on alcohol. Olds supplies engine "kits" that consist of a block, sump, cam covers and heads but from that point on, the builder is free to chose his own ancillary parts such as crankshaft, camshafts, valves, fasteners and the hundreds of other parts that make up an engine. All of the development work on the Olds Aurora racing engine has been done in its own in-house technical facility in Warren, Michigan.
Nissan, on the other hand, is fighting time. The unit used is based on the Infiniti Q45 powerplant and Nissan Motorsports was only given the green light on the project last February. Its basic tenets are the same as those for the Olds engine but in looking over the dimensions of the two, it appears that the Nissan has more in common with its production stablemate than the competition. Nissan public relations makes much of the fact that the Infiniti Indy V8 (official name of the unit) is the handiwork of a half-dozen Southern California speed merchants who have used their combined talents to produce an engine capable to win at Indy in just 17 months.
Nissan logistical strategy is to supply complete engines to the teams that utilize the Infiniti Indy V8 complete with all ancillary parts, most of which have come from suppliers in the immediate Southern California area. Unfortunately, the engine has yet to prove it's reliability on the track and a year-and-a-half may be asking too much from a design team, no matter how talented.
I queried several other auto makers who produced passenger car engines that could fit the IRL formula as to why they weren't contesting the IRL series in general, and the 500 in particular, and their answers were uniformly pessimistic as to the success of the new formula. "Look at how many of them (Oldsmobile and Nissan) have blown in practice and at the first two events, and you have our reason for not getting into it," one candid representative of a famous German make told me.
At this point, I'm afraid I have to agree with him.