Team Chevy introduces new R07 racing engine

[Flybrian]

Team Chevy Rolls Out New Chevrolet R07 Racing Engine
Transition to New-Generation NASCAR Small-Block V-8 Begins at Texas Motor Speedway

FORT WORTH, Texas – On the heels of the successful introduction of the new Impala SS race car in NASCAR Nextel Cup competition, Team Chevy is beginning the transition to the new Chevrolet R07 racing engine. Approved by NASCAR for competition in 2007, the Chevrolet R07 is making its debut this weekend in the Samsung 500 at Texas Motor Speedway.

The Chevrolet R07 marks another step in the evolution of the GM small-block V-8. It is the successor to GM's SB2 (Small-Block/2nd Generation) engine that was introduced in NASCAR Cup competition in 1998. The Chevrolet R07 will eventually replace the SB2 as teams turn over their inventories of engines and components.

"The GM Racing engine development team had four key objectives in mind throughout the design and development of the Chevrolet R07 engine," said Mark Kent, director of GM Racing. "Our goal was to create an engine that produces competitive power, delivers excellent reliability, enhances safety, and reduces costs for Chevrolet teams. Based on the feedback we have received from Chevy teams after extensive dynamometer and track testing, I believe we have achieved our objectives."

The evolution of the GM small-block V-8 racing engine mirrors the development of the GM small-block V-8 production engine, which is now in its fourth generation. Until the introduction of the Chevrolet R07, all of GM's small-block racing engines shared key dimensions such as cylinder bore spacing, camshaft location and deck height with the original small-block V-8 introduced in 1955.

"The Chevrolet R07 is GM Racing's first purpose-built NASCAR racing engine," said Pat Suhy, GM Racing Group Manager, Oval Track. "NASCAR's parameters for the new generation of engines provide a range of choices on key dimensions and design features. Our job was to make the critical decisions and carefully balance the tradeoffs that would enable the Chevrolet R07 to continue Chevy's success in NASCAR. In the long run, the results will show whether we made the right choices."

GM Racing supplies the major components that define the Chevrolet R07 engine package – the cylinder block, cylinder heads, and intake manifold. GM Racing also developed engineered assemblies such as the water pump, rocker covers, valley plate, and front cover. Teams and independent engine builders prepare and assemble these components using their own proprietary parts and processes, including the rotating and reciprocating assemblies, valvetrain, oil pump, fuel and ignition systems, and accessories.

"New manufacturers coming into NASCAR pushed the envelope with engines that had no links to production powerplants, while GM engines were based on the architecture of the first small-block V-8," explained Jim Covey, NASCAR engine development manager for GM Racing. "NASCAR Nextel Cup Series director John Darby addressed this issue by developing a list of parameters that define the envelope for all manufacturers, thus giving Chevrolet an opportunity to develop the R07 engine. Now with the introduction of the Chevrolet R07, Chevy teams have an optimized engine design that reflects the advances in racing technology that have been made over the last 50 years."

Per NASCAR regulations, the R07 displaces a maximum of 358 cubic inches and retains the classic two-valve pushrod design that has been the mainstay of American motorsports for more than 50 years. The R07's key technical advances over the SB2 include 4.500-inch cylinder bore centers (vs. 4.400 inches in SB2) that enhance coolant flow, a raised camshaft that improves valvetrain dynamics, a new six-bolt head bolt pattern that reduces cylinder bore distortion, and a targeted cooling system that minimizes temperatures at critical locations. A cast camshaft tunnel, integral piston squirter galleries, and overhead oil feed galleries reduce engine assembly time. Relocating the fuel pump and eliminating external oil and coolant lines enhance safety.

GM Racing engineers created the Chevrolet R07 in-house using many of the advanced development tools employed by GM Powertrain engineers to design production engines. These included computer-aided engineering (CAE), computational fluid dynamics (CFD), finite element analysis (FEA), and solid 3D modeling. Extensive use of computer modeling accelerated the production and testing of prototype Chevrolet R07 components while reinforcing the connection to GM production powerplants.

"The introduction of the Chevrolet R07 this weekend marks the beginning of a new era for the GM small-block V-8 engine," said Kent. "The Chevrolet R07 is the heir to the winning tradition of GM production-based engines that have powered Chevy to more than 600 victories in NASCAR Cup competition. As we look to the future, we are confident that the Chevrolet R07 engine and the Impala SS race car will continue Team Chevy's winning ways in NASCAR."

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GM Racing White Paper: Inside the New Chevrolet R07 Small-Block V-8
Technical Insights on GM's First Purpose-Built Small-Block V-8 NASCAR Racing Engine

DETROIT – For the first time since 1955, Team Chevy is introducing an all-new small-block V-8 engine in the top tier of stock car racing. The new Chevrolet R07 is the first purpose-built engine designed and developed by GM Racing specifically for NASCAR Nextel Cup competition. This purebred engine is the successor to the production-based powerplants that have made Chevrolet the most successful manufacturer in NASCAR history. This white paper highlights the Chevrolet R07's development and summarizes its technical features.

Design and Development

The Chevrolet R07 is succeeding the championship-winning SB2 (Small-Block/2nd Generation) engine that has been used by GM teams in NASCAR Cup racing since 1998. NASCAR approved the Chevrolet R07 for competition in 2007, and it is expected that the R07 small-block V-8 will become the exclusive Chevrolet powerplant in the Nextel Cup series as teams turn over their inventory of SB2 engines and components.

Work on a successor to the SB2 began in earnest in 1999, and several variations of the conventional small-block V-8 were designed, tested, and evaluated. In 2004, NASCAR held discussions with the automotive manufacturers about a possible "Engine of the Future" that paralleled the Car of Tomorrow body/chassis program. Although the Engine of the Future did not become reality, the meetings did establish a framework for future NASCAR engines.

"The discussions with NASCAR and the other manufacturers about the Engine of the Future were extremely productive," said Jim Covey, NASCAR engine development manager for GM Racing. "Although the Engine of the Future program was put on the shelf in 2005, NASCAR Nextel Cup Series director John Darby developed a list of parameters that define the envelope for all manufacturers, thus giving Chevrolet an opportunity to develop the R07 engine. This 'box' set the boundaries for specific design features and minimum and maximum dimensions for key engine components.

"We had already started to lay the foundation for a future Chevrolet engine, and we were able to adapt that design to the Chevrolet R07," Covey continued. "That was the key to designing, testing and submitting the engine for approval on a very tight schedule. A prototype R07 engine was running durability tests on a dyno six months after we kicked off the program. The R07 engine development team included Ed Keating and Ron Sperry, who focused on cylinder heads and intake manifolds, and Ondrej Tomek, who was responsible for the cylinder block. We also worked with our key Chevrolet teams, GM Powertrain, and our suppliers."

Just as in all forms of motorsports, the rulebook defined the basic engine package. GM Racing's objective was to produce the most competitive and reliable engine within the boundaries established by NASCAR.

"NASCAR's box provides considerable latitude for manufacturers to design their engines, and there are many parameters that have to be balanced," explained Pat Suhy, GM Racing Group Manager, Oval Track. "If a manufacturer maximizes one aspect of the engine design then it may limit what can be done in another area. Our goal at GM Racing was to find the optimum point for all of them. We relied on our computer-aided engineering and design tools, our experience, and input from our affiliated teams to make informed decisions on the engine configuration. It was all about balancing those tradeoffs to produce an engine that would produce competitive power with exceptional reliability while also improving safety and reducing costs for Chevy teams."

Advanced Technology

Many of the advanced technical resources used by GM Racing engineers to develop the Chevrolet R07 racing engine are also used to develop GM production engines. By employing technology such as computational fluid dynamics (CFD), finite element analysis (FEA), and solid 3D modeling, GM Racing engineers were able to evaluate and analyze various designs in computer simulations. This extensive use of computer modeling also accelerated the production of prototype parts after the specifications were finalized.

While CFD is commonly associated with aerodynamic development of race cars, it can also be used to analyze the behavior of fluids such as the coolant flow through the Chevrolet R07's block and cylinder heads. FEA was used to analyze the strength and minimize the weight of the R07's block and cylinder heads.

"Although we use many of the same engineering tools, the timeframe for racing engines is much shorter than it is for production engines," Suhy noted. "The rapid turnaround in racing allows us to get feedback on the accuracy of GM's computer simulations and models very quickly. The same programs can then be refined to make them more accurate when used to develop future production engines."

In this way, the Chevrolet R07 racing engine will lead to better production GM powerplants. "The concepts and processes that are used to improve the performance of our racing engines are shared with the production engine designers to improve the efficiency of our production engines," said Tom Stephens, group vice president of GM Powertrain.

Technical Features

The Chevrolet R07 retains the pushrod/two-valve layout that has been the mainstay of American motorsports since the introduction of the first-generation GM small-block V-8 in 1955. This classic design has now evolved into a highly advanced racing engine.

Per NASCAR specifications, the Chevrolet R07 displaces a maximum of 358 cubic inches with a maximum cylinder bore diameter of 4.185 inches. The block is a precision iron casting with integral oil and coolant passages that eliminate the need for most exterior lines. The distance between the Chevrolet R07's cylinder bores is 4.500-inch (vs. 4.400 inches in the SB2 small-block). This wider bore spacing improves coolant circulation around the cylinder barrels. In conjunction with a targeted cooling system, the R07 block design minimizes temperatures at critical locations.

The R07 block has a new six-bolt head bolt pattern instead of the small-block's traditional five-bolt design. The revised head bolt pattern improves head gasket sealing and reduces cylinder bore distortion.

The R07's camshaft is located higher in the block than the camshaft in the SB2. The raised cam operates pushrods that are correspondingly shorter and stiffer, thereby improving valvetrain dynamics at high rpm. The raised cam also provides clearance for inboard piston squirters that spray the underside of the pistons with oil for cooling. The camshaft tunnel is isolated from the crankcase to minimize windage losses caused by oil falling onto the rotating crankshaft assembly from the cam and to contain the valvetrain parts in the event of breakage.

In contrast to the SB2's "mirror port" cylinder heads, the Chevrolet R07's aluminum cylinder heads resemble production LS-series small-block cylinder heads with alternating intake and exhaust valves. The R07's shallow valve angle produces a compact, efficient combustion chamber design that produces the required compression ratio with a lightweight flat-top or slightly domed piston. GM Racing engineers optimized the R07's intake port layout for the single, centrally mounted four-barrel carburetor mandated by NASCAR.

The aluminum intake manifold has an extended plenum to equalize fuel distribution among the cylinders. The manifold is dry; a separate valley cover carries coolant from the cylinder heads. The R07's distributor is located at the front of the engine to facilitate adjustments in ignition timing.

The Chevrolet R07 rocker covers are rigid cast aluminum with O-ring seals. The covers incorporate integral valve spring oilers that are pressure fed from passages in the cylinder heads, eliminating the need for external oil lines. GM Racing also designed a high-efficiency water pump and a carbon fiber front cover that shields the aftermarket camshaft belt drives used by NASCAR teams.

The R07 has provisions for driving a conventional diaphragm fuel pump off of the camshaft. A remote-mounted mechanical fuel pump can also be driven via a cable from the rear of the camshaft. When using the cable drive, the fuel pump can be relocated to the rear of the car near the fuel cell. This enhances safety in an accident by mounting the fuel pump in a less vulnerable location.

Key Partners

"Chevy NASCAR teams were deeply involved in the design of the Chevrolet R07," said Suhy. "We meet monthly with representatives from our four key partners – Hendrick Motorsports, Richard Childress Racing, Joe Gibbs Racing and Dale Earnhardt, Inc. – to get their input on how we can make Chevrolet racing engines more reliable and easier to build and service. Many of their ideas were incorporated in the R07's final design, such as the integration of the oil and cooling systems.

"It's not about helping our affiliated teams to build the most powerful engine because each of them has developed their own proprietary parts and processes," he noted. "GM Racing's role is to provide premium quality, easy-to-use components. We want Chevy teams to be able to devote more of their energy and resources to winning races and less energy to preparing engines."

The introduction of the Chevrolet R07 small-block V-8 represents another milestone in the continuous evolution of the small-block V-8 engine. GM's first purpose-built NASCAR racing engine was designed, built and tested to continue Team Chevy's winning tradition in NASCAR.

[91z4me]

So this is LSx or LS-X based. Makes sense. The oil squirters should allow for higher compression w/out detonation. That could produce some more power. I wonder if a production LS7 could still outpower this engine (w/ a restrictor plate).

[gm4life]

I kinda doubt it, I bet this one is good for close to 600hp.

[SuperSport623]

i wonder how much they cost.... and how streetable they are.. i want one in my nova

[balthazar]

So the clarifier is: this is the first purpose-built small-block NASCAR engine with unique spec parameters.... because I believe there have been numerous race motors (primarily big- or mid-blocks) that either appeared first or simultaneously for race, then production. Some were built for race and never saw production.

I hate when in an eagerness to proclaim a 'first', and entire catalog of effort and engineering is brushed aside.

[Screaming Trees]

i wonder how much they cost.... and how streetable they are.. i want one in my nova

Depending on the team enging costs can easily go $100k and up. They are not really streetable as they are built to last about 1,000 miles, give or take.

So far the results on the new R07 have been mixed, such is to be expected with an engine still in R&D stages. Not all Chevy teams are running it yet. Jeff Gordon ran the old motor today and led @ 150 laps. Dale Earnhardt ran the new R07 led 95 laps but the motor failed late in the race.

I am not sure if eventual race winner Jeff Burton (# 31 Cingular Chevy) was running the R07 or not.

Edited April 16, 2007 by Screaming Trees

[Z-06]

I wonder how much the compression ratio is.

The engines are easily in the 6 figures mark as Mr. Trees noted. However, that life is based on considering how much close to the RPM these engines run.

They are however not street version ones.

I once had a talk with the team principle of a 24-hours ALMS racing team, he said that the LS series they had in their GTO's lasted them for about 2 Races and was about $60k per pop by the time they put one in the car.

[FloydHendershot]

Dale Earnhardt ran the new R07 led 95 laps but the motor failed late in the race.

Yes but they wrecked the $h! out of his car so who knows.

btw, Nascar Now on ESPN is a great show. I understand NASCAR a little bit more after catching an episode tonight. Good show.

[ToniCipriani]

Interesting... so in the next NASCAR we expect to see Camlees with Chevrolet engines?

[Screaming Trees]

Yes but they wrecked the $h! out of his car so who knows.

btw, Nascar Now on ESPN is a great show. I understand NASCAR a little bit more after catching an episode tonight. Good show.

You are correct, sir. According to Dale Jr. the wreck had nothing to do with killing the motor.