When you consider the glacial pace of change in stock car racing, NASCAR has really been shaking things up with a tidal wave of changes in the past year. These changes aren't limited to the Car of Tomorrow on the Nextel Cup front. The sanctioning body's new spec motor for its Grand National Division touring series (along with a new composite body) is just as radical.
Although it is still carbureted and utilizes a cam-in-block design, NASCAR's new spec motor shares little else with current engines racing in the division. This engine package became legal midway through the '06 race season and has been tested by a few teams already, but we expect 2007 to be the year it catches on in a big way. And make no mistake, although nothing has been said officially, there is no way NASCAR would go to the trouble to introduce a completely new engine package to the Grand National Series' two divisions (the AutoZone West Series and the Busch East Series) if they weren't considering using it in other touring classes and even some weekly racing divisions.
Early returns on the engine seem promising. At last October's Toyota All-Star Showdown at Irwindale (CA) Speedway, Matt Kobyluck defeated 30 other Grand National drivers from both divisions in a car powered by NASCAR's new spec motor. In fact, spec motors claimed 4 of the top 10 positions in the all-star event. Kobyluck describes the new engine by saying, "It really fits my driving style well. The transition in the throttle is really smooth all the way up through [the rpm range]. It reminds me of my Late Model days, where you had a real beefed-up carburetor and you could really get after the motor and use everything you had. That's what [the spec engine] does and it really fits my driving style well. We've been able to make it work the way we wanted."
Although the LS2 engine is designed exclusively for electronic fuel injection, NASCAR's sp
The engine is based on General Motors' fourth-generation small-block V-8, commonly referred to as the LS2. And just like stock car racing in its formative years, this engine uses many off-the-shelf stock parts. That isn't something that can be said about current engines since neither Chevrolet nor Ford have used the blocks or heads from passenger cars for the past several years. By using modern stock components, such as the block and cylinder heads, the engine's price is reduced to a fraction of the cost of a built motor. All spec engines are sold by Provident Race Supply in Concord, North Carolina. Owner Gary Nelson says that the spec motor is available either assembled or as a kit you can take to the engine builder of your choice. Preliminary pricing was $20,000 for the kit and $22,000 for a complete engine, but those prices may have changed somewhat by the time you read this.
Before Nelson started Provident Race Supply he was in charge of NASCAR's R&D and had a role in developing the engine. "Brian France asked me to investigate a sealed motor for the touring divisions," he says of the beginning stages of the engine's development. "The next day I had a set of the seals in my hand. If they are that easy to get, it isn't hard to cheat that engine up. So we decided, OK, why not build a motor that is OK to take apart?"
The result is a collaboration with Carl Wegner of Wegner Automotive that produced NASCAR's new spec motor. Capable of producing 520 lb-ft of torque and 625 hp with a redline somewhere around 8,200 rpm, this engine is two years in the making and an interesting mixture of off-the-shelf OE components and race-specific parts. In developing the engine, Wegner used General Motors' LS2 engine as a foundation, using the block and heads and even keeping the major dimensions such as main and rod journal sizes, valve sizes, cam tunnel location and size, and even bore and stroke. This allows the block to be pulled directly off the assembly line, making it significantly cheaper than a properly prepared Bow Tie block.
One of the more interesting parts of this engine is the custom front cover/water pump that
"Our intention was to make the block almost a consumable," Nelson says. "Currently, racers have so much in their block [that] they are willing to sacrifice all the other components just to save it. You can have $1,200 wrapped up in just machining and preparing a new block easily, which can get you one of these all-aluminum blocks race-ready."
In addition to the block, other stock components include heads (although Wegner ports them), rocker arms (with a modified trunnion), and most surprisingly, stock hydraulic roller lifters. The hydraulic lifters, in addition to being relatively inexpensive, act as a natural rpm limiter. Still, because the valvetrain is relatively light with beehive valvesprings, lightweight retainers, and titanium valves, the hydraulic lifters can manage a very racy 8,000 rpm. Race-specific components include JE-forged aluminum pistons, a Comp Cams cam (no specs yet) and pushrods, a Holley 830-cfm four-barrel carburetor, Lunati crank and rods, an Edelbrock intake, a custom Stewart Components water pump, and titanium valves.
"It's definitely a race engine," Wegner says. "It's not a crate motor that somebody is selling to racers that won't hold up. It was designed for this purpose. And it isn't sealed, so if something does break you don't have to throw it out, you can tear it down and have it fixed.
Because the LS2 uses an in-tank electric fuel pump, a little engineering was required to g
"Just because it isn't your standard small-block," he continues, "that doesn't mean that your engine builder won't be able to work on it. I'd say any second-year auto mechanic can put one together. We'll build one for anybody who wants one, but we aren't trying to cut out the other engine builders out there. Any racer can buy a parts kit and take it to any engine builder he likes. We've built $2,500 into the suggested price for the engine builder to assemble and dyno test the thing. So we are definitely not trying to cut the other engine builders out of the business."
Although the motor isn't sealed, both Nelson and Wegner are confident they have found a reasonable method to ensure cheating will be held to a minimum. Instead of a complex set of rules limiting what can be done to the engine, Wegner essentially overbuilt the engine with a few specific choke points to keep power in check.
For example, instead of using an overly small carburetor to limit airflow into the engine, the 830-cfm four-barrel Wegner has spec'd in is larger than necessary. Likewise, he says the CNC port design he puts into all the heads is large, so additional port work will not make much of an improvement in terms of power. The intake and exhaust valves, however, are smaller than the optimal size. The reduced valve size holds the engine's power in check.
Nelson says this engine's purpose is to make life easier for the racers, so he tries to in
"I tried to make the engine so that there is no point in cheating it up," Wegner says. "A lot of teams know they can make power by cheating up the carburetor spacer if the rules only allow an open spacer or a four-hole spacer. But I cut my spacers on a CNC machine, and it only takes me a couple more minutes on the program to make a nice tapered spacer. So we put that on the engine and there is no reason to try to cheat it up.
"Everything is oversized except for the valves, which are the stock size for that head. I've already ported the heads bigger than what they need to be for that valve size. I left the valve size in there because it is a distinct, non-discretionary measurement. All the tech guys get themselves into trouble when the rules allow one to say something is OK and another to say it's illegal. You must give them a way to measure everything, and it is easy to measure the size of the valves. We've tried to take the discretionary calls out of this engine so it's easy for the tech man to know whether an engine is legal and everybody racing knows they are competing against a level field."
Internal components include a Lunati crank and rods, and JE-forged aluminum pistons.
In addition to the component choices, Wegner and Nelson have also collaborated on a unique and possibly revolutionary tagging system that essentially fingerprints every component on the engine. Each piece is tagged with an identification code that is as unique as a person's fingerprint. It's similar to a bar code, except this is a series of dots arranged in a square less than an inch wide. The design is extremely difficult to reproduce or counterfeit because the dots are a unique diamond shape. Nelson says the computer-controlled machine that makes the imprint uses a diamond tip that precisely controls the size and shape of each dot. When scanned into a reader, the tags can be used to learn everything about that component, including its date of sale, who it was sold to, and even if it was originally sold with the rest of the engine package. Only tagged engine components are legal, so everything must go through Provident Race Supply, which will ensure that all the parts and pieces are consistent. Tags are also strategically placed in areas such as the intake ports, where racers may be tempted to make their own "alterations" in search of more power.
The '07 season will be the litmus test for NASCAR's new spec engine. Many teams were already set with an engine program and unable to consider a change when the new spec engine was introduced last season. But given the engine's early success, it will certainly get a long look from many teams this time. Although racers are some of the most inventive people on earth, we are also notoriously unwilling to accept change when it is forced upon us by a rule book or sanctioning body. This new powerplant certainly has potential, but whether it gains acceptance will be decided only when racers determine if it saves them money while adding a little more fun to racing. After all, for most of us, fun is what it's all about.
When it comes right down to it, the only thing that matters about a race engine is how much power it produces. To find out, we pulled a dyno sheet for a random engine that Provident Race Supply was shipping to a race team (every complete engine includes a dyno sheet). Certainly, 520.7 and 624.3 are nice numbers when it comes to torque and horsepower production, but equally impressive are the flat power curves.
Here's the restrictor plate. Wegner chose to keep the stock valve sizes in the LS2 cylinde
The oiling system is based on a dry-sump pump.
No stock pan here. The spec pan is custom fabricated for this engine with a right-side kic
The motor is shipped with this engine plate for easier mounting between the framerails of
Another difference from the standard small-blocks is the starter must be mounted backward,
The output side of the bellhousing is machined to accept the T10-style transmission common
Although the cylinder heads are GM stock components, Wegner CNC-machines the ports and cyl
It is interesting to see how intelligent design choices were made for this engine.
This engine uses a unique firing order that may confuse racers who are accustomed to the t
Wegner Automotive uses this computer-controlled machine to tag a unique fingerprint on eve
Here's a close-up of one of the tags on a balancer. It may not look like much, but it cont
|4,500 ||490.9 ||420.6 |
|4,600 ||493.0 ||431.8 |
|4,700 ||494.1 ||442.2 |
|4,800 ||496.7 ||453.9 |
|4,900 ||500.4 ||466.9 |
|5,000 ||504.3 ||480.1 |
|5,100 ||506.8 ||492.2 |
|5,200 ||511.4 ||506.3 |
|5,300 ||514.6 ||519.4 |
|5,400 ||518.2 ||532.8 |
|5,500 ||520.7 ||545.3 |
|5,600 ||520.3 ||554.8 |
|5,700 ||518.2 ||562.4 |
|5,800 ||516.7 ||570.6 |
|5,900 ||514.7 ||578.2 |
|6,000 ||511.5 ||584.3 |
|6,100 ||507.6 ||589.5 |
|6,200 ||504.5 ||595.6 |
|6,300 ||501.4 ||601.4 |
|6,400 ||497.4 ||606.1 |
|6,500 ||492.6 ||609.7 |
|6,600 ||488.4 ||613.7 |
|6,700 ||484.3 ||617.8 |
|6,800 ||479.1 ||620.4 |
|6,900 ||474.1 ||622.9 |
|7,000 ||468.4 ||624.3 |
|7,100 ||460.5 ||622.5 |
|7,200 ||453.3 ||621.5 |
|7,300 ||446.1 ||620.1 |
|7,400 ||440.0 ||620.0 |
|7,500 ||432.8 ||618.1 |
|7,600 ||425.7 ||616.0 |
|7,700 ||419.7 ||615.4 |
|7,800 ||411.7 ||611.4 |
|7,900 ||401.9 ||604.6 |
|8,000 ||391.0 ||595.6 |