Performance tricks are usually just sleight-of-hand changes that do little to improve performance. After all, if it was that easy, everyone would be doing it, right? But the simple fact is, valvespring technology has been moving on-in giant leaps these days. Ask any NASCAR engine builder behind closed doors, and he'll tell you about his lightweight retainers and valvesprings, perhaps the most significant change in the last 10 years. These beehive-shaped springs feature a lighter retainer and a lighter-weight spring. The effect is a better-revving, more durable engine, and a big-block that revs like a small-block.
What does this mean for your street-driven Corvette? The same new technology that helps improve the performance of Jeff Gordon's small-block can work for your big-block (and small-block) Corvette engine. Through extensive testing, Comp Cams has created the ultimate big-block "beehive" valvespring, which you can add to your current engine (without having to take it completely apart) or your next engine project. The benefits, as we found out during our comparison testing, were more far-reaching than just the obvious improvement from simply installing a set of fresh springs. As it turned out, the change altered the personality of the entire engine and allowed us to do some interesting performance enhancements.
SpintronThe Spintron has changed the look of engine component testing today. It's a device that spins the valvetrain (with the lower end of the engine removed) while four sensors, high speed cameras, and lasers map out the internal dynamics of what's going on inside. Comp Cams' Spintron testing program helped develop its new beehive valvespring.
The beehive spring shape has become the buzz lately, and it's commonly used in many OE engines as well as Nextel Cup competition. Why? The beehive shape is more stable than standard cylindrical springs, as we learned in our testing. The benefit? Larger valve stems, like those commonly used in big-block engines, aren't required.
With performance engines, weight is the enemy. Valve retainers are costly items, but the weight savings is real. The entire titanium valvespring retainer business is based on the need to lower valvetrain weight to improve performance. Lower-weight valvetrain components improve the durability of the engine, allowing it to rev higher and quicker. If valvesprings are the limiting components in today's big-block engines (and they are), making them better and lighter is a big deal.
"Beehive springs feature smaller, lighter retainers, greatly helping the engine achieve much higher peak rpm," said Chris Douglas of Comp Cams. "That allows the engine builder to switch to higher-lift, more aggressive camshafts to increase performance."
Our test was to compare cylindrical valvesprings to the new beehive springs. For the test, we used Comp Cams' big-block engine on the Spintron. We featured their traditional 924 cylindrical springs with titanium and steel retainers. This very traditional yet high-performance spring features both an inner and an outer spring. Total weight of the spring, as noted in the chart, was 140 grams. The beehive spring (PN 26120-1) is a single-coil spring. The total weight was 99 grams. While it may appear the dual spring is stronger than the single-coil beehive, we were told the comparison was a good one.
"The beehive design, which incorporates the ovate wire (a uniquely shaped and innovative design), does not require a second inner spring," said Douglas. It's more than capable of handling equivalent if not enhanced performance demands. That is one of the main benefits of the spring-lighter weight and better performance."
The ovate wire used in the beehive spring is a teardrop shape rather than round. According to Comp, this allows the spring to deliver better performance with less seat pressure and better durability. Sounds good. Now it's time for the test.
Weight A MinuteThe test began by installing the 924-1 cylindrical valvesprings on the engine and chucking it into the Spintron. We used both steel (test No. 1) and titanium (test No. 2) valve retainers, along with 31/48-inch steel valves and steel valve locks. We ran the engine up to 7,000 rpm and watched what happened.
For tests No. 3 and No. 4, we installed the 26120 Comp beehive valvesprings. Again, we used steel and titanium valve retainers. While the look was considerably different, there was no difference in sound or any required part changes. The same valve locks were used as well. Obviously, the biggest change was the weight. The retainers were significantly lighter with the beehive units-dead weight, according to the Comp engineers. "It's like installing titanium valves in your engine," said Douglas. "Guys spend a lot of money on lightweight valves when they can get the same effect and the better performance of the beehive spring for a lot less money. These springs are not expensive comparatively to standard cylindrical springs. It's almost like free power."
What This MeansOur tests, as the charts clearly show, demonstrate that the beehive springs, with less weight, are quicker revving and more stable than the traditional cylindrical springs. Corvette owners who change springs with the engine in the car can achieve the benefits of this lighter valvetrain mass. If your engine is older, a valvespring change can be a quick lift to the engine's performance. If you're ready for a camshaft change, installing these springs allows you to select a hotter-performing camshaft due to the increased abilities of the valvesprings to keep the valvetrain in line. If you're building an engine, these springs are a simple upgrade that any big-block engine builder should consider.