The Spintron engine testbed...
The Spintron engine testbed has become a staple for engine andvalvetrain testing. This big-block, at Comp Cams' R&D Center, has beenused many times to test springs, camshafts, retainers, and all otherrelated parts.
Performance tricks are usually just sleight-of-hand changes that dolittle to improve performance. After all, if it was that easy, everyonewould be doing it, right? But the simple fact is, valvespring technologyhas been moving on--in giant leaps these days. Ask any NASCAR enginebuilder behind closed doors, and he'll tell you about his lightweightretainers and valvesprings, perhaps the most significant change in thelast 10 years. These beehive-shaped springs feature a lighter retainerand a lighter-weight spring. The effect is a better-revving, moredurable engine, and a big-block that revs like a small-block.
What does this mean for your street-driven Corvette? The same newtechnology that helps improve the performance of Jeff Gordon'ssmall-block can work for your big-block (and small-block) Corvetteengine. Through extensive testing, Comp Cams has created the ultimatebig-block "beehive" valvespring, which you can add to your currentengine (without having to take it completely apart) or your next engineproject. The benefits, as we found out during our comparison testing,were more far-reaching than just the obvious improvement from simplyinstalling a set of fresh springs. As it turned out, the change alteredthe personality of the entire engine and allowed us to do someinteresting performance enhancements.
The Spintron uses this specially...
The Spintron uses this specially modified big-block engine with sensorslocated throughout. This sensor sits in the seat pocket of thevalvespring and reports back its findings, which allows us to chartvalvetrain dynamics.
The Spintron has changed the look of engine component testing today.It's a device that spins the valvetrain (with the lower end of theengine removed) while four sensors, high speed cameras, and lasers mapout the internal dynamics of what's going on inside. Comp Cams' Spintrontesting program helped develop its new beehive valvespring.
The beehive spring shape has become the buzz lately, and it's commonlyused in many OE engines as well as Nextel Cup competition. Why? Thebeehive shape is more stable than standard cylindrical springs, as welearned in our testing. The benefit? Larger valve stems, like thosecommonly used in big-block engines, aren't required.
Valvesprings now come in different...
Valvesprings now come in different strengths and different shapes. Thetwo springs on the right are the traditional cylindrical shape, and theone to the right is the new beehive spring. Our test incorporated bothsteel and titanium retainers. Steel valve locks were used for alltesting.
With performance engines, weight is the enemy. Valve retainers arecostly items, but the weight savings is real. The entire titaniumvalvespring retainer business is based on the need to lower valvetrainweight to improve performance. Lower-weight valvetrain componentsimprove the durability of the engine, allowing it to rev higher andquicker. If valvesprings are the limiting components in today'sbig-block engines (and they are), making them better and lighter is abig deal.
"Beehive springs feature smaller, lighter retainers, greatly helping theengine achieve much higher peak rpm," said Chris Douglas of Comp Cams."That allows the engine builder to switch to higher-lift, moreaggressive camshafts to increase performance."
Our test was to compare cylindrical valvesprings to the new beehivesprings. For the test, we used Comp Cams' big-block engine on theSpintron. We featured their traditional 924 cylindrical springs withtitanium and steel retainers. This very traditional yet high-performancespring features both an inner and an outer spring. Total weight of thespring, as noted in the chart, was 140 grams. The beehive spring (PN26120-1) is a single-coil spring. The total weight was 99 grams. Whileit may appear the dual spring is stronger than the single-coil beehive,we were told the comparison was a good one.
Our lightest retainers were...
Our lightest retainers were made of titanium, and this beehive retainerweighed 9 grams.
"The beehive design, which incorporates the ovate wire (a uniquelyshaped and innovative design), does not require a second inner spring,"said Douglas. It's more than capable of handling equivalent if notenhanced performance demands. That is one of the main benefits of thespring--lighter weight and better performance."
The ovate wire used in the beehive spring is a teardrop shape ratherthan round. According to Comp, this allows the spring to deliver betterperformance with less seat pressure and better durability. Sounds good.Now it's time for the test.