Competition cylinder heads: How would you know if air-fuel movement is good or bad?

Competition cylinder heads: How would you know if air-fuel movement is good or bad?

By Ben Mozart: The race engine requires a precise mixture of air and fuel, approximately 13.0:1 by weight ratio.   But the power it makes depends upon how well the mixture is emulsified and atomized. How well it is delivered through the intake manifold runners and cylinder head ports. And it’s ability to negotiate the intake valves and to swirl in the combustion chambers, which are an extension of the ports, and to occupy the cylinders.   For most of us, arranging and controlling the movements of the gases in the cylinder head ports are beyond our imaginings. Is the air-fuel mixture moving efficiently in the intake tracts or clinging, vexingly, to its sides? If so, how could it be reintroduced into the air stream? And further downstream, how is it negotiating the short turn, the five valve-angles in the throat, and does it demonstrate swirl as it moves into the combustion chamber? Read...

Steering Feel: Use right flow valve get better steering

By Archie Bosman Kennesaw, GA: Electric steering in mass-produced road cars is now widespread. It is a little like ethanol in our fuel: you’ll be hard pressed to find an enthusiast who favors it yet we are stuck with it. But actually we aren’t. Hydraulic power steering systems that provide superior feel are still readily available to the racer. However, it is not widely known that steering pumps can be tuned for more feel or alternatively for more assistance. Optimizing feel to the racer’s steering is a bewildering task for most of us. But it has been accomplished by introducing a range of replaceable flow control valves to the hydraulic steering pump. The flow control valves, nine in number, perform a function similar to that of jets in a carburetor. In varying their flow from 4 to 12 liters per minute, approximately one to three gallons, the largest orifice provides maximum steering assistance while the smallest provides maximum steering feel. How it works Though the standard KRC pump flows 8 liters per minute, by using flow control valves with larger orifices, those marked B, C, D, or E, the flow rate can be increased to 12 liters per minute (3.17gals) in one-liter increments. The higher letter indicates greater hydraulic assistance, although less feel. In contrast, flow valves marked with numbers 4, 5, 6, and 7 provide less assistance; the lower the number, the greater the feel but the less assistance. Momentary loss of power or “pump catch” So how do you achieve optimum steering feel? According to KRC’s Ken Roper you reduce the size of flow valve orifice until you...

First aftermarket 8-rib serpentine pulley system for LS engines with Whipple 2.9 liter superchargers

By Fergus Ogilvy If you ask LS engine specialist Gary Grimes about serpentine pulley systems, he might shock you. He’ll tell you that some pulley systems masquerading as billet are no more than aluminum castings machined to give the appearance of billet. And he’ll prove his case by revealing broken pulleys shattered by the additional demands of forced-induction engines. So he selects Concept One. Here below are the details of their latest pulley system for LS engines fitted with the W175FF 2.9-liter Whipple supercharger. ________________________________________________________________________________ -First single-belt 8-rib pulley system for Whipple 2.9L blowers -High traction serpentine arrangement sustains up to 10lbs boost -Compressor moved to upper right from lower right provides vital clearance -Machine finish or in-house polished or low-maintenance black or clear anodized   Cumming GA: LS-powered Muscle cars using the Whipple W175FF 2.9-liter blower now have access to the first high-traction eight-rib serpentine pulley kit. Driving a blower that creates up to 10lbs of boost requires adequate belt grip and by increasing the ribbed surface area by 33 percent—substituting eight ribs for the traditional six—Concept One’s latest single-belt system achieves this without belt stretch or slippage. Created and fully CNC-machined from pure aircraft-quality 6061-T6 billet aluminum, this kit, in common with its predecessors for Magnuson, GM LSA,  and Edelbrock superchargers, is engineered for easy installation and perfect fit with pulley ratios calculated for optimum drivability. To ease the installation prospects of the fully dressed LS power unit, Concept One relocated the A/C compressor from its original position on the lower right to the upper right. In doing so, LS transplants now possess adequate clearance around most...