Tech Tips

COMP

Monitor valve lash for signs of trouble

When it comes to valve lash, don’t just check and adjust periodically. Carefully monitoring changes in lash over time can give you a good clue to the health of your valves, seats, lifters, and camshaft. If you find the lash in one or more of the valves opening up, it may be the first sign that your valvetrain needs to be looked at.

FAST

Can I increase power with a larger throttle-body diameter?

This is a major misunderstanding in our market. Throttle “diameter” has absolutely nothing to do with torque curves or if an engine makes power down low or up high. All it does is dictate how much restriction the intake will see (less is better), and the size is directly proportional to throttle metering. If you open a large-diameter throttle 10 percent, it is equivalent to opening a smaller diameter throttle 15 percent. FAST only recommends 102mm throttle bodies with “convolute” barrels for proper driveability.

Inglese

How does Weber carburetor terminology work?

Every Weber carburetor has an alphanumeric model number stamped on. This number is made up of a numeric prefix indicating the carburetor bore and throttle plate diameter, and an alphabetic suffix that indicates what type of carb it is. For example, the Weber 48 IDA model number tells us the carburetor has a bore and throttle plate diameter of 48 mm, while the IDA suffix tells us that this is a high-performance twin-throat downdraft carburetor. DCNFs are compact twin-throats with a cold-start feature and all sidedraft carburetors carry the suffix DCOE.