Inexpensive and lightly constructed, worm-gear clamps can be used on the smaller rubber hose sizes, but on the larger sizes, they are best used only in temporary installations, such as when prototyping a system. They work fine while you are ironing out the details of your system. Once you have your final configuration figured out, you can purchase the proper size and number of T-Bolt clamps to make it a professional-looking and reliably performing installation. Can be used in pairs for more holding power. Not recommended for silicone hoses (silicone is softer, so a fully-lined clamp is recommended). All stainless, including the screw. Very economical.
T - Bolt Clamps:
T-Bolt clamps are the standard hose clamp used on intake hoses throughout the industry. Very high holding power. A wider band provides for superior system stability. Thicker metal in the band means higher strength and longer life. The only disadvantage is a narrow range - you must have the correct size in order for it to work properly. Fully lined, so can be used on silicone hoses. Stainless band, anodized bolt and locknut. Medium cost.
Constant - Torque Clamps:
Constant-Torque clamps are the only type of clamp available that maintains constant pressure on the joint regardless of expansion or contraction due to heat, and therefore widely used in air-to-air aftercooler systems. Requires proper adjustment to work correctly (see below). Wide range. Fully lined - protects soft hoses, such as silicone. All stainless. Complex construction means higher cost.
Constant-Torque Clamp Adjustment: Use of a torque wrench for initial adjustment is recommended. Adjust to between 90 and 125 in/lbs. These clamps utilize a "Torque-Check" feature - you can visually check for the proper torque. Look at the end of the bolt opposite the hex end. It should extend out of the housing about 1/4". At rest, the bolt extends about 1/8", so you need to make sure it is closer to 1/4" - then you know the clamp is properly tightened. DO NOT OVER-TIGHTEN - these clamps will strip if grossly overtightened. No refunds or returns of any stripped clamps. Note: All types of hose clamps, including Constant-Torque, should be re-tightened after the first few weeks of use.
Spring-Loaded T-Bolt Clamps:
These clamps are the old standard for maintaining a constant tension on silicone hoses on air-to-air aftercoolers. Largely superceded by newer constant-torque technologies, but still widely used, widely available, and popular with customers. They also happen to look really cool. The only real disadvantages compared to Constant-Torque are a narrower range, less capability to handle rapid pressure spikes, and slowly losing tension in the spring over time (which is easily combatted by adjusting the clamp periodically, which should be done with any style of clamp anyway). Their ability to compensate for the expansion and contraction of hoses and fittings due to temperature is about the same as Constant-Torque. Most are floating-bridge type, using a trunnion-style bridge, which keeps the clamp aligned during tightening, and tightens more evenly around the entire diameter of the hose. Stainless band and bridge. Bolts, nuts, washers and springs are plated or anododized. Medium-high cost.
OK, So Which One Should I Use?
It depends on your situation:
If you already know your final configuration, go ahead and order T-Bolt (black rubber or silicone hoses) or Constant-Torque (silicone hoses and especially Charge Air Cooler hoses). Start out with the best - you won't regret it.
If you are not sure of your final configuration and don't want to buy a bunch of clamps you may not end up using, order the economical worm-gear for now (rubber hoses only), and then replace with the better clamps when your system configuration is finalized. If you have silicone hoses, you will have to use T-Bolt or some other type of fully-lined clamp.
If you are on a very tight budget, use worm-gear on smaller size rubber hoses (up to 3") and either a T-Bolt or a pair of worm-gear on larger rubber hoses. Purchase the better clamps when your budget allows. Silicone hoses really have to have a fully-lined clamp because silicone is relatively soft and can be weakened by unlined worm-gear clamps (the slots, and especially the back of the saddle, can cut into soft silicone). Therefore, T-Bolt or Constant-Torque (or some other type of fully lined clamp) is recommended on silicone hoses.