Page 13 of Weiand Superchargers by Holley Performance Products, Inc.

for maximum boost and horsepower applications 12 pounds or more we recommend the following engine specifications · high quality forged or billet crankshaft with double keyways · four bolt main caps with quality bolts or studs · steel harmonic balancer sfi approved or crank hub with double keyways · high quality steel rods h or i beam · forged blower pistons · o-ringing the block mandatory · severe duty stainless steel valves or iconel · fully ported and polished heads · solid or roller cam designed for high boost · roller rockers · chromoly push rods · high output ignition management system · high octane race fuel 112 rating · minimum of a 3 diameter dual exhaust with free flowing street/race mufflers and large tube headers · recommended primary tube diameters and collector sizes are small blocks 1-7/8 to 2 with 3-1/2 collectors big blocks 2-1/8 to 2-1/4 with 4 collectors · maximum effective compression ratio on gas not to exceed 20:1 consult gas manufacturer it s important to realize that there are no hard and fast rules and the suggestions made here are general in nature question my engine has 9.5-1 compression can i run a blower and still use pump gas answer we do not recommend it the higher the static compression ratio of the engine the less boost you can run and still use 93-94 octane pump fuel usually on a 9.5-1 engine the most boost you can run is about 2 psi before you get above the octane rating of pump gas that level of boost will usually not make enough additional horsepower increase to offset the cost of the blower kit remember it takes horsepower to make horsepower with a roots type blower question my supercharger uses a serpentine style drive belt do i need a pop off plate if it backfires answer no the serpentine style drives do not require a pop off plate if the engine backfires it will slip the belt on the pulleys if the blower is running a gilmer tooth style drive setup then it does require a pop off plate if a backfire occurs on a gilmer drive setup the belt will not slip and it may lift the blower off of the intake manifold superchargers question i have installed one of your superchargers and my engine seems to run hot and my headers glow at idle what could cause this answer usually an issue with glowing headers and a hot running engine are caused by two basic things either incorrect timing or the engine is extremely lean there are others but these two are the main cause blower engines like timing advance if the initial timing advance is not enough it will cause these issues most blower engines will run between 12-20 degrees of initial timing and a total of 30-32 degrees you do want a fairly fast timing curve all the timing should be in by 2500-2800rpm this is just a guideline all engines are different the other main cause is a lean running engine make sure the carbs are tuned correctly for the setup and there are no vacuum leaks remember the blower moves a lot more air through the engine so it needs more fuel as well maintenance weiand superchargers require little in the way of maintenance they are machined and set up to operate with tight clearances with no rotor-to-case contact make sure the rotors always turn freely and check immediately if the engine backfires monitoring lubricant levels is also important lubricant should be changed every 100 hours of operation if boost pressure drops dramatically the unit should be overhauled call weiand technical service for details regarding supercharger rebuilding frequently asked questions question can i run a supercharger on a stock engine answer in most cases you can depending on the size of the blower if you use a smaller blower you can get away with 5-6 psi of boost on a stock engine and premium pump gas if you are looking to utilize a larger blower such as a 6-71 or bigger you need a specifically built engine for the blower in most cases with a bigger blower you can t get the boost level down low enough to run pump gas on a stock engine question do i need to run a blower calibrated carb with a supercharger answer a lot is going to depend on what the setup is and what you are going to do with it if it is strictly a race setup with no street use then usually you can get away with a standard carb with the power valves plugged and the carb jetted up to compensate this does not work well on an application that will get mostly street time for those applications we do offer out of the box holley carbs with manifold referenced power valves which will work correctly on the blower these carbs will allow the use of the power valves which will give better idle quality and street driveability with a blower tech line 270-781-9741 73

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