super charger boost seup?

Question

Can anybody tell me if the way to alter the amount of boost to a 671 super charger is the sizing of the drive pulleys or is there some adjustment on the super charger.I would imagine it would be the pulley sizing.

Nick

Answer 1

it's all in the pulley size of the crank and the blower drive. if the blower pulley is larger--the blower is under driver. If the blower pulley is smaller--them it's over driven (just terms--in rotation speed). There are formulas to help figure out how to do it---but you need to know total cubic inches, max. rpms, fuel being used, compression ratio, valve over lap, total cfm ----and some is trial and effort. Most cases the starting point is 6% under driven.
The 271, 471, 671, 6v71, 871, 1271, and 1471 blowers were designed for Detroit Diesel engines 71 series engine. the first numbers give the amount of cylinders they where originally designed for 671= 6 cylinder 71 series Detroit diesel. They were also used on the 53 series and other engines--but have always kept their original identification as per size.Because of over-driving and under-driving a 671 blower can be used on anything from a 289 cubic inches to approx 710 cubic inches. Yes, I agree that you should invest in a blow off plate--but that is only a safe guard in case of a backfire. There are blow off valves that can installed--but they vent a mixture of air/fuel--not something that is safe on a gas engine--because you draw fuel down threw the blower--and gating dispenses explosive vapors--unless your using direct injection.

Answer 2

The pulley size is the only way to go. I hope that you have considered upgrading the internals to handle the extra boost. A 6-71 blower was designed for a 426 cu in diesel engine. You should also consider installing a blow out plate so you don't blow out the bottom of your engine. check with Wiend.com for the right go fast pars.

Answer 3

yup, your right, its the size of the pulley that gives it more spin.