What is the difference between the 65mm sc pulley vs 62mm vs 178 crank vs 181 vs 185.
Is the 65 and 178 the same.
Thanks in advance

 

Crank pulleys cost a lot more, are harder to install, turn every accessory faster (as opposed to just the SC), and require a smaller water pump pulley. The SC pulleys only increase supercharger RPMs and take about 20 minutes to install. The 65 and 178 don't require fuel system upgrades like all other pulleys will. The 62 and 185 are about equivalent and will need the addition of higher fuel flow. The 181 falls in the middle of the two groups and should be treated like the 62 and 185 in regards to fueling.

Boost increase that I've seen or documented on our cars has varied with the amount of additional mods on the car. With a 65 it has ranged from 15.8 to 18.7 psi. Have seen a 62 do 21 psi. A 178 at 17.4. But all that can vary with weather and altitude. Hope that helps you out. Personally, I'm not a huge fan of crank pulleys. Just my $0.02.

 

If you install a crank pulley, be sure to purchase the correct pulley saver kit from NeedsWings. This kit will slow all the accessories back down to the correct speed rotation. Do a fuel upgrade then keep a firm grip onto your steering wheel while enjoying the trouble free new power. Squirrel Crusher

 

Chuk hit the nail right on the head with his comment... me personally I ran the 65mm pulley for 40,000 mile with zero problems. I'm at 20 ft above sea level and peaked at 18psi.. now I have the 185 crank pulley with all the fuel mods and every mod you can get and I peak at 22psi.. crank pulley is AMAZING if done and prepared for correctly..

 

65mm sc and 178 crank are similar in boost pressure I take it
Thanks for all the info.

 

You are correct.. although for some reason or another I've heard the 178 edges out the 65 in performance... the 181 seems to be the perfect median for overall driving... but I tell you what if you can battle the heat soak and fuel issues the 185 is like night and day difference

 

To compare the different combo's know your crank pulley and SC pulley diameters, Divide the crank pulley by the SC pulley and multiply that number times our engine's redline(6200rpm). For example the most common pulley change is going to the 65mm SC pulley. The stock crank is 155mm in diameter. So 155 divided by 65 is 2.3846. Multiply that by 6200rpm and we get 14,784. In comparison a 155 crank and a 74mm SC(stock diameter) yields 12,986.
I am running a 178 crank and a 70mm SC pulley. Doing the math yields 15,765. Running just a 62mm SC pulley yields 15,500.
The nice thing about changing both pulleys is the amount of boost the motor sees at lower rpm's. Getting the boost quicker, at a lower engine rpm is what gives that "push me back into the seat feeling. I have not played with the figures to find what I would feel is the "best" combination".

 

Thanks for everyone's input.