underpressureWs6

iTrader: (17)

ok so i need some help before tomorrow when i drop the car off, car has the sdce setup on it with their 7.25 crank pulley and a 3.70 blower pulley on my d1-sc im seeing 11#'s right now and need to be seeing around 15-16 #'s i called procharger and they said a 3.40 pulley will only bring me to around 14#'s that doesnt seem right to me so i wanted your opinions on what size blower pulley i should run to see at least 15#'s thanks!

The Alchemist

iTrader: (19)

The problem with going smaller than a 3.40" head unit pulley is belt slip. Honestly, to run a 3.4 head unit pulley, you need a 7.65" crank pulley to max out the blower.

Also, don't fixate on psi. Look at what else you can do to maximize the efficiency of your setup, specifically the inlet to the head unit, as well as the piping and intercooler setup. You'd be surprised how much hidden boost is in the inlet and intercooler setups.

underpressureWs6

iTrader: (17)

i hear ya man, my plan is next year maybe to up to an F1-C head unit and a front mount so thats why for now i want to get the most out of my setup, East Coast Supercharging ditched my 7.65 procharger pulley for the sdce 7.25 because of belt alignment issues so ill be sticking with the 7.25 crank pulley, ill run a 3.40 blower pulley, see where it sits and just be done with it for now i guess..

Bob@BruteSpeed

iTrader: (16)

You have to run the 7.25 crank pulley with the SDCE kit, unless an LS2 Corvette water pump will give the necessary clearance. Not knowing what your engine combination is, makes it impossible to tell you how much boost your combination is going to make. Bob

How much boost the blower can produce depends on many variables.
* Cubic inch. The larger the engine the less boost it will make with a supercharger.
* Headers and exhaust. A better flowing system will produce less boost, requires a smaller pulley to regain the loss in boost. Ultimately though, more power will be gained.
* Camshaft and heads. A camshaft with some overlap will leak out some boost through the valves. Better flowing heads react a lot like a better flowing exhaust system.
* Altitude. Elevation plays a big part in how much boost is produced. Those people living in the higher elevations have to spin the blower harder to see boost.
* Condition of engine. An engine with real good sealing rings will ultimately produce more boost than one with worn rings.
* Rpm. An engine that is spun up higher in the rpm range will normally produce more boost.

underpressureWs6

iTrader: (17)

Thanks for the advice bob the engines an LS2 365 C.I. 1-3/4 longtubes with catless y-pipe and borla catback full open, its East Coast Superchargings "big" blower cam which is similar to yours they dont release exact specs on it, PRC 2.5 LS6 heads, im at pretty much sea level lol im right next to manhattan, engine is brand new 700 miles on it so far, and it revs to 6k

Bob@BruteSpeed

iTrader: (16)

To determine the impeller speed, the following formula is used:

Maximum impeller speed = crankshaft pulley diameter (N1) divided by supercharger pulley diameter (N2),multiplied by the step-up ratio (4.10 for the P-series/D series - 5.40 for the F series), multiplied by engine rpm at redline.
The D-1SC has a max impeller speed of 62,000 rpm. 52,455 rpm isn't going to get you a whole lot of boost. Bob

underpressureWs6

iTrader: (17)

so with a 3.40 blower pulley i have to rev to 7k rpm's to get the impellar speed up to 61,198 can i safely spin the motor that high? its got prc .650 lift springs and valves, manley forged pistons and r&r steel billet connecting rods on a stock crank

Bob@BruteSpeed

iTrader: (16)

The engine might be able to handle 7000 rpm, but your power may be down even though it is making more boost. I'd settle for 6500 rpm and try to be happy with it until you step up to a larger blower. In reality it is going to make more power than what the streets can handle. Bob

underpressureWs6

iTrader: (17)

good enough for me thanks bob! ill let you know how it turns out

underpressureWs6

iTrader: (17)

Honestly anything over 700 to the ground ill be happy this is through an auto and high stall also

Z-28

Check this out:
https://ls1tech.com/forums/forced-in...e-upgrade.html

https://ls1tech.com/forums/forced-in...ulate-psi.html