How much boost to expect on a d1sc
How much boost to expect on a d1sc I just hooked up my boost gauge and let me tell you.... little disappointed. I'm only pulling around 4# on my D1sc. I hooked up the line from the brake booster if that makes a difference. It seems to almost always be in the vaccum side until it's full throttle and around 4k. Is this right? Part of me says that's about right but it still seems on the low side. I've got about 4 miles on the kit and I'm thinking pulley swap. I'm messed up. 
there is no stock pulley, you select a pulley size when you buy kit......post up what size pulley you have and then we can help you.....have you checked for boost leaks, or belt dust?
I just hooked up my boost gauge and let me tell you.... little disappointed. I'm only pulling around 4# on my D1sc. I hooked up the line from the brake booster if that makes a difference. It seems to almost always be in the vaccum side until it's full throttle and around 4k. Is this right? Part of me says that's about right but it still seems on the low side. I've got about 4 miles on the kit and I'm thinking pulley swap. I'm messed up.
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TECH Enthusiast
Joined: Nov 2007
Posts: 719
Likes: 0
From: Evans, Colorado
What elevation are you at?? that is a big consideration. Procharger messed up when they sent me mine. i made sure to give the info that i wanted to see 8 lbs at my elevation (5200 ft). the sent me the 4.25 pulley and i was only at 5-6lbs. I now have the 4 inch and I am now seeing about 8lbs.
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.
4 psi of boost will indeed result in disappointment... lol
* 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.
4 psi of boost will indeed result in disappointment... lol
Six inch crank pulley and four inch blower pulley. Also, it hasn't been tuned but its running rich. I can't see the tune producing more boost will it? I'm also planning on checking for knock retard.
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
well, a few things i see wrong here.. 1- i wouldnt hook to the brake booster. find another vacuum line to take your readings from. 2- the pulley ratios are way off. and 3- upgrade to an 8 rib kit. the 6 rib is askin for troubles with belt slip!
I found out that I had a leak at the actual boost gauge, I couldn't here it with the my cut out open and the window down. I'm sure that had something to do with it. Unfortuneately I just ate another belt so something isnt' lined up right. Either that or it's hitting the trans line. So back to the drawing board.
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
the ratio is the numbers divided by each other.. like the ratio of your pulleys is 4/6. thats .667:1 thats not gonna get much boost at all! i would guess that you would need more like a 4" blower pulley with a 7.65" crank pulley, so 4/7.65 or a .523:1 ratio for 8psi on a stock engine.
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
well, between that, a measly 6 rib belt, and a bad place to measure it from such as the brake booster, yea, that seems like a recipe for a 4psi reading on your gauge to me 
Your problems arent at all big or hard to fix 
Your problems arent at all big or hard to fix 
I'm with Chad, pulleys are off if they are what you said. Here is my experience on a 9.7:1 396ci (first 3 are with an LS6 intake, all with a 7.65" crank pulley); 4.5" pulley - 8psi, 3.7" pulley - 13psi, 3.4" pulley - 16psi, 3.4" pulley with Vic. Jr. and no air filter - 19psi.
I was at TRP last weekend and some dude thought I was you, lol, sorry to mimic! "Does this car have a ProCharger?" "Yep" "Is that a Mecham hood?" "Yep" "Are you ChevyChad?" "Nope".
I was at TRP last weekend and some dude thought I was you, lol, sorry to mimic! "Does this car have a ProCharger?" "Yep" "Is that a Mecham hood?" "Yep" "Are you ChevyChad?" "Nope".
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
classic! i should put that in my sig 