need help with pulley sizes
08-13-2008, 03:42 PM
#1
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need help with pulley sizes Ok guys just got my procharger installed, I am only making about 2.5 to 3lbs of boost max. I measured my pullies and here is what I have. Crank pulley is a 6" which seems small compared to what everyone else is running. Blower pulley is a 4" do you guys think the pulley setup is why I am not seeing much boost, I would like around 8lbs. My car has a small cam, full exhaust, off road y pipe, stock ported polished heads.
08-13-2008, 05:53 PM
#2
I was wondering the same but BOB came to the rescue.He said
"There is no set pulley for making x amount of boost. The reason is due to many variables such as: Does the car have headers or exhaust manifolds, cats, cat back exhaust, cam, heads, cubic inch, elevation, etc. Say you are making 8 psi with a bone stock Camaro and you add headers, better flowing cats and a cat back exhaust. You will find your boost level now at somewhere around 6.5 psi, as the system is less restrictive now. To get the boost back to 8 psi a smaller pulley will need to be installed on the blower, and possibly a shorter belt. There is a number stamped on the side of the pulley, so that you know which one you have now.
When I place a ProCharger order, I take into account all of the above variables, so that the customer gets the psi he or she is looking for. Bob"
BOB is the man!!!!!!!!!!!!!!!!!
"There is no set pulley for making x amount of boost. The reason is due to many variables such as: Does the car have headers or exhaust manifolds, cats, cat back exhaust, cam, heads, cubic inch, elevation, etc. Say you are making 8 psi with a bone stock Camaro and you add headers, better flowing cats and a cat back exhaust. You will find your boost level now at somewhere around 6.5 psi, as the system is less restrictive now. To get the boost back to 8 psi a smaller pulley will need to be installed on the blower, and possibly a shorter belt. There is a number stamped on the side of the pulley, so that you know which one you have now.
When I place a ProCharger order, I take into account all of the above variables, so that the customer gets the psi he or she is looking for. Bob"
BOB is the man!!!!!!!!!!!!!!!!!
08-13-2008, 06:06 PM
#3
2.5lbs of boost seems pretty low to me, I'd check to make sure you're not leaking boost anywhere. My 396 w/AFR's, 1 7/8 Kooks and TD's made 10psi on a 4.5" pulley and should make around 17-18 on the new 3.7" pulley. I'd double check everything and make sure that no clamps are loose etc. then look into a smaller pulley. Are you measuring boost by a mechanical gauge or a electronic gauge?
08-13-2008, 06:57 PM
#4
I was wondering the same but BOB came to the rescue.He said
"There is no set pulley for making x amount of boost. The reason is due to many variables such as: Does the car have headers or exhaust manifolds, cats, cat back exhaust, cam, heads, cubic inch, elevation, etc. Say you are making 8 psi with a bone stock Camaro and you add headers, better flowing cats and a cat back exhaust. You will find your boost level now at somewhere around 6.5 psi, as the system is less restrictive now. To get the boost back to 8 psi a smaller pulley will need to be installed on the blower, and possibly a shorter belt. There is a number stamped on the side of the pulley, so that you know which one you have now.
When I place a ProCharger order, I take into account all of the above variables, so that the customer gets the psi he or she is looking for. Bob"
BOB is the man!!!!!!!!!!!!!!!!!
"There is no set pulley for making x amount of boost. The reason is due to many variables such as: Does the car have headers or exhaust manifolds, cats, cat back exhaust, cam, heads, cubic inch, elevation, etc. Say you are making 8 psi with a bone stock Camaro and you add headers, better flowing cats and a cat back exhaust. You will find your boost level now at somewhere around 6.5 psi, as the system is less restrictive now. To get the boost back to 8 psi a smaller pulley will need to be installed on the blower, and possibly a shorter belt. There is a number stamped on the side of the pulley, so that you know which one you have now.
When I place a ProCharger order, I take into account all of the above variables, so that the customer gets the psi he or she is looking for. Bob"
BOB is the man!!!!!!!!!!!!!!!!!
08-13-2008, 06:58 PM
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I talked to Bob earlier he said the 6" crand pulley is way to small. I defiently need to go to atleast a 7" to get around 7to8lbs. I had bought this kit used, so far this is the only problem I have had. I have check and double checked all hoses and hose clamps all that seems to be ok.
08-13-2008, 07:01 PM
#6
2.5lbs of boost seems pretty low to me, I'd check to make sure you're not leaking boost anywhere. My 396 w/AFR's, 1 7/8 Kooks and TD's made 10psi on a 4.5" pulley and should make around 17-18 on the new 3.7" pulley. I'd double check everything and make sure that no clamps are loose etc. then look into a smaller pulley. Are you measuring boost by a mechanical gauge or a electronic gauge?
The op has a very small 6.0" crank pulley which is one inch smaller than the standard 6 rib crank pulley. The 8 rib system uses a 7.65 crank pulley. This is a huge difference! My old D-1SC 6 rib kit had a 4.0" blower pulley and with headers and exhaust it made 7 psi of boost. With his 6.0" crank pulley I'd say the boost he is making is about right.
The first thing I'd say for him to do is to get a 7.0" crank pulley. Bob
08-13-2008, 07:13 PM
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Hey Bob I emailed you on ordering that pulley, if you could give me a call or if you still have my info from the computer just go ahead and get it ordered for me. Thanks alot
