I didn't do the install and don't have the directions but i knew something was wrong. The stock 3.8 pulley should make 10.5 psi with an open air filter and 12 psi without any tube or filter at 7500 rpms. Im seeing 13 psi with the 3.47 pulley and an open air filter, without the tube and filter it'll make another pound or two. Beefcakes didn't bother to read the post that I linked above to modford, I specifically asked in that post what pulley makes 12 psi on his car and he responded "stock pulley" without any filter or tube. I'll take a picture later today.
Anybody change to a smaller pulley on a paxton
- Thread starter stang910
- Start date
I didn't do the install and don't have the directions but i knew something was wrong. The stock 3.8 pulley should make 10.5 psi with an open air filter and 12 psi without any tube or filter at 7500 rpms. Im seeing 13 psi with the 3.47 pulley and an open air filter, without the tube and filter it'll make another pound or two. Beefcakes didn't bother to read the post that I linked above to modford, I specifically asked in that post what pulley makes 12 psi on his car and he responded "stock pulley" without any filter or tube. I'll take a picture later today.
I did read it. The stock pulley is setup for 7.5 to 8.5 psi. I have yet to see a kit pushing 12psi on the stock 3.8 pulley. I don't believe it's possible at 7500 rpms
better intake and breathing is going to get you a little more, but not 3.5
Try actually reading the post before responding next time.
Ok cool thanks. The most amount of boost I have made on the stock pulley and stock airbox is 8 pounds. Everything I have ever heard, that's the most the stock pulley will make with the stock airbox.
It's the same results I'm having now, open filter + 3.8 pulley @ 7500 rpm is 10.5 psi, pull the intake tube off and it'll make 12 psi. The 3.47 Will make 13 psi with the filter on and I'm guessing another pound or two without the filter ( haven't tested this yet)
The stock air box is a totally different deal, it's a huge restriction. If your making 8 psi with the stock pulley and stock air box most likely you don't have a problem.
yes, rated for 7.5 to 8.5 with the stock box, 8 is right in the middle
I didn't think that I did! Im just trying to figure out how you made more boost than I did with the same setup.
Are you talking about a check valve in the line coming from the brake booster? Mines on a manual car, I'm not sure if it is different on a auto car. I just got done installing mine but haven't started it yet still waiting on spark plugs and Bap, just don't wanna run into any problems.
I ordered my Paxton with a 3.60 pulley, it makes 10lbs with the JLT intake. I stepped it back from a 3.30 pulley that was making 12-13 psi and made 759/583. These motors are strong, but I was worried I was pushing it.
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You sure can, just use a pair of channel lock pliers to hold the pulley,
and a rag so you don't scratch the pulley, and break the nut loose with a wrench. Then remove the belt, unscrew the pulley bolt, (be sure not to lose the key that holds the pulley on the shaft) remove the pulley, and slap the new one on, tighten the bolt back and put the belt back on.
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No problem!
My car hit 12psi @ 7500 with the stock pulley. I am also running the paxton kit. The reason for the high boost im sure is because I am utilizing my factory headers. I have had my SW long tubes sitting in my basement for some time now. Just dont have the funds to put them on. I know it will make a huge difference in power and also decrease my manifold pressure by at least 2 pounds. My car was worked on by JPC and dyno'd 570/480 on a very conservative tune. Once I get the long tubes on and incorporate some race gas in the mix it will be putting down a minimum of 620whp conservatively.
JPC is a great company to deal with and looking forward to doing some business with them in the new year.
JPC is a great company to deal with and looking forward to doing some business with them in the new year.
Whatever pulley you run the higher you spin it the more boost it will make! A stock pulley is not gonna make the same boost at 6500rpm and 7500rpm! Also any removal of restriction before the blower will increase boost, and any removal of restriction after the blower will decrease the boost reading! Its still gonna move the same amout of air, but the back-pressure has decreasd.
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The more flow open up front the more psi you will see. If you start opening exhaust restrictions the boost will go down though. So depending what headers, or muffler you run will also play a part in boost.
easiest way
loosen s/c pulley bolt
loosen idler pulley bolt
lift tensioner, pull out idler pulley, let down
slide pulley off, replace, and reverse
loosen s/c pulley bolt
loosen idler pulley bolt
lift tensioner, pull out idler pulley, let down
slide pulley off, replace, and reverse
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