# Vortec supercharger boost issues?
**URL:** https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908
**Category:** Shift518 Automotive
**Created:** [April 29, 2013, 5:58pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908 "2013-04-29T17:58:30Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@love4boost](https://forums.speedlife.net/u/love4boost)
#### Post date: [April 29, 2013, 5:58pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/1 "2013-04-29T17:58:30Z")
Mustangs body work is all done and now focusing on mechanical work… Car had like zero brakes, checked everything and finally installed new brake booster which fixed the brake issue… It wasnt building any boost at all and now it is hitting 3-4psi at higher rpms… it has a 3.48" 6 rip pulley which iirc is an 8 psi pulley.
Any ideas on what this could be or does it sound like the supercharger is dicked?
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### Author:  [@SRS\_BZNS](https://forums.speedlife.net/u/SRS_BZNS)
#### Post date: [April 29, 2013, 6:17pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/2 "2013-04-29T18:17:55Z")
Does that set up have a purge valve or whatever. Could be bleeding all your boost out of that
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### Author:  [@love4boost](https://forums.speedlife.net/u/love4boost)
#### Post date: [April 29, 2013, 6:20pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/3 "2013-04-29T18:20:48Z")
no valve
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### Author:  [@sbardy](https://forums.speedlife.net/u/sbardy)
#### Post date: [April 29, 2013, 6:22pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/4 "2013-04-29T18:22:17Z")
check the enis hole by the nut on drivers side.
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### Author:  [@SRS\_BZNS](https://forums.speedlife.net/u/SRS_BZNS)
#### Post date: [April 29, 2013, 6:23pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/5 "2013-04-29T18:23:13Z")
How old is the belt might be slipping or not have enough tension
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### Author:  [@love4boost](https://forums.speedlife.net/u/love4boost)
#### Post date: [April 29, 2013, 6:27pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/6 "2013-04-29T18:27:32Z")
> [@Is everyone OK?](https://forums.speedlife.net/t/is-everyone-ok/50718/195):
>
> How old is the belt might be slipping or not have enough tension
was thinking that too, but i guess my buddy said naw…
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### Author:  [@Eatonualive](https://forums.speedlife.net/u/Eatonualive)
#### Post date: [April 29, 2013, 6:47pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/7 "2013-04-29T18:47:05Z")
does the car have head work, cam, or long tube headers?
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### Author:  [@Eatonualive](https://forums.speedlife.net/u/Eatonualive)
#### Post date: [April 29, 2013, 6:47pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/8 "2013-04-29T18:47:33Z")
what headunit (blower model) do you have?
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### Author:  [@love4boost](https://forums.speedlife.net/u/love4boost)
#### Post date: [April 29, 2013, 6:55pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/9 "2013-04-29T18:55:02Z")
> [@Weak Sauce](https://forums.speedlife.net/t/weak-sauce/52545/2):
>
> does the car have head work, cam, or long tube headers?
> [@WTB: DD under 2k](https://forums.speedlife.net/t/wtb-dd-under-2k/52527/5):
>
> what headunit (blower model) do you have?
heads are stock, i think cam is stock too, does have h pipe… its a vortec v3, not sure if sc or si trim though… has 3.48" pulley on it.
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### Author:  [@Eatonualive](https://forums.speedlife.net/u/Eatonualive)
#### Post date: [April 29, 2013, 7:16pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/10 "2013-04-29T19:16:52Z")
ok. does it have longtube headers? what size is the lower pulley?
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### Author:  [@love4boost](https://forums.speedlife.net/u/love4boost)
#### Post date: [April 29, 2013, 7:24pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/11 "2013-04-29T19:24:46Z")
> [@Weak Sauce](https://forums.speedlife.net/t/weak-sauce/52545/4):
>
> ok. does it have longtube headers? what size is the lower pulley?
short headers and im not sure
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### Author:  [@Johawk](https://forums.speedlife.net/u/Johawk)
#### Post date: [April 30, 2013, 4:39am UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/12 "2013-04-30T04:39:20Z")
My GTP used to go thru a belt ever 5-6 months depending on how hard I beat it. Small blower pulley + High tension to keep it from slipping would kill it. It would usually begin slipping again on a cool night where boost would normally be in the 15psi range and would drop to 10psi at high RPM. New belt and fixed. They never looked really bad, except the first one before the tensioner upgrade, and you could never hear them slip like a power steering or Alternator squeal. For $40 get a good quality belt and try that.
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### Author:  [@88slowmarro](https://forums.speedlife.net/u/88slowmarro)
#### Post date: [April 30, 2013, 5:35am UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/13 "2013-04-30T05:35:54Z")
I’m wondering if the blower is to small for him , it’s a entry level blower and from what I see it don’t push to many c.f.m,s and pulley swapping the shit out of it to make any boost may over spin the blower
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### Author:  [@love4boost](https://forums.speedlife.net/u/love4boost)
#### Post date: [April 30, 2013, 6:53am UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/14 "2013-04-30T06:53:34Z")
> [@THE \*\*iPhone\*\* Thread (GPS, JailBreak, Apps, Etc)](https://forums.speedlife.net/t/the-iphone-thread-gps-jailbreak-apps-etc/52832/72):
>
> I’m wondering if the blower is to small for him , it’s a entry level blower and from what I see it don’t push to many c.f.m,s and pulley swapping the shit out of it to make any boost may over spin the blower
Def not, its a car specific blower in which they made 2 models of… A 5-6 psi unit that produced 275whp on a stock 5-0 and an 8-9 psi iirc which produced 331whp on a stock 5.0, both not alot of power… My original thought was it haad to be the cheapest unit possible bc of the condition i aquired the thing in lol, BUT it does have the 3.48" pulley… Either way the blower is set up for that car
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### Author:  [@88slowmarro](https://forums.speedlife.net/u/88slowmarro)
#### Post date: [April 30, 2013, 7:02am UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/15 "2013-04-30T07:02:48Z")
Right but u have a bbk Siamese intake and headers , a possible cam etc so ya may be using more air than the blower can push ! I’m not doubting its the right blower at all
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### Author:  [@love4boost](https://forums.speedlife.net/u/love4boost)
#### Post date: [April 30, 2013, 8:13am UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/16 "2013-04-30T08:13:26Z")
> [@MSTR TWO's going away party - 8/1/08 @ Brennan's](https://forums.speedlife.net/t/mstr-twos-going-away-party-8-1-08-brennans/52327/40):
>
> Right but u have a bbk Siamese intake and headers , a possible cam etc so ya may be using more air than the blower can push ! I’m not doubting its the right blower at all
wanna pick it up for me and bring it to your shop? lol, its ready to go now
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### Author:  [@Eatonualive](https://forums.speedlife.net/u/Eatonualive)
#### Post date: [April 30, 2013, 10:30am UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/17 "2013-04-30T10:30:00Z")
john, we still have no idea how big the lower pulley is. if its smaller than it should be, you will decrease boost. its more than just the pulley size on the blower that dictates boost. if you have headwork and a cam that could also LOWER boost. you are making your motor more efficient. dave, did you measure boost at redline? bc thats where you will see you max psi on a centri type blower.
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### Author:  [@88slowmarro](https://forums.speedlife.net/u/88slowmarro)
#### Post date: [April 30, 2013, 11:08am UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/18 "2013-04-30T11:08:28Z")
I’m getting it I guess , I’m gonna measure pulleys and whatnot and see what it does
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### Author:  [@Eatonualive](https://forums.speedlife.net/u/Eatonualive)
#### Post date: [May 1, 2013, 3:49pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/19 "2013-05-01T15:49:17Z")
def do that. boost is just a measurement of restriction. if the motor breathes better and flows more air, your boost will drop a little. but will make more power. does it have a dedicated belt system for the blower, or does it just use a longer serpentine belt? either way. a smaller upper pulley and larger crank pulley will increase boost. larger upper and smaller lower will decrease boost.
…ooorrrrrr just put an LS1 in it and you’re done lol!
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### Author:  [@88slowmarro](https://forums.speedlife.net/u/88slowmarro)
#### Post date: [May 1, 2013, 4:18pm UTC](https://forums.speedlife.net/t/vortec-supercharger-boost-issues/266908/20 "2013-05-01T16:18:47Z")
I don’t have it yet man , when i do I’m measuring pulleys and seeing what blower specs r first so I now I don’t overdrive it to high and over spin the blower etc .