Procharger proflow not holding boost! Help I have a 2002 A4 corvette D1SC LS6 only seeing around 5lbs of boost on an autometer guage. I know I should be making more than that on a 4.38 pulley especially in cold weather. Anyway I should be making around 10 lbs boost, but the guage is showing only 5lbs. I checked the piping and also got new Fast 102 gaskets which I did not need. No other leaks, I also checked the boost guage and it works so I am thinking its the blow off valve not fully closing. Is their an adjustment screw somewhere? Its very frustrating trying to find this problem. Is bob here? Any help would be great Thanks in advance. |
What's the rest of the setup? That's an awfully large pulley so I wouldn't expect much more boost. I only make about 7 or 8 with a 4 inch pulley but I have a healthy cam. What size crank pulley? If you suspect the the bypass valve, I got a good tip from Bob at Brutespeed that you can just plug it or remove it and seal it off for a quick pull just to check if you make way more boost. It won't hurt anything for a brief pull. Also have you checked for belt slip? |
Originally Posted by ddnspider
(Post 19805688)
What's the rest of the setup? That's an awfully large pulley so I wouldn't expect much more boost. I only make about 7 or 8 with a 4 inch pulley but I have a healthy cam. What size crank pulley? If you suspect the the bypass valve, I got a good tip from Bob at Brutespeed that you can just plug it or remove it and seal it off for a quick pull just to check if you make way more boost. It won't hurt anything for a brief pull. Also have you checked for belt slip? |
So blower cam ported heads and a fast 102? I don't think your boost level is unreasonable given how large that pulley is. You need to step it down. |
Originally Posted by ddnspider
(Post 19805739)
So blower cam ported heads and a fast 102? I don't think your boost level is unreasonable given how large that pulley is. You need to step it down. Side note I have your issue in GM high tech performance mag. I seen your turbo car. |
Originally Posted by corvet786c
(Post 19805761)
I understand but I am still having this issue where my boost guage is not reading boost so back to my original question is there an adjustment nut on the BOV, maybe it became loose and is not holding pressure? Side note I have your issue in GM high tech performance mag. I seen your turbo car. Side note...thanks, my avatar pic is from the 1st time it was on a cover. The 2nd time it was on the cover of high performance Pontiac. That's when it actually ran a decent time. Lol. Tough to launch a turbo stock with a 10 bolt. Once I got the 9 inch in it, different story. I think it's changed hands a couple times since I sold it, but the current owners having fun with it to my knowledge. It was a solid car. |
The guage is showing about 5lbs now, but a few months ago in cold weather it showed 10lbs, I just looked over the BOV and it seems fine good spring pressure closed, No leaks in vacuum line I just don't know where else to look. Had no intake seals installed on Fast 102 car runs great otherwise. Doubled checked hoses, everything is fine. On a normal 85 degree day it shows around 7lbs. |
Ah ok that makes more sense. Have you tried retensioning the belt or is it an automatic tensioner? Is the belt worn? You do have the option of pressure testing the cold side too. |
Originally Posted by ddnspider
(Post 19805688)
What's the rest of the setup? That's an awfully large pulley so I wouldn't expect much more boost. I only make about 7 or 8 with a 4 inch pulley but I have a healthy cam. What size crank pulley? If you suspect the the bypass valve, I got a good tip from Bob at Brutespeed that you can just plug it or remove it and seal it off for a quick pull just to check if you make way more boost. It won't hurt anything for a brief pull. Also have you checked for belt slip? If you can't feel any air that's a good sign with the line removed. If you can feel some air as you rev it a few rpms, it's probable the gasket has deteriorated and has a pinhole and/or the blade mechanism is binding or is not closing completely. How old is the valve? My Proflow valve is the first version purchased in ( 2007. I understand there is a newer version of the ProFlow. Don't know production date. Having the same issue as you thinking the valve wasn't closing, I replaced the bladder. However, when I took the valve apart, the bladder was in nearly perfect condition with no holes. ProCharger sent me a new bladder overnight and I replaced the old bladder, however. My Proflow valve has a nut extending out of the valve. But all I found is that it adjusts the butterfly to full open. So after reassembling the valve with a new bladder (the new bladder wasn't as soft and plieable as the old) I discovered that at idle with no boost the butterfly was only open about 45 percent. After adjusting the nut, the adjustment allowed the valve to open so the blade was exactly 90 degrees (full open)- same as the position of the throttle blade on the throttle body at full throttle. How did I know something was amiss after assembly? Less noise at idle from air exiting the Proflow. If you had 10 lbs at one time and now don't, I suspect a vacuum leak or leak in one the silicone pipe connections. Or even perhaps a leak in the intercooler(s) or piping. Intercoolers are easy to test for leaks. Fill with water and wait. If there is a leak water will find its way out. Bar and plate intercoolers are more durable than tube and fin but imagine under worst case scenario an object kicked up off of the road might create a pin hole leak. If there is a minor leak at a silicone connection, I have noticed that dust will collect inside the silicone hose at the leak. Will even see dust on the pipe at the connection where the leak is. Note the flow of air at each pipe connection. Is it sucking in or blowing out? IMO cold temps allow a worn out belt to slip more easily that warm temps so you might have some belt slip even thought you don't see any belt dust. Pipe connectors aren't as pliable and soft either. HTH So what was my issue? Dry rotted vacuum line at the tip at the vacuum source along with leaks at two silicone pipe connectors. I also had a tranny with a pump that was failing on the dyno. |
Originally Posted by dlandsvZ28
(Post 19805879)
Vacuum pulls the valve open, so simply removing the vacuum line will close the valve. Simply pull the line off of the valve. At idle, you can stick it back on, the valve should open, pull it off the valve should close easily if the hinge mechanism isn't binding. If you can't feel any air that's a good sign with the line removed. If you can feel some air as you rev it a few rpms, it's probable the gasket has deteriorated and has a pinhole and/or the blade mechanism is binding or is not closing completely. How old is the valve? My Proflow valve is the first version purchased in ( 2007. I understand there is a newer version of the ProFlow. Don't know production date. Having the same issue as you thinking the valve wasn't closing, I replaced the bladder. However, when I took the valve apart, the bladder was in nearly perfect condition with no holes. ProCharger sent me a new bladder overnight and I replaced the old bladder, however. My Proflow valve has a nut extending out of the valve. But all I found is that it adjusts the butterfly to full open. So after reassembling the valve with a new bladder (the new bladder wasn't as soft and plieable as the old) I discovered that at idle with no boost the butterfly was only open about 45 percent. After adjusting the nut, the adjustment allowed the valve to open so the blade was exactly 90 degrees (full open)- same as the position of the throttle blade on the throttle body at full throttle. How did I know something was amiss after assembly? Less noise at idle from air exiting the Proflow. If you had 10 lbs at one time and now don't, I suspect a vacuum leak or leak in one the silicone pipe connections. Or even perhaps a leak in the intercooler(s) or piping. Intercoolers are easy to test for leaks. Fill with water and wait. If there is a leak water will find its way out. Bar and plate intercoolers are more durable than tube and fin but imagine under worst case scenario an object kicked up off of the road might create a pin hole leak. If there is a minor leak at a silicone connection, I have noticed that dust will collect inside the silicone hose at the leak. Will even see dust on the pipe at the connection where the leak is. Note the flow of air at each pipe connection. Is it sucking in or blowing out? IMO cold temps allow a worn out belt to slip more easily that warm temps so you might have some belt slip even thought you don't see any belt dust. Pipe connectors aren't as pliable and soft either. HTH So what was my issue? Dry rotted vacuum line at the tip at the vacuum source along with leaks at two silicone pipe connectors. I also had a tranny with a pump that was failing on the dyno. I guess I am going to have to inspect all the hoses and connections sometime. My Fast 102 has new gaskets and was sealed with rtv a couple of yrs ago, it should be fine right? |
Cap the BOV and see if you get more boost. A little surge one time isn't' going to hurt anything. This was the issue on a friends car. It did pop the air filter off onto the header when he let off though, so might want to pull that. |
The other option I mentioned is to pressure test the cold side. This will show whether or not there is a leak that only shows up when in boost. Pressure test it for 10psi and see what leaks. |
Originally Posted by ddnspider
(Post 19805955)
The other option I mentioned is to pressure test the cold side. This will show whether or not there is a leak that only shows up when in boost. Pressure test it for 10psi and see what leaks. |
on a buddy's procharged car we boost tested the whole system found the maf adapter leaking, the bypass valve was leaking and the head unit it self was leaking |
Originally Posted by ls3fox
(Post 19805979)
on a buddy's procharged car we boost tested the whole system found the maf adapter leaking, the bypass valve was leaking and the head unit it self was leaking Any other suggestions? |
A couple things, hoses can leak, I have had them pull apart (conns.) and go back under boost, def hard to find. Also, are you sure of 100% throttle, sometimes on the street you may think its 100%, but self preservation takes over and you are not 100%-when I switched to data logging, I was surprised, lol. Easy enough to eliminate the surge valve, but I suspect that isn't it. |
Originally Posted by forcd ind
(Post 19806325)
A couple things, hoses can leak, I have had them pull apart (conns.) and go back under boost, def hard to find. Also, are you sure of 100% throttle, sometimes on the street you may think its 100%, but self preservation takes over and you are not 100%-when I switched to data logging, I was surprised, lol. Easy enough to eliminate the surge valve, but I suspect that isn't it. |
Found another leak coming from the I/C to the y-pipe it was a pin hole leak at idle. I used the windex. Could imagine how it opens up during wide boost. Also I am still getting some air coming from the MAF. I wonder if the coupler is the right size? |
Are you using T bolt clamps or radiator clamps on the conns. |
2 Attachment(s)
Originally Posted by forcd ind
(Post 19806577)
Are you using T bolt clamps or radiator clamps on the conns. |
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