Bypass Valve, How Do You Know If Its Leaking?GM SC - Boost Forum

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Bypass Valve, How Do You Know If Its Leaking?GM SC
Tuesday, September 19, 2006 5:54 PM
I am having problems with my built 2.4, I ran a 15.3 at the track and was very pissed because the car is professionally tuned with HPT, eagle H beams, .020 over bore, JE pistons the works. I have every bolt on imaginable including meth injection and the secret cam swap.

I am assuming I am loosing boost since I have never to date seen over 5 psi of boost on my guage and also the car is slower than hell.

So my questions are as follows

How can I tell if the bypass valve is bad?

I stripped the GM sc of all of the paint maybe some of the stripper got into the bypass, could this F it up?

Whats the GM part number for the bypass valve and cost?

Has anyone else had this problems with the bypass valves?

Also I am running the 2.6 inch pulley with methanol.



http://members.cardomain.com/vertz24 1998 Z24 Convertible

Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 5:59 PM
hmm I keep looking through my price list and don't see the valve you're saying listed.... or maybe I just can't find it, I am still kinda tired from finals...

here you go chris. me and eric put this together a while ago...


--------------------------------





Bracket, S/C Support, Lower 88960232 -121.98

Bracket, S/C Support, Top 88960233 -39.46

Duct, Intake Air 88960234 -142.06

Bracket, S/C Snout Support, Lower 88960235 - 39.46

Bracket, S/C Snout Support, Upper 88960236 -39.46

Bracket, Cruise Control Relocation 88960480 105.18

Plug, Inlet Air Temparature Sensor 88960479 - 1.98

Adapter, Intake Air Duct 88960237 -DISCONTINUED

Hose Clamp, Hose for Reducer 10039976 - 9.42

Hose, PCV, Baffle to Intake Air Duct 09436383 - DISCONTINUED

Hose, EVAP to Throttle Body 09438315 - 97.58

Hose, MAP Sensor to S/C 12387951 - 50.30

Belt, Accessory Drive 88960481 - 193.72

Tube, Brake Booster to Throttle Body 58960482 - DISCONTINUED

Flat Washer, PCV Bent Tube 94127883 - 1.04

Bolt, Nose Support, Upper to Lower 24503664 - DISCONTINUED

Bolt, Idler to Lower Nose Support 11515755 - 4.84

Bolt, Top/Bottom Bracket to Manifold 11515756 - 0.74

Bolt, Manifold Flange 11508476 - 0.86

Bolt, Bottom Bracket to Block 11515769 - 4.84

Spiral Lock Washer, Lower Bracket to Block 11500046 - 0.74

External Tooth Lock Washer, Upper to Lower Support 11501869 - 4.30

Spiral Lock Washer, Top/Bottom Brackets to Manifold & PCV Bent Tube 09439511 - 0.74

Spiral Lock Washer, MAP Sensor & Cruise 09439510 - 6.44

Nut, Cruise Control Bracket 03530297 - 1.48

Sensor, MAP 09350899 - 225.75

Clamp, 5/8" hose 10293740 - 4.84

Decal, Accessory belt routing 88960577 - 17.62

Injectors, Fuel 17113399 132.74 (EACH?)

Spark Plugs 05613717 - 2.66 (EACH?)

Decal, Fuel Use 88960578 - 13.32

Nylon flex loom, Hose PCV Elbow to Intake Air Duct 88960622 - 4.56

Barbed Hose Coupler, EVAP Hose to Rubber Elbow 88960623 - 8.32

Wire loom, Aire Temp Sensor Wire 12051375 - 38.34

Baffle Assembly, PCV 88960484 - 499.41

Seal, PCV Baffle 88894217 - 25.90

Actuator, Supercharger By-pass 88960487 - 163.78

O-ring, Throttle Body 88960488 - DISCONTINUED

O-ring, Intake Manifold Runner 88960489 - 39.56

O-ring, PCV Port 88960490 - 4.46

Grommet, Air Temperature Sensor 15705446 - 1.42

Clamp, Air Temperature Sensor 88960491 - 7.18

Bolt, Air Temperature Sensor and MAP Sensor Mounting 52368558 - 1.68

Bracket Assembly, Idler 12498289 - 267.22

Pulley, Idler 88960493 - DISCONTINUED

Bearing, Idler Pulley 88960581 - DISCONTINUED




Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 6:03 PM
actually. I just realized it wouldn't be on there...

god I'm tired.


Sorry Chris, I can't be of more help....

You say you're not seeing 5? that's odd, if there's no leakage..... hmm I know on my stock pulley I make 5 consistently. but you're farther ahead of me as far as engine mods go....

Sorry man.



Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 6:03 PM
I may have to go to eaton for it I guess, all I know is my car is slowwwwwww.



http://members.cardomain.com/vertz24 1998 Z24 Convertible
Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 6:10 PM
Wow nari, you actually got one? I did not know, I dont get on much any more, the car just pisses me off. Also it looks nothing like my sig any more. Just wish the car ran fast, POS.



http://members.cardomain.com/vertz24 1998 Z24 Convertible
Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 6:59 PM
course I got one. I've had it for a few months now. It's still every bit as fun as when I got it too.

haven't had any issues at all either.

and yes my car still looks the same as in the pictures haha I don't really change much...



Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 7:06 PM
same here man, im not seeing anything over 5psi with the 2.6 pulley and injection. my car seems to get up and go alright i guess, not as fast as i think it should though but i dunno what else to do either. once venom contacts me back i can get my module back and install the 4.3 blazer fuel pump and hopefully see low 13's, if not then i have some thinking to do as far as turboing the car and selling the charger.




Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 9:33 PM
how do you guys only see 5psi with the 2.6 pulley? lately with it being really damp and cold i have been able to consistently hold 10-13 psi with my alky not working




Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 10:34 PM
yep im only seeing 6psi on the 2.6" and meth.....ive asked this question b4 and got no answer for it....so gl



2000 Camaro V6.
| SLP Loudmouth | CAI Intake | HID's |


Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 10:37 PM
its seems to obvious but could the reason you guys arent getting the same results on pulley sizes be slippage?



2007 GM Tuner Bash...HELL YEA
PA,MD,NJ,DE,NY and all states north caravan
Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 11:05 PM
Boardorgohome wrote:its seems to obvious but could the reason you guys arent getting the same results on pulley sizes be slippage?


i was just gonna ask that to them





Re: Bypass Valve, How Do You Know If Its Leaking?G
Tuesday, September 19, 2006 11:23 PM
Chris when I tuned the car and did the cams I did check out the belt and it seemed decent, however it wasn't as tight as mine is on my car. There could be some slippage though, that kinda crossed my mind as well. Your car should definately be seeing more than 5psi, however how much more is so hard to tell. I've seen so many gm s/c read very different boost numbers.

John - when i tuned your car i was very satisfied with the results, but i would definately like to see some track numbers to see what gains the hptuners made on your car. Your car is a bit different that Chris' car though, you have a completely modded head which is going to lower your boost numbers substantially due to it making each psi of boost more efficient by the increase of airflow. If i can get my hands on a boost gauge I will get you guys some reading on the boost numbers I am seeing on my car. My bypass valve has been "tweaked" a bit and my belt is tighter than @!#$. However i wouldnt be surprised if i was losing a tad bit of boost in the upper rpms seeing that the thing is spinning at oh about 15000rpms



"Horsepower is the Ultimate Accessory"
Re: Bypass Valve, How Do You Know If Its Leaking?G
Wednesday, September 20, 2006 5:20 AM
PSI is a measure of resistance... I'm only seeing 6-7 PSI with water/meth and all the mods. BUT on a DYNO I'm putting down 217whp and 235tq. without the No2 and that was before HPtuners. Haven't had time to test and tune yet.

15.3 1/4mi. could be the result of alot of things. If you can , get your car on a dyno to see if you've got any HP gains.







Edited 1 time(s). Last edited Wednesday, September 20, 2006 5:35 AM


"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
Re: Bypass Valve, How Do You Know If Its Leaking?G
Wednesday, September 20, 2006 1:18 PM
I dont know of any dynos which are affordable, I want to take apull but dont know any good places affordable.

But Gary, you have a race head right? If so then you may only see 6-7 right?

Mine is not ported so i should be seeing something over 8, and I have an autometer guage not a junk one.

So does anyone know the gatorback belt number? I have the one reccomended and cut it in half and works fine, maybe it is slipping. Also could there be a chance I am not getting boost at all? After all if the guage is tapped to the bottom vac of the SC isnt that before it gets to the head? I could see doing 15.3 with my mods minus the charger but otherwise my car just sucks.

Anyone find a part number or price for the bypass valve? I cant.

So anyone with the gm super craper seeing over 8 psi be thankful, lol. And yea turbocharging would be sweet and smarter but I wanted reliability.



http://members.cardomain.com/vertz24 1998 Z24 Convertible
Re: Bypass Valve, How Do You Know If Its Leaking?G
Wednesday, September 20, 2006 1:34 PM
i only put down 174whp


boo for me



2000 Camaro V6.
| SLP Loudmouth | CAI Intake | HID's |


Re: Bypass Valve, How Do You Know If Its Leaking?G
Wednesday, September 20, 2006 1:51 PM
Chris if you want to try a smaller belt get the gates belt....Search in the boost forum for s/c belt.........you should find the part#...its the one I've been using for a while now....



Car is for Sale!Supercharger kit is for sale!
Re: Bypass Valve, How Do You Know If Its Leaking?G
Wednesday, September 20, 2006 4:36 PM
If the vacuum actuator is leaking it won't cause a boost leak. Vacuum opens the valve and allows intake air to bypass the rotors in the charger, so if the valve has a boost leak it would close sooner. Now if the internal bypass valve is not fully closing then that would cause a boost leak, but thats an internal part. Take your throttle body off and look inside the charger you may be able to actually see the bypass valve door and see if its seated correctly, with the car off it should be closed.



Re: Bypass Valve, How Do You Know If Its Leaking?G
Wednesday, September 20, 2006 7:20 PM
i put down 207whp and 197wtq but i got some things to get worked out




Re: Bypass Valve, How Do You Know If Its Leaking?G
Wednesday, September 20, 2006 10:25 PM
do you run alchy LAFNGAS?



'00 Grand Am 2.4L LD9
http://www.cardomain.com/ride/816505
Re: Bypass Valve, How Do You Know If Its Leaking?G
Wednesday, September 20, 2006 11:11 PM
mike wrote:do you run alchy LAFNGAS?


that was without the alky working but i did change a few things. freebs and i are gonna be getting my alky working again but this time with a throttle body spacer and then im adding 440cc injectors and getting everything tuned




Re: Bypass Valve, How Do You Know If Its Leaking?G
Thursday, September 21, 2006 9:13 AM
SPDDMON wrote:If the vacuum actuator is leaking it won't cause a boost leak. Vacuum opens the valve and allows intake air to bypass the rotors in the charger, so if the valve has a boost leak it would close sooner. Now if the internal bypass valve is not fully closing then that would cause a boost leak, but thats an internal part. Take your throttle body off and look inside the charger you may be able to actually see the bypass valve door and see if its seated correctly, with the car off it should be closed.


So the actuator (Black thing on the outside) does not do everything? If that was messed up what would happen would I looses boost? When I was stripping the charger of all the paint it is likely I could have got something in there. Would that give me low boost numbers? So if I take off my tb and look in what should I see exactly?

Also this belt, any idea on cost and where to get it?

Whinin(BLWN Z24) - You have this problem to whith the gm sc? Any times yet? I hate this thing, lol, what a waste.

Also like I said first gear feels okay and then 2345 all feel like naturally asperated, any ideas people?

GM SC = Junk



http://members.cardomain.com/vertz24 1998 Z24 Convertible

Re: Bypass Valve, How Do You Know If Its Leaking?G
Thursday, September 21, 2006 3:28 PM
The black thing is a vacuum actuator. At idle you have high vacuum which operates the actuator which opens the internal bypass. When the bypass is opened you can't make boost, intake air is allowed to go around the rotors. So if the vacuum actuator is stuck open then yes it can cause low boost psi.



Re: Bypass Valve, How Do You Know If Its Leaking?G
Thursday, September 21, 2006 3:36 PM
john317(AKA Gary the Old guy) wrote:PSI is a measure of resistance...

the resistance of how much more air your car can not intake. Making your bore larger would allow more air to me displaced, Causing a lower boost level. how much more that I don't know.


horsepower is how hard you hit the wall, Torque is how far you push the wall with you
Re: Bypass Valve, How Do You Know If Its Leaking?G
Thursday, September 21, 2006 4:33 PM
Alright i got that gates belt on and going and did not see a difference.

What is the vaccume line that goes from the intake flange to wherever it goes. The one that is under the sc near the head? If there was a leak there what would happen?

Does anyone have a part number for the vaccumm actuator? Also how do I check it?



http://members.cardomain.com/vertz24 1998 Z24 Convertible
Re: Bypass Valve, How Do You Know If Its Leaking?G
Thursday, September 21, 2006 5:02 PM
Quote:

What is the vaccume line that goes from the intake flange to wherever it goes. The one that is under the sc near the head? If there was a leak there what would happen?


Listening....


NEW SIG COMING SOON FOR 07'!!!
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