boost problem?
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From: Ohio
well i think it could be possible its a vacumm leak after so much boost...but the boost gauge is fine because i also have the aeroforce interceptor scan gauge and it is reading the same...... belt has tension trust me....it was a bitch to put the belt over the pulley when i changed it ...im running all the same exhaust as i was before( i have replaced flex pipe but same as last and i have the gm cat back...
Joined: 12-30-07
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From: NEPA
A vacuum leak is a good possibility ....
The stock downpipe has nothing to do with the OP's problems .... The stock downpipe is not as restrictive as everyone on here really thinks. I have spoke to Bill (More Torque More HP), and the downpipe was designed for high flow. Also, the cat is a high flow unit. I have gone back and forth from the production downpipe to a highflow 3" downpipe, and have hardly noticed any change in performance.
Back on topic .... The OP is claiming he is loosing boost. A restriction in the exhaust system would cause boost to increase. It sounds more like he either has a boost/vacuum leak somewhere, a bad bypass valve, or possibly even belt slip.
The stock downpipe has nothing to do with the OP's problems .... The stock downpipe is not as restrictive as everyone on here really thinks. I have spoke to Bill (More Torque More HP), and the downpipe was designed for high flow. Also, the cat is a high flow unit. I have gone back and forth from the production downpipe to a highflow 3" downpipe, and have hardly noticed any change in performance.
Back on topic .... The OP is claiming he is loosing boost. A restriction in the exhaust system would cause boost to increase. It sounds more like he either has a boost/vacuum leak somewhere, a bad bypass valve, or possibly even belt slip.
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Joined: 09-10-07
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From: Ohio
A vacuum leak is a good possibility ....
The stock downpipe has nothing to do with the OP's problems .... The stock downpipe is not as restrictive as everyone on here really thinks. I have spoke to Bill (More Torque More HP), and the downpipe was designed for high flow. Also, the cat is a high flow unit. I have gone back and forth from the production downpipe to a highflow 3" downpipe, and have hardly noticed any change in performance.
Back on topic .... The OP is claiming he is loosing boost. A restriction in the exhaust system would cause boost to increase. It sounds more like he either has a boost/vacuum leak somewhere, a bad bypass valve, or possibly even belt slip.
The stock downpipe has nothing to do with the OP's problems .... The stock downpipe is not as restrictive as everyone on here really thinks. I have spoke to Bill (More Torque More HP), and the downpipe was designed for high flow. Also, the cat is a high flow unit. I have gone back and forth from the production downpipe to a highflow 3" downpipe, and have hardly noticed any change in performance.
Back on topic .... The OP is claiming he is loosing boost. A restriction in the exhaust system would cause boost to increase. It sounds more like he either has a boost/vacuum leak somewhere, a bad bypass valve, or possibly even belt slip.
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From: Akron, Ohio
1. borrow someone else's, see if it boosts properly
2. get on a dyno, load it, have someone listen to if its opening up.
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From: ky
The stock downpipe is not as restrictive as everyone on here really thinks. I have spoke to Bill (More Torque More HP), and the downpipe was designed for high flow. Also, the cat is a high flow unit. I have gone back and forth from the production downpipe to a highflow 3" downpipe, and have hardly noticed any change in performance.
let me guess, the oem manifold is a "high flow unit" as well
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From: NEPA
So your're saying Bill doesnt know what he's talking about ? He is one of the few people I trust on this site for valid information about our cars.
i didnt say it wasnt restrictive for some set ups (i wouldnt run it with a TVS), but it isnt as restrictive as people think. i have gone from a 3" catted downpipe back to the stock downpipe more than once, and hardly noticed a change in power with my GM Stage 3 setup. So if it was really as restrictive as people think, I should have felt a big power loss. have you ever dynoed an aftermarket catted downpipe vs the stock one back to back ? i dont think anyone on here has. i bet you gain maybe 5-10 whp with one. not a huge difference in power if you ask me.
I'm not going to turn the OP's thread into a battle on downpipes. He is looking for the cause for his boost problem. I only brought up downpipes, because one member kept mentioning the stock downpipe/exhaust as a possible problem. so if you want to debate this more feel free to send me a PM.
OP .... sorry about the thread jack.
Last edited by Staged07SS; Apr 9, 2010 at 11:58 AM.
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From: Ohio
no need for the smartass response ....
So your're saying Bill doesnt know what he's talking about ? He is one of the few people I trust on this site for valid information about our cars.
i didnt say it wasnt restrictive for some set ups (i wouldnt run it with a TVS), but it isnt as restrictive as people think. i have gone from a 3" catted downpipe back to the stock downpipe more than once, and hardly noticed a change in power with my GM Stage 3 setup. So if it was really as restrictive as people think, I should have felt a big power loss. have you ever dynoed an aftermarket catted downpipe vs the stock one back to back ? i dont think anyone on here has. i bet you gain maybe 5-10 whp with one. not a huge difference in power if you ask me.
I'm not going to turn the OP's thread into a battle on downpipes. He is looking for the cause for his boost problem. I only brought up downpipes, because one member kept mentioning the stock downpipe/exhaust as a possible problem. so if you want to debate this more feel free to send me a PM.
OP .... sorry about the thread jack.
So your're saying Bill doesnt know what he's talking about ? He is one of the few people I trust on this site for valid information about our cars.
i didnt say it wasnt restrictive for some set ups (i wouldnt run it with a TVS), but it isnt as restrictive as people think. i have gone from a 3" catted downpipe back to the stock downpipe more than once, and hardly noticed a change in power with my GM Stage 3 setup. So if it was really as restrictive as people think, I should have felt a big power loss. have you ever dynoed an aftermarket catted downpipe vs the stock one back to back ? i dont think anyone on here has. i bet you gain maybe 5-10 whp with one. not a huge difference in power if you ask me.
I'm not going to turn the OP's thread into a battle on downpipes. He is looking for the cause for his boost problem. I only brought up downpipes, because one member kept mentioning the stock downpipe/exhaust as a possible problem. so if you want to debate this more feel free to send me a PM.
OP .... sorry about the thread jack.
Only reason I say it is possible is from (also reliable sources who are not on CobaltSS.net) state that too much back pressure can cause vacuum leaks.
Perhaps I am wrong, but I feel like you shouldn't have went that out of your way to prove it.
That aside, have you found anything yet kyle?
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From: ky
no need for the smartass response ....
So your're saying Bill doesnt know what he's talking about ? He is one of the few people I trust on this site for valid information about our cars.
i didnt say it wasnt restrictive for some set ups (i wouldnt run it with a TVS), but it isnt as restrictive as people think. i have gone from a 3" catted downpipe back to the stock downpipe more than once, and hardly noticed a change in power with my GM Stage 3 setup. So if it was really as restrictive as people think, I should have felt a big power loss. have you ever dynoed an aftermarket catted downpipe vs the stock one back to back ? i dont think anyone on here has. i bet you gain maybe 5-10 whp with one. not a huge difference in power if you ask me.
I'm not going to turn the OP's thread into a battle on downpipes. He is looking for the cause for his boost problem. I only brought up downpipes, because one member kept mentioning the stock downpipe/exhaust as a possible problem. so if you want to debate this more feel free to send me a PM.
OP .... sorry about the thread jack.
So your're saying Bill doesnt know what he's talking about ? He is one of the few people I trust on this site for valid information about our cars.
i didnt say it wasnt restrictive for some set ups (i wouldnt run it with a TVS), but it isnt as restrictive as people think. i have gone from a 3" catted downpipe back to the stock downpipe more than once, and hardly noticed a change in power with my GM Stage 3 setup. So if it was really as restrictive as people think, I should have felt a big power loss. have you ever dynoed an aftermarket catted downpipe vs the stock one back to back ? i dont think anyone on here has. i bet you gain maybe 5-10 whp with one. not a huge difference in power if you ask me.
I'm not going to turn the OP's thread into a battle on downpipes. He is looking for the cause for his boost problem. I only brought up downpipes, because one member kept mentioning the stock downpipe/exhaust as a possible problem. so if you want to debate this more feel free to send me a PM.
OP .... sorry about the thread jack.
Thread Starter
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Joined: 09-10-07
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From: Ohio
no i was going to check today. i went and bought the starter fluid and dustin is coming over and im going to switch his bypass valve on mine and see what happens. and stage07ss ...thanks for everything so far. but this is a noob question...what is op stand for?.... and ill let you guys know if anything works...all i am trying is spraying it while running and then switching valves....lets hope its the valve...
Joined: 12-30-07
Posts: 14,079
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From: NEPA
no i was going to check today. i went and bought the starter fluid and dustin is coming over and im going to switch his bypass valve on mine and see what happens. and stage07ss ...thanks for everything so far. but this is a noob question...what is op stand for?.... and ill let you guys know if anything works...all i am trying is spraying it while running and then switching valves....lets hope its the valve...
good luck !! i hope you find the problem.
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Joined: 09-10-07
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From: Ohio
well i started up the car and sprayed the starter fluid all around where i could ....nothing....then i took off mine and my friends bypass valves....mine when you pushed in had a spring noise to it.....his ..nothing....i put his on and went for a test drive... after a couple pulls.... more and more boost....finally ended up with 17 to 18....and to me thats a win.. i haven't tested since i switched back, but my next step is to order one, so ill keep you posted......does anyone know where to order one other than the dealer????
ok next note.... i went to zzperformance and saw one there for 45 dollars and its a little bit of a different design. it relocates the top vacum line to the boost solnoid.....is this better or should i stick with stock?
ok next note.... i went to zzperformance and saw one there for 45 dollars and its a little bit of a different design. it relocates the top vacum line to the boost solnoid.....is this better or should i stick with stock?
Last edited by kyle1853; Apr 9, 2010 at 07:35 PM. Reason: Automerged Doublepost
Joined: 12-30-07
Posts: 14,079
Likes: 197
From: NEPA
well i started up the car and sprayed the starter fluid all around where i could ....nothing....then i took off mine and my friends bypass valves....mine when you pushed in had a spring noise to it.....his ..nothing....i put his on and went for a test drive... after a couple pulls.... more and more boost....finally ended up with 17 to 18....and to me thats a win.. i haven't tested since i switched back, but my next step is to order one, so ill keep you posted......does anyone know where to order one other than the dealer????
ok next note.... i went to zzperformance and saw one there for 45 dollars and its a little bit of a different design. it relocates the top vacum line to the boost solnoid.....is this better or should i stick with stock?
ok next note.... i went to zzperformance and saw one there for 45 dollars and its a little bit of a different design. it relocates the top vacum line to the boost solnoid.....is this better or should i stick with stock?
Joined: 12-30-07
Posts: 14,079
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From: NEPA
Kyle: I know you are having your boost bypass problem taken care of at the dealership, but below is a link to purchase a new boost bypass valve from ZZP's site. This should be helpful for anyone else in need of a new bypass valve.
http://www.zzperformance.com/cobalt_...=840&catid=189
http://www.zzperformance.com/cobalt_...=840&catid=189
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