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Would anyone be able to please give me as much information as you know about how the boost gauge in the cobalt SS SC works, what it is, and why it is there?

(I would rather read forum goer information than the cobalts manual which has half a page for the boost)
 

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well, the guage shows you vacuum and boost
the increments doesnt matter
its mainly for looks.
but you can watch it for gas mileage where you can not use any boost while accelerating.
and to make sure its producing the proper boost
 

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Just like jonsstockrocket said, It displays the MAP readings in an analog style fashion. Nothing technical there. It's just for looks.
 

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i believe the increments are 2.5 psi.
thats while the supercharger is producing boost right?
in vacuum the spaces are the same as boost, but in vacuum it shows in tens and in boost it shows in fives
\ 10 /
\ 5 / 15 /
0 / 20
- /
10 quick boost guage pic
/ 20
/ 30
 

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that was supposed to be a picture
 

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lets try it this way
20
15
10
5
0
10
20
30
 

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they as in gm says 12.5 psi but the guage will sometimes show higher in the cold
 

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I've spiked at 16-16.5 in the cold with stage 2
 

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1st off sorry about the long thread but i have a bit of a disagreement with the "boost" guage in our cars. if you think about it,(just for an example) if your putting out 10psi of boost at full throttle at 3000rpm, you should also have 10psi of boost at partial throttle at 3000rpm. i have noticed that in my car cruising speed down the hwy at 75mph 3000rpm the guage is showing vacuum. put my foot on the floor and i have 10psi of boost. this is incorrect, the supercharger is putting out the boost at 3000rpm no matter where the throttle is at. the only time you should be in a vacuum state is when you are at idle, never at 3000rpm. has anyone installed a differant boost guage and source for the boost?
 

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1st off sorry about the long thread but i have a bit of a disagreement with the "boost" guage in our cars. if you think about it,(just for an example) if your putting out 10psi of boost at full throttle at 3000rpm, you should also have 10psi of boost at partial throttle at 3000rpm. i have noticed that in my car cruising speed down the hwy at 75mph 3000rpm the guage is showing vacuum. put my foot on the floor and i have 10psi of boost. this is incorrect, the supercharger is putting out the boost at 3000rpm no matter where the throttle is at. the only time you should be in a vacuum state is when you are at idle, never at 3000rpm. has anyone installed a differant boost guage and source for the boost?
Im not calling bs, im not calling you a liar or whatever, but think of it as this. Your engine has to create energy to get up to speed, after it gets up to speed, the boost kills off. If it was constant boost, the fuel would have to compensate thus creating a force. When your going down a hill for example with the clutch engaged, the tires are spinning the trans, in turn, spinning the engine also, so it creates vacuum. In other words, the engine is "free-wheeliing" and instead of boosting, the engine gets a break and doesnt have to work hard. It runs leaner, and less hp going downhill vs. uphill.
 

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trust me, i have a friend with a WRX, and if it was pushing 20psi all the time, part throttle, or full throttle, he'd have no engine left because of the heat generated from the extra fuel/air.
 

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1st off sorry about the long thread but i have a bit of a disagreement with the "boost" guage in our cars. if you think about it,(just for an example) if your putting out 10psi of boost at full throttle at 3000rpm, you should also have 10psi of boost at partial throttle at 3000rpm. i have noticed that in my car cruising speed down the hwy at 75mph 3000rpm the guage is showing vacuum. put my foot on the floor and i have 10psi of boost. this is incorrect, the supercharger is putting out the boost at 3000rpm no matter where the throttle is at. the only time you should be in a vacuum state is when you are at idle, never at 3000rpm. has anyone installed a differant boost guage and source for the boost?
this ma not be true
the comp. controlles boost and it does not allow boost at highway speeds unless you are accelerating it does this with an internal bov
this is why i like the sc setup it gets really good gas mileage for this reason
in tubo cars it does have full boost because it has no computerized contro bov
 

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and yes it is producing 10 psi at 3000 rpm but the comp blows it out= no boost
and at 75 the vacuum is not much under 0 maybe -10 or so and this sounds right
 

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this ma not be true
the comp. controlles boost and it does not allow boost at highway speeds unless you are accelerating it does this with an internal bov
this is why i like the sc setup it gets really good gas mileage for this reason
in tubo cars it does have full boost because it has no computerized contro bov
well, maybe not 100% true, because it has a wastegate that bypasses the turbo when it is not forcong enough exhaust gasses through it.
 

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Im not calling bs, im not calling you a liar or whatever, but think of it as this. Your engine has to create energy to get up to speed, after it gets up to speed, the boost kills off. If it was constant boost, the fuel would have to compensate thus creating a force. When your going down a hill for example with the clutch engaged, the tires are spinning the trans, in turn, spinning the engine also, so it creates vacuum. In other words, the engine is "free-wheeliing" and instead of boosting, the engine gets a break and doesnt have to work hard. It runs leaner, and less hp going downhill vs. uphill.
add this w/ what i said too
 

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well, maybe not 100% true, because it has a wastegate that bypasses the turbo when it is not forcong enough exhaust gasses through it.
ur probably right i know but very few things w/ turbos but the sc thing is right and thats all that matters
 

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Let me just conclude with this, the supercharger, or turbo, take your pic, is going to be spinning regardless of what speed it is going. Boost does not kick in until another determining factor is added: force as well as throttle position.
 

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guys guys guys.....

our SC is ALWASY compressing air...thats why the roots style blowers has fast throttle responce and good torque down low....

our ECM controls a solenoid that actuates a boost by pass valve....its open when the car isnt under load...no matter what speed if the ecm does not see a load(accel, ect) it opens it thus giving us good MPG and lowers our AIT's

turbos are always sping however when your not making boost the engine is sucking in more air then the turbo is pushing in...thus no boost, only when the turbo starts to force air into the engine do we see boost.
 
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