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2009 Cobalt SS Turbocharged in Progress


DTM Brian

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A friend of mine came into the shop tonight with his Cobalt. He wanted to make some pulls on the car and see if I could help figure out why the car was going into limp mode under boost. To make a long story short, this car has a ETC vs RPM vs Airflow table that is different then anything I have ever seen before in the GM PCM's The car has a manual boost controller on it. Lets just say I learned a lot tonight on how these pcm's work.

 

The factory turbo, intercooler, and plumbing is all gone. It now has a prototype turbo kit that was done by a shop here in Ohio using a newly designed turbo and intercooler from precision. This car maintains the factory fuel system. What is even more impressive is the exhaust is totally stock from the factory down pipe to the back. It still retains the factory cats. The car is coming back in two weeks with a 3 inch down pipe and a cut-out. It will be interesting to see how the power increases along with the spooling of the turbo.

 

Pump Gas

24-25 PSI

18 degrees of timing

0 Knock

Coolant temps were 210 degrees during the pulls.

A/F still needs some attention

 

http://75.180.27.125:50001/Dyno%20Graphs%20and%20Pictures./Dyno%20Graphs/2009%20Cobalt%20SS%20Turbo.jpg

Edited by Mobile Chassis Dyno
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no i know alot of people with high boost cars, what is this cars psi stock at and stock base dyno run brian? its got good TQ but i would think at 24-25 psi it would have more HP figured mid 5's to 600 range.

 

Has a lot to do with how well the head flows and the manifolds.. they're not always the most efficient in design from factory. A change of manifolds, pistons and head work can make large improvements.

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Has a lot to do with how well the head flows and the manifolds.. they're not always the most efficient in design from factory. A change of manifolds, pistons and head work can make large improvements.

 

true but i thought it has a kit on it now so the exhaust manifold has been changed although a lil head work would do alot. im glad to hear that it holds 25psi on stock internals wonder how much these new motors can be pushed.

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no i know alot of people with high boost cars, what is this cars psi stock at and stock base dyno run brian? its got good TQ but i would think at 24-25 psi it would have more HP figured mid 5's to 600 range.

 

You need to read up on pressure vs. flow boss. The "Psi" is all but irrelevant for how much power the car is making.

 

For example.

 

My Colt at 25psi on a 14b- 239whp.

 

At 25 psi on a 60-1 441whp

 

At 25psi on a GT42 659whp.

 

 

 

According to your sig, your some kind of Honda tuner? As a tuner, I feel like I should not be explaining this too you.

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You need to read up on pressure vs. flow boss. The "Psi" is all but irrelevant for how much power the car is making.

 

For example.

 

My Colt at 25psi on a 14b- 239whp.

 

At 25 psi on a 60-1 441whp

 

At 25psi on a GT42 659whp.

 

 

 

According to your sig, your some kind of Honda tuner? As a tuner, I feel like I should not be explaining this too you.

 

completely understand but there is also an upgraded turbo on this car and no size was said. i didn't know you could push that much boost on a 14b without having problems with the wastegate actuator, actually thought that was a problem with all internal wastegates and weren't supposed to put to much pressure on them.

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Aren't those PCM's ridiculously complex, and therefore very difficult to work with?

 

The guy on here with the Saturn Sky knows a shit ton about them, hopefully he will chime in because I don't remember all the details, but it was discussed on here before. Very interesting stuff

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Aren't those PCM's ridiculously complex, and therefore very difficult to work with?

 

The guy on here with the Saturn Sky knows a shit ton about them, hopefully he will chime in because I don't remember all the details, but it was discussed on here before. Very interesting stuff

 

The ecm is different. Like I said I learned alot.

 

 

As far as the size of the turbo. I am told it is good for 500 whp. The stock turbo would make over 20 pounds under 3000 rpm's

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Here is a graph of what the car made in 100% Stock Form

 

http://75.180.27.125:50001/Dyno%20Graphs%20and%20Pictures./Dyno%20Graphs/2009%20Cobalt%20SS%20Stock.jpg

 

 

Here is a graph of Stock vs Modified

 

http://75.180.27.125:50001/Dyno%20Graphs%20and%20Pictures./Dyno%20Graphs/2009%20Cobalt%20Stock%20vs%20Precision%20Turbo.jpg

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completely understand but there is also an upgraded turbo on this car and no size was said. i didn't know you could push that much boost on a 14b without having problems with the wastegate actuator, actually thought that was a problem with all internal wastegates and weren't supposed to put to much pressure on them.

 

But it could have been upgraded to a say GT28, or V-trim, both of which are not even capable of the HP numbers you quoted. Again, just get that PSI number out of your mind. (unless we had more information)

 

You can run 30+ on a 14b. No signal to the gate=party time. People have gone 10's on a 14b. Ideal? No. But you can do it.

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no i know alot of people with high boost cars, what is this cars psi stock at and stock base dyno run brian? its got good TQ but i would think at 24-25 psi it would have more HP figured mid 5's to 600 range.

 

Remember this car does not rev like a Honda with VTEC. Also keep in mind the exhaust is only 2 1/2" and both CATS are still in place. Just wait for the 3" down pipe and cut out

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But it could have been upgraded to a say GT28, or V-trim, both of which are not even capable of the HP numbers you quoted. Again, just get that PSI number out of your mind. (unless we had more information)

 

You can run 30+ on a 14b. No signal to the gate=party time. People have gone 10's on a 14b. Ideal? No. But you can do it.

 

Hmm makes me look at internal gated turbos in a whole new light thanks. was always known of the waste gate arms breaking so naturaly didnt think they could handle to much pressure. the numbers on this car is solid and its a great gain over stock.

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completely understand but there is also an upgraded turbo on this car and no size was said. i didn't know you could push that much boost on a 14b without having problems with the wastegate actuator, actually thought that was a problem with all internal wastegates and weren't supposed to put to much pressure on them.

 

Your posts are making my head hurt more and more as I read them.

 

Problems with an internal gate? Do you have a clue what you're talking about?

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