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Discussion Starter · #1 ·
Today I got my Pulley Technology 3,0" pulley installed on my 2005 Victory Red Cobalt SS / SC ... (We measured it and it measures 2,95" instead of the stock 3,35").

Here is the data we measured: HP, torque, air / fuel ratio, timing and boost. Remember it's was a Mustang dyno ! All test are in 4th gear. Each pull reached the cut-off (6500 RPM on the tachometer; 6300 RPM on the dyno !). Air temp was 65 farenheit degrees; pretty good.

At this very moment, I am only able to post these quick results. All my dyno graphs (HP, torque, air / fuel) will be posted next monday, since I haven't any scanner at my house but at work.

Bone stock : 191 WHP, 170 ft-lb torque, air / fuel ratio varies slightly from 10.9 to 11.4 between 3500 and 6300 RPM.

Magnaflow 2,5" exhaust + 2,25" rear section replaced to 2,5": 200 WHP, 174 ft-lb torque, air / fuel ratio varies slightly from 10.5 to 10.9 between 3500 and 6300 RPM.

Magnaflow + 3" pulley : 215 WHP, 187 ft-lb torque, air / fuel ratio varies slightly from 11.3 to 11.5 between 3500 and 5200, then is rising in straigth line from 11.3 to max at 12.8 at 6300 RPM.

Magnaflow + 3" pulley + one range colder BKR7E plug: 213 WHP, 185 ft-lb torque, air / fuel ratio varies slightly from 11.1 to 11.3 between 3500 and 5200, then is rising in straigth line from 11.1 to max at 12.45 at 6300 RPM. The goal of the colder plugs was to get the air / fuel ratio richer a little bit, and it worked for a 0.2 to 0.35 air / fuel ratio rise.

(One comment: I think the stock injectors are giving their max flow at 5200 RPM.)

About the timing, we recorded 0 knock, but last 100 to 150 RPM before redline were between 0.5 and 1.5 degrees of knock.

General comments: The very first dyno run after the 3" pully has been installed, the following thing happened: The max boost achieved 14 PSI near 5500 RPM, then drop at 10 PSI the reach 12 PSI for the last RPM's. As we all know, it has been caused by the signal the PCM give to the selenoid that control the max boost.

So I had to disconnect the vaccuum hose between the selenoid and the by-pass valve actuator. This way the maximum boost has been reached.

My bone stock max boost have always been 12 PSI on the stock gauge, and with the 3" pulley we recorded a max of 15,2 PSI on a mechanical gauge and 14,5 PSI on the stock gauge. At this very moment, my vaccuum hose is unpluged from the actuator, and the hose's tip is plugged with a screw. I installed a little filter on the "now opened to air" by-pass valve actuator's nipple.

To conclude, I gain roughly 25 WHP and 17 ft-lb torque from the 2,5" catback and the 3" pully. (The 3" pully itself gives roughly 15 WHP and 13 to 15 ft-lbs torque.)

Remember that a Mustang dyno is usually 10-12 % lower than a Dynojet. Making the calculation (3" pulley and catback) gives 238 WHP and 207 ft-lbs torque. Plus the 16% drivetrain lost, it gives roughly 275 BHP (at the motor).

Last week (on another post) I said that we tested a K&N conical replacement filter (and got the lower cover of the airbox removed). I repeat that on 2 different Cobalt SS / SC, we Mustang DYNOed a LOSS of 8 to 10 HP. My point of view is that the MAF is too close of the air filter, so the increase of flow and turbulency cause the PCM to compensate and getting the air / fuel ratio richer (0.5) than stock.

I am very proud of the result, the boost is achieved sooner also; it gives 13 PSI at 5000 RPM and 15 PSI near redline !

Have a nice weekend and have good kills !
 

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That 238whp sounds about right since I hit 231 with a 3", intake and 2.5" exhaust. Some damn good info, thanks...
 

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Discussion Starter · #3 ·
Dyno sheets ...

I did scan my dyno sheets today and all the 6 sheets are included in one single PDF file. Since the file is 500 Ko, I was not able to upload it. People who wants to see my dyno sheets, just e-mail me. The answer time can be up to one day. It's the better I can do at this moment. Have a nice day !
 

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Discussion Starter · #6 ·
I didn't buy the pulley puller. The install was made by a speed shop; they had previously made the tool (custom made) and the install is about an hour or so. The supercharger must be removed, and to got the pulley removed a press can be also used. To reinstall it we got the pulley heated, so we have been able to install it manually, then we got the supercharger noise (pulley) colded in water.
 

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Discussion Starter · #7 ·
No CEL yet with the 3,0" pully. Running it for 3 weeks now and roughly 500 miles of hard and moderate driving ...
 

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Discussion Starter · #8 ·
About the last paragraph on my first post of this very thread, the dyno loss wasn't cause by the MAF ... I am pretty damn sure it was caused by the by-pass valve selenoid.
 

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^^WTF does that have to do with a 3inch pulley?? :confused:

JMC, how much louder is the blower with the 3inch with no intake mod?

and how bad does the pulley throw off the A/F ratio?, is it at a safe level?
 

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Discussion Starter · #12 ·
The blower is not that much louder with only a pulley, but with a high low filter and the lower lid removed, it's nice. The air fuel ratio with only a 3" pulley is usually "safe", but for the last RPM's it tends to be a little bit lean, leaner for the 2006 Cobalt SS/SC.
 
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