Matt Hauffe of Tune Time Performance...
Matt Hauffe of Tune Time Performance used HP Tuners equipment to modify our Cobalt SS ECU.
Our first dyno pull, in completely stock trim and only 2,400 miles on the odometer rewarded us with 248 horsepower and 251 lb-ft of torque at the front wheels. Not a bad start and Hauffe decided that the first move was to add some more boost. At this point, we asked Hauffe about changing the MAP sensor from the stock 2.5 bar setup to a 3 bar one like some people have suggested on various message boards. The MAP sensor is used to detect vacuum and boost for the computer to reference. The 2.5 bar sensor is capable of readings up to 21.5 psi, which isn't a problem with our new tune because Hauffe cranked the boost to a maximum of 20 psi. In stock trim, the boost gauge only swept to 15 psi. A few dyno pulls later, the car registered 268 hp and 290 lb-ft peak numbers. There was a spike up to 313 lb-ft, but we dismissed it as irrelevant, 290 lb-ft is the accurate measurement.
Our third set of chassis dyno pulls were performed with some more mods to the tune up, once again using the HP Tuners software to make the changes. The boost was left alone at 20 psi and this time Hauffe played with the timing curves. Adjusting timing in the Cobalt SS computer is vastly different than other cars. The ECU just doesn't command a set timing number, "this Bosch computer bases the timing on several factors like cam timing," commented Hauffe. He made a few more pulls on the Mustang Dyno and the final figures were an impressive 278 hp and 300 lb-ft. That works out to a gain of 30 in the horsepower department and 49 in torque--at the wheels. Hauffe concluded our dyno testing by saying, "we could make more power but then you run the risk of smoking the stock clutch." Thankfully, GM Performance Parts sells a replacement clutch for the turbocharged Cobalt SS cars, something we will be looking into before performing any more modifications.
The laptop plugs into this...
The laptop plugs into this converter, which is then run to the OBD-II port under the dashboard. It is how the HP Tuners software accesses the factory ECU. Other companies use separate handheld tuners to re-flash the computer, whereas a laptop is connected directly with the HP way of doing things.
"With these things, the horsepower is cool, but it's the torque that makes the car fun to drive on the street," commented Franco after getting in the car and making a blast up the street on the way back home. He continued, "you can feel the turbo kick in so much faster now, there is no more lag. On the highway, you tap the gas and the car goes from 65 mph up to 90 almost instantly. The tune definitely helps the turbo spool faster. Before, I wouldn't be able to smoke the tires in Second gear. Now, I just get on it quickly (with the traction control off) and the tires beg for mercy!"
Hauffe was quick to comment that in looking at the dyno graphs, the car's engine accelerates much quicker to his self-imposed peak rpm of 6,200. In stock trim, the complete dyno run took 22 seconds. All runs were made in Fourth gear and recording started at 2,800 rpm and shut off at 6,200. By adding more boost, the car accelerated the Mustang Dyno rollers from 2,800 to 6,200 rpm in only 18 seconds. The final pull, with both more boost and increased timing, the Cobalt SS impressed us even more by slashing the dyno pull down to a mere 16.5 seconds for the same 2,800-to-6,200 rpm zone--in Fourth gear. That means quicker overall acceleration. It is no wonder we felt the gains immediately as we took turns beating on the car on the way back home.
Franco has yet to line up against a Mustang, but that time is drawing near as the warm weather in the Northeast is finally here and the tracks are open. We expect the Cobalt SS to run with the new Mustangs thanks to the tune from Tune Time Performance. We are left wondering--what other mods can we add to GM's best-kept secret?
 It took nearly 20 minutes...  It took nearly 20 minutes for the software to access and download the factory tune. |  |  After our baseline, the second...  After our baseline, the second test consisted of only increasing boost from the factory setting of 15 psi to a tire-shredding 20 psi. |
 The boost alone brought output...  The boost alone brought output up to 268 whp (5,500 rpm) and 290 wtq (3,000 rpm). |  The richest air/fuel ratio...  The richest air/fuel ratio we saw on the gauge registered 10.9:1, a very safe reading for a forced induction combination. If this were a naturally aspirated combo, we would want to see air/fuel results that were much leaner. For our turbo ride, we will stick with the max of 10.9:1 for safety. |  The HP Tuner software allows...  The HP Tuner software allows for live data to be shown on the laptop while it is connected to the OBD-II. This allows Hauffe to keep an eye on everything during the dyno runs. |