http://cobaltss.net/forums/showthread.php?t=120393
Cobalt SS/TC Product Development Testing, 7-01-08
2008 Cobalt SS turbo, 13.20 @ 104 MPH
Location: Route 66 Raceway, Joliet Illinois
Elevation: 660 feet
Conditions: 77-84 degrees, high humidity, 2500 feet adjusted altitude
Modifications:
• Hahn RaceCraft 3” SS CatBack Exhaust
• Hahn/BSR PPC Tuner
Weight with driver: 3165 lbs.
Boost Level: 21-23 PSI
Fuel: Shell 93 Octane
Video Links
http://videos.streetfire.net/video/H...1-4_169448.htm http://videos.streetfire.net/video/H...2-4_169449.htm http://videos.streetfire.net/video/H...3-4_169451.htm http://videos.streetfire.net/video/H...4-4_169452.htm
Driving Impressions:
Overall, the Cobalt’s driving dynamics are impressive. On the road, its suspension is super-poised, with .90G cornering capability, and a taut but smooth and supple ride. There’s no harshness for such a competent car. Cornering is the best I’ve experienced in a FWD car, and I am seriously considering autocrossing it as well. Braking is also superb, with front Brembo brakes and well-balanced ABS.
Tuned at the Nurburgring, it’s apparent that GM’s Performance Division put extensive effort into the handling dynamics of the car, also setting a world record with it at The Ring. This immensely capable package is not quite as well-suited to dragstrip use, for the low-profile tires and significant low-end torque of the car make it challenging to launch hard. However, this is not unusual, for no one wheel/tire combination can do it all, and great handling, low-profile tires just can’t create the footprint needed for strong dragstrip launch performance.
The direct-injected (DI) engine is almost eerily smooth! At lower RPM, where port-injected engines can be a bit rough, causing you to downshift, this DI engine is just as content as can be. It begs to be shifted early in regular commuting, which can only help fuel economy. I also find myself not remembering to upshift in cruising mode, as the engine is not buzzy when revved. Overall, this is one smooth operator!
On to the Track!
The car does really fun 2nd gear burnouts, as the videos will show. Fact is, I was overdoing the burnouts, but it was hard not to...the car just boils the tires once they get moving! Next time I will take it easier, but tonight was time to have some fun with the new toy.
I first tried the stock launch control, and quickly moved past it. I don’t doubt that with more track time, one could optimize it more, but I was on a mission, and I needed to get right to the best launches I was capable of. It seemed that the aggressiveness of the launch control system was more targeted for street-style traction, not the much harder bite of the dragstrip.
Launching conventionally, with a few whips of the throttle to spool the turbo, netted me much better results. I got to the 2.3 and 2.2 range of 60-foot times immediately. But tirespin was still evident, and I knew I’d have to really tiptoe through first gear to get the results I craved.
13.60’s came quickly as I continued to refine my launch technique. I also experimented with conventional shifting, then with ‘no-lift’ shifting. While the ‘no-lift’ shift seemed quite foreign to me, after a few passes trying both methods, I realized it was the way to go. Standard shifting, while effective on the street, was less effective at the track, especially once I got comfortable with ‘no-lift’. My experience with drag racing my 11.9 second Solstice has taught me that these ETC (Electronic Throttle) cars are just not the same as manual throttles for fast upshifts. Data shows no matter how quick you are, there is a lag from throttle closing to re-opening. Sure, it’s fractions of a second, but in drag-style upshifts of 0.3 seconds, a tenth is 33% longer, 2 tenths almost twice as long. These longer throttle closed times diminish turbo response as the throttle opens in the next gear. So, no-lift shift was the way to go if I wanted the best possible Elapsed Time (ET).
Fortunately, my PPC Tuner also extended the redline in 1st and 2nd to 7000 RPM. This is effective to keep the driver from hitting the rev limiter with the faster revving additional power enables. The 3rd – 4th upshift came a bit earlier, at 6200. Very little time spent in 4th, but running out 3rd with no upshift is not a possibility with 105+ MPH trap speeds.
The last two passes of the night saw me really figure it out. I skipped right past the 13.50’s with a 13.45, and while there was still a lot of tirespin in 1st, I knew I was closer than ever to the sweet spot. I was right! Next I skipped right past the 13.30’s (and almost the 13.20’s!) with a solid 13.20 @ 104.33 pass. The 2.09 60-foot time was far and away the best of the night, and the rest of the pass was spot-on, with perfect shift points. I tend to save the best for last on these nighttime tuning sessions!
What could stand improvement?
Well, even though these are excellent numbers for a car with just an exhaust and a tune, the current package is not optimized…yet. Weather was poor for high power.
The tire combination can be improved dramatically. As a skilled FWD racer, it took me a number of passes to coax out that 2.09 60 foot. I’ve been as quick as 1.79 on small drag radials with my dumdumdumdumdum. That alone would take this car into the 12.80’s easily, even in the same weather. The still relatively new engine may also develop a bit more power as the piston rings seat in fully.
Intake air temperature data was collected and analyzed. The temperatures, especially deep into the run, can be improved with a more efficient intercooler. The stock piece, while fairly good-sized, uses the typical tube-and-fin type core common to OEM applications. It heats up more quickly with the additional airflow and boost we’re making now. We’ll apply an intercooler very similar to what we currently build for this LNF turbo engine in Solstice and Sky. These intercooler units are massive, and not only improve peak power and reduce heat intake to the engine, they also improve low-speed turbo response.
And that’s what we will do next. First improve traction, and then upgrade the intercooler. We should have more results later this month!
What else are we working on for SS/TC?
• Performance Intercooler
• Air Intake Upgrade
• Intercooler Tube Upgrade
• Blow-Off Valve Upgrade
• Downpipe / Cat Con Upgrade
• Turbocharger Upgrades (a couple of flavors TBA)
All of these items will be complimentary to one another, as well as to our SS 3” Cat-Back Exhaust and PPC Tuner. Using them as a system will allow one to avoid the problems we’ve seen with mixing up items from different vendors on Solstice GXP and Sky Redline (other cars we’re noted for that feature the turbo LNF engine).
What should I get first for my SS/TC?
Hahn/BSR PPC Tuner and Hahn 3” SS exhaust. Without a doubt, as we’ve proved in other turbo LNF applications, this is the best bang for your buck.
What are the goals of our SS/TC development program?
We intend to meet, and then surpass, the performance of our dumdumdumdumdum program, which resulted in 11.8 second, 122 MPH runs with true bolt-ons and street tires. In doing so, the car must retain 100% daily driveability and fuel economy, with no tradeoffs to the new power level save for excessive tire wear!
2008 Cobalt SS turbo, 13.20 @ 104 MPH 
Been there, done that....got the LS _____ (insert 1, 2, 3, 6, 7, X, etc.) t-shirt.... 
01 SS Rally Red A4 #4987 
