08-10 SS Turbocharged General Discussion Discuss the 2008 - 2009 Chevy Cobalt SS Turbocharged. On sale since the second quarter of 2008.

GMPP kit results - real results!

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Old 07-08-2010, 09:25 PM
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GMPP kit results - real results!

I just completed my GMPP stage kit on my 08 SS turbo. Here are my before and after comparisons, both dyno and road tests.

Keep in mind all dynos read a little different so your results may vary. Road Tests were done on the same roads with another person in the car using a stop watch, so they aren't exactly perfectly scientific in their execution but they are fairly accurate. I did two runs of each test and averaged the two runs.

Cobalt GMPP Stage Kit road test results

6/27/10 0800ish and 7/8/10 1000ish --- Difference
Temp 65-70* / 65*
Gas 5/8 / ¾ --- + 1/8th
Odometer 16181 / 16768 --- + 587 miles
A/C off for all tests

5-60 mph 7.48 (start in 1st gear 1k rpm) / 6.52 --- -.96 sec
30-50 mph 3.74 (start in 2nd gear 2.8k rpm) / 3.24 --- -.50 sec
50-70 mph 4.70 (start in 3rd gear 3k rpm) / 3.98 --- -.72 sec
50-100 mph 18.20 (5th gear roll on) / 16.27 --- -1.93 sec
50-100 mph 10.60 (start in 3rd gear 3k rpm) / 9.60 --- -1.0 sec

Top speed in gears
(just under 200 rpm limit raised with kit)
Except for 3rd and 5th gear, Speeds are as indicated on the speedometer and approximate since I didn’t want to run on the rev limit too long

1st 30 mph / 35 mph --- +5 ish
2nd 60 mph / 65 mph --- +5 ish
3rd 98 mph (actual speed on dyno) / 102 mph --- +4 mph
4th 135 mph / 140 mph --- +5 ish
5th 161 mph (actual dyno no road test) / 163 mph --- +2 mph

Dynamometer runs were done at Blacktrax performance in Milpitas, CA which is a tuner shop that does a bunch of cool import and custom work. If you're in the Bay Area I highly recommend them. You can google the name for a link. Dyno runs were done the same day. Before Dyno (stock) in the morning, kit installed mid-day, and Dyno after kit install in the afternoon. Install of GMPP kit was done at Boardwalk Chevrolet in Redwood City. I highly recommend them as well. Both businesses provided excellent service at very reasonable rates. They both were also extremely accommodating with my plan to dyno, install, and dyno on the same day so I could get accurate results.



Before and After Power and Torque. Don't just look at the peak increases. Look at the space between the curves. Off idle horsepower and torque are almost doubled. At some rpms it's 50 hp difference and torque is as much as a 75 lb/ft difference. Look closely at the bottom end. The curve is much less steep now which makes taking off from a stop waaaay easier


Before and After Boost
[IMG][/IMG]

All Numbers Before top of page


All Numbers Before bottom of page
[IMG][/IMG]

All Numbers After top of page
[IMG][/IMG]

All Numbers After bottom of page



So far my impressions are:

1. The car is easier to drive when taking off from a stop because of the increase of power at low rpm combined with the smoother (less steep) power curve from 1500-2300.

2. The car is quicker overall.

3. The slightly raised (180 rpm) rev limit allows approximately 2-5 mph more in each gear.

4. The "Launch Control" feature now actually works. I've only tried this a couple times, but stock if you used launch control (car in competitive mode, at a stop, full throttle, in 1st gear, car holds at 4700 rpm, drop the clutch and keep it full throttle) the car would squeal the tires a little, bog down, then take off. Now with the kit installed the car actually has the power to get you going without bogging as it gets traction. It squeals the tires a little and then accelerates more as it gets traction. This is my best effort at real world results and what you can expect by installing the GMPP kit on your 08 or newer SS.

Dog

Last edited by meldog21; 07-09-2010 at 12:43 PM.
Old 07-08-2010, 09:51 PM
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Great results! Right where we would expect GM tune to be....+20 HP and around +50 Ft Lbs Torque peak gain. Just as advertised!
BTW, I used same type dyno you did..*Dynapack* (in my Images Link). They hooked up your HUBS instead of putting wheels directly on a roller. The HP readings are around 10HP more than you might get on a dynojet.
Old 07-08-2010, 09:57 PM
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Originally Posted by ronn
Great results! Right where we would expect GM tune to be....+20 HP and around +50 Ft Lbs Torque peak gain. Just as advertised!
BTW, I used same type dyno you did..*Dynapack* (in my Images Link). They hooked up your HUBS instead of putting wheels directly on a roller. The HP readings are around 10HP more than you might get on a dynojet.
wow thats a high reading dyno!
Old 07-08-2010, 10:02 PM
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Originally Posted by beast10007
wow thats a high reading dyno!
10HP high give or take. You can add the *!* , don't think it's that big of a deal.
The REAL value is the BEFORE and AFTER to compare..not the absolute #s.
Old 07-08-2010, 10:07 PM
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Originally Posted by beast10007
wow thats a high reading dyno!
x2.. those dynapacks do read ubber high, but at least he did it right by using the same dyno to see true gains.

That's an awfully big spike in the middle of that GMS1 torque curve. Peak numbers might be a little skewed by that
Old 07-08-2010, 10:13 PM
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Originally Posted by beast10007
wow thats a high reading dyno!
I thought so too, but it does say "flywheel HP" at the top, and I think those numbers are pretty much what we were told. 260ftlbs stock, 320 with the kit.

Seems like it might be pretty close?
Old 07-08-2010, 10:16 PM
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Originally Posted by Koz
I thought so too, but it does say "flywheel HP" at the top, and I think those numbers are pretty much what we were told. 260ftlbs stock, 320 with the kit.

Seems like it might be pretty close?
haha.. good eyes man. I totally didn't pick up on that. It seems pretty logical to usually assume wheel hp for a dyno. So maybe those number are pretty solid then
Old 07-08-2010, 10:27 PM
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Originally Posted by Koz
I thought so too, but it does say "flywheel HP" at the top, and I think those numbers are pretty much what we were told. 260ftlbs stock, 320 with the kit.

Seems like it might be pretty close?
It says *Flywheel* and its actually somewhere between wheels and Flywheel for this Dyno. The actual LOSS through the drive train is LESS, because the wheels are off and it's to the HUBS. So, it reads around 10HP MORE than actual Flywheel and 10 HP MORE than a Dyno jet (to the wheels). Again, as I said we want to look at the differences between the mods..not absolute #s.

Last edited by ronn; 07-08-2010 at 11:07 PM. Reason: Information error
Old 07-08-2010, 10:45 PM
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Originally Posted by ronn
It says *Flywheel* and its actually somewhere between wheels and Flywheel for this Dyno. The actual LOSS through the drive train is LESS, because the wheels are off and it's to the HUBS. So, it reads around 10HP MORE than actual Flywheel and 10 HP LESS than a Dyno jet (to the wheels). Again, as I said we want to look at the differences between the mods..not absolute #s.
If you said it reads 10whp more than a mustang dyno, then I would agree with you, but not 10 LESS than a dynojet. I have gms1 dyno graphs from a mustang dyno that read almost exactly 10whp less than this, however the torque numbers on this dynopack are WAYYYY higher.. almost 40wtrq higher than the mustang dyno.. A dynojet is pretty well known to read 10-15% higher than a mustang. Just for instance, I baselined 240whp on a mustang dyno, so this dynapack definite reads even higher than a dynojet. Hopefully you won't take this as me arguing or being a dick. I'm just throwing some hard numbers out there that I have to compare from personal dyno experiences.

Either way, good numbers OP and you definitely did it right by having a baseline to compare to..
Old 07-08-2010, 11:06 PM
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Originally Posted by 09CobaltSS1
If you said it reads 10whp more than a mustang dyno, then I would agree with you, but not 10 LESS than a dynojet.
Either way, good numbers OP and you definitely did it right by having a baseline to compare to..

sorry, I meant meant 10 HP more than a dynojet..I will edit that.
Thanks
Old 07-08-2010, 11:18 PM
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Great write up and thanks for sharing your results man

Only one word of advice, don't do any 5th gear roll ons... Your clutch and motor will thank you, especially your clutch.
Old 07-08-2010, 11:25 PM
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u got up to 161 on a dyno?
Old 07-08-2010, 11:31 PM
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Originally Posted by meldog21
Blah Blah Blah

Dog
...the Bounty Hunter???
Old 07-09-2010, 07:58 AM
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sorry maybe this is a newbie Q but whats the deal with hammer down in top gear? how is that bad for any thing? my chevelle has so much torq i never down shift to pass and my lil cobalt is damn close to being as fast, i am obviously missing something. if anyone can help me with my Cultural Learnings of top gear for Make Benefit Glorious Nation of Chevrolet that be just great
Old 07-09-2010, 11:06 AM
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Originally Posted by 1971/2009 Chevy
sorry maybe this is a newbie Q but whats the deal with hammer down in top gear? how is that bad for any thing? my chevelle has so much torq i never down shift to pass and my lil cobalt is damn close to being as fast, i am obviously missing something. if anyone can help me with my Cultural Learnings of top gear for Make Benefit Glorious Nation of Chevrolet that be just great
2 main reasons.. predetination and clutch slip.

If you introduce too much boost to then engine at too low of an RPM (mainly under 2500) with that much of a load, you can get predetination and damage the engine

As far as the clutch goes.. These cars produce a buttload of torque really quick, so combine that sudden torque spike with the amount of load 5th gear puts on the drivetrain at that low of an RPM.. well you can get some nasty clutch slip.. particularly in the 08's due to the weaker clutch
Old 07-09-2010, 11:31 AM
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Ummmmm...all LNF's have the same stock clutch.
Old 07-09-2010, 11:39 AM
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nope... 08's have a weaker preasure plate
Old 07-09-2010, 11:43 AM
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Originally Posted by 09CobaltSS1
nope... 08's have a weaker preasure plate
learn something new everyday
Old 07-09-2010, 01:09 PM
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Originally Posted by 09CobaltSS1
nope... 08's have a weaker preasure plate
Part numbers please?

GMPD shows the same part # for '08 - 10. 24239996

I guess I'll go in the attic and see if I can find a P/N on my stocker.
Old 07-09-2010, 01:57 PM
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Originally Posted by 09CobaltSS1
nope... 08's have a weaker preasure plate
Could you provide some documentation..link..etc. Not questioning you, but I would like to know how you found that out! You seem to be the first to point this out?
Old 07-09-2010, 02:01 PM
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Only numbers on my '08 stock pressure plate that are close are 2423998 but doesn't cross to anything on GMPD. Mine was mfg on Aug 31, '08.
Old 07-09-2010, 02:02 PM
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Originally Posted by Iam Broke
Part numbers please?

GMPD shows the same part # for '08 - 10. 24239996

I guess I'll go in the attic and see if I can find a P/N on my stocker.
The part itself could have been updated/revised without an actual # change. The revised parts sometimes have a *-* after the part # indicating the latest revision but it will still show up under the original part#. Porsche did this. Also, you would have the same part # for 08-10 since they are compatable and interchangeable.

Last edited by ronn; 07-09-2010 at 02:21 PM.
Old 07-09-2010, 02:34 PM
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Originally Posted by ronn
The part itself could have been updated/revised without an actual # change. The revised parts sometimes have a *-* after the part # indicating the latest revision but it will still show up under the original part#. Porsche did this. Also, you would have the same part # for 08-10 since they are compatable and interchangeable.
Yep that would be correct. Part number was never changed however the 09-10 clutches have a stronger clamping force due to the stronger pressure plate. Sort of like the NSRT-4's, the first model year the clutch for the car was ****. Dodge then beefed up the clutch system, yet still retained the same part number.
Old 07-09-2010, 02:57 PM
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Originally Posted by 09CobaltSS1
Yep that would be correct. Part number was never changed however the 09-10 clutches have a stronger clamping force due to the stronger pressure plate. Sort of like the NSRT-4's, the first model year the clutch for the car was ****. Dodge then beefed up the clutch system, yet still retained the same part number.
Again..how did you find out about this? Really curious, because I haven't seen jack. Was there a TSB? How did GM *announce* this or at least make it *known* at all?
Old 07-09-2010, 03:00 PM
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Very good work!!!

This thread should be stickied as it would quell all of the repetitive questions we get on GMS1.


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