Close

    • PorscheBoost Porsche Performance Forum member reviews his Cobb 991.2 GTS ECU tune and Accessport

      After some teething pains PorscheBoost member @LavaGTS finally received his ECU back for his 991.2 GTS from Cobb. The review below is in his own words and provides some data regarding temps (inercoolers are a must) as well as his impressions.


      Overall he is quite happy but wishes Cobb included a boost gauge and air/fuel ratio gauge as they do on other platforms.

      His review:

      Finally got this tune installed today, drove around for about 60 miles trying different things. Lots of traffic everywhere so I was not able to get a pull in my favorite gear (4th).

      This things rips. The torque is big and it keeps climbing and climbing faster and harder to redline. It almost feels more NA than before. The ride feels a little more eager in a good way. It's ready to go hard and fast. It flows like silk through the wind in normal mode with little throttle. You can glide to 60/70 so freely now with such little effort. The torque gauge on the AP showed that I was making 523 ft/lb of torque at the crank. Not sure if it's accurate but it's pretty cool to see.

      I decided to be greedy and drove over to a station with 95 octane and loaded up the 93 map. Since 93 is not readily available in AZ I'll be having to revert the 91 which is going to make me a little sad. I also have headers/bypass pipes/BMC filter.

      All my runs were in 100+ weather. Bone dry out there today and the night is ending with a storm so I can't get any cooler temp runs in. We'll see.

      I have a few interesting thing to note. First the heat soak. My friend managed to film the Accessport and my tach/speedo at the same time during a test run from 1st gear to early 4th gear. The intake air temps rose tremendously. I will post some screen shots of the video clip. The air intake temp can be seen on the AP's left center gauge. Now I'm not saying I felt the car heat soak because I didn't. It took hard pulls and driving from first through third in the heat with issues or signs of choke what so ever.

      In this first screen shot. Im just hitting the throttle from a roll. Note the IAT at 118.4f.


      In this second screen shot we are nearing redline in third gear, still at WOT. IAT at 132.8f.


      In the final screen shot, I have just let off the throttle. Note the IAT at 154.4f


      YIKES. Not sure if this is due to the pavement being between 140-150 degrees. Pavement in AZ radiates heat off the ground. When winter comes around along with stage 2 or stage 2+. This thing is gonna be a laser beam (sorry east coast guys).

      More things I noted:

      -AP oil temp reading was at 188f but the stock gauge was showing 204f
      -OEM boost gauge stays pegged at 19psi. Stock it would flicker 19psi near redline only.
      - Tires break loose on concrete roads from a dig. Grips on tarmac better.
      - I managed to get a launch with no wheel spin... Holy crap. AP showed a 0-60 time of 3.2. I short shifted 1st gear on that run prematurely as I was anticipating wheel spin. I wouldn't be surprised if I could get to 60 in 3.0 seconds or less.

      Lastly, Cobb has hidden the Air/Fuel gauge from us. This is BS. There's also no real boost gauge like all the other AP's for other cars. Every other damn platform gets the AFR/Boost gauge but they've censored it on the 991.2. Why? Intellectual property? Who knows but it's effin BS. I wan't my AFR/Boost numbers.

      This article was originally published in forum thread: Cobb 991.2 GTS ECU tune review started by LavaGTS View original post
      Comments 26 Comments
      1. magnumpsi's Avatar
        magnumpsi -
        Hey guys,

        Boost and lambda should be there. Look for Lambda 1 and 2. Also look for pre throttle pressure as that is boost pressure. If for some reason it's not there let me know I will get it fixed.

        -mitch
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by magnumpsi Click here to enlarge
        Hey guys,

        Boost and lambda should be there. Look for Lambda 1 and 2. Also look for pre throttle pressure as that is boost pressure. If for some reason it's not there let me know I will get it fixed.

        -mitch
        Good support.
      1. LavaGTS's Avatar
        LavaGTS -
        Click here to enlarge Originally Posted by magnumpsi Click here to enlarge
        Hey guys,

        Boost and lambda should be there. Look for Lambda 1 and 2. Also look for pre throttle pressure as that is boost pressure. If for some reason it's not there let me know I will get it fixed.

        -mitch
        Thank you, will check on my next ride and report.
      1. LavaGTS's Avatar
        LavaGTS -
        Click here to enlarge Originally Posted by magnumpsi Click here to enlarge
        Hey guys,

        Boost and lambda should be there. Look for Lambda 1 and 2. Also look for pre throttle pressure as that is boost pressure. If for some reason it's not there let me know I will get it fixed.

        -mitch
        Hey mitch, there's Lambda which worked for AFR, but there's no Lambda 2.. There's a pre cat Lambda but that's not boost.

        None of the boost gauges in the AP work as a boost gauge. They show PSI but it starts at 14 and goes up to 40+. Is there a certain way I need to read the gauge?
      1. nito822's Avatar
        nito822 -
        Accessport is displaying absolute pressure? Subtract atmospheric at your elevation.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LavaGTS Click here to enlarge
        They show PSI but it starts at 14 and goes up to 40+. Is there a certain way I need to read the gauge?
        I guess it starts at 1 BAR
      1. LavaGTS's Avatar
        LavaGTS -
        Interesting, I'll be taking a like minded friend for a ride tonight. We should see "cooler" 90 degree weather and maybe into the high 70s if we head near the lake area.

        Will try to get some data logs done and I'll post them up.
      1. flsupraguy's Avatar
        flsupraguy -
        Howd it go?
      1. ///M3THOD's Avatar
        ///M3THOD -
        Click here to enlarge Originally Posted by LavaGTS Click here to enlarge
        Interesting, I'll be taking a like minded friend for a ride tonight. We should see "cooler" 90 degree weather and maybe into the high 70s if we head near the lake area.

        Will try to get some data logs done and I'll post them up.
        Did you data log your highway pulls? Your IAT's are very high.

        I was seeing lower temps than this on the dyno after a couple pulls. Im not seeing seeing temperature increases as high as you are when logging my hwy pulls.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by ///M3THOD Click here to enlarge
        Did you data log your highway pulls? Your IAT's are very high.

        I was seeing lower temps than this on the dyno after a couple pulls. Im not seeing seeing temperature increases as high as you are when logging my hwy pulls.
        You were tuned then on the dyno? What was the weather like?
      1. ///M3THOD's Avatar
        ///M3THOD -
        I was tuned, it was also very hot. It was raining and it was in the high 80's - low 90's.

        My cars at the dealer right now, but Im going to do some logs when I get it back. Ive not logged it since then, but Ive watch the IAT's when I do hwy pulls. I have not noticed climbing that high. I think it could be the conditions. If the roads hot enough, exactly as Lava speculated, the baseline temps and resulting climbs would be in line with what I am seeing and around those temps.

        I am seeing between 20-30F increase in temps on pulls. My dyno IAT temps pretty much are identical to this. I am also seeing AP estimate 523 ft/lb of torque also.

        Im also wondering if the 153 number is under acceleration. The IAT's climbed as the car spun down as the turbo was very hot, the hottest being in the mid 150's around 5800RPM.


        Mods: Stg. 1/93 oct. , BMS, AWE Sport cats.
      1. LavaGTS's Avatar
        LavaGTS -
        Click here to enlarge Originally Posted by ///M3THOD Click here to enlarge
        I was tuned, it was also very hot. It was raining and it was in the high 80's - low 90's.

        My cars at the dealer right now, but Im going to do some logs when I get it back. Ive not logged it since then, but Ive watch the IAT's when I do hwy pulls. I have not noticed climbing that high. I think it could be the conditions. If the roads hot enough, exactly as Lava speculated, the baseline temps and resulting climbs would be in line with what I am seeing and around those temps.

        I am seeing between 20-30F increase in temps on pulls. My dyno IAT temps pretty much are identical to this. I am also seeing AP estimate 523 ft/lb of torque also.

        Im also wondering if the 153 number is under acceleration. The IAT's climbed as the car spun down as the turbo was very hot, the hottest being in the mid 150's around 5800RPM.


        Mods: Stg. 1/93 oct. , BMS, AWE Sport cats.
        In the last pic showing 154f it was under deceleration. Had just let off, you can see this in the G force meter and stock boost gauge. If you take a closer look it shows the max temp of 161f but I'm not sure when I hit that.

        I did some data logs but haven't found the time to view them on my computer yet. I'll post them up when I can.

        I'll be installing the AMS intercoolers after I come back from Greece. Hopefully I can see and show actual results.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LavaGTS Click here to enlarge
        I'll be installing the AMS intercoolers after I come back from Greece. Hopefully I can see and show actual results.
        Timetable?
      1. LavaGTS's Avatar
        LavaGTS -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Timetable?
        Mid to late September.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LavaGTS Click here to enlarge
        Mid to late September.
        It will still be plenty hot to test them out. Have fun!
      1. LavaGTS's Avatar
        LavaGTS -
        I've attached 3 different datalogs. 3rd Gear Pull, 4th Gear pull, and a 3rd-4th redline pull. You can view them in excel.

        You can see where I hit the throttle in Column B where "Accelerator Position %" starts showing 100.

        It was 83 degrees outside at night. Surprisingly the IAT's stayed low and consistent.

        -In 4th gear pull temps rose from 104-129.. At one point the temps starting dipping lower at WOT from 5k-6k RPM.

        -In the 3rd gear pull the IAT's only went up 3 degrees! From 111-114f

        -Finally the 3rd to 4th redline IAT's went from 114 to 147

        Looks like boost is spiking at times and not too consistent. Normally getting a net of 21 PSI but spiking up to 24/25. Cobb, if you're reading can you please take a peek and give me your opinion on how it's running with my mods?

        Seems like on my first run in hot weather the pavement was definitely not helping those temps.

        AFR looks healthy. Enjoy!
      1. arter's Avatar
        arter -
        Running at Laguna Seca, my IAT's cycled between 131 and 162F during a 20 minutes session. Cant plot it yet as I dont have a enough posts. It would rise 30F going down the front and back straights ( about 12 seconds of boost, going uphill each time), and then recover during the following turns and corners when not at full boost.

        Also saw boost up to 24 psi although the cars guage read 19 the whole time.

        calculated torque values up to 540 ft-lbs after a shift (throttle angle showed ECU was trying to reduce this to under 500). You should plot throttle angle to see what the ECU is doing while you have your foot planted on the pedal.
      1. arter's Avatar
        arter -
        Full open throttle angle is 81 degrees
      1. LavaGTS's Avatar
        LavaGTS -
        Thanks for sharing arter, I'll be keeping an eye on that too. Good looking out!

        What other mods are on your car? If I remember correctly, you do have the 3rd rad kit right?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LavaGTS Click here to enlarge
        you do have the 3rd rad kit right?
        Is this worth adding @arter?