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    • Champion Motorsport 997 GT3 RS MKI custom bored and stroked 4.2 liter flat-6 hits 485 wheel horsepower

      PorscheBoost member Lock N Load has been documenting his absolutely jaw dropping 997 GT3 build by Champion Motorsport. In addition to suspension and interior work he chose to have Champion build him a custom 4.2 liter flat-6 motor. Now the 997 GT3 RS MKI was already putting out a healthy amount of power from its 3.6 liter with a baseline of 396 wheel horsepower. That is over 100 wheel horsepower per liter, simply outstanding.

      What did it put out at 4.2 (4.17 to be exact) liters? 485 wheel horsepower for a gain of 89 wheel horsepower. That is all motor folks, simply phenomenal.

      To put this in perspective a factory 997.2 GT3 RS 3.8 puts out 419 wheel horsepower and the 997.2 GT3 RS 4.0 puts out 457 wheel horsepower. This exceeds the 4.0 by almost 30 wheel horsepower and Champion is not finished. They have been testing different sized throttle bodies and trying to get every last pony. With a weight in the 2800 pound range suffice it to say this car is going to move.

      This build gives us a preview of what the next generation GT3 will be able to hit as this is essentially the maximum from the flat-6. Maybe 500 wheel can be cracked but we are reaching the absolute limit. We wish to congratulate Champion Motorsport and our member Lock N Load for this incredible build and the great results so far. Simply phenomenal work.

















      The Baseline:



      After at 4.2 liters:



      GT3 RS 3.8 versus GTR RS 4.0:

      This article was originally published in forum thread: GT3 Ranger / Lock n Load Champion Motorsport 997 GT3 RS 4.2-4.3 liter engine build started by Lock n Load View original post
      Comments 88 Comments
      1. Lock n Load's Avatar
        Lock n Load -
        Okay a few more updates:

        996 GT3 Cup shift cables
        Click here to enlarge

        Matte black aluminum track mats (Rennline)Click here to enlarge

        OMP steering wheelClick here to enlarge

        Whoops somethings missing
        Click here to enlarge

        Time to strip Click here to enlarge


        More strippingClick here to enlarge


        Recaro Profi seats (14.3 lbs each)
        Click here to enlarge


        Porsche Motorsport rear lexan window (very light)
        Click here to enlarge

        996 GT3 Cup shifter assemblyClick here to enlarge

        Some track shoes ... Yokohama race slicks
        Click here to enlarge

        The engine components have all arrived and the special machining has been done.

        Boring the spigots
        https://mail.google.com/mail/?ui=2&i...2&disp=safe&zw

        Cross drilling the oil passages
        https://mail.google.com/mail/?ui=2&i...2&disp=safe&zw

        Fixture the water jackets
        https://mail.google.com/mail/?ui=2&i...3&disp=safe&zw

        Re-threading the cases for A1 studs (longer & thicker studs)
        https://mail.google.com/mail/?ui=2&i...5&disp=safe&zw

        Lots more will be done.
        I love the HRE P40S wheels but they only come in 19". Spoke with HRE and they built me 18" P40S monoblocks.
        Still striving for that vehicle weight of 2,800 ? Will be difficult but not giving up.

        More later :-)

        Ranger
      1. Lock n Load's Avatar
        Lock n Load -
        Mistake above.

        Boring the spigots
        https://mail.google.com/mail/?ui=2&i...1&disp=safe&zw

        Ranger
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Lock n Load Click here to enlarge
        Okay a few more updates:

        996 GT3 Cup shift cables
        http://www.PorscheBoost.com/images/i...c809bc_c-1.jpg

        Matte black aluminum track mats (Rennline)http://www.PorscheBoost.com/images/i...c65ce8_c-1.jpg

        OMP steering wheelhttp://www.PorscheBoost.com/images/i...95a1cd_c-1.jpg

        Whoops somethings missing
        http://www.PorscheBoost.com/images/i...00dc92_c-1.jpg

        Time to strip http://www.PorscheBoost.com/images/i...33a31f_b-1.jpg


        More strippinghttp://www.PorscheBoost.com/images/i...821b63_b-1.jpg


        Recaro Profi seats (14.3 lbs each)
        http://www.PorscheBoost.com/images/i...58c8ce_b-1.jpg


        Porsche Motorsport rear lexan window (very light)
        http://www.PorscheBoost.com/images/i...8e30dc_b-1.jpg

        996 GT3 Cup shifter assemblyhttp://www.PorscheBoost.com/images/i...f5ca04_b-1.jpg

        Some track shoes ... Yokohama race slicks
        http://www.PorscheBoost.com/images/i...5f884e_b-1.jpg

        The engine components have all arrived and the special machining has been done.

        Boring the spigots
        https://mail.google.com/mail/?ui=2&i...2&disp=safe&zw

        Cross drilling the oil passages
        https://mail.google.com/mail/?ui=2&i...2&disp=safe&zw

        Fixture the water jackets
        https://mail.google.com/mail/?ui=2&i...3&disp=safe&zw

        Re-threading the cases for A1 studs (longer & thicker studs)
        https://mail.google.com/mail/?ui=2&i...5&disp=safe&zw

        Lots more will be done.
        I love the HRE P40S wheels but they only come in 19". Spoke with HRE and they built me 18" P40S monoblocks.
        Still striving for that vehicle weight of 2,800 ? Will be difficult but not giving up.

        More later :-)

        Ranger
        This is the sickest build Ranger!!

        Is this pretty much only going to see track duty?
      1. 0-60Motorsports's Avatar
        0-60Motorsports -
        Amazing! keep up the good work.
      1. Lock n Load's Avatar
        Lock n Load -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        This is the sickest build Ranger!!

        Is this pretty much only going to see track duty?
        Thank you and yes there's more to come. I want to make this epic.
        The engine is coming along very well. Very exquisite machining work is being done. We'll be testing with different exhaust designs, intake systems, re-worked intake manifold and throttle bodies. All to see what works best while dyno'ing / tuning. Initially the engine will be broken in on the engine dyno.

        HRE is making more wheels for me and the RS will see some street use. Will run 18" Toyo R888's (255 / 335's).

        All the best

        Ranger (Sua Sponte)
      1. M3_WC's Avatar
        M3_WC -
        This is fantastic!
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by M3_WC Click here to enlarge
        This is fantastic!
        It's amazing, he's going all out.
      1. Lock n Load's Avatar
        Lock n Load -
        A few more pics but many more taken today during the dry build. Those will come later.

        Attachment 17055

        Attachment 17052

        Attachment 17059

        Attachment 17056

        Attachment 17053

        Attachment 17057

        Attachment 17054

        Attachment 17058

        Coming together slowly but surely.

        Ranger (Sua Sponte)
      1. Sticky's Avatar
      1. Lock n Load's Avatar
        Lock n Load -
        Sorry
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Lock n Load Click here to enlarge
        Sorry
        It's ok, not your fault, it's rennlists.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Lock n Load Click here to enlarge
        Sorry
        Do you want me to fix it for you?
      1. 0-60Motorsports's Avatar
        0-60Motorsports -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Do you want me to fix it for you?
        Fix it bro, Fix it.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by 0-60Motorsports Click here to enlarge
        Fix it bro, Fix it.
        Fixed.
      1. ur20v's Avatar
        ur20v -
        Hey Ranger,

        Good luck with this project and to Champion Motorsport. I will be following closely.

        Finally got me a GT3 club sport in Viper Green, couldn't quite justify a RS as here they are another $100k AUD over the $200k AUD I just paid for my car! Anyway I love it just want more power, the GT3 is quick in first and second but the M5 was so fast from there!

        Cheers
        Jay
      1. 1cleanAMG's Avatar
        1cleanAMG -
        Sick Build. Reminds me of this 3.6L to 3.9L build by EVOMS.

        Forward to 7:16 so you can see a drag race 3.9L vs 3.6L and 3.9L vs MKII GT3



        I can only imagine how fast the 4.2L is going to be...
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by ur20v Click here to enlarge
        Finally got me a GT3 club sport in Viper Green
        Thread on your car?
      1. ur20v's Avatar
        ur20v -
        Will do Sticky, over the weekend.

        Cheers
        Jay
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by ur20v Click here to enlarge
        Will do Sticky, over the weekend.

        Cheers
        Jay
        Awesome, thanks Jay.
      1. Lock n Load's Avatar
        Lock n Load -
        The engine is built. Now waiting on the tranny which is totally being re-geared (1 thru 6th) done by Guard Transmission.
        Click here to enlargeClick here to enlargeClick here to enlargeClick here to enlargeClick here to enlargeClick here to enlargeClick here to enlarge Street shoes running 255 fronts and 335 rears
        Click here to enlarge
        First sets of HRE P40S's in 18"

        Click here to enlarge Track shoes, Yokohama slicks from Patron Cup car seriesClick here to enlarge
        Suspension bits

        Look around the "dirty" shop at Champion Motorsport :-)Click here to enlarge
        Click here to enlarge
        Click here to enlarge
        Click here to enlarge

        More to come. Need some body work done & painted. New M&M exhaust arrives Monday so need to to tune and dyno test with different header/exhaust sytems. Champion has also built different TB's (OEM is 82 mm) 84 & 86 mm to see if any power gains (doubt).

        Ranger (Sua Sponte)