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Any interest in a Grp5 "Silhouette" proxy for 2010?

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  • Any interest in a Grp5 "Silhouette" proxy for 2010?

    This is an idea I have had for quite some time, and with the experience gathered from organizing the SCX Classic Rally Proxy, I feel confident enough to share my vision for a Grp5. "Silhouette" car proxy series, staring up in 2010.

    BTW: For those who wonder, the SCX CRP will most likely start up again next year regardless of these Grp5 plans.

    My intention is to develop and bring to life a small specialized proxy series, with a limited amount of entrants and get the racing done in a short time frame. To achieve this planning must be done early and the racing must happen on one continent. I also wish to involve more people in the administration to make the series less dependent of one person.

    Before I talk too much just take a look at the cars we are talking about here:

    4th Generation Group 5 – “Special Production Cars” (1976 to 1982)
    Porsche 935 (includes the 935-77, 935-78 known as the Moby-Dick and the customer Kremer K3 and K4 and the JLP variation)
    BMW 320i Turbo
    Toyota Celica Turbo A22 (1st generation)
    Toyota Celica Turbo A45 (2nd generation)
    Nissan Skyline RS Silhouette Formula
    Nissan Nichira Impul Silvia
    Mazda RX-7 SA22
    Nissan Bluebird SSS Turbo
    BMW 3.0 CSL
    BMW M1
    Ferrari 512BB
    Lancia Stratos Turbo
    Lancia Beta Montecarlo Turbo
    Ferrari 512BB LM
    Ford Capri
    Ford Escort
    Zakspeed Lotus Europa Gr.5

    The 4th generation Grp5 cars raced in the following racing series:
    World Championship for Makes (1976 to 1980)
    World Endurance Championship (1981 to 1982)
    Deutsche Rennsport Meisterschaft
    All Japan Sports Prototype Championship
    Formula Silhouette

    Most of the cars are available as RTR slotcars, like these from Fly, Carrera and Revell:

    The 1:1 cars where highly developed lightweight space frame "sedans" and GT cars, mostly small bore turbocharged engines that developed a lots of power built to barely last through an endurance race.

    I'm sure there is a lot of love for these cars here on the forum, and many of you probably know more about them than me, so I won't talk more about the specific cars now, there are other issues that must be addressed first.

    Before I start any work to get this proxy series alive, I want feedback from those who could be interested in entering a car next year, and I also want to hear if you would prefer it to be a modified "box stock" series or a full blown custom chassis series, or something in between?

    At the moment I can only promise one thing, it will not become a "NC-1" style low power series

    Let me know how you want it!

  • #2
    Sounds good. Count me in.


    • #3
      Group 5 is probably my favourite era of sports car racing so yes indeed I'd be very interested!


      • #4
        If the rules end with allowing all the cars that ran as Gp5 or GTX during the time span 1976-1982 in the series' indicated that would go far to get me interested. Setting a spec tire compound would also help with that.

        World Championship for Makes (1976 to 1980)
        World Endurance Championship (1981 to 1982)
        Deutsche Rennsport Meisterschaft
        IMSA GTX
        All Japan Sports Prototype Championship
        Formula Silhouette


        • #5
          If you could modify the original chassis with a motor pod I have one already to go.

          Spec tire brand will also be a plus for me as well.


          • #6
            I have a Toyota LB Turbo (MRRC) with a Slot.It pod and an orange endbell motor. I have Ortmanns on rims and Supertires on rims ready to go. It needs retuning but the body work and chassis work is done. It competed in the Global Proxy Race.

            The orange endbell feels right for this class of car, which had in excess of 500 HP. The turbos really changed things around. The HP of a Chevy Rat motor could be had from a small 4 cylinder.

            Or were you thinking of using the Slot.It 19k for Grp. 5?

            The GPR required plastic chassis only, except you could use a metal guide bracket. I'd rather see the chassis left open.
            Last edited by Robert Livingston; 05-12-2009, 06:32 PM.


            • #7
              A very liberal set of motor rules would be nice.
              Spec tire compound not spec tire size. After all not every Gp5 car ran 19x15" rear wheels.


              • #8
                Originally posted by Robert Livingston View Post
                Or were you thinking of using the Slot.It 19k for Grp. 5?

                The GPR required plastic chassis only, except you could use a metal guide bracket. I'd rather see the chassis left open.
                I agree with the 19k and open chassis. Seems like as soon as you open it up to orange endbells, you may as well say anything goes. Seems to me, a car weighing 80-95 grams, can only make use of so much power, say 180 g*cm. Or so it seems.



                • #9
                  I'd say some form of modified original chassis rule would be good. Kinda like the Gp5 rules of the day.


                  • #10
                    Thanks for the replies so far, here are some more of my reflections around this series.

                    As for the cars, I would like it to be open for all "silhouette style" Sedan/GT's from the 1975/76 --> 1982/83 that looks good together with the Grp5 cars.

                    Here is my current list of available RTR slotcars:

                    BMW 320 Turbo (Revell)
                    BMW 3.0 CSL (Fly)
                    BMW M1 (Fly, Fly Racing, SCX)
                    Chevrolet "Greenwood" Corvette (Revell)
                    Chevrolet "Dekon" Monza (Carrera)
                    DeTomaso Pantera Grp.5 (Carrera)
                    Ferrari 512BB LM (Carrera)
                    Ford Capri Turbo (Fly, Fly Racing)
                    Ford Capri RS3100 (Comming soon from Carrera)
                    Ford Escort zakspeed (Teamslot)
                    Lancia Beta Montecarlo Turbo (Fly/GB)
                    Opel Commodore "Steinmetz" (Carrera)
                    Porsche 935 -76/-78/"moby"/K3 (Fly, Carrera, Racer, SCX)
                    Toyota Celica Turbo (MRRC)

                    Let me know if there are other RTR cars to consider adding to the list. At the moment I am focusing on available RTR cars. But please inform me of plastic and resin kits too.

                    A "RTR" or "box stock" class will be very difficult to make fair. There are chassis ranging from front motored stub axle nightmares to super smooth pods (Racer 935), so I am drifting away from that idea, unless there is a very big demand for it.

                    I have a dream for this proxy, to see "mechanical beautiful" cars, not the typical hacked up chassis with a bolted in HRS pod accompanied by a smeared out blob of steel epoxy to hold everything together. Maybe I'm hoping for too much.

                    As I mentioned in my first post, this proxy series will be more "specialized" so I have some rough ideas to the chassis rules, but I expect that not everyone will agree with me on these since you might have to build something you are not familiar with, and something you consider less than optimal. My vision is a class that replicates the 1:1 cars better, and that will also make this proxy series unique.

                    You probably guessed it already, and yes we are talking front motors, or motor placement that replicates the 1:1 car to be more specific. Of the 14 cars listed above 10 should be front motored, 3 should be sidewinders, and one "rear winder". So this series Will most likely be an "open chassis" class but with requirement for motor placement as in the 1:1 car it replicates. The three SW cars will get a small "handicap" to even out the field, but we got the whole summer to discuss how to best solve this.

                    There will be "spec" urethane or rubber tire for this series, limited to one or maybe two manufacturers. The old "gray" Ortmann's are banned, I want something that is widely available in many dimensions and with a realistic looking tire wall, yet with decent grip. Tire manufacturers interested in showcasing their tires may contact me

                    I will use Watt to rate motors, and there will be a minimum "watt per gram" (Watt/Weight) limit to make sure we don't build too anemic cars. Motors with missing data to calculate Watt will either have to be tested or banned. I don't see the need for a maximum power limit, but I will limit the motors to S-cans only which makes it easier to build a front motored car, because of the lighter weight.

                    Your thoughts, ideas and flames are welcome
                    Last edited by 356speedster; 05-13-2009, 04:01 AM.


                    • #11
                      Good so far. Would we use PeteN95's definition of front motor (motor must be forward of the midpoint between front and rear axle)?

                      So, the Slot.It pods are out. Good!

                      How much of the original chassis must remain? In most rules I've written in the past, this is not specified. Hopefully we can build new chassis components out of metal. I dislike building chassis in plastic, and I think the real Group 5 and GTX cars were framed with custom built tubular steel chassis. Does anyone have the actual rules for Grp 5? GTX? We should start with the facts.

                      How to keep out the "the typical hacked up chassis with a bolted in HRS pod accompanied by a smeared out blob of steel epoxy to hold everything together"? The front motor rule eliminates the HRS, but what about the craftsmanship? I've seen some pretty rough looking cars in which things are crooked, but the important mechanical parts are good, and the car is a winner. I'm not sure you can legislate chassis appearance. If you can think of a way, I'm all for it.

                      Adapting the pod concept to a front motor design sounds interesting. I'd like to try.


                      • #12
                        I would love enter a proxy like that. Bring it on.


                        • #13
                          I would very much like to see the actual Grp5/GTX rules too, so if anyone has a link to it please share it with us.

                          I suspect the 1:1 rules allowed the front motor cars to move the motor a bit backward by the look of some of the cars, so something like the "in front of the centerline" or "no more than 36 mm behind the front axle" (not counting the drive shaft) could be a place to start, the later might even give the shorter wheelbase cars a slight weight distribution advantage and still allow space for a solid front axle.

                          With open chassis rules, except for motor placement, virtually anything is legal, from a stock Fly front motor chassis to a lengthened HRS pod crafted into a RTR chassis, or a completely scratch built chassis from plastic brass, steel or any other material.

                          The intention is to inspire creative solutions and craftsmanship, so maybe awards for best looking and most creative chassis could inspire the builders to dig up their soldering irons instead of the JB Weld tube?


                          • #14
                            Sounds good. I have 5 cars to choose from to build.


                            • #15
                              There are basically three likely motor performance brackets, discounting the NC1 group as too weak. The standard Scalextric motor (4 watts), the slightly hotter standard motors (6 watts, as used in the current RAA GT1 class), and the orange endbell (10 watts). Anything more doesn't get you more speed, just more power.

                              Adjusting by power to weight ratios is OK, but has minimal impact. With the basic mechanical components in place, the floor is about 80 grams; anything more than ~110 grams and you run a higher risk of guide breakage. I haven't worked this problem through.

                              I'd like to see the option for using SCX motors. Although the 16 gram FC-130 is fine, the real cars used a variety of mills. As long as we have wattage-output limits, motors should be otherwise open, in my opinion.

                              I can test any motors anyone wants tested, since I have all the test equipment ready to go.